CN103131843A - Stabilization continuous annealing process of low-alloy and high-strength steel cold-rolled sheet used for automobile structural components - Google Patents
Stabilization continuous annealing process of low-alloy and high-strength steel cold-rolled sheet used for automobile structural components Download PDFInfo
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- CN103131843A CN103131843A CN2013100002036A CN201310000203A CN103131843A CN 103131843 A CN103131843 A CN 103131843A CN 2013100002036 A CN2013100002036 A CN 2013100002036A CN 201310000203 A CN201310000203 A CN 201310000203A CN 103131843 A CN103131843 A CN 103131843A
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Abstract
The invention relates to a stabilization continuous annealing process of a low-alloy and high-strength steel cold-rolled sheet CR340LA used for automobile structural components and belongs to the technical field of the production process of automobile-used steel. According to the technical scheme, corresponding belt speeds are determined for band steel with different thicknesses. The steps comprises determining the function relationship between thicknesses of the band steel and the corresponding speeds and establishing a mathematical model V=A / T<b>, wherein V represents the continuous annealing belt speeds, T represents the thicknesses of the band steel, A and b are fitting coefficients, and after fitting, A is 160 and b is 0.7; determining the continuous annealing belt speeds of the belt steel with different specifications; and determining corresponding continuous annealing temperatures of the belt steel with different thicknesses. According to the stabilization continuous annealing process of the low-alloy and high-strength steel cold-rolled sheet CR340LA used for the automobile structural components, appropriate annealing temperatures are set and appropriate belt speeds are determined for the steel with different thicknesses, and therefore performance of low-alloy and high-strength steel is enabled to meet requirements of the Chinese standard, mechanical property deviation of all specifications is enabled to be less than 30 MPa, and stability is improved.
Description
Technical field
The present invention relates to a kind of automobile structure with the stabilization continuous annealing process of low-alloy high-strength steel cold-reduced sheet, the particularly automobile structure stabilization continuous annealing process with low-alloy high-strength steel cold-reduced sheet CR340LA, belong to the automobile steel technical field of producing.
Background technology
Automobile structure general requirement steel plate has the characteristics of high strength and high-yield-ratio, also has simultaneously certain forming property.For guaranteeing the stability of client's punching course, must guarantee the stability of its mechanical property.For above characteristics Handan Iron and Steel Co exploitation automobile structure low-alloy high-strength steel CR340LA.The exploitation of CR340LA, by means of adding Nb, Ti alloying element and this steel grade is strengthened, main mechanism has grain refining, precipitation strength.In microalloy element and steel, carbon, nitrogen, oxygen and sulphur form multiple compounds, and low-alloy high-strength steel mainly relies on separating out of Ti, Nb precipitate to reach the effect that improves the strength of materials.Yet for the company of the low-alloy high-strength steel treatment process of bringing down a fever, connect and move back temperature, connect and move back belt speed to the precipitate size, reinforcing degree produces different impacts.(1) basic identical in type and the grain fineness number of different annealing temperatures, annealing speed lower steel plate annealed structure, but the rising of annealing temperature or reduction affect the precipitation strength effect, thus affect the intensity of steel plate; (2) annealing speed all has certain impact to ferrite content, grain size, thereby affects armor plate strength; (3) for each gauge strip steel, connect and move back the heating efficiency difference, cooling power is different, causes the difference of each specification automobile steel product mechanical property.Therefore, in order to obtain uniform low-alloy high-strength steel performance, how according to the belt steel thickness specification, explore desirable annealing temperature and belt speed, become the technical problem that this area needs to be resolved hurrily.
Summary of the invention
The object of the invention is to provide the stabilization continuous annealing process that a kind of automobile structure is used the low-alloy high-strength steel cold-reduced sheet, band steel according to the different thickness specification, temperature, belt speed are moved back by the company that determines correspondence, make each thickness specification low-alloy high-strength steel performance inconsistency less, within yield strength, tensile strength etc. are controlled at 30MPa, solve the problems referred to above that background technology exists.
