阅读说明：本技术 一种改善冷轧热镀锌高强双相钢边部成形的控制方法 (Control method for improving edge forming of cold-rolled hot-galvanized high-strength dual-phase steel ) 是由 李长胜 周焕能 曾松盛 蒙诗贵 刘学良 肖兵 李翔 于 2020-12-10 设计创作，主要内容包括：本发明公开了一种改善冷轧热镀锌高强双相钢边部成形的控制方法包括以下步骤：S1、满足800MPa级C-Si-Mn-Cr系冷轧热镀锌双相钢成份设计的钢进行脱硫、转炉吹炼、RH真空精炼、连铸得到连铸坯；S2、将连铸坯经常规加热后进行热轧,终轧温度控制在850～950℃；S3、层冷过程中,降低开始层冷冷却速度,控制在50～60℃/s,卷取温度控制在530～650℃；S4、经常规酸洗后进行冷轧,控制冷轧总压下率为50～70％,冷轧板卷厚度为0.5～2.2mm。通过组织工艺降低软硬相之间的硬度差异,同时匹配合适的剪切间隙量和重叠量等参数,可明显改善高强热镀锌双相钢边部冲压成形的生产控制方法。(The invention discloses a control method for improving the edge forming of cold-rolled hot-galvanized high-strength dual-phase steel, which comprises the following steps: s1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet; s2, carrying out hot rolling on the continuous casting billet after conventional heating, wherein the final rolling temperature is controlled to be 850-950 ℃; s3, in the process of layer cooling, reducing the cooling speed of the initial layer cooling, controlling the cooling speed at 50-60 ℃/S, and controlling the coiling temperature at 530-650 ℃; and S4, carrying out cold rolling after conventional pickling, wherein the total rolling reduction rate of the cold rolling is controlled to be 50-70%, and the thickness of the cold rolled sheet coil is 0.5-2.2 mm. The hardness difference between the soft phase and the hard phase is reduced through the organization process, and meanwhile, the production control method for the edge stamping forming of the high-strength hot-dip galvanized dual-phase steel can be obviously improved by matching parameters such as proper shearing clearance amount, overlapping amount and the like.)

1. A control method for improving the edge forming of cold-rolled hot-galvanized high-strength dual-phase steel is characterized by comprising the following steps:

s1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet;

s2, carrying out hot rolling on the continuous casting billet after conventional heating, wherein the final rolling temperature is controlled to be 850-950 ℃;

s3, in the process of layer cooling, reducing the cooling speed of the initial layer cooling, controlling the cooling speed at 50-60 ℃/S, and controlling the coiling temperature at 530-650 ℃;

s4, carrying out cold rolling after conventional pickling, controlling the total rolling reduction rate of the cold rolling to be 50-70%, and controlling the thickness of a cold-rolled sheet coil to be 0.5-2.2 mm;

s5, when annealing is carried out on the continuous galvanizing line, the temperature of strip steel at the tail section of a heating section is controlled to be 790-810 ℃, the temperature base of a heat preservation section is controlled to be 790-810 ℃, the heat preservation time is 60-130S, the temperature of a slow cooling tail section is controlled to be 730-750 ℃, the slow cooling speed is 0.5-1.5 ℃/S, then the strip steel is rapidly cooled to be 450-470 ℃, and the fast cooling speed is 20-45 ℃/S;

s6, when hot dip galvanizing is carried out, the temperature of a zinc pot is 460-462 ℃, the galvanizing time is 2-5S, the galvanized steel plate is cooled to 260-300 ℃ after galvanizing, the cooling speed is 8-20 ℃/S, and finally the galvanized steel plate enters a water quenching tank to be cooled to the room temperature;

s7, after finishing, entering a trimming process, controlling the quantity of the shear blade gap to be 0.2-0.3 mm, controlling the quantity of the shear blade overlap to be-0.9-0.7 mm, controlling the shear blade gap according to the middle lower limit of the range when the annealing temperature and the slow cooling temperature both go to the middle lower limit, controlling the shear blade overlap according to the middle upper limit of the range, and otherwise, controlling the shear blade gap according to the middle upper limit of the range and controlling the shear blade overlap according to the middle lower limit of the range when the annealing temperature and the slow cooling temperature both go to the middle lower limit.

