CN114535523A - Production method of weathering resistant steel Q355NHD casting blank - Google Patents
Production method of weathering resistant steel Q355NHD casting blank Download PDFInfo
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- CN114535523A CN114535523A CN202210274060.7A CN202210274060A CN114535523A CN 114535523 A CN114535523 A CN 114535523A CN 202210274060 A CN202210274060 A CN 202210274060A CN 114535523 A CN114535523 A CN 114535523A
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- 238000005266 casting Methods 0.000 title claims abstract description 30
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 28
- 239000010959 steel Substances 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 8
- 238000009749 continuous casting Methods 0.000 claims abstract description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910000870 Weathering steel Inorganic materials 0.000 claims abstract description 20
- 238000001816 cooling Methods 0.000 claims abstract description 15
- 238000007670 refining Methods 0.000 claims abstract description 14
- 239000002893 slag Substances 0.000 claims abstract description 14
- 229910052742 iron Inorganic materials 0.000 claims abstract description 12
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 8
- 230000023556 desulfurization Effects 0.000 claims abstract description 8
- 238000010079 rubber tapping Methods 0.000 claims abstract description 6
- 239000000843 powder Substances 0.000 claims abstract description 5
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 4
- 238000003723 Smelting Methods 0.000 claims abstract description 4
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 239000004571 lime Substances 0.000 claims abstract description 4
- 238000010907 mechanical stirring Methods 0.000 claims abstract description 4
- 238000003860 storage Methods 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 15
- 238000004140 cleaning Methods 0.000 claims description 9
- 230000004907 flux Effects 0.000 claims description 9
- 230000007547 defect Effects 0.000 claims description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- 238000005070 sampling Methods 0.000 claims description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- 230000002159 abnormal effect Effects 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 238000007664 blowing Methods 0.000 claims description 3
- 238000004886 process control Methods 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 239000007790 solid phase Substances 0.000 claims description 3
- 239000002436 steel type Substances 0.000 claims description 3
- 229910052717 sulfur Inorganic materials 0.000 claims description 3
- 239000011593 sulfur Substances 0.000 claims description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 229910000975 Carbon steel Inorganic materials 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 210000001787 dendrite Anatomy 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000003466 welding Methods 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
-
- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/34—Blowing through the bath
-
- 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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
-
- 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
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- 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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a production method of a weathering steel Q355NHD casting blank, comprising the steps of molten iron pretreatment, 120t converter, LF refining and continuous casting; smelting components, wherein the components comprise iron and impurities in percentage by mass; 0.075-0.095 of C, 0.20-0.30 of Si, 0.95-1.15 of Mn, 0.020 of P, 0.006 of S, 0.26-0.35 of Cu, 0.15-0.25 of Ni, 0.42-0.55 of Cr, 0.020-0.040 of Al, 0.020-0.03 of Ti and 0.0015-0.004 of Ca; pretreating molten iron: lime powder or Mg + CaO is added into the steel ladle to carry out mechanical stirring pre-desulfurization treatment, and slag skimming treatment is carried out after desulfurization is finished; tapping is carried out for 8 minutes, and the refining furnace needs to ensure that the white slag can be tapped for more than 10 minutes; the casting powder is special for weathering steel, and the casting blank cooling standard is as follows: and (5) performing ordinary air cooling, wherein the storage cooling time is 72 hours.
Description
Technical Field
The invention relates to a production method of a weathering steel Q355NHD casting blank.
Background
The weathering steel, namely the atmospheric corrosion resistant steel, is low alloy steel between ordinary steel and stainless steel, the weathering steel is made of plain carbon steel with a small amount of corrosion resistant elements such as copper, nickel, etc., and has the characteristics of high-quality steel such as obdurability, ductility, molding, welding and cutting, abrasion, high temperature, fatigue resistance, etc.; the weather resistance is 2-8 times of that of the plain carbon steel, and the coating property is 1.5-10 times of that of the plain carbon steel. Meanwhile, it has the characteristics of rust resistance, corrosion resistance, long service life, thinning, consumption reduction, labor saving, energy saving and the like.
Analysis of causes of internal defects of the weathering steel Q355NHD continuous casting billet:
(1) corner cracks. After the lower opening of the crystallizer is seriously worn, a larger air gap is generated between a copper pipe of the crystallizer and a casting blank to form larger thermal resistance, so that the cooling of the lower opening is too weak, the blank shell is thinned, meanwhile, the zero-section corner is excessively cooled due to the serious wear of the lower opening, the cooling gradient from weak to strong is too large, stress concentration is generated, and corner cracks are easily generated due to the fact that the thickness of the blank shell is uneven and the casting blank is transformed.
(2) Center porosity and general porosity. The looseness at the axial center of the steel ingot is called central looseness. When molten steel solidifies and contracts in the ingot mold, if the upper unset molten steel cannot be effectively replenished to the lower portion, the structure of the central portion is not dense. The columnar crystal direction centers on the two surfaces of the casting blank are grown and contacted together to form a bridge, the supplement of the solidification shrinkage of the molten steel above the bridge to the molten steel below the bridge is prevented, and a plurality of small pores are left after the molten steel below the bridge is completely solidified. In addition, the developed columnar crystal grows with developed dendrites, and some fine dendrites (such as cubic dendrites) are partially melted and collapsed, and also form a central porosity.
