CN104313470A - Seamless steel tube for rare-earth-containing L485QO submerged pipeline and production method of seamless steel tube - Google Patents
Seamless steel tube for rare-earth-containing L485QO submerged pipeline and production method of seamless steel tube Download PDFInfo
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- CN104313470A CN104313470A CN201410621086.XA CN201410621086A CN104313470A CN 104313470 A CN104313470 A CN 104313470A CN 201410621086 A CN201410621086 A CN 201410621086A CN 104313470 A CN104313470 A CN 104313470A
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Abstract
The invention relates to a seamless steel tube for a rare-earth-containing L485QO submerged pipeline and a production method of the seamless steel tube. The production method comprises the following steps: carrying out pretreatment on blast furnace molten iron so that the S content of the blast furnace molten iron is reduced to below 0.010% in percentage by mass; adding the treated blast furnace molten iron and steel scrap to a top-bottom combined blowing converter for smelting, adopting deoxidation alloy in the steel tapping process for deoxidation alloying, carrying out final deoxidation by adopting an aluminum deoxidation technology, carrying out slag blocking or deslagging in the steel tapping process, adding lime blocks after adding the alloy in the steel tapping process, then adding the smelted molten iron to an LF (Ladle Furnace) for refining, blowing argon during refining, and heating for warming in a manner of gradually accelerating the warming speed; then carrying out slag making, desulfurization, composition adjustment and warming operations; adopting the operation of white slag making, and adding ferrovanadium alloy and ferrotitanium alloy; finally continuously blowing argon gas softly at the bottom, adding rare earth wires, and then carrying out VD (Vacuum Distillation) vacuum treatment, round billet continuous casting, tube blank heating, perforating, continuous rolling, sizing, cooling, saw cutting, heat treatment, straightening, flaw detection and chamfering.
Description
Technical field
The invention belongs to ferrous metal smelting and metal-pressed machine technical field, relate to a kind of containing rare earth high-strength high-ductility L485QO subsea pipeline weldless steel tube and production method thereof.
Background technology
China's Marine oil and gas resource rich reserves, along with the exploitation of offshore oil and gas resource, will grow with each passing day to the demand of Submarine linepipe.Severe ocean environment proposes very high requirement to the quality of Submarine linepipe, by the impact that process of deployment side curvature and subsea current change, requires that Submarine linepipe has high intensity, high toughness and high dimensional precision.In order to realize the long-distance transportation of pipeline, need to adopt high pressure conveying; In order to reduce the laying cost of pipeline and reduce the use of steel, need to adopt Hi-grade steel thin-walled tube; In order to ensure the welding property of line pipe, need to adopt low-carbon-equivalent design mix, and there is contradiction each other in low-carbon-equivalent and high strength.For this reason, JP sends out L485QO subsea pipeline weldless steel tube,
Through retrieval, Chinese invention patent " a kind of steel plate for making subsea pipeline and rolling method thereof " (number of patent application: CN 200710052601.7), this invention, based on the Rolling Production of steel plate, is not suitable for the production of seamless tube, and it exists following problem and shortcoming:
Containing noble element Mo, Ni and Nb, therefore production cost is relatively high, production technique relative complex, production difficulty are relatively large.
Summary of the invention
The object of this invention is to provide that a kind of production cost is low, toughness and tenacity coupling is high, homogeneous microstructure is tiny, unrelieved stress is low containing rare earth L485QO subsea pipeline weldless steel tube and production method thereof.
To achieve these objectives, the present invention's one is containing rare earth L485QO subsea pipeline weldless steel tube, and described weldless steel tube chemical composition by weight percentage content is respectively: C 0.06%-0.12%; Si 0.15%-0.35%; Mn 1.20%-1.50%; P 0%-0.020%; S 0%-0.010%; V 0.03%-0.09%; Ti 0.01%-0.03%; Al 0.01%-0.04%; Rare earth elements RE 0.0005%-0.0100%; Cu 0-0.10%; Surplus is matrix Fe and micro impurity element; Wherein rare earth elements RE component is: the Ce of the 67% and La of 33% makes.
Wherein said containing rare earth L485QO subsea pipeline weldless steel tube, the component comprising following weight part is prepared from:
Blast-melted: 90 parts;
Steel scrap: 10 parts;
Pre-deoxidation alloy: 1.5-2.0 part;
Ferroaluminium: 0.03-0.12 part;
Lime block: 0.2 part;
Ferro-vanadium: 0.06-0.18 part;
Ferro-titanium: 0.04-0.12 part;
Rare-earth wires: 0.02 part;
Silicon-calcium wire: 0.05 part;
Wherein said rare-earth wires by rare earth elements RE component is: the Ce of the 67% and La of 33% makes.
