CN103088255A - Manufacturing process of automobile low-alloy high-strength steel cold-rolled sheet with high product of strength and elongation - Google Patents
Manufacturing process of automobile low-alloy high-strength steel cold-rolled sheet with high product of strength and elongation Download PDFInfo
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Abstract
The invention relates to a manufacturing process of an automobile low-alloy high-strength steel cold-rolled sheet with high product of strength and elongation, and belongs to the technical field of metallurgy. The technical scheme of the invention is as follows: the manufacturing process comprises a smelting process, a hot rolling process and a cold rolling process, wherein in the cold rolling process, the annealing temperature control is as follows: the soaking temperature is 840-860 DEG C, the slow cooling temperature is 670-700 DEG C, the rapid cooling temperature is 410-430 DEG C, and the aging finish temperature is 350-370 DEG C; and according to strip steel of different thickness specifications, different annealing tape speed target values are planed: the tape speed of the strip steel of 0.8mm specification is 205m/min, the tape speed of the strip steel of 1.0mm specification is 165m/min, the tape speed of the strip steel of 1.2mm specification is 137m/min, the tape speed of the strip steel of 1.5mm specification is 110m/min, the tape speed of the strip steel of 1.8mm specification is 92m/min, the tape speed of the strip steel of 2.0mm specification is 82m/min, and the tape speed of the strip steel of 2.5mm specification is 66m/min. The manufacturing process of the automobile low-alloy high-strength steel cold-rolled sheet with the high product of strength and elongation disclosed by the invention has the beneficial effects that the low-alloy high-strength steel cold-rolled sheet with high product of strength and elongation is produced by modifying the chemical elements and optimizing the hot rolling and cold rolling processes so that the product of strength and elongation of the low-alloy high-strength steel cold-rolled sheet reach 15GPa%, and simultaneously the quality is stably controlled.
Description
Technical field
The present invention relates to a kind of automobile with the production technique of the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, belong to metallurgical technology field.
Background technology
Along with the development of automobile industry, the kind of domestic low and middle-grade cars, commercial truck and output are more and more.For above-mentioned automobile, due to its cost restriction, the parts that its structural part, stiffener equal strength are had relatively high expectations seldom adopt the steel grades such as advanced high-strength steel DP, TRIP, mainly adopt the low-alloy high-strength steel cold-reduced sheet.Yet general low-alloy high-strength steel strength and ductility product only has the 12GPa% left and right, when intensity is brought up to 500MPa when above, unit elongation is very low, when producing the structural part that is shaped complicated a little, the mechanical property surplus capacity is very low, can not satisfy the special requirement of low and middle-grade cars, commercial truck, therefore be necessary to study a kind of low-alloy high-strength steel of high strength and ductility.
Summary of the invention
The object of the invention is to provide the production technique that a kind of automobile is used the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, by chemical composition is modified, optimize hot rolling, cold-rolling process, produce the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, make simultaneously steady quality control, solve the problems referred to above that background technology exists.
Technical scheme of the present invention is: a kind of automobile comprises smelting, hot rolling, cold rolling process with the production technique of the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, and low-alloy high-strength steel adopts the mass percent of chemical composition to be: C:0.05%-0.08%; Si:0.25%～0.35%; Mn:0.85%～0.95%; S≤0.008%; P≤0.015%; Ti:0.005%～0.02%; Nb:0.04%～0.05%; All the other are Fe; In described cold rolling process, even move back temperature and control as follows: soaking temperature: 840～860 ℃; Slow cooling temperature: 670～700 ℃; Fast cold temperature: 410～430 ℃; Completion of prescription temperature: 350～370 ℃; Band steel according to the thickness different size, formulated different companies and moved back the belt speed target value: specification 0.8mm belt speed is 205m/min, specification 1.0mm belt speed is 165m/min, specification 1.2mm belt speed is 137m/min, specification 1.5mm belt speed is 110m/min, specification 1.8mm belt speed is 92m/min, and specification 2.0mm belt speed is 82m/min, and specification 2.5mm belt speed is 66 m/min.
Be the stability of guaranteed performance, the company of requirement moves back the belt speed fluctuation range and is ± 10m/min.