The general distribution of porosity in the cross section of the casting blank is called general porosity, which is small point gaps uniformly distributed in the cross section of the casting blank. The main reason for this is that the steel contains too much gas and non-metallic inclusions or the casting speed is too fast, and the key is to do full degassing and reduction deoxidation work and good casting operation during steel making.
Under the harsh service environment of the weathering steel, the weathering steel has the problems that a rust layer is difficult to densify, and in addition, the appearance corrosion of a steel structure presents uneven and the like at the initial service stage, so the application environment and the surface treatment technology of the weathering steel always troubles the application of the weathering steel.
Disclosure of Invention
The invention aims to provide a production method of a weather-resistant steel Q355NHD casting blank, which can effectively improve the internal quality of the casting blank and eliminate corner cracks.
The technical scheme adopted by the invention is that the production method of the weathering steel Q355NHD casting blank comprises the following steps:
1) the whole process flow is as follows: pretreatment of molten iron, 120t of converter, LF refining and continuous casting;
2) smelting components, by mass percentage, 0.075-0.095 of C, 0.20-0.30 of Si, 0.95-1.15 of Mn, 0.020 of P, 0.006 of S, 0.26-0.35 of Cu, 0.15-0.25 of Ni, 0.42-0.55 of Cr, 0.020-0.040 of Al, 0.020-0.03 of Ti, and 0.0015-0.004 of Ca; the balance of iron and impurities;
3) pretreatment of molten iron: lime powder or Mg + CaO is added into the steel ladle to carry out mechanical stirring pre-desulfurization treatment, and slag skimming treatment is carried out after desulfurization is finished;
4) when the tapping target time t is more than or equal to 4min, slag must be strictly blocked, and the ladle is tapped to ensure that the thickness of a slag layer is controlled within 50 mm; strictly controlling the reblowing times of the converter, wherein the reblowing times cannot exceed 2 times, and bottom blowing argon in the whole process;
5) refining requirements: the micro-positive pressure in the ladle is ensured in the refining process, the reducing atmosphere and the inert protective atmosphere are ensured, and the refining furnace is required to ensure that the white slag can be tapped for more than 10 minutes;
6) continuous casting process control: the mold flux is special mold flux for weathering steel, the model of the mold flux is determined according to the components, the liquidus temperature: 1524 deg.C; solid phase temperature: 1475 ℃; TD superheat degree of 30 ℃; TD minimum molten steel amount, pouring by changing a tundish: 5 tons, maximum pull rate: 1.2m/min, continuous casting standard of different steel grades: continuous casting is not carried out, and the number of continuous casting furnaces of one tundish is not more than 12;
7) continuous casting slab management: casting blank cooling reference: ordinary air cooling is carried out, and the storage cooling time is longer than 36 hours; casting blank cleaning reference: flame cleaning abnormal blanks, carefully checking by naked eyes, and performing edge part gun pulling, chamfering and peeling process cleaning if necessary to ensure that the plate blanks are free of defects; casting blank internal quality sampling reference: sampling TOP sides of a first plate blank in a first furnace and a second plate blank in a fourth furnace in the same steel type and CAST; and (5) carrying out slab defect sulfur print rating according to the metallurgical standard YB/T4003-1997 on the requirement of the casting blank internal quality.
By adopting the measures, the internal quality of the weathering steel Q355NHD continuous casting billet is greatly improved, and the low-power inspection result of the continuous casting billet shows that corner cracks are basically eliminated, the central shrinkage cavity is 0.5-1.0 grade, and the central porosity is 1.0-1.5 grade.
The method is suitable for the same type of steel rolling enterprises, analyzes the internal quality problem of the weathering steel Q355NHD continuous casting billet caused by the problems of secondary cooling process and continuous casting equipment, adopts the measures of optimizing process and improving equipment, reduces the internal defect rate of the weathering steel Q355NHD continuous casting billet and the steel plate to a lower level, and improves the quality of the weathering steel Q355NHD continuous casting billet and the steel plate.