Wherein said pre-deoxidation alloy is selected from the mixture of silicomanganese and manganeseirom arbitrary proportion.
Produce a described method containing rare earth L485QO subsea pipeline weldless steel tube, comprise the steps:
(1) blast-melted pre-treatment: described blast-melted middle S content is reduced to weight percent less than 0.010%;
(2) top and bottom combined blown converter smelting: the blast-melted and described steel scrap after described process is added top and bottom combined blown converter smelting, described pre-deoxidation alloy is adopted to carry out pre-deoxidation alloying in tapping process, final deoxygenation adopts ferroaluminium to carry out there is aluminium deoxidation technique, tapping process carries out pushing off the slag or skims, and adds described lime block after tapping process interalloy adds;
(3) LF stove refining: the molten steel after step (2) being smelted adds the refining of LF stove, blowing argon gas during refining, adopts and counts to the mode heat temperature raising that senior number improves heat-up rate gradually from rudimentary temperature is risen to 1620 DEG C from 1530 DEG C; Employing is made white slag and is operated and add described ferro-vanadium and described ferro-titanium; Finally keep bottom soft blow argon gas, add described rare-earth wires;
(4) VD vacuum-treat: vacuum treated vacuum tightness≤0.10KPa, behind dark vacuum time >=13 minute, feeds described silico-calcium silk, carries out >=8 minutes soft blow argon gas after feeding silk;
(5) round billet continuous casting: adopt the fixed speed control of low pulling rate and induction stirring technique and control molten steel overheat≤30 DEG C and carry out round billet continuous casting: strand goes out the laggard row aligning in cooling twice region, is then cut into circular pipe blank;
(6) heating of pipe blank, perforation, tandem rolling, sizing, cooling, sawing, thermal treatment, aligning, flaw detection, chamfered edge is carried out after, wherein thermal treatment process is: come out of the stove after 900 ± 10 DEG C of insulation 45min and carry out shrend, comes out of the stove and carry out air cooling after 600 ± 20 DEG C of insulation 70min; Steel pipe straightening temperature controls at 520 ~ 530 DEG C.
Wherein said pre-deoxidation alloy is selected from the mixture of silicomanganese and manganeseirom arbitrary proportion.
Wherein said rare-earth wires by rare earth elements RE component is: the Ce of the 67% and La of 33% makes.
The invention difference from existing technology is that the present invention achieves following technique effect:
1. because this product is not containing noble element Mo, Ni and Nb, therefore production cost is relatively low, production difficulty is relatively little;
2. straight owing to carrying out band temperature correction more than 500 DEG C, the unrelieved stress of steel pipe is lower, unrelieved stress :≤25MPa (adopting ring cutting method);
3. because " unique component containing rare earth element designs " is in conjunction with ripe production technique, make the properties of steel pipe excellent, specific performance index is as follows:
Yield strength 500 ~ 560MPa; Tensile strength 610 ~ 690MPa; Yield tensile ratio≤0.85; Unit elongation>=23%; Traverse impact value a when-15 DEG C
kV>=150J/cm
2; Shear than 100%; Grain fineness number>=8.0 grade.
The present invention is directed to Problems existing in background technology, by technical measures such as " unique chemical composition design and be unique production technique of raw material with blast-melted ", solve the problems referred to above well, achieve significant progress.
Embodiment
Below in conjunction with embodiment 1 ~ embodiment 3, to above-mentioned being described in more detail with other technical characteristic and advantage of the present invention.
The whole smelting technology of embodiment 1 ~ embodiment 3, rolling technology and thermal treatment process are identical, and difference is alloy addition and chemical composition, and specific implementation process is as follows:
90 tons of blast-melted use 0.03 ton " metal magnesium powder " is done desulfurization pre-treatment, makes measuring containing S in molten iron be reduced to (weight percent) less than 0.010%;
Described 90 tons of preprocessed molten irons are blended in the top and bottom combined blown converter of 100 tonnes, add 10 tons of high-quality steel scraps again, then single slag technique is adopted to smelt, in finishing slag, the weight percent of calcium oxide and silicon-dioxide controls by 3.0, adopt silicomanganese and ferromanganese to carry out deoxidation alloying, the ferroaluminium adopted when tapping carries out final deoxygenation, the necessary pushing off the slag of tapping process, pushing off the slag unsuccessfully must be skimmed, and adds 0.2 ton of lime block after tapping process interalloy adds;
The molten steel smelted being loaded ladle enter furnaceman LF position and carry out refining: by wanting blowing argon gas (argon flow amount be per minute 100 mark rise) during refining, adopting and counting to the mode heat temperature raising that senior number improves heat-up rate gradually from rudimentary temperature is risen to 1620 DEG C from 1530 DEG C; Slag making desulfurization, composition adjustment and warming temperature is carried out according to converter molten steel composition and temperature; White slag operation is made in employing, adds vanadium iron and ferro-titanium; .