Technical scheme of the present invention is: a kind of automobile structure stabilization continuous annealing process of low-alloy high-strength steel cold-reduced sheet, and the mass percent of low-alloy high-strength steel chemical composition is: C:0.04%-0.07%; Si≤0.030%; Mn:0.70%～0.90%; S :≤0.012%; P≤0.015%; Ti:0.005%～0.02%; Nb:0.04%～0.05%; All the other are Fe; The slab of mentioned component is heated at 1200～1240 ℃ of temperature, and hot rolling finishing temperature is controlled in 890～910 ℃ of scopes, and batches in 565～595 ℃ of temperature ranges; After hot rolling, the band steel rolls through peracid, is rolled into different thickness; According to the band steel of different thickness specification, determine corresponding belt speed, concrete steps are as follows: at first determine the funtcional relationship of belt steel thickness and belt speed, set up mathematical model; Mathematical model is
, wherein:
Move back belt speed for connecting,
Be belt steel thickness, A, b are fitting coefficient; By match, A is that 160, b is 0.7; Then determine that according to above-mentioned model the company of different size band steel moves back belt speed.
Band steel according to the different thickness specification, temperature is moved back by the company that determines correspondence, the acid of different thickness specification 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 795～805 ℃, by the air-cooled section quenching to 670 of 70m～690 ℃, then be cooled to 470～490 ℃ by fast cold section of 16m after 250m soaking zone insulation; Then carry out ageing treatment by the overaging section of 921m, the completion of prescription temperature is 340～360 ℃.
It is as follows that belt speed is moved back by the company of several typical thickness gauge strip steel:
Thickness 0.8mm belt speed is 190m/min; Thickness 1.0mm belt speed is 160m/min; Thickness 1.2mm belt speed is 140m/min; Thickness 1.5mm belt speed is 120m/min; Thickness 1.8mm belt speed is 105m/min; Thickness 2.0mm belt speed is 100m/min; Thickness 2.5mm belt speed is 85 m/min.Be the stability of guaranteed performance, the company of requirement moves back the belt speed fluctuation range and is ± 10m/min.
Beneficial effect of the present invention: by optimizing the continuous annealing process parameter, formulate suitable continuous annealing process, the CR340LA ferrite crystal grain is tiny, and grain-size is 6-9 μ m, and main precipitate is Nb(C, N); For guaranteeing the stability of mechanical property, mainly considered ferrite grain size and Nb(C, N) precipitate distributes, size is on the impact of performance, in order to obtain stable grain-size and precipitate, move back belt speed by the company that optimizes each thickness specification, make the final stable mechanical property of CR340LA.The present invention not only makes the low-alloy high-strength steel performance satisfy the requirement of GB by suitable annealing temperature being set and each thickness steel grade having been stipulated suitable belt speed, make simultaneously each specification mechanical property deviation less than 30MPa, the stability that has improved.
Embodiment
The present invention will be further described by the following examples.
A kind of automobile structure stabilization continuous annealing process of low-alloy high-strength steel cold-reduced sheet, the mass percent of low-alloy high-strength steel chemical composition is: C:0.04%-0.07%; Si≤0.030%; Mn:0.70%～0.90%; S :≤0.012%; P≤0.015%; Ti:0.005%～0.02%; Nb:0.04%～0.05%; All the other are Fe; The slab of mentioned component is heated at 1200～1240 ℃ of temperature, and hot rolling finishing temperature is controlled in 890～910 ℃ of scopes, and batches in 565～595 ℃ of temperature ranges; After hot rolling, the band steel rolls through peracid, is rolled into different thickness; According to the band steel of different thickness specification, determine corresponding belt speed, concrete steps are as follows: at first determine the funtcional relationship of belt steel thickness and belt speed, set up mathematical model; Mathematical model is
, wherein:
Move back belt speed for connecting,
Be belt steel thickness, A, b are fitting coefficient; By match, A is that 160, b is 0.7; Then determine that according to above-mentioned model the company of different size band steel moves back belt speed.