Described smelting procedure except obtaining aforesaid chemical composition, also needs to make molten steel pure, comprises the following steps:
(1) the blowing pattern that top rifle oxygen blast, omnidistance furnace bottom blowing argon gas stir is adopted in converter, and converting process adds the slag materials such as lime, the full range slag, and basicity of slag is controlled at 4.0～4.5; Blow off is controlled target: [C]≤0.05%, [P]＜0.007%, [S]≤0.025%, [N]≤20ppm;
(2) dual pushing off the slag technique before and after converter tapping adopts is controlled ratio that tapping process flows into slag amount and molten steel amount in ladle less than 0.8%, mass ratio;
(3) add lime, magnalium calcium iron to carry out slag making deoxidation, desulfurization operations in LF stove refining process, require the slag making target: in slag, FeO+MnO mass percent content is less than 1.0%; The ratio of refining process argon bottom-blowing flow and molten steel amount is 0.3～1.8Nl/ (min.t), keeps pressure-fired in stove; Add ferro-niobium, ferrotianium, electrolytic manganese that molten steel composition is adjusted;
(4) LF calcium is processed, and after calcium is processed, the clean blowing argon gas churning time of molten steel is 5～12 minutes, and the ratio of clean blowing argon gas flow and molten steel amount is controlled at 0.1～1.0Nl/ (min.t).After calcium is processed, liquid steel temperature is liquidus temperature+30～50 ℃;
(5) LF processes to end and requires: [S]≤0.008%, [Als]=400～450ppm in molten steel composition, and the content of carbon, silicon, manganese, phosphorus, niobium, titanium satisfies the Composition Design requirement;
(6) cast follows that high temperature is poured into a mould at a slow speed, the principle of low temperature Quick pouring, and the pouring molten steel temperature is liquidus temperature+15-30 ℃; Annotate speed control scope 0.9～1.4 m/min processed.
Described steel rolling process heats the slab of aforementioned composition at 1200～1240 ℃ of temperature, hot rolling finishing temperature is controlled in 840～860 ℃ of scopes, and batches in 540～570 ℃ of temperature ranges; After hot rolling, the band steel rolls through peracid, is rolled into the thickness that needs; Follow the difference according to the thickness specification, acid is rolled and is moved back belt speed with steel with different companies and connect by 709m and move back stove afterwards, by complete radiator tube gradient-heated to 840～860 ℃, by the air-cooled section quenching to 670 of 70m～700 ℃, then be cooled to 410～430 ℃ by fast cold section of 16m after the insulation of 250m soaking zone; Then carry out ageing treatment by the overaging section of 921m, the completion of prescription temperature is 350～370 ℃.
Beneficial effect of the present invention: by chemical composition is modified, optimize hot rolling, cold-rolling process, produce the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, make this low-alloy high-strength steel cold-reduced sheet strength and ductility product reach 15GPa%, make simultaneously steady quality control.
Embodiment
The present invention will be further described by the following examples.
A kind of automobile comprises smelting, hot rolling, cold rolling process with the production technique of the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, and low-alloy high-strength steel adopts the mass percent of chemical composition to be: C:0.05%-0.08%; Si:0.25%～0.35%; Mn:0.85%～0.95%; S≤0.008%; P≤0.015%; Ti:0.005%～0.02%; Nb:0.04%～0.05%; All the other are Fe.
Described smelting procedure except obtaining aforesaid chemical composition, also needs to make molten steel pure, comprises the following steps:
(1) the blowing pattern that top rifle oxygen blast, omnidistance furnace bottom blowing argon gas stir is adopted in converter, and converting process adds the slag materials such as lime, the full range slag, and basicity of slag is controlled at 4.0～4.5; Blow off is controlled target: [C]≤0.05%, [P]＜0.007%, [S]≤0.025%, [N]≤20ppm;
(2) dual pushing off the slag technique before and after converter tapping adopts is controlled ratio that tapping process flows into slag amount and molten steel amount in ladle less than 0.8%, mass ratio.
(3) add lime, magnalium calcium iron to carry out slag making deoxidation, desulfurization operations in LF stove refining process, require the slag making target: in slag, FeO+MnO mass percent content is less than 1.0%; The ratio of refining process argon bottom-blowing flow and molten steel amount is 0.3～1.8Nl/ (min.t), keeps pressure-fired in stove; Add ferro-niobium, ferrotianium, electrolytic manganese that molten steel composition is adjusted;
(4) LF calcium is processed, and after calcium is processed, the clean blowing argon gas churning time of molten steel is 5～12 minutes, and the ratio of clean blowing argon gas flow and molten steel amount is controlled at 0.1～1.0Nl/ (min.t); After calcium is processed, liquid steel temperature is liquidus temperature+30～50 ℃;
(5) LF processes to end and requires: [S]≤0.008%, [Als]=400～450ppm in molten steel composition, and the content of carbon, silicon, manganese, phosphorus, niobium, titanium satisfies the Composition Design requirement;
(6) cast follows that high temperature is poured into a mould at a slow speed, the principle of low temperature Quick pouring, and the pouring molten steel temperature is liquidus temperature+15-30 ℃; Annotate speed control scope 0.9～1.4 m/min processed.