Bottom soft blow argon gas (flow is that per minute 40 marks liter) to be kept after the refining of LF stove terminates, add 0.02 ton of rare-earth wires simultaneously;
Then good to refining molten steel carries out VD vacuum-treat again: dark vacuum tightness≤0.10KPa, dark vacuum time >=13 minute; Feed the silicon-calcium wire of 200 meters long (quality is 0.05 ton) again, after feeding silk, keep 10 minutes soft blow argon gas (flow is that per minute 40 marks liter).
Large for molten steel after VD vacuum-treat bag is hung on ladle turret to carry out 5 machines 5 and flow round billet continuous casting, molten steel overheat Δ T≤30 DEG C; Strand goes out cooling twice region laggard row aligning, is then circular pipe blank with flame cutting.
The concrete alloy addition of embodiment 1 ~ embodiment 3 is in table 1.
Alloy addition (kilogram) in table 1 embodiment 1 ~ embodiment 3
| Silicomanganese | Ferromanganese | Ferro-aluminum | Vanadium iron | Ferrotianium | |
| Embodiment 1 | 600 | 1000 | 130 | 80 | 50 |
| Embodiment 2 | 1000 | 750 | 100 | 120 | 60 |
| Embodiment 3 | 1300 | 600 | 60 | 160 | 90 |
To specification in embodiment 1 ~ embodiment 3 be
pipe sampling carry out chemically examining, checking, its chemical composition result of laboratory test (weight percent content) is in table 2.
Table 2 chemical composition detected result (% by weight)
Described rare earth elements RE is: the norium that the La of the Ce+33% of 67% is formed, its chemical composition and content qualified.
Sufur printing: be all no more than 1.0 grades, macroscopic examination is qualified.
The pipe changed, be up to the standards is carried out tubulation, and tubulation process is as follows:
In order to make pipe have good rolling performance, continuous detecting and controlling each heating zone temperature of process furnace, ensure that heating is thorough evenly and not overheated, the temperature that ring furnace is each section is in table 3.
Table 3 rotary heating furnace each section of temperature controls (DEG C)
| Heat one section | Heat two sections | Heat three sections | Heat four sections | Heat five sections | Heat six sections |
| 1050～1120 | 1150～1250 | 1250～1290 | 1240～1300 | 1240～1300 | 1240～1300 |
Carry out automatically controlling and automatic record to process furnace each section of temperature with microcomputer.
Hot tool must be measured before use, must check, processes roller-way before rolling, and avoids scratching tube wall.
On Ф 460mmPQF Tube Rolling Train, be rolled into the weldless steel tube that specification is ф 355.6mm × 15.50mm after being bored a hole by the pipe heated, often criticize and carry out once heat sampling, check geometrical dimension; Cold bed carries out scale sawing after cooling; The steel pipe of dimensional precision passed examination is heat-treated again: strictly control the furnace temperature of quenching heating furnace, thermal-stable and cooling water flow, ensures quenching quality; The furnace temperature of strict control tempering process furnace and temper resistance.
Heat treating regime is: come out of the stove after 900 ± 10 DEG C of insulation 45min and carry out shrend, comes out of the stove and carry out air cooling after 600 ± 20 DEG C of insulation 70min.
Steel pipe straightening temperature controls at 520 ~ 530 DEG C.
Through above-mentioned explained hereafter and non-destructive test(ing)(NDT) process, namely eligible becomes the finished product of " containing rare earth high-strength high-ductility L485QO subsea pipeline weldless steel tube " of the present invention.Produce sample with it and carry out mechanical properties test.Through inspection, embodiment 1 ~ 3 produce the mechanics properties testing value of seamless steel pipe for line pipe in table 4.
Table 4 mechanical properties of pipe detected result
Note: impact specimen is that laterally test temperature is-15 DEG C.