Embodiment 1, automobile structure low-alloy high-strength steel cold-reduced sheet CR340LA, thickness 1.0mm, width 1250mm.Hot rolling raw thickness 3.2mm, acid rolls into the chill volume of 1.0mm thickness.Connecting that to move back belt speed be 160-170m/min, is the heating zone of 709m through length, will be with the steel ladder degree to be heated to 800-805 ℃, and the band steel is incubated 90s, then is with the steel slow cooling to 675-685 ℃, after be quickly cooled to 475-485 ℃, the completion of prescription temperature is 340～360 ℃.
Embodiment 2, automobile structure low-alloy high-strength steel cold-reduced sheet CR340LA, thickness 1.5mm, width 1000mm and 1250mm.Hot rolling raw thickness 3.8mm, acid rolls into the chill volume of 1.5mm thickness.Even moving back belt speed is 110-125m/min, is the heating zone of 709m through length, will be with the steel ladder degree to be heated to 798-806 ℃, band steel insulation 120s left and right, then be with the steel slow cooling to 674-683 ℃, after be quickly cooled to 472-583 ℃, the completion of prescription temperature is 340～360 ℃.
Embodiment 3, automobile structure low-alloy high-strength steel cold-reduced sheet CR340LA, thickness 2.5mm, width 1000mm and 1500mm.Hot rolling raw thickness 5.2mm, acid rolls into the chill volume of 2.5mm thickness.Connecting that to move back belt speed be 80-89m/min, is the heating zone of 709m through length, will be with the steel ladder degree to be heated to 800-808 ℃, about band steel insulation 170s, then is with the steel slow cooling to 670-687 ℃, after be quickly cooled to 470-490 ℃, the completion of prescription temperature is 340～360 ℃.
Embodiment 4-25 processing parameter is close with embodiment 1-3, lists no longer one by one.
The low-alloy high-strength steel that embodiment 1-25 is rolling, the product mechanical property sees the following form:
| Embodiment | Thickness (mm) | Width (mm) | Yield strength (MPa) | Tensile strength (MPa) | Unit elongation (%) | Yield tensile ratio (%) |
| 1 | 1 | 1250 | 370 | 465 | 27.5 | 80% |
| 2 | 1 | 1250 | 385 | 475 | 26 | 81% |
| 3 | 1.5 | 1000 | 390 | 470 | 31 | 83% |
| 4 | 1.5 | 1000 | 385 | 465 | 31.5 | 83% |
| 5 | 1.5 | 1250 | 370 | 470 | 29 | 79% |
| 6 | 1.5 | 1250 | 370 | 470 | 30 | 79% |
| 7 | 1.5 | 1250 | 380 | 470 | 28 | 81% |
| 8 | 1.5 | 1000 | 385 | 470 | 28 | 82% |
| 9 | 1.5 | 1250 | 385 | 470 | 30 | 82% |
| 10 | 2.5 | 1000 | 370 | 455 | 26 | 81% |
| 11 | 2.5 | 1003 | 365 | 475 | 27.5 | 77% |
| 12 | 2.5 | 1003 | 370 | 480 | 27 | 77% |
| 13 | 2.5 | 1003 | 375 | 475 | 28 | 79% |
| 14 | 2.5 | 1003 | 375 | 480 | 29.5 | 78% |
| 15 | 2.5 | 1003 | 375 | 460 | 27.5 | 82% |
| 16 | 2.5 | 1003 | 380 | 475 | 25.5 | 80% |
| 17 | 2.5 | 1003 | 380 | 480 | 27.5 | 79% |
| 18 | 2.5 | 1003 | 365 | 460 | 29 | 79% |
| 19 | 2.5 | 1003 | 370 | 470 | 26.5 | 79% |
| 20 | 2.5 | 1003 | 390 | 485 | 27.5 | 80% |
| 21 | 2.5 | 1003 | 380 | 465 | 28.5 | 82% |
| 22 | 2.5 | 1003 | 370 | 460 | 28.5 | 80% |
| 23 | 2.5 | 1003 | 380 | 475 | 26 | 80% |
| 24 | 2.5 | 1500 | 365 | 470 | 27 | 78% |
| 25 | 2.5 | 1500 | 370 | 475 | 26 | 78% |
The low-alloy high-strength steel yield strength mean value 376MPa of various embodiments of the present invention, tensile strength mean value 471MPa, unit elongation mean value 28%, yield tensile ratio mean value are 80%.Wherein yield strength fluctuates in 376 ± 15MPa scope, the poor 25MPa of maximum yield strength.The tensile strength fluctuation is in 471 ± 15MPa scope.