Described steel rolling process heats the slab of aforementioned composition at 1200～1240 ℃ of temperature, hot rolling finishing temperature is controlled in 840～860 ℃ of scopes, and batches in 540～570 ℃ of temperature ranges; After hot rolling, the band steel rolls through peracid, is rolled into the thickness that needs; Follow the difference according to the thickness specification, acid is rolled and is moved back belt speed with steel with different companies and connect by 709m and move back stove afterwards, by complete radiator tube gradient-heated to 840～860 ℃, by the air-cooled section quenching to 670 of 70m～700 ℃, then be cooled to 410～430 ℃ by fast cold section of 16m after the insulation of 250m soaking zone; Then carry out ageing treatment by the overaging section of 921m, the completion of prescription temperature is 350～370 ℃.
Connect and move back in stove, different thickness gauge strip steel heating efficiency is different, and desired belt speed is also different.According to Gleeble3500 thermal simulation experiment result and actual industrial trial-production situation, band steel according to the width different size, formulated different companies and moved back the belt speed target value: the 0.8mm belt speed is 205m/min, 1.0mm belt speed is 165m/min, 1.2mm belt speed is 137m/min, the 1.5mm belt speed is 110m/min, and the 1.8mm belt speed is 92m/min, 2.0mm belt speed is 82m/min, the 2.5mm belt speed is 66 m/min.Be the stability of guaranteed performance, the company of requirement moves back the belt speed fluctuation range and is ± 10m/min.
The below is the chemical component table of three embodiment of the present invention, hot rolling, cold-rolling process table, mechanical property table.
(1) the low-alloy high-strength steel cold-reduced sheet chemical composition of the embodiment of the present invention sees Table 1.
The actual chemical composition of table 1 low-alloy high-strength steel cold-reduced sheet (Wt%)
| ? | C | Si | Mn | P | S | Ti | Nb |
| Embodiment 1 | 0.067 | 0.30 | 0.91 | 0.014 | 0.002 | 0.012 | 0.045 |
| Embodiment 2 | 0.067 | 0.30 | 0.91 | 0.014 | 0.002 | 0.012 | 0.045 |
| Embodiment 3 | 0.070 | 0.28 | 0.89 | 0.012 | 0.003 | 0.013 | 0.043 |
(2) low-alloy high-strength steel cold-reduced sheet of the present invention hot rolling, cold-rolling process see Table 2.
The actual hot rolling of table 2 low-alloy high-strength steel cold-reduced sheet, cold-rolling process
| Reel number | Heating temperature ℃ | Finishing temperature ℃ | Coiling temperature ℃ | Cold rolling thickness mm | Connect and to move back Heating temperature ℃ | Slow cooling temperature ℃ | Fast cold temperature ℃ | Connect and move back belt speed m/min |
| Embodiment 1 | 1224 | 864 | 548 | 1.0 | 850 | 690 | 420 | 159 |
| Embodiment 2 | 1224 | 860 | 563 | 2.0 | 860 | 700 | 425 | 83 |
| Embodiment 3 | 1223 | 846 | 562 | 2.5 | 847 | 669 | 420 | 65 |
(3) product mechanical property
According to the rolling technique rolling low-alloy high-strength steel mechanical property such as table 3.
Table 3 low-alloy high-strength steel mechanical property
| Example | Thickness (mm) | Yield strength (MPa) | Tensile strength (MPa) | Unit elongation A 80mm（%） | Strength and ductility product GPa% |
| Embodiment 1 | 1.0 | 395 | 505 | 29 | 14.6 |
| Embodiment 2 | 2.0 | 410 | 495 | 30 | 14.9 |
| Embodiment 3 | 2.5 | 405 | 505 | 30 | 15.2 |
Tensile strength average of the present invention is 502MPa, and the unit elongation average is 30%, and strength and ductility product mean value reaches 15 GPa%.