Above-described embodiment is only be described the preferred embodiment of the present invention; not scope of the present invention is limited; under not departing from the present invention and designing the prerequisite of spirit; the various distortion that those of ordinary skill in the art make technical scheme of the present invention and improvement, all should fall in protection domain that claims of the present invention determines.
Claims (6)
1., containing a rare earth L485QO subsea pipeline weldless steel tube, it is characterized in that: described weldless steel tube chemical composition by weight percentage content is respectively: C 0.06%-0.12%; Si 0.15%-0.35%; Mn 1.20%-1.50%; P0%-0.020%; S0%-0.010%; V 0.03%-0.09%; Ti 0.01%-0.03%; Al 0.01%-0.04%; Rare earth elements RE 0.0005%-0.0100%; Cu0-0.10%; Surplus is matrix Fe and micro impurity element; Wherein rare earth elements RE component is: the Ce of the 67% and La of 33% makes.
2., according to claim 1 containing rare earth L485QO subsea pipeline weldless steel tube, it is characterized in that the component that it comprises following weight part is prepared from:
Blast-melted: 90 parts;
Steel scrap: 10 parts;
Pre-deoxidation alloy: 1.5-2.0 part;
Ferroaluminium: 0.03-0.12 part;
Lime block: 0.2 part;
Ferro-vanadium: 0.06-0.18 part;
Ferro-titanium: 0.04-0.12 part;
Rare-earth wires: 0.02 part;
Silicon-calcium wire: 0.05 part;
Wherein said rare-earth wires by rare earth elements RE component is: the Ce of the 67% and La of 33% makes.
3., according to claim 1 containing rare earth L485QO subsea pipeline weldless steel tube, it is characterized in that described pre-deoxidation alloy is selected from the mixture of silicomanganese and manganeseirom arbitrary proportion.
4. produce the method containing rare earth L485QO subsea pipeline weldless steel tube according to any one of claim 1-3, it is characterized in that comprising the steps:
(1) blast-melted pre-treatment: described blast-melted middle S content is reduced to weight percent less than 0.010%;
(2) top and bottom combined blown converter smelting: the blast-melted and described steel scrap after described process is added top and bottom combined blown converter smelting, described pre-deoxidation alloy is adopted to carry out pre-deoxidation alloying in tapping process, final deoxygenation adopts ferroaluminium to carry out there is aluminium deoxidation technique, tapping process carries out pushing off the slag or skims, and adds described lime block after tapping process interalloy adds;
(3) LF stove refining: the molten steel after step (2) being smelted adds the refining of LF stove, blowing argon gas during refining, adopts and counts to the mode heat temperature raising that senior number improves heat-up rate gradually from rudimentary temperature is risen to 1620 DEG C from 1530 DEG C; Employing is made white slag and is operated and add described ferro-vanadium and described ferro-titanium; Finally keep bottom soft blow argon gas, add described rare-earth wires;
(4) VD vacuum-treat: vacuum treated vacuum tightness≤0.10KPa, behind dark vacuum time >=13 minute, feeds described silico-calcium silk, carries out >=8 minutes soft blow argon gas after feeding silk;
(5) round billet continuous casting: adopt the fixed speed control of low pulling rate and induction stirring technique and control molten steel overheat≤30 DEG C and carry out round billet continuous casting: strand goes out the laggard row aligning in cooling twice region, is then cut into circular pipe blank;
(6) heating of pipe blank, perforation, tandem rolling, sizing, cooling, sawing, thermal treatment, aligning, flaw detection, chamfered edge is carried out after, wherein thermal treatment process is: come out of the stove after 900 ± 10 DEG C of insulation 45min and carry out shrend, comes out of the stove and carry out air cooling after 600 ± 20 DEG C of insulation 70min; Steel pipe straightening temperature controls at 520 ~ 530 DEG C.
5. the production method containing rare earth L485QO subsea pipeline weldless steel tube according to claim 4, is characterized in that: described pre-deoxidation alloy is selected from the mixture of silicomanganese and manganeseirom arbitrary proportion.
6. the production method containing rare earth L485QO subsea pipeline weldless steel tube according to claim 4, is characterized in that: described rare-earth wires by rare earth elements RE component is: the Ce of the 67% and La of 33% makes.
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Cited By (1)
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| CN114855072A (en) * | 2022-03-11 | 2022-08-05 | 包头钢铁（集团）有限责任公司 | Manufacturing method of hot-rolled seamless steel tube for rare earth microalloying machining |
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