The rolling CR340LA microstructure of embodiment is ferrite+perlite, and the ferrite average grain size is 7 μ m.
Claims (4)
1. an automobile structure is with the stabilization continuous annealing process of low-alloy high-strength steel cold-reduced sheet, and it is characterized in that: the mass percent of low-alloy high-strength steel chemical composition is: C:0.04%-0.07%; Si≤0.030%; Mn:0.70%～0.90%; S :≤0.012%; P≤0.015%; Ti:0.005%～0.02%; Nb:0.04%～0.05%; All the other are Fe; The slab of mentioned component is heated at 1200～1240 ℃ of temperature, and hot rolling finishing temperature is controlled in 890～910 ℃ of scopes, and batches in 565～595 ℃ of temperature ranges; After hot rolling, the band steel rolls through peracid, is rolled into different thickness; According to the band steel of different thickness specification, determine corresponding belt speed, concrete steps are as follows: at first determine the funtcional relationship of belt steel thickness and belt speed, set up mathematical model; Mathematical model is
, wherein:
Move back belt speed for connecting,
Be belt steel thickness, A, b are fitting coefficient; By match, A is that 160, b is 0.7; Then determine that according to above-mentioned model the company of different size band steel moves back belt speed.
2. a kind of automobile structure according to claim 1 is with the stabilization continuous annealing process of low-alloy high-strength steel cold-reduced sheet, it is characterized in that the band steel according to the different thickness specification, temperature is moved back by the company that determines correspondence, the acid of different thickness specification 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 795～805 ℃, by the air-cooled section quenching to 670 of 70m～690 ℃, then be cooled to 470～490 ℃ by fast cold section of 16m after 250m soaking zone insulation; Then carry out ageing treatment by the overaging section of 921m, the completion of prescription temperature is 340～360 ℃.
3. a kind of automobile structure according to claim 1 and 2 with the stabilization continuous annealing process of low-alloy high-strength steel cold-reduced sheet, is characterized in that: it is as follows that belt speed is moved back by the company of typical thickness gauge strip steel:
Thickness 0.8mm belt speed is 190m/min; Thickness 1.0mm belt speed is 160m/min; Thickness 1.2mm belt speed is 140m/min; Thickness 1.5mm belt speed is 120m/min; Thickness 1.8mm belt speed is 105m/min; Thickness 2.0mm belt speed is 100m/min; Thickness 2.5mm belt speed is 85 m/min.
4. a kind of automobile structure according to claim 3 with the stabilization continuous annealing process of low-alloy high-strength steel cold-reduced sheet, is characterized in that even moving back the belt speed fluctuation range is ± 10m/min.
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| CN201310000203.6A CN103131843B (en) | 2013-01-02 | 2013-01-02 | Stabilization continuous annealing process of low-alloy and high-strength steel cold-rolled sheet used for automobile structural components |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104152656A (en) * | 2014-08-12 | 2014-11-19 | 首钢京唐钢铁联合有限责任公司 | Control method for stable plate passing of cold-rolled strip steels based on thickness and width specifications |
| 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 |
| CN112962021A (en) * | 2021-01-25 | 2021-06-15 | 唐山钢铁集团有限责任公司 | Strong plastic steel plate for integral hot stamping forming after laser tailor-welding and production method thereof |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104152656A (en) * | 2014-08-12 | 2014-11-19 | 首钢京唐钢铁联合有限责任公司 | Control method for stable plate passing of cold-rolled strip steels based on thickness and width specifications |
| 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 |
| CN112962021A (en) * | 2021-01-25 | 2021-06-15 | 唐山钢铁集团有限责任公司 | Strong plastic steel plate for integral hot stamping forming after laser tailor-welding and production method thereof |
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