CN114892106B - Martensitic precipitation hardening stainless steel for fracturing pump valve box and short-flow production method of fracturing pump valve box - Google Patents
Martensitic precipitation hardening stainless steel for fracturing pump valve box and short-flow production method of fracturing pump valve box Download PDFInfo
- Publication number
- CN114892106B CN114892106B CN202210490076.1A CN202210490076A CN114892106B CN 114892106 B CN114892106 B CN 114892106B CN 202210490076 A CN202210490076 A CN 202210490076A CN 114892106 B CN114892106 B CN 114892106B
- Authority
- CN
- China
- Prior art keywords
- forging
- valve box
- steel
- oxygen
- molten steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000010935 stainless steel Substances 0.000 title claims abstract description 48
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 48
- 229910000734 martensite Inorganic materials 0.000 title claims abstract description 36
- 238000004881 precipitation hardening Methods 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 27
- 238000005242 forging Methods 0.000 claims abstract description 163
- 238000000034 method Methods 0.000 claims abstract description 52
- 238000010438 heat treatment Methods 0.000 claims abstract description 48
- 230000008569 process Effects 0.000 claims abstract description 27
- 238000003723 Smelting Methods 0.000 claims abstract description 26
- 238000004512 die casting Methods 0.000 claims abstract description 15
- 239000000126 substance Substances 0.000 claims abstract description 15
- 238000010891 electric arc Methods 0.000 claims abstract description 11
- 229910000831 Steel Inorganic materials 0.000 claims description 156
- 239000010959 steel Substances 0.000 claims description 156
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 98
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 75
- 239000001301 oxygen Substances 0.000 claims description 75
- 229910052760 oxygen Inorganic materials 0.000 claims description 75
- 238000007664 blowing Methods 0.000 claims description 53
- 238000001816 cooling Methods 0.000 claims description 50
- 229910052786 argon Inorganic materials 0.000 claims description 49
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 34
- 238000007670 refining Methods 0.000 claims description 29
- 238000005266 casting Methods 0.000 claims description 28
- 238000000137 annealing Methods 0.000 claims description 16
- 239000002893 slag Substances 0.000 claims description 16
- 230000009467 reduction Effects 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 13
- 230000032683 aging Effects 0.000 claims description 11
- 238000007599 discharging Methods 0.000 claims description 11
- 239000007789 gas Substances 0.000 claims description 11
- 238000009849 vacuum degassing Methods 0.000 claims description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 10
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims description 10
- 238000010079 rubber tapping Methods 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 9
- 230000003647 oxidation Effects 0.000 claims description 9
- 238000007254 oxidation reaction Methods 0.000 claims description 9
- 239000006104 solid solution Substances 0.000 claims description 9
- 238000013461 design Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 238000004321 preservation Methods 0.000 claims description 8
- 238000005070 sampling Methods 0.000 claims description 8
- 238000009792 diffusion process Methods 0.000 claims description 7
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 6
- 238000000265 homogenisation Methods 0.000 claims description 6
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 5
- 229910000592 Ferroniobium Inorganic materials 0.000 claims description 5
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 5
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 5
- 239000010436 fluorite Substances 0.000 claims description 5
- ZFGFKQDDQUAJQP-UHFFFAOYSA-N iron niobium Chemical compound [Fe].[Fe].[Nb] ZFGFKQDDQUAJQP-UHFFFAOYSA-N 0.000 claims description 5
- 239000004571 lime Substances 0.000 claims description 5
- 238000003754 machining Methods 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 5
- 238000005086 pumping Methods 0.000 claims description 5
- 230000001105 regulatory effect Effects 0.000 claims description 5
- 238000011049 filling Methods 0.000 claims description 4
- 230000008859 change Effects 0.000 claims description 2
- 238000005553 drilling Methods 0.000 claims description 2
- 239000004615 ingredient Substances 0.000 claims description 2
- 229910052745 lead Inorganic materials 0.000 claims description 2
- 238000003801 milling Methods 0.000 claims description 2
- 230000035515 penetration Effects 0.000 claims description 2
- 238000012546 transfer Methods 0.000 claims description 2
- 239000010949 copper Substances 0.000 description 20
- 239000011651 chromium Substances 0.000 description 17
- 230000007797 corrosion Effects 0.000 description 16
- 238000005260 corrosion Methods 0.000 description 16
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 16
- 239000011572 manganese Substances 0.000 description 10
- 238000005520 cutting process Methods 0.000 description 7
- 238000005204 segregation Methods 0.000 description 7
- 229910000859 α-Fe Inorganic materials 0.000 description 7
- 239000000243 solution Substances 0.000 description 6
- 238000007514 turning Methods 0.000 description 6
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- 229910052804 chromium Inorganic materials 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 239000011159 matrix material Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 238000012545 processing Methods 0.000 description 4
- 102220287746 rs587781383 Human genes 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 241000519995 Stachys sylvatica Species 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 229910000765 intermetallic Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000009828 non-uniform distribution Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/002—Hybrid process, e.g. forging following casting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/20—Making machine elements valve parts
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses martensitic precipitation hardening stainless steel for a fracturing pump valve box and a short-flow production method of the fracturing pump valve box, wherein smelting and pouring are carried out by optimizing stainless steel chemical components for the fracturing pump valve box through an EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting process route, forging and heat treatment processes are reasonably designed, so that a 15-5PH stainless steel valve box forging has the characteristic of short-flow production.
Description
Technical Field
The invention belongs to the technical field of processing technology of steel materials, and particularly relates to a stainless steel valve box forging and a short-process production method for the petroleum fracturing industry.
Background
With the development of unconventional oil gas represented by shale gas, the total amount and scale of domestic fracturing construction are promoted to rapidly increase. The special requirements of continuous construction, heavy load and long time fracturing are met, and the stability requirements on fracturing equipment are also higher and higher. The long-time stable construction of the fracturing equipment is closely related to the manufacturing quality of the hydraulic end valve box of the core part. The service life of the valve box of the low alloy steel fracturing pump adopted in China is short, and the valve box is frequently replaced and maintained, so that the development efficiency and economic benefit of an oil-gas field are seriously affected, and the progress of the domestic fracturing technology is restricted.
At present, the domestic high-quality fracturing pump valve box mainly adopts 15-5PH, 17-4PH, X3CrNiMo13-4 and other materials, the product quality is uneven, the service life is 600-1000 h unequal, the difference is large, and the production period of valve box blanks is long. Through optimizing design valve box material chemical composition, research valve box forging production overall process technology, optimize the process flow, shorten valve box forging output cycle and manufacturing cost, guarantee simultaneously that the obdurability of valve box is good to match, improve life, finally strengthen valve box durability and maintainability, under the condition that functionality, economic nature allow, improve the reliability index, increase of service life is industry's key problem to be solved.
Disclosure of Invention
The invention provides a martensitic precipitation hardening stainless steel chemical composition design and a material smelting, forging and heat treatment method, which shorten the production process and achieve the purpose of low cost and quick production under the premise of ensuring the excellent comprehensive properties of strength, hardness, low-temperature impact toughness, grain size, microstructure and the like.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the martensitic precipitation hardening stainless steel for the fracturing pump valve box has the chemical components within the standard range of 15-5PH steel, and is designed with internal control components according to the performance requirement of the fracturing pump valve box, and comprises the following components in percentage by mass: 0.02-0.055% of C, 0.30-0.50% of Si, 0.50-0.80% of Mn, less than or equal to 0.020% of P, less than or equal to 0.005% of S, 14.30-14.70% of Cr, 3.50-5.50% of Ni, 3.00-3.40% of Cu, 0.20-0.35% of Nb, less than or equal to 0.35% of Mo, 0.008% of Pb, less than or equal to 0.005% of Bi, less than or equal to 0.008% of Sn, less than or equal to 0.010% of As, less than or equal to 0.005% of Sb, less than or equal to 0.05% of Co, less than or equal to 0.03% of Al, less than or equal to 0.00018% of [ H ] < 0.027% of [ O ], and the balance of Fe and unavoidable impurities, wherein Pb, bi, sn, as, sb, co, al is a residual element, [ H ], [ N ], [ O ] is a gaseous element.