Technical Field

The invention relates to the technical field of cold-rolled hot-galvanized high-strength dual-phase steel edge forming, in particular to a control method for improving the cold-rolled hot-galvanized high-strength dual-phase steel edge forming.

Background

The cold-rolled hot-galvanized dual-phase steel has the characteristics of low yield ratio, high initial work hardening rate, good strength and toughness matching, good baking hardening performance, good collision energy absorption capacity and the like, meets the requirements of light weight, safety, corrosion resistance and the like of automobiles, has more and more application range and usage amount on the automobiles, and simultaneously the competition of the automobile industry is intensified day by day, in order to further improve the profit margin, the stamping process of part of parts is adjusted to be the direct stamping of the original coil edge of the coil stock after the edge cutting of a main engine plant or a supporting company, and the profit margin of the main engine plant or the supporting company can be further enhanced. Because the cold-formed high-strength dual-phase steel is very sensitive to the quality of the edge part during stamping, some of the cold-formed high-strength dual-phase steel cracks in a drawing process and some of the cold-formed high-strength dual-phase steel cracks in flanging and other processes according to the quality of the edge part. Therefore, the edge quality directly affects the edge formability of the material, and has become an object of important control in the production of cold-rolled hot-dip galvanized dual-phase steel. In the research of the press forming of high-strength steel, domestic and foreign scholars have more research on the forming limit, but the research on the cracking of the high-strength steel edge is less, the material often does not reach the limit deformation capability when the high-strength steel edge cracks, the research and analysis can not be carried out by using a common forming limit method, the problem of edge cracking is difficult to obtain effective solution, and the research is one of the main problems of the quality of high-strength steel products.

Application No.: 201210220145.3, patent name: a method for controlling the quality of acid-washing and edge-cutting of high-strength steel. The invention providesThe method for controlling the quality of the acid-washing cut edges of the high-strength steel mainly comprises the following steps: separately aligning the gap H of the circle shear by using a process computer system₁And the overlap amount H₂The obtained set value is calculated and then transmitted to an operation computer system, and the operation computer system adjusts the disc shear transmission device according to the obtained set value and controls the disc shear to shear the high-strength steel. The method provided by the invention can improve the yield strength to be between 380N/mm²To 600N/mm²The edge shearing quality of the high-strength steel product is controlled, and the edge shearing quality control method for reducing abnormal conditions such as knife breakage and the like is adopted, so that the actual production requirement of the high-strength steel product in a cold continuous rolling unit is met.

When cold-rolled hot-galvanized dual-phase steel is produced, according to the existing process control method, irregular shearing marks exist on the edge of the ultra-high-strength dual-phase steel with the pressure of above 800MPa after normal trimming, stress concentration or microcracks usually exist in the shearing mark areas, an obvious secondary bright band can be seen macroscopically, the cold-stamped high-strength dual-phase steel is very sensitive to the quality of the edge, the stress concentration or microcrack areas can become crack sources for original rolled edge stamped parts, and finally 100% cracking of the edge stamping is caused. The hardness of hard phases such as bainite and martensite and ferrite soft phases of the existing materials is greatly different, so that the edges are easy to crack at the joint of phase interfaces when being locally deformed.

The existing edge quality control method for improving the pickling of high-strength steel considers the influence of material thickness and material strength at the same time when a shearing process is determined, but does not consider the influence of material microstructure, and the quality performance of different edges of the microstructure is different in the same strength grade material. Aiming at the defects of the prior art, the invention provides a production control method which can obviously improve the edge stamping forming of the high-strength hot-dip galvanized dual-phase steel by reducing the hardness difference between soft and hard phases through a tissue process and matching appropriate parameters such as shearing clearance amount, overlapping amount and the like.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides a control method for improving the edge forming of cold-rolled hot-galvanized high-strength dual-phase steel.