Detailed Description
A production method of a weathering steel Q355NHD casting blank comprises the following steps:
1) the whole process flow is as follows: pretreatment of molten iron, 120t of converter, LF refining and continuous casting;
2) smelting components, by mass percentage, 0.075-0.095 of C, 0.20-0.30 of Si, 0.95-1.15 of Mn, 0.020 of P, 0.006 of S, 0.26-0.35 of Cu, 0.15-0.25 of Ni, 0.42-0.55 of Cr, 0.020-0.040 of Al, 0.020-0.03 of Ti, and 0.0015-0.004 of Ca; the balance of iron and impurities;
3) pretreatment of molten iron: lime powder or Mg + CaO is added into the steel ladle to carry out mechanical stirring pre-desulfurization treatment, and slag skimming treatment is carried out after desulfurization is finished;
4) when the tapping target time is 8 minutes, strictly blocking slag, tapping in a red ladle, and controlling the thickness of a slag layer within 50 mm; strictly controlling the reblowing times of the converter, wherein the reblowing times cannot exceed 2 times, and bottom blowing argon in the whole process;
5) refining requirements: the micro-positive pressure in the ladle is ensured in the refining process, the reducing atmosphere and the inert protective atmosphere are ensured, and the refining furnace is required to ensure that the white slag can be tapped for more than 10 minutes;
6) continuous casting process control: the mold flux is special mold flux for weathering steel, the model of the mold flux is determined according to the components, the liquidus temperature: 1524 deg.C; solid phase temperature: 1475 ℃; TD superheat degree of 30 ℃; TD minimum molten steel amount, pouring by changing a tundish: 5 tons, pulling speed: 1.1m/min, continuous casting standard of different steel grades: continuous casting is not carried out, and the number of furnaces for continuous casting of one tundish is 6;
7) continuous casting slab management: casting blank cooling reference: ordinary air cooling is carried out, and the storage cooling time is 72 hours; casting blank cleaning reference: flame cleaning abnormal blanks, carefully checking by naked eyes, and performing edge part gun pulling, chamfering and peeling process cleaning if necessary to ensure that the plate blanks are free of defects; casting blank internal quality sampling reference: sampling TOP sides of a first plate blank in a first furnace and a second plate blank in a fourth furnace in the same steel type and CAST; and (3) carrying out slab defect sulfur mark rating according to the metallurgical standard YB/T4003-1997 on the requirement of casting blank internal quality.
Claims (1)
1. A production method of a weathering steel Q355NHD casting blank is characterized by comprising the following steps:
1) the whole process flow is as follows: pretreatment of molten iron, 120t of converter, LF refining and continuous casting;
2) smelting components, the mass percentage content, and the balance of iron and impurities;
C 0.075-0.095、Si 0.20-0.30、Mn 0.95-1.15、P<0.020、S <0.006、Cu 0.26-0.35、Ni 0.15-0.25、Cr 0.42-0.55、Al 0.020-0.040、Ti 0.020-0.03、Ca 0.0015-0.004；
3) pretreatment of molten iron: lime powder or Mg + CaO is added into the steel ladle to carry out mechanical stirring pre-desulfurization treatment, and slag skimming treatment is carried out after desulfurization is finished;
4) when the steel tapping target time t is more than or equal to 4min, slag must be strictly blocked, and steel tapping in a red ladle ensures that the thickness of a slag layer is controlled within 50 mm; strictly controlling the reblowing times of the converter, wherein the reblowing times cannot exceed 2 times, and bottom blowing argon in the whole process;
5) refining requirements: the micro-positive pressure in the ladle is ensured in the refining process, the reducing atmosphere and the inert protective atmosphere are ensured, and the refining furnace is required to ensure that the white slag can be tapped for more than 10 minutes;
6) continuous casting process control: the mold flux is special mold flux for weathering steel, the model of the mold flux is determined according to the components, the liquidus temperature: 1524 deg.C; solid phase temperature: 1475 ℃; TD superheat degree of 30 ℃; TD minimum molten steel amount, pouring by changing a tundish: 5 tons, maximum pull rate: 1.2m/min, continuous casting standard of different steel grades: continuous casting is not carried out, and the number of furnaces for continuous casting of one tundish is not more than 12;
7) continuous casting slab management: casting blank cooling reference: ordinary air cooling is carried out, and the storage cooling time is longer than 36 hours; casting blank cleaning reference: flame cleaning abnormal blanks, carefully checking by naked eyes, and performing edge part gun pulling, chamfering and peeling process cleaning if necessary to ensure that the plate blanks are free of defects; casting blank internal quality sampling reference: sampling TOP sides of a first plate blank in a first furnace and a second plate blank in a fourth furnace in the same steel type and CAST; and (5) carrying out slab defect sulfur print rating according to the metallurgical standard YB/T4003-1997 on the requirement of the casting blank internal quality.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210274060.7A CN114535523A (en) | 2022-03-20 | 2022-03-20 | Production method of weathering resistant steel Q355NHD casting blank |
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| CN202210274060.7A CN114535523A (en) | 2022-03-20 | 2022-03-20 | Production method of weathering resistant steel Q355NHD casting blank |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111363972A (en) * | 2018-12-25 | 2020-07-03 | 新疆八一钢铁股份有限公司 | Production method of weathering resistant steel Q355NHD |
| WO2020215688A1 (en) * | 2019-04-23 | 2020-10-29 | 南京钢铁股份有限公司 | Process for smelting ultra-low-carbon and ultra-low-sulfur steel |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111363972A (en) * | 2018-12-25 | 2020-07-03 | 新疆八一钢铁股份有限公司 | Production method of weathering resistant steel Q355NHD |
| WO2020215688A1 (en) * | 2019-04-23 | 2020-10-29 | 南京钢铁股份有限公司 | Process for smelting ultra-low-carbon and ultra-low-sulfur steel |
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