A short-flow martensitic precipitation hardening stainless steel fracturing pump valve box production method, (1) according to the composition design ingredients of the stainless steel, smelting and pouring steel ingots by adopting an EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting process route to obtain steel ingots; wherein VOD vacuum refining comprises the steps of pre-blowing oxygen, main blowing oxygen, slow blowing oxygen, stopping oxygen, extremely vacuum and in-tank slagging reduction;
(2) Hot-feeding and demolding the steel ingot for forging to obtain a stainless steel forging stock; wherein the forging comprises five steps of steel ingot hot feeding and charging, steel ingot pre-deformation treatment, forging stock homogenization treatment, three-way upsetting forging and water cooling treatment after forging;
(3) Carrying out heat treatment on the stainless steel blank to obtain a fracturing pump valve box forging; firstly, carrying out preliminary heat treatment and complete annealing, then carrying out rough machining on valve box forging stock, carrying out six-sided milling, drilling double rows of holes after flaw detection is qualified, and obtaining valve box blanks, wherein the final heat treatment comprises a solid solution treatment step and an aging treatment step.
Specific: the hot feeding and charging is to demould the steel ingot obtained by smelting, the demould temperature is not lower than 650 ℃, hot feed is carried out to a forging heating furnace, and the heating furnace is preheated to 650 ℃ for charging the steel ingot;
the steel ingot pre-deformation treatment is to heat and preserve the temperature of the hot-delivered steel ingot to 1200 ℃, round the steel ingot, upsetting and drawing out the steel ingot after heat penetration, and heat chopping a riser and an ingot bottom, wherein the forging ratio is more than 2, so as to obtain a pre-deformed forging stock;
the forging stock homogenization treatment is to heat and preserve the pre-deformed forging stock to 1200 ℃ for 30-35h;
the three-way upsetting forging is to change the forging stock after homogenization treatment into upsetting forging in the directions of x, y and z for 5 times, wherein the forging temperature of the first 3 times is 920-1200 ℃, the forging temperature of the last 2 times is 920-1180 ℃, a flame cutting gun is adopted to clean surface cracks and folds in the forging process, the upsetting is changed into three-way upsetting forging, and the forging ratio is more than 8, so that a valve box forging stock is obtained;
the water cooling treatment after forging is to transfer the valve box forging stock after forging back to a heating furnace to heat up to 1000 ℃, and take the valve box forging stock out of the heating furnace to water-cool; and (5) water-cooling to 400 ℃ and discharging water to obtain the valve box forging stock after water cooling.
Specific: the complete annealing is to carry out complete annealing treatment on valve box forging stock cooled to 400 ℃, keep the temperature at 900 ℃, cool the valve box forging stock to 400 ℃ in a cooling speed furnace of 50 ℃/h after finishing the heat preservation, cool the valve box forging stock to room temperature at a cooling speed of 10 ℃/h, and discharge the valve box forging stock from the furnace; the solid solution treatment is to keep the temperature at 1040-1050 ℃ for 5-6h and cool the water to room temperature; the aging treatment is to keep the temperature at 550-560 ℃ for 8-10h and air-cool to room temperature.
The EBT electric arc furnace smelting is to sort and match scrap steel, the steel grade return material and alloy according to the carbon content of 0.8-1.0%, adopt an oxidation method for smelting, and the tapping component requirements are as follows: 0.40-0.80% of C, less than or equal to 0.015% of P, less than or equal to 0.008% of S, less than or equal to 0.30% of Si, less than or equal to 0.50% of Mn, 14.3-14.7% of Cr, 5.0-5.3% of Ni and 3.0-3.5% of Cu. Nb is added during VOD reduction. The impurity elements are ensured to be within the internal control requirement range. The tapping temperature is 1660-1680 ℃, and coarse molten steel is formed.
The VOD vacuum refining is to clean slag on the surface of molten steel from crude molten steel, hang the molten steel into a VOD tank, and then switch in argon gas with the pressure of 300 mm-500 mm of slag surface, close a cover and vacuumize to 32kPa, start oxygen blowing, control the vacuum degree at 25kPa, and set the oxygen flow to 150m 3 And/h, argon flow is 20NL/min. Entering a pre-oxygen blowing stage, and setting the oxygen flow to be 400-420m 3 And/h, argon flow is 30NL/min, and vacuum degree is 20-25Kpa. After pre-blowing oxygen for 6min, entering a main oxygen blowing stage, and setting the oxygen flow to be 460-550m 3 And/h, argon flow is 30NL/min, and vacuum degree is 10-20kPa. After the main oxygen blowing is carried out for 15-20min, the oxygen enters a slow oxygen blowing stage, and the oxygen flow is set to 480m 3 And/h, argon flow is 90-95NL/min, and vacuum degree is 5kPa. After slowly blowing oxygen for 5-8min, observing oxygen concentration potential E.fwdarw.0, and tail gas temperatureThe degree is obviously reduced (inflection point appears) compared with the highest value, and the CO are combined 2 After the concentration changes and the intersection point is generated, observing the condition Kuang Shi in the tank, and stopping oxygen blowing after 3-5min of over blowing. And (3) entering a stage of extreme vacuum, pumping the vacuum degree to 67Pa, regulating the argon flow to 80NL/min, and maintaining for 15min. After the pressure maintaining is completed, nitrogen is adopted for breaking the air. After the air break, pre-reducing the molten steel, keeping the argon flow at 80NL/min, adding high-quality lime at 22-25kg/t and fluorite at 4-5kg, simultaneously adding deoxidizer aluminum cake at 2kg/t and ferrosilicon at 6kg/t, and adding ferroniobium according to the components. After pre-reduction, the molten steel after VOD vacuum refining is formed.
And the LF refining is to adjust the molten steel subjected to VOD vacuum refining to an LF external refining station, adjust chemical components and finally deoxidize. Adopting ferrosilicon powder for diffusion deoxidation, maintaining white slag with good fluidity, and feeding Al wires according to the residual Al content of molten steel and 0.030 percent. And after adjusting the components to meet the requirements of finished products, forming LF refined molten steel.
And the VD vacuum degassing is carried out by hanging LF refined molten steel to a VD station for vacuum degassing, wherein the vacuum degree is less than or equal to 67Pa, the vacuum degree is kept for 10min, the vacuum breaking and sampling are carried out, argon is blown for 10min, and the molten steel temperature reaches 1550-1560 ℃ to form the VD refined molten steel.
The die casting is to hoist VD refined molten steel to a die casting station for steel ingot casting, the casting temperature is 1540-1550 ℃, the casting speed is strictly controlled during casting, the molten steel is ensured to stably rise in the die, the liquid surface is not bright, the middle is not cracked, the periphery of the die is not turned over, the molten steel is not broken, and the liquid surface rises to a riser for more than 60min to properly reduce flow and supplement. And argon is used for protecting the whole casting process, so that secondary oxidation of molten steel is prevented.