The invention provides a control method for improving the edge forming of cold-rolled hot-galvanized high-strength dual-phase steel, which comprises the following steps:

s1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet;

s2, carrying out hot rolling on the continuous casting billet after conventional heating, wherein the final rolling temperature is controlled to be 850-950 ℃;

s3, in the process of layer cooling, reducing the cooling speed of the initial layer cooling, controlling the cooling speed at 50-60 ℃/S, and controlling the coiling temperature at 530-650 ℃;

s4, carrying out cold rolling after conventional pickling, controlling the total rolling reduction rate of the cold rolling to be 50-70%, and controlling the thickness of a cold-rolled sheet coil to be 0.5-2.2 mm;

s5, when annealing is carried out on the continuous galvanizing line, the temperature of strip steel at the tail section of a heating section is controlled to be 790-810 ℃, the temperature base of a heat preservation section is controlled to be 790-810 ℃, the heat preservation time is 60-130S, the temperature of a slow cooling tail section is controlled to be 730-750 ℃, the slow cooling speed is 0.5-1.5 ℃/S, then the strip steel is rapidly cooled to be 450-470 ℃, and the fast cooling speed is 20-45 ℃/S;

s6, when hot dip galvanizing is carried out, the temperature of a zinc pot is 460-462 ℃, the galvanizing time is 2-5S, the galvanized steel plate is cooled to 260-300 ℃ after galvanizing, the cooling speed is 8-20 ℃/S, and finally the galvanized steel plate enters a water quenching tank to be cooled to the room temperature;

s7, after finishing, entering a trimming process, controlling the quantity of the shear blade gap to be 0.2-0.3 mm, controlling the quantity of the shear blade overlap to be-0.9-0.7 mm, controlling the shear blade gap according to the middle lower limit of the range when the annealing temperature and the slow cooling temperature both go to the middle lower limit, controlling the shear blade overlap according to the middle upper limit of the range, and otherwise, controlling the shear blade gap according to the middle upper limit of the range and controlling the shear blade overlap according to the middle lower limit of the range when the annealing temperature and the slow cooling temperature both go to the middle lower limit.

The invention has the beneficial effects that:

1. after heating and finish rolling of the continuous casting billet, in the layer cooling process, reducing the cooling speed of the initial layer cooling, controlling the cooling speed at 50-60 ℃/s, and controlling the coiling temperature at 530-650 ℃;

2. controlling the total cold rolling reduction rate to be 50-70% in the cold rolling process;

3. when the continuous galvanizing line is annealed, the temperature of strip steel at the tail section of a heating section is controlled to be 790-810 ℃, the temperature base of a heat preservation section is controlled to be 790-810 ℃, the heat preservation time is 60-130 s, the temperature of a slow cooling tail section is controlled to be 730-750 ℃, the slow cooling speed is 0.5-1.5 ℃/s, then the strip steel is rapidly cooled to be 450-470 ℃, and the fast cooling speed is 20-45 ℃/s;

4. and after finishing, entering a trimming process, controlling the clearance of the shear blade to be 0.2-0.3 mm, controlling the overlapping amount of the shear blade to be-0.9-0.7 mm, controlling the clearance of the shear blade according to the middle lower limit of the range and controlling the overlapping amount of the shear blade according to the middle upper limit of the range when the annealing temperature and the slow cooling temperature both reach the middle upper limit, and controlling the clearance of the shear blade according to the middle upper limit of the range and controlling the overlapping amount of the shear blade according to the middle lower limit of the range when the annealing temperature and the slow cooling temperature both reach the middle lower limit.

The invention reduces the hardness difference between the soft phase and the hard phase through the organization process, and simultaneously matches with the parameters such as proper shearing clearance amount, overlapping amount and