Claims (4)
1. an automobile is with the production technique of the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, and it is characterized in that: comprise smelting, hot rolling, cold rolling process, low-alloy high-strength steel adopts the mass percent of chemical composition to be: C:0.05%-0.08%; Si:0.25%～0.35%; Mn:0.85%～0.95%; S≤0.008%; P≤0.015%; Ti:0.005%～0.02%; Nb:0.04%～0.05%; All the other are Fe; In described cold rolling process, even move back temperature and control as follows: soaking temperature: 840～860 ℃; Slow cooling temperature: 670～700 ℃; Fast cold temperature: 410～430 ℃; Completion of prescription temperature: 350～370 ℃; Band steel according to the thickness different size, formulated different companies and moved back the belt speed target value: specification 0.8mm belt speed is 205m/min, specification 1.0mm belt speed is 165m/min, specification 1.2mm belt speed is 137m/min, specification 1.5mm belt speed is 110m/min, specification 1.8mm belt speed is 92m/min, and specification 2.0mm belt speed is 82m/min, and specification 2.5mm belt speed is 66 m/min.
2. a kind of automobile according to claim 1 with the production technique of the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, is characterized in that even moving back the belt speed fluctuation range is ± 10m/min.
3. a kind of automobile according to claim 1 and 2 with the production technique of the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, is characterized in that described smelting procedure, except obtaining aforesaid chemical composition, also needs to make molten steel pure, comprises the following steps:
(1) the blowing pattern that top rifle oxygen blast, omnidistance furnace bottom blowing argon gas stir is adopted in converter, and converting process adds the slag materials such as lime, the full range slag, and basicity of slag is controlled at 4.0～4.5; Blow off is controlled target: [C]≤0.05%, [P]＜0.007%, [S]≤0.025%, [N]≤20ppm;
(2) dual pushing off the slag technique before and after converter tapping adopts is controlled ratio that tapping process flows into slag amount and molten steel amount in ladle less than 0.8%, mass ratio;
(3) add lime, magnalium calcium iron to carry out slag making deoxidation, desulfurization operations in LF stove refining process, require the slag making target: in slag, FeO+MnO mass percent content is less than 1.0%; The ratio of refining process argon bottom-blowing flow and molten steel amount is 0.3～1.8Nl/ (min.t), keeps pressure-fired in stove; Add ferro-niobium, ferrotianium, electrolytic manganese that molten steel composition is adjusted;
(4) LF calcium is processed, and after calcium is processed, the clean blowing argon gas churning time of molten steel is 5～12 minutes, and the ratio of clean blowing argon gas flow and molten steel amount is controlled at 0.1～1.0Nl/ (min.t); After calcium is processed, liquid steel temperature is liquidus temperature+30～50 ℃;
(5) LF processes to end and requires: [S]≤0.008%, [Als]=400～450ppm in molten steel composition, and the content of carbon, silicon, manganese, phosphorus, niobium, titanium satisfies the Composition Design requirement;
(6) cast follows that high temperature is poured into a mould at a slow speed, the principle of low temperature Quick pouring, and the pouring molten steel temperature is liquidus temperature+15-30 ℃; Annotate speed control scope 0.9～1.4 m/min processed.
4. a kind of automobile according to claim 1 and 2 is with the production technique of the low-alloy high-strength steel cold-reduced sheet of high strength and ductility, it is characterized in that described steel rolling process, the slab of aforementioned composition is heated at 1200～1240 ℃ of temperature, hot rolling finishing temperature is controlled in 840～860 ℃ of scopes, and batches in 540～570 ℃ of temperature ranges; After hot rolling, the band steel rolls through peracid, is rolled into the thickness that needs; Follow the difference according to the thickness specification, acid is rolled and is moved back belt speed with steel with different companies and connect by 709m and move back stove afterwards, by complete radiator tube gradient-heated to 840～860 ℃, by the air-cooled section quenching to 670 of 70m～700 ℃, then be cooled to 410～430 ℃ by fast cold section of 16m after the insulation of 250m soaking zone; Then carry out ageing treatment by the overaging section of 921m, the completion of prescription temperature is 350～370 ℃.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106929632A (en) * | 2017-01-17 | 2017-07-07 | 唐山钢铁集团有限责任公司 | The method that the low-carbon low-silicon cold rolled steel of LF refining SPHC improves silicon hit rate |
| CN109338061A (en) * | 2018-11-09 | 2019-02-15 | 唐山钢铁集团有限责任公司 | A kind of production method of high corrosion-resistant continuous annealing low-alloy high-strength steel band |
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| CN109338061A (en) * | 2018-11-09 | 2019-02-15 | 唐山钢铁集团有限责任公司 | A kind of production method of high corrosion-resistant continuous annealing low-alloy high-strength steel band |
| CN109338061B (en) * | 2018-11-09 | 2020-05-01 | 唐山钢铁集团有限责任公司 | Production method of high-corrosion-resistance continuous annealing low-alloy high-strength steel strip |
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