The invention provides an optimized martensitic precipitation hardening stainless steel chemical composition based on short-process production, which has low content of carbon (C) element, is favorable for forming a high-strength and high-toughness martensitic matrix, and improves the plastic toughness and corrosion resistance. The content of silicon (Si) element is controlled, the precipitation sensitivity of brittle phase is reduced, and the plasticity, toughness and corrosion resistance of steel are improved. Manganese (Mn) is too high, which can reduce the corrosion resistance, especially pitting corrosion resistance and crevice corrosion resistance, of stainless steel. Chromium (Cr) element is an important element affecting the performance of stainless steel, and as the content of the chromium (Cr) element increases, the chromium (Cr) element is beneficial to improving the strength, stress corrosion resistance, pitting corrosion resistance and crevice corrosion resistance of the stainless steel, but when the content is too high, delta-ferrite is generated, and the plasticity of the steel is reduced. The nickel (Ni) element can promote the stability of the stainless steel passivation film, obviously strengthen the stainless property and corrosion resistance of the stainless steel, and improve the plasticity and toughness of the stainless steel. Copper (Cu) plays a role in improving strength in martensitic precipitation hardening stainless steel, and the addition of the copper (Cu) can be a way of dispersing and separating epsilon intermetallic compounds in the aging process of the martensitic precipitation hardening stainless steel, so that the copper (Cu) is a main strengthening means of the martensitic precipitation hardening stainless steel containing copper. In order to effectively control delta-ferrite formation, the invention controls the ratio of chromium equivalent to nickel equivalent to be about 2 on the basis of 15-5PH standard components, controls chromium (Cr) element to be 14.30-14.70%, controls nickel (Ni) element to be 3.50-5.50%, and finally controls delta ferrite to be within 2%; the content of carbon (C) is controlled below 0.05%, the toughness and corrosion resistance of the steel are improved, nb/C is ensured to be less than 6, precipitation of NbC at a grain boundary is reduced, the toughness of the steel is improved, and Nb is controlled to be 0.20-0.35%. The copper-rich phase is 15-5PH main strengthening phase, but the excessive Cu content is easy to generate grain boundary segregation, reduces the plasticity and toughness, and controls Cu to 3.00-3.40%.
The invention has the beneficial effects that: the invention adopts the steel ingot production route of EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting, adopts high-quality steel grade return materials, reasonably matches with scrap steel structures, controls the hydration clearing components of steel, adopts the refining processes of EBT electric arc furnace roughing, special slag system LF external refining, reasonably designs VOD vacuum carbon (C) deoxidizing (O) technological parameters, VD extreme vacuum degassing and the like, adopts argon protection pouring, and directly carries out forging production by hot feeding of steel ingots, has few production procedures, compact procedure connection, low production cost and high production efficiency, and can meet the inspection and rating of nonmetallic inclusion according to ASTM E45A method without carrying out steel ingot cooling annealing and electroslag remelting procedures: class A (sulfides) < 0.5, class B (alumina) < 0.5, class C (silicates) < 1.0, class D (spherical oxides) < 0.5, ds (single particle spheres) < 1.0.
The forging production method adopted by the invention can effectively control the structure morphology of the martensitic precipitation hardening stainless steel designed by the invention. After hot delivery of the steel ingot, the steel ingot is subjected to pre-deformation treatment, so that coarse dendrites of the steel ingot are crushed, the compactness and the heat conductivity are improved, the effect of high-temperature diffusion is achieved, and the non-uniformity of chemical components of the steel ingot and the non-uniform distribution of nonmetallic inclusions are improved. The pre-deformation treatment and the large-deformation forging are helpful for dissolving delta ferrite, and the content of delta ferrite is reduced. The forging process of three-way upsetting and pulling can effectively improve the uniformity of the structure and the consistency of longitudinal and transverse properties.
The water cooling method after forging is favorable for grain refinement. The martensitic precipitation hardening stainless steel has a martensitic transformation start temperature (Ms) of 187 ℃ and an end temperature (Mf) of 52 ℃ and has no phase transformation process above the Ms point. After forging, the forging stock is heated to 1000 ℃ for austenitizing treatment, then directly enters water for cooling, and the water entering time and cooling speed are accurately controlled to ensure that the water outlet temperature is not lower than 400 ℃ and the tissue is ensured not to generate martensitic transformation. Through water cooling after forging, the cooling speed is improved, grains are effectively refined, and the uniformity of a structure is ensured.
The invention adopts a heat treatment method to carry out complete annealing, solution treatment and aging treatment on three parts, the structure after forging and water cooling is subjected to complete annealing by heat preservation at the temperature of 150 ℃ above the austenitizing temperature, so that carbide is incompletely dissolved and exists on an austenitic matrix in the form of particles, the carbide can be used as a core for nucleation, and ferrite grows to the austenitic matrix through diffusion of carbon to form a spheroidized structure. The water cooling and complete annealing treatment after forging provide good preparation structure for solution aging treatment. After 1040-1050 ℃ solution treatment, alloy elements in steel are completely dissolved into an austenite matrix, then water cooling is carried out to form a supersaturated solid solution of alpha-ferrite, and then 550-560 ℃ aging treatment is carried out, epsilon-Cu is separated out from the supersaturated solid solution to cause strain of a tissue structure, so that the effect of strengthening a metal structure lattice is achieved, heat preservation time is reasonably set at 550-560 ℃, epsilon-Cu phases can be dispersed and distributed in a martensite matrix, separated intermetallic compounds do not exceed critical dimensions and form a coherent relation with a parent phase, and the precipitation strengthening effect is achieved.
By utilizing the technical scheme of the invention, the manufactured valve box forging has the average grain size of more than or equal to 5 levels according to ASTM E112 standard, the same field-of-view level difference is not more than 2 levels, and the microstructure is tempered martensite. The mechanical properties according to ASTM A370 meet the requirements of tensile strength (Rm) more than 1000MPa, yield strength (Rel) more than 920MPa, elongation (A) more than 16%, reduction of area more than 50%, room temperature impact absorption energy (Akv) more than 80J and low temperature impact absorption energy (Akv) more than 55J at-40 ℃. The difference of the mechanical properties in the longitudinal and transverse directions is small.
Drawings
FIG. 1 is a diagram showing a 100-fold polished state rating of nonmetallic inclusion in example 1;
FIG. 2 is a photograph showing a microstructure of a valve box 1 according to embodiment 1;
FIG. 3 is a photograph showing a microstructure of a valve box of example 1, item 2;
FIG. 4 is a diagram showing a 100-fold polished state rating of nonmetallic inclusion of example 2;
FIG. 5 is a photograph of a microstructure of a valve box of embodiment 2;
FIG. 6 is a diagram showing a 100-fold polished state rating of nonmetallic inclusion of embodiment 3;
FIG. 7 is a photograph showing a microstructure of a valve box according to embodiment 3.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings.
Example 1
A high-strength corrosion-resistant martensitic precipitation-hardening stainless steel for a fracturing pump valve box comprises, by weight, 0.03% of C, 0.34% of Si, 0.58% of Mn, 0.019% of P, 0.002% of S, 14.61% of Cr, 5.09% of Ni, 3.12% of Cu, 0.23% of Nb, 0.10% of Mo, 0.008% of residual elements Pb, 0.005% of Bi, 0.001% of Sn, 0.003% of As, 0.001% of Sb, 0.05% of Co, 0.01% of Al, 0.00016% of gaseous elements [ H ], [ N ]:0.0075% ], 0.0028% of [ O ], and the balance of Fe and unavoidable impurities.
And (3) preparing materials according to the stainless steel chemical composition, and smelting and pouring by adopting a 30-ton EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting process route to obtain 3 steel ingots with 9 tons. The smelting process of the high-strength corrosion-resistant martensitic precipitation hardening stainless steel for the fracturing pump valve box comprises the following steps of:
step one, refining molten steel by using a 30 ton EBT electric furnace. Sorting and collocating scrap steel and the steel grade return material and alloy according to the carbon content of 0.8-1.0%, smelting by adopting an oxidation method, and tapping the steel components according to the requirements: 0.72% of C, 0.021% of P, 0.008% of S, 0.18% of Si, 0.17% of Mn, 12.09% of Cr, 4.51% of Ni and 0.05% of Cu. Nb is added during VOD reduction. Impurity elements are within the internal control requirement range. The tapping temperature is 1660-1680 ℃, and coarse molten steel is formed.
Step two, VOD vacuum refining. Cleaning molten steel from rough smelting, removing molten steel slag on the surface of molten steel, hanging into a VOD tank, introducing argon after entering the tank, wherein the argon pressure is 300-500 mm based on the slag surface blowing, closing a cover, vacuumizing to 32kPa, starting oxygen blowing, controlling the vacuum degree at 25kPa, and setting the oxygen flow to 150m 3 And/h, argon flow is 20NL/min. Entering a pre-oxygen blowing stage, and setting the oxygen flow to 400m 3 And/h, argon flow is 30NL/min, and vacuum degree is 20kPa; after pre-blowing oxygen for 6min, entering a main oxygen blowing stage, and setting the oxygen flow to 500m 3 Argon flow rate is 30NL/min, and vacuum degree is 12kPa; after the main oxygen blowing is carried out for 15min, the slow oxygen blowing stage is carried out, and the oxygen flow is set to 480m 3 And/h, argon flow is 90NL/min, and vacuum degree is 5kPa; after oxygen is slowly blown for 6min, the oxygen concentration potential E-0 is observed, and the tail gas temperature is obviously reduced (inflection point appears) compared with the highest value, and the CO are combined 2 After the concentration is changed and the intersection point is generated, the oxygen blowing is stopped by observing the tank conditions Kuang Shi after 5min of over blowing. And (3) entering a stage of extreme vacuum, pumping the vacuum degree to 67Pa, regulating the argon flow to 80NL/min, and maintaining for 15min. After the pressure maintaining is completed, nitrogen is adopted for breaking the air. After the empty breaking, pre-reducing the molten steel, keeping the argon flow at 80NL/min, adding 25kg/t of high-quality lime and 5kg of fluorite, simultaneously adding 2kg/t of deoxidizer aluminum cake and 6kg/t of ferrosilicon, and adding ferroniobium according to the components. After pre-reduction, the molten steel after VOD vacuum refining is formed.
And thirdly, refining outside the LF furnace. And (3) transferring the VOD vacuum refined molten steel to an LF external refining station, adjusting chemical components and finally deoxidizing. Adopting ferrosilicon powder for diffusion deoxidation, maintaining white slag with good fluidity, and feeding Al wires according to the residual Al content of molten steel and 0.030 percent. And after adjusting the components to meet the requirements of finished products, forming LF refined molten steel.
And step four, VD vacuum degassing. And (3) hanging the LF refined molten steel to a VD station for vacuum degassing, keeping the vacuum degree at 20Pa for 10min, breaking the air and sampling, and carrying out soft argon blowing for 10min, wherein the molten steel temperature reaches 1550-1560 ℃, so that the VD refined molten steel is formed.
And fifthly, casting the steel ingot. And (3) lifting the VD refined molten steel to a die casting station for steel ingot casting, wherein the casting temperature is 1540-1550 ℃, the casting speed is strictly controlled during casting, the molten steel is ensured to stably rise in the die, the liquid level is not bright, the middle is not cracked, the periphery of the die is not turned over, the molten steel is not cut off, and the liquid level rises to a riser for more than 60min for proper flow reduction and filling. And argon is used for protecting the whole casting process, so that secondary oxidation of molten steel is prevented.
The forging process of the fracturing pump valve box comprises the following steps of:
step one, hot turning and charging. Demolding 9 tons of steel ingots obtained by smelting, wherein the demolding temperature is not lower than 650 ℃, and heating to a forging heating furnace, and preheating the heating furnace to 650 ℃ for loading the steel ingots;
and step two, pre-deformation treatment. And (5) heating the hot-charged steel ingot, maintaining the temperature at 1200 ℃, maintaining the temperature for 6 hours, and discharging and forging. Rolling, upsetting and drawing out the steel ingot, and then thermally chopping a riser and an ingot bottom, wherein the forging ratio is 2, so as to obtain a pre-deformed forging stock;
and step three, homogenizing. Heating and preserving the pre-deformed forging stock to 1200 ℃ for 30h;
and step four, three-way upsetting and pulling forging. Forging the homogenized forging stock in the upsetting and pulling directions of x, y and z for 5 times, wherein the forging temperature of the first 3 times is 920-1200 ℃, the forging temperature of the last 2 times is 920-1180 ℃, a flame cutting gun is adopted to clean surface cracks, folding is carried out in the forging process, and the forging ratio is 6; obtaining a valve box forging stock of 686mm multiplied by 588mm multiplied by 1700 mm;
and fifthly, cooling after forging. After the forging is finished, a valve box forging stock of 686mm multiplied by 588mm multiplied by 1700mm is turned back to a heating furnace to be heated to 1000 ℃, and the valve box forging stock is discharged from the heating furnace to be put into a quenching water tank for water cooling; and (5) water-cooling to 400 ℃ and discharging water to obtain the valve box forging stock after water cooling.
The fracturing pump valve box heat treatment process comprises the following steps of:
and step one, complete annealing. And (3) carrying out complete annealing treatment on the valve box forging stock cooled to 400 ℃ by water, keeping the temperature at 900 ℃ for 28 hours, cooling the valve box forging stock to 400 ℃ by a cooling speed furnace of 50 ℃/h after finishing heat preservation, and slowly cooling the valve box forging stock to room temperature at a cooling speed of 10 ℃/h and discharging the valve box forging stock.
And step two, rough machining. Six sides of the valve box forging stock are polished, ultrasonic flaw detection is carried out, and the standard B-level requirements of SAE-AMS-STD-2154 are met. The end surface saw cutting sampling is carried out for low-power observation, and defects such as shrinkage cavities, bubbles, cracks, inclusions, turning skins, white spots, intercrystalline cracks and the like which affect the strength are not visible, and general punctiform segregation and edge punctiform segregation are not generated. Nonmetallic inclusion analysis was performed, and nonmetallic inclusion was rated according to ASTM E45A method, as shown in fig. 1. A. The coarse system and the fine system of B, C, D inclusions are all less than grade 1. And processing the valve box forging stock into two rows of through holes.
And step three, solution treatment. Heating the valve box forging stock to 1040 ℃, preserving heat for 15h, and cooling to room temperature;
and step four, aging treatment. And heating the valve box forging stock subjected to solid solution to 550 ℃, preserving heat for 30h, and air-cooling to room temperature. And obtaining the martensitic precipitation hardening stainless steel fracturing pump valve box forging meeting the design requirements.
For the 2 valve box forgings prepared as described in example 1, shoulder samples were taken for microstructure and mechanical property detection, including room temperature yield strength (Rel) and tensile strength (Rm), room temperature impact toughness (Kv 8), 40 ℃ low temperature impact toughness (Kv 8), grain size. The detection results are as follows:
1 st valve chest shoulder sample, longitudinal mechanical properties: the room temperature yield strength (Rel) is 986MPa, the tensile strength (Rm) is 1048MPa, the room temperature impact toughness (Kv 8) is 127J, the low temperature impact toughness (Kv 8) at-40 ℃ is 60J, and the grain size is 5 grade. Transverse mechanical properties: the room temperature yield strength (Rel) was 1007MPa, the tensile strength (Rm) was 1051MPa, the room temperature impact toughness (Kv 8) was 125J, and the low temperature impact toughness (Kv 8) at-40℃was 55J. The hardness HRC is 32, the grain size is 5.5 grade, the metallographic structure is tempered martensitic structure, and the microstructure photograph is shown in figure 2.
2 nd valve chest shoulder sample, longitudinal mechanical properties: the room temperature yield strength (Rel) was 959MPa, the tensile strength (Rm) was 1000MPa, the room temperature impact toughness (Kv 8) was 156J, and the low temperature impact toughness (Kv 8) at-40℃was 72J. Transverse mechanical properties: the room temperature yield strength (Rel) was 950MPa, the tensile strength (Rm) was 1003MPa, the room temperature impact toughness (Kv 8) was 162J, and the low temperature impact toughness (Kv 8) at-40℃was 64J. The hardness HRC is 31, the grain size is 5.5 grade, the metallographic structure is tempered martensitic structure, and the microstructure photograph is shown in figure 3.
Example 2
A high-strength corrosion-resistant martensitic precipitation-hardening stainless steel for a fracturing pump valve box comprises, by weight, 0.042% of C, 0.39% of Si, 0.62% of Mn, 0.016% of P, 0.003% of S, 14.32% of Cr, 5.35% of Ni, 3.33% of Cu, 0.32% of Nb, 0.17% of Mo, 0.007% of residual elements Pb, 0.003% of Bi, 0.002% of Sn, 0.005% of As, 0.003% of Sb, 0.04% of Co, 0.02% of Al, 0.00014% of gaseous elements [ H ], [ N ]:0.0085% ], 0.0024% of [ O ], and the balance of Fe and unavoidable impurities.
And (3) preparing materials according to the stainless steel chemical composition, and smelting and pouring by adopting a 30-ton EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting process route to obtain 3 steel ingots with 9 tons. The smelting process of the high-strength corrosion-resistant martensitic precipitation hardening stainless steel for the fracturing pump valve box comprises the following steps of:
step one, refining molten steel by using a 30 ton EBT electric furnace. Sorting and collocating scrap steel and the steel grade return material and alloy according to the carbon content of 0.8-1.0%, smelting by adopting an oxidation method, and tapping the steel components according to the requirements: 0.52% of C, 0.020% of P, 0.006% of S, 0.15% of Si, 0.20% of Mn, 12.84% of Cr, 4.78% of Ni and 0.04% of Cu. Nb is added during VOD reduction. Impurity elements are within the internal control requirement range. The tapping temperature is 1660-1680 ℃, and coarse molten steel is formed.
Step two, VOD vacuum refining. Cleaning molten steel from rough smelting, removing molten steel slag on the surface of molten steel, hanging into a VOD tank, introducing argon after entering the tank, wherein the argon pressure is 300-500 mm based on the slag surface blowing, closing a cover, vacuumizing to 32kPa, starting oxygen blowing, controlling the vacuum degree at 25kPa, and setting the oxygen flow to 150m 3 And/h, argon flow is 20NL/min. Entering a pre-oxygen blowing stage, and setting oxygen flowQuantity 410m 3 And/h, argon flow is 30NL/min, and vacuum degree is 20kPa; after pre-blowing oxygen for 6min, entering a main oxygen blowing stage, and setting the oxygen flow to 520m 3 Argon flow rate is 30NL/min, and vacuum degree is 12kPa; after the main oxygen blowing is carried out for 15min, the slow oxygen blowing stage is carried out, and the oxygen flow is set to 480m 3 And/h, argon flow is 90NL/min, and vacuum degree is 5kPa; after oxygen is slowly blown for 6min, the oxygen concentration potential E-0 is observed, and the tail gas temperature is obviously reduced (inflection point appears) compared with the highest value, and the CO are combined 2 After the concentration is changed and the intersection point is generated, the oxygen blowing is stopped by observing the tank conditions Kuang Shi after 5min of over blowing. And (3) entering a stage of extreme vacuum, pumping the vacuum degree to 67Pa, regulating the argon flow to 80NL/min, and maintaining for 15min. After the pressure maintaining is completed, nitrogen is adopted for breaking the air. After the empty breaking, pre-reducing the molten steel, keeping the argon flow at 80NL/min, adding 25kg/t of high-quality lime and 5kg of fluorite, simultaneously adding 2kg/t of deoxidizer aluminum cake and 6kg/t of ferrosilicon, and adding ferroniobium according to the components. After pre-reduction, the molten steel after VOD vacuum refining is formed.
And thirdly, refining outside the LF furnace. And (3) transferring the VOD vacuum refined molten steel to an LF external refining station, adjusting chemical components and finally deoxidizing. Adopting ferrosilicon powder for diffusion deoxidation, maintaining white slag with good fluidity, and feeding Al wires according to the residual Al content of molten steel and 0.030 percent. And after adjusting the components to meet the requirements of finished products, forming LF refined molten steel.
And step four, VD vacuum degassing. And (3) hanging the LF refined molten steel to a VD station for vacuum degassing, keeping the vacuum degree at 20Pa for 10min, breaking the air and sampling, and carrying out soft argon blowing for 10min, wherein the molten steel temperature reaches 1550-1560 ℃, so that the VD refined molten steel is formed.
And fifthly, casting the steel ingot. And (3) lifting the VD refined molten steel to a die casting station for steel ingot casting, wherein the casting temperature is 1540-1550 ℃, the casting speed is strictly controlled during casting, the molten steel is ensured to stably rise in the die, the liquid level is not bright, the middle is not cracked, the periphery of the die is not turned over, the molten steel is not cut off, and the liquid level rises to a riser for more than 60min for proper flow reduction and filling. And argon is used for protecting the whole casting process, so that secondary oxidation of molten steel is prevented.
The forging process of the fracturing pump valve box comprises the following steps of:
step one, hot turning and charging. Demolding 9 tons of steel ingots obtained by smelting, wherein the demolding temperature is not lower than 650 ℃, and heating to a forging heating furnace, and preheating the heating furnace to 650 ℃ for loading the steel ingots;
and step two, pre-deformation treatment. And (5) heating the hot-charged steel ingot, maintaining the temperature at 1200 ℃, maintaining the temperature for 6 hours, and discharging and forging. Rolling, upsetting and drawing out the steel ingot, and then thermally chopping a riser and an ingot bottom, wherein the forging ratio is 2, so as to obtain a pre-deformed forging stock;
and step three, homogenizing. Heating and preserving the pre-deformed forging stock to 1200 ℃ for 30h;
and step four, three-way upsetting and pulling forging. Forging the homogenized forging stock in the upsetting and pulling directions of x, y and z for 5 times, wherein the forging temperature of the first 3 times is 920-1200 ℃, the forging temperature of the last 2 times is 920-1180 ℃, a flame cutting gun is adopted to clean surface cracks, folding is carried out in the forging process, and the forging ratio is 6; obtaining a valve box forging stock of 686mm multiplied by 588mm multiplied by 1700 mm;
and fifthly, cooling after forging. After the forging is finished, a valve box forging stock of 686mm multiplied by 588mm multiplied by 1700mm is turned back to a heating furnace to be heated to 1000 ℃, and the valve box forging stock is discharged from the heating furnace to be put into a quenching water tank for water cooling; and (5) water-cooling to 390 ℃ and discharging water to obtain the valve box forging stock after water cooling.
The fracturing pump valve box heat treatment process comprises the following steps of:
and step one, complete annealing. And (3) carrying out complete annealing treatment on the valve box forging stock cooled to 390 ℃ by water, keeping the temperature at 900 ℃ for 28 hours, cooling the valve box forging stock to 400 ℃ at a cooling speed of 50 ℃/h in a high-temperature section after finishing heat preservation, and slowly cooling the valve box forging stock to room temperature at a cooling speed of 10 ℃/h and discharging the valve box forging stock.
And step two, rough machining. Six sides of the valve box forging stock are polished, ultrasonic flaw detection is carried out, and the standard B-level requirements of SAE-AMS-STD-2154 are met. The end surface saw cutting sampling is carried out for low-power observation, and defects such as shrinkage cavities, bubbles, cracks, inclusions, turning skins, white spots, intercrystalline cracks and the like which affect the strength are not visible, and general punctiform segregation and edge punctiform segregation are not generated. Nonmetallic inclusion analysis was performed, and nonmetallic inclusion was rated according to ASTM E45A method, as shown in fig. 4. A. The coarse system and the fine system of B, C, D inclusions are all less than grade 1. And processing the valve box forging stock into two rows of through holes.
And step three, solution treatment. Heating the valve box forging stock to 1040 ℃, preserving heat for 15h, and cooling to room temperature;
and step four, aging treatment. And heating the valve box forging stock subjected to solid solution to 550 ℃, preserving heat for 30h, and air-cooling to room temperature. And obtaining the martensitic precipitation hardening stainless steel fracturing pump valve box forging meeting the design requirements.
A1-piece valve box forging prepared according to the method described in example 2 was subjected to microstructure and mechanical property measurements, including room temperature yield strength (Rel) and tensile strength (Rm), room temperature impact toughness (Kv 8), 40 ℃ low temperature impact toughness (Kv 8), grain size. The detection results are as follows:
example 2 valve box shoulder test sample: longitudinal mechanical properties: the room temperature yield strength (Rel) is 967MPa, the tensile strength (Rm) is 1032MPa, the room temperature impact toughness (Kv 8) is 131J, the low temperature impact toughness (Kv 8) at-40 ℃ is 58J, and the grain size is 5 grade. Transverse mechanical properties: the room temperature yield strength (Rel) was 957MPa, the tensile strength (Rm) was 1028MPa, the room temperature impact toughness (Kv 8) was 128J, and the low temperature impact toughness (Kv 8) at-40℃was 61J. The hardness HRC is 33, the grain size is 5 grade, the metallographic structure is tempered martensitic structure, and the microstructure photograph is shown in figure 5.
Example 3
A high-strength corrosion-resistant martensitic precipitation-hardening stainless steel for a fracturing pump valve box comprises the following components, by weight, 0.024% of C, 0.31% of Si, 0.52% of Mn, 0.019% of P, 0.004% of S, 14.65% of Cr, 4.55% of Ni, 3.02% of Cu, 0.22% of Nb, 0.21% of Mo, 0.008% of residual elements Pb, 0.004% of Bi, 0.003% of Sn, 0.006% of As, 0.004% of Sb, 0.03% of Co, 0.015% of Al, 0.00018% of gaseous elements [ H ], [ N ] [ O ]:0.0027%, and the balance of Fe and unavoidable impurities.
And (3) preparing materials according to the stainless steel chemical composition, and smelting and pouring by adopting a 30-ton EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting process route to obtain 3 steel ingots with 9 tons. The smelting process of the high-strength corrosion-resistant martensitic precipitation hardening stainless steel for the fracturing pump valve box comprises the following steps of:
step one, refining molten steel by using a 30 ton EBT electric furnace. Sorting and collocating scrap steel and the steel grade return material and alloy according to the carbon content of 0.8-1.0%, smelting by adopting an oxidation method, and tapping the steel components according to the requirements: 0.64% of C, 0.019% of P, 0.007% of S, 0.23% of Si, 0.29% of Mn, 12.44% of Cr, 4.03% of Ni and 0.05% of Cu. Nb is added during VOD reduction. Impurity elements are within the internal control requirement range. The tapping temperature is 1660-1680 ℃, and coarse molten steel is formed.
Step two, VOD vacuum refining. Cleaning molten steel from rough smelting, removing molten steel slag on the surface of molten steel, hanging into a VOD tank, introducing argon after entering the tank, wherein the argon pressure is 300-500 mm based on the slag surface blowing, closing a cover, vacuumizing to 32kPa, starting oxygen blowing, controlling the vacuum degree at 25kPa, and setting the oxygen flow to 150m 3 And/h, argon flow is 20NL/min. Entering a pre-oxygen blowing stage, and setting the oxygen flow to 420m 3 And/h, argon flow is 30NL/min, and vacuum degree is 20kPa; after pre-blowing oxygen for 6min, entering a main oxygen blowing stage, and setting the oxygen flow to 540m 3 Argon flow rate is 30NL/min, and vacuum degree is 12kPa; after the main oxygen blowing is carried out for 15min, the slow oxygen blowing stage is carried out, and the oxygen flow is set to 480m 3 And/h, argon flow is 85NL/min, and vacuum degree is 5kPa; after oxygen is slowly blown for 6min, the oxygen concentration potential E-0 is observed, and the tail gas temperature is obviously reduced (inflection point appears) compared with the highest value, and the CO are combined 2 After the concentration is changed and the intersection point is generated, the oxygen blowing is stopped by observing the tank conditions Kuang Shi after 5min of over blowing. And (3) entering a stage of extreme vacuum, pumping the vacuum degree to 67Pa, regulating the argon flow to 80NL/min, and maintaining for 15min. After the pressure maintaining is completed, nitrogen is adopted for breaking the air. After the empty breaking, pre-reducing the molten steel, keeping the argon flow at 80NL/min, adding 25kg/t of high-quality lime and 5kg of fluorite, simultaneously adding 2kg/t of deoxidizer aluminum cake and 6kg/t of ferrosilicon, and adding ferroniobium according to the components. After pre-reduction, the molten steel after VOD vacuum refining is formed.
And thirdly, refining outside the LF furnace. And (3) transferring the VOD vacuum refined molten steel to an LF external refining station, adjusting chemical components and finally deoxidizing. Adopting ferrosilicon powder for diffusion deoxidation, maintaining white slag with good fluidity, and feeding Al wires according to the residual Al content of molten steel and 0.030 percent. And after adjusting the components to meet the requirements of finished products, forming LF refined molten steel.
And step four, VD vacuum degassing. And (3) hanging the LF refined molten steel to a VD station for vacuum degassing, keeping the vacuum degree at 20Pa for 10min, breaking the air and sampling, and carrying out soft argon blowing for 10min, wherein the molten steel temperature reaches 1550-1560 ℃, so that the VD refined molten steel is formed.
And fifthly, casting the steel ingot. And (3) lifting the VD refined molten steel to a die casting station for steel ingot casting, wherein the casting temperature is 1540-1550 ℃, the casting speed is strictly controlled during casting, the molten steel is ensured to stably rise in the die, the liquid level is not bright, the middle is not cracked, the periphery of the die is not turned over, the molten steel is not cut off, and the liquid level rises to a riser for more than 60min for proper flow reduction and filling. And argon is used for protecting the whole casting process, so that secondary oxidation of molten steel is prevented.
The forging process of the fracturing pump valve box comprises the following steps of:
step one, hot turning and charging. Demolding 9 tons of steel ingots obtained by smelting, wherein the demolding temperature is not lower than 650 ℃, and heating to a forging heating furnace, and preheating the heating furnace to 650 ℃ for loading the steel ingots;
and step two, pre-deformation treatment. And (5) heating the hot-charged steel ingot, maintaining the temperature at 1200 ℃, maintaining the temperature for 6 hours, and discharging and forging. Rolling, upsetting and drawing out the steel ingot, and then thermally chopping a riser and an ingot bottom, wherein the forging ratio is 2, so as to obtain a pre-deformed forging stock;
and step three, homogenizing. Heating and preserving the pre-deformed forging stock to 1200 ℃ for 30h;
and step four, three-way upsetting and pulling forging. Forging the homogenized forging stock in the upsetting and pulling directions of x, y and z for 5 times, wherein the forging temperature of the first 3 times is 920-1200 ℃, the forging temperature of the last 2 times is 920-1180 ℃, a flame cutting gun is adopted to clean surface cracks, folding is carried out in the forging process, and the forging ratio is 6; obtaining a valve box forging stock of 686mm multiplied by 588mm multiplied by 1700 mm;
and fifthly, cooling after forging. After the forging is finished, a valve box forging stock of 686mm multiplied by 588mm multiplied by 1700mm is turned back to a heating furnace to be heated to 1000 ℃, and the valve box forging stock is discharged from the heating furnace to be put into a quenching water tank for water cooling; and (5) water-cooling to 390 ℃ and discharging water to obtain the valve box forging stock after water cooling.
The fracturing pump valve box heat treatment process comprises the following steps of:
and step one, complete annealing. And (3) carrying out complete annealing treatment on the valve box forging stock cooled to 390 ℃ by water, keeping the temperature at 900 ℃ for 28 hours, cooling the valve box forging stock to 400 ℃ at a cooling speed of 50 ℃/h in a high-temperature section after finishing heat preservation, and slowly cooling the valve box forging stock to room temperature at a cooling speed of 10 ℃/h and discharging the valve box forging stock.
And step two, rough machining. Six sides of the valve box forging stock are polished, ultrasonic flaw detection is carried out, and the standard B-level requirements of SAE-AMS-STD-2154 are met. The end surface saw cutting sampling is carried out for low-power observation, and defects such as shrinkage cavities, bubbles, cracks, inclusions, turning skins, white spots, intercrystalline cracks and the like which affect the strength are not visible, and general punctiform segregation and edge punctiform segregation are not generated. Nonmetallic inclusion analysis was performed, and nonmetallic inclusion was rated according to ASTM E45A method, as shown in fig. 6. A. The coarse system and the fine system of B, C, D inclusions are all less than grade 1. And processing the valve box forging stock into two rows of through holes.
And step three, solution treatment. Heating the valve box forging stock to 1040 ℃, preserving heat for 15h, and cooling to room temperature;
and step four, aging treatment. And heating the valve box forging stock subjected to solid solution to 550 ℃, preserving heat for 30h, and air-cooling to room temperature. And obtaining the martensitic precipitation hardening stainless steel fracturing pump valve box forging meeting the design requirements.
A1-piece valve box forging prepared according to the method described in example 3 was examined for microstructure and mechanical properties, including room temperature yield strength (Rel) and tensile strength (Rm), room temperature impact toughness (Kv 8), 40℃low temperature impact toughness (Kv 8), grain size, by taking shoulder samples. The detection results are as follows:
example 3 valve chest shoulder test specimen, longitudinal mechanical properties: the room temperature yield strength (Rel) is 921MPa, the tensile strength (Rm) is 1012MPa, the room temperature impact toughness (Kv 8) is 146J, the low temperature impact toughness (Kv 8) at-40 ℃ is 57J, and the grain size is 6.5 grade. Transverse mechanical properties: the room temperature yield strength (Rel) was 930MPa, the tensile strength (Rm) was 1018MPa, the room temperature impact toughness (Kv 8) was 134J, and the low temperature impact toughness (Kv 8) at-40℃was 55J. The hardness HRC is 31, the grain size is 6 grade, the metallographic structure is tempered martensitic structure, and the microstructure photograph is shown in figure 7.
According to the method, 15-5PH stainless steel chemical components are optimized for the fracturing pump valve box, smelting and pouring are carried out by adopting an EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting process route, and a forging and heat treatment process is reasonably designed, so that the 15-5PH stainless steel valve box forging has the characteristic of short-flow production.
Claims (7)
1. A short-process martensitic precipitation hardening stainless steel fracturing pump valve box production method comprises the following components in percentage by mass: 0.020-0.055% of C, 0.30-0.50% of Si, 0.50-0.80% of Mn, less than or equal to 0.020% of P, less than or equal to 0.005% of S, 14.30-14.70% of Cr, 3.50-5.50% of Ni, 3.00-3.40% of Cu, 0.20-0.35% of Nb, less than or equal to 0.35% of Mo, less than or equal to 0.008% of Pb, less than or equal to 0.005% of Bi, less than or equal to 0.008% of Sn, less than or equal to 0.010% of As, less than or equal to 0.005% of Sb, less than or equal to 0.05% of Co, less than or equal to 0.03% of Al, less than or equal to 0.00018% of [ N ], [ N ]. Less than or equal to 0.027% of O, and the balance Fe and unavoidable impurities, wherein Pb, bi, sn, as, sb, co, al is a residual element, [ H ], [ N ], [ O ] is a gas element, characterized in that: (1) According to the composition design ingredients of the stainless steel, smelting and pouring steel ingots by adopting an EBT electric arc furnace smelting-VOD vacuum refining-LF furnace refining-VD vacuum degassing-die casting process route to obtain steel ingots; wherein VOD vacuum refining comprises the steps of pre-blowing oxygen, main blowing oxygen, slow blowing oxygen, stopping oxygen, extremely vacuum and in-tank slagging reduction;
(2) Hot-feeding and demolding the steel ingot for forging to obtain a stainless steel forging stock; wherein the forging comprises five steps of steel ingot hot feeding and charging, steel ingot pre-deformation treatment, forging stock homogenization treatment, three-way upsetting forging and water cooling treatment after forging; the hot feeding and charging is to demould the steel ingot obtained by smelting, the demould temperature is not lower than 650 ℃, hot feed is carried out to a forging heating furnace, and the heating furnace is preheated to 650 ℃ for charging the steel ingot;
the steel ingot pre-deformation treatment is to heat and preserve the temperature of the hot-delivered steel ingot to 1200 ℃, round the steel ingot, upsetting and drawing out the steel ingot after heat penetration, and heat chopping a riser and an ingot bottom, wherein the forging ratio is more than 2, so as to obtain a pre-deformed forging stock;
the forging stock homogenization treatment is to heat and preserve the pre-deformed forging stock to 1200 ℃ for 30-35h;
the three-way upsetting forging is to change the forging stock after homogenization treatment into upsetting forging in the directions of x, y and z for 5 times, wherein the forging temperature of the first 3 times is 920-1200 ℃, the forging temperature of the last 2 times is 920-1180 ℃, and the forging ratio is more than 8, so as to obtain valve box forging stock;
the water cooling treatment after forging is to transfer the valve box forging stock after forging back to a heating furnace to heat up to 1000 ℃, and take the valve box forging stock out of the heating furnace to water-cool; water cooling to 400 ℃ and water discharging;
(3) Carrying out heat treatment on the stainless steel blank to obtain a fracturing pump valve box forging; firstly, carrying out preliminary heat treatment and complete annealing, then carrying out rough machining on valve box forging stock, carrying out six-sided milling, drilling double rows of holes after flaw detection is qualified, and obtaining valve box blanks, wherein the final heat treatment comprises a solid solution treatment step and an aging treatment step.
2. The method for producing the short-process martensitic precipitation-hardening stainless steel fracturing pump valve box, which is characterized in that: the complete annealing is to carry out complete annealing treatment on valve box forging stock cooled to 400 ℃ by water, the heat preservation temperature is 900 ℃, the high temperature section is cooled to 400 ℃ in a cooling speed furnace of 50 ℃/h after finishing heat preservation, and the valve box forging stock is cooled to room temperature at a cooling rate of 10 ℃/h and is discharged from the furnace;
the solid solution treatment is to keep the temperature at 1040-1050 ℃ for 5-6h and cool the water to room temperature;
the aging treatment is to keep the temperature at 550-560 ℃ for 8-10h and air-cool to room temperature.
3. The method for producing the short-process martensitic precipitation-hardening stainless steel fracturing pump valve box, which is characterized in that: the EBT electric arc furnace smelting is to sort and match scrap steel, the steel grade return material and alloy according to the carbon content of 0.8-1.0%, adopt an oxidation method for smelting, and the tapping component requirements are as follows: 0.40-0.80% of C, less than or equal to 0.015% of P, less than or equal to 0.008% of S, less than or equal to 0.30% of Si, less than or equal to 0.50% of Mn, 14.3-14.7% of Cr, 5.0-5.3% of Ni, 3.0-3.5% of Cu, and impurity elements within the internal control requirement range, wherein the tapping temperature is 1660-1680 ℃ to form rough molten steel.
4. A short-flow horse according to claim 1The production method of the stainless steel fracturing pump valve box for precipitation hardening of the shi body is characterized by comprising the following steps of: the VOD vacuum refining is to clean slag on the surface of molten steel from crude molten steel, hang the molten steel into a VOD tank, and then switch in argon gas with the pressure of 300 mm-500 mm of slag surface, close a cover and vacuumize to 32kPa, start oxygen blowing, control the vacuum degree at 25kPa, and set the oxygen flow to 150m 3 H, argon flow is 20NL/min; entering a pre-oxygen blowing stage, and setting the oxygen flow to be 400-420m 3 And/h, argon flow is 30NL/min, and vacuum degree is 20-25kPa; after pre-blowing oxygen for 6min, entering a main oxygen blowing stage, and setting the oxygen flow to be 460-550m 3 And/h, argon flow is 30NL/min, and vacuum degree is 10-20kPa; after the main oxygen blowing is carried out for 15-20min, the oxygen enters a slow oxygen blowing stage, and the oxygen flow is set to 480m 3 And/h, argon flow is 90-95NL/min, and vacuum degree is 5kPa; after oxygen is slowly blown for 5-8min, the oxygen concentration potential E-0 is observed, meanwhile, the temperature of the tail gas is reduced to generate an inflection point, and the CO are combined 2 After the concentration changes and the intersection point is generated, observing the condition of over blowing in the tank for 3-5min, and stopping blowing oxygen; entering an extreme vacuum stage, pumping the vacuum degree to 67Pa, regulating the argon flow to 80NL/min, and maintaining for 15min; after the pressure maintaining is completed, nitrogen is adopted for breaking the air; after the air break, pre-reducing the molten steel, keeping the argon flow at 80NL/min, adding 22-25kg/t of lime and 4-5kg of fluorite, simultaneously adding 2kg/t of deoxidizer aluminum cake and 6kg/t of ferrosilicon, and adding ferroniobium according to the components; after pre-reduction, the molten steel after VOD vacuum refining is formed.
5. The method for producing the short-process martensitic precipitation-hardening stainless steel fracturing pump valve box, which is characterized in that: and in the LF refining step, the molten steel subjected to VOD vacuum refining is transferred to an LF external refining station, chemical components are adjusted, final deoxidation is carried out, ferrosilicon powder is adopted for diffusion deoxidation, white slag with good fluidity is maintained, al wires are fed according to the content of residual Al of the molten steel by 0.030%, and the LF refined molten steel is formed after the components are adjusted to meet the requirements of finished products.
6. The method for producing the short-process martensitic precipitation-hardening stainless steel fracturing pump valve box, which is characterized in that: and the VD vacuum degassing is carried out by hanging LF refined molten steel to a VD station for vacuum degassing, wherein the vacuum degree is less than or equal to 67Pa, the vacuum degree is kept for 10min, the vacuum breaking and sampling are carried out, argon is blown for 10min, and the molten steel temperature reaches 1550-1560 ℃ to form the VD refined molten steel.
7. The method for producing the short-process martensitic precipitation-hardening stainless steel fracturing pump valve box, which is characterized in that: and the die casting is to hoist and transport VD refined molten steel to a die casting station for steel ingot casting, the casting temperature is 1540-1550 ℃, the casting speed is controlled during casting, the molten steel is enabled to stably rise in the die, the flow is reduced and the filling is carried out when the liquid level rises to more than 60min of a riser, and argon protection is carried out during the whole casting process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210490076.1A CN114892106B (en) | 2022-05-07 | 2022-05-07 | Martensitic precipitation hardening stainless steel for fracturing pump valve box and short-flow production method of fracturing pump valve box |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210490076.1A CN114892106B (en) | 2022-05-07 | 2022-05-07 | Martensitic precipitation hardening stainless steel for fracturing pump valve box and short-flow production method of fracturing pump valve box |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114892106A CN114892106A (en) | 2022-08-12 |
| CN114892106B true CN114892106B (en) | 2023-07-25 |
Family
ID=82719937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210490076.1A Active CN114892106B (en) | 2022-05-07 | 2022-05-07 | Martensitic precipitation hardening stainless steel for fracturing pump valve box and short-flow production method of fracturing pump valve box |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114892106B (en) |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004018988A (en) * | 2002-06-20 | 2004-01-22 | Aichi Steel Works Ltd | Method for warm-forging precipitation-hardening martensitic stainless steel, and forged parts manufactured by the method |
| CN101210304A (en) * | 2006-12-27 | 2008-07-02 | 沈阳鼓风机(集团)有限公司 | Martensite precipitation hardening stainless steel for compressor impeller and preparation method thereof |
| JP5293596B2 (en) * | 2007-03-22 | 2013-09-18 | 日立金属株式会社 | Precipitation hardening type martensitic stainless cast steel with excellent machinability and manufacturing method thereof |
| CN102251084B (en) * | 2011-07-04 | 2013-04-17 | 南京迪威尔高端制造股份有限公司 | Heat treatment process of steel forging for hydraulic cylinder of deep-sea oil recovery equipment |
| CN105506497B (en) * | 2015-12-25 | 2017-12-12 | 中石化四机石油机械有限公司 | A kind of clack box stainless steel alloy and manufacture method |
| CN113774270A (en) * | 2020-06-10 | 2021-12-10 | 宝武特种冶金有限公司 | High-strength high-toughness precipitation hardening stainless steel bar and preparation method thereof |
| CN113122782B (en) * | 2021-04-21 | 2022-03-15 | 浙江中煤机械科技有限公司 | Stainless steel for pump head body and preparation method thereof |
| JP7018537B1 (en) * | 2021-08-19 | 2022-02-10 | 日本冶金工業株式会社 | Precipitation hardening martensitic stainless steel with excellent weldability and its manufacturing method |
-
2022
- 2022-05-07 CN CN202210490076.1A patent/CN114892106B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN114892106A (en) | 2022-08-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2022148492A1 (en) | Steel for cold forging universal joint fork of passenger vehicle, and manufacturing method therefor | |
| CN110343954B (en) | Steel for automobile engine connecting rod and manufacturing method thereof | |
| CN110157988B (en) | Steel alloy material for high-purity homogeneous rare earth cold roll and preparation method thereof | |
| CN108220766B (en) | Cr-V hot work die steel and preparation method thereof | |
| CN110029268B (en) | 09MnNiDR steel plate for low-temperature pressure vessel with core low-temperature toughness protection and manufacturing method thereof | |
| CN116287941B (en) | Production method of steel for high-strength wind power bolt | |
| CN111850399B (en) | Corrosion-resistant plastic die steel with good wear resistance and preparation method thereof | |
| CN114672723A (en) | 46MnVS series steel for expansion-fracture connecting rod and manufacturing method thereof | |
| CN112575255A (en) | Preparation method of 15MnNiNbDR steel plate for ultralow-temperature storage tank | |
| CN107557690A (en) | Low-temperature-resistant and lamellar-tearing-resistant super-thick steel plate and manufacturing method thereof | |
| CN113502434B (en) | Aviation 30CrMnSiNi2A high-strength steel and production method thereof | |
| CN115896634B (en) | High-temperature-resistant nonferrous metal die-casting forming die steel material and preparation method thereof | |
| CN114892106B (en) | Martensitic precipitation hardening stainless steel for fracturing pump valve box and short-flow production method of fracturing pump valve box | |
| CN113444978B (en) | Preparation method of ultrahigh-strength steel | |
| CN115094307B (en) | Hot die steel continuous casting round billet for electroslag remelting and production process thereof | |
| CN114635094B (en) | Martensitic stainless steel for valve body and preparation method thereof | |
| CN113462951B (en) | Preparation method of ultrahigh-strength and high-toughness alloy steel | |
| CN115044823A (en) | Production process of ultra-supercritical high-pressure boiler steel P92 continuous casting round billet | |
| CN109778073B (en) | Free-cutting steel for automobile synchronizer and preparation method thereof | |
| CN109234632B (en) | Easy-to-weld corrosion-resistant high-strength Q690E steel plate for deep sea submarine with thickness of 80-120mm and production method thereof | |
| CN111534738A (en) | Small-batch manufacturing method of tens of kilogram-level nuclear reactor pressure vessel steel | |
| CN116949353B (en) | Bi-containing free-cutting non-quenched and tempered steel for automobile engine crankshaft and manufacturing method thereof | |
| CN115786808B (en) | 420 MPa-level wind power flange steel and preparation method thereof | |
| CN114807558B (en) | Production method of EX50V round steel for mine drill bit | |
| CN117947239B (en) | Low-phosphorus converter smelting method and production method of low-temperature steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20231108 Address after: No.506, west section of Yellow River Avenue, Lanzhou New Area, Lanzhou City, Gansu Province Patentee after: Lanzhou Lanshi Superalloy New Materials Co.,Ltd. Address before: 730310 No. 506, west section of Huanghe Avenue, Lanzhou New Area, Lanzhou City, Gansu Province Patentee before: Lanzhou Lanshi Group Co.,Ltd. Casting and Forging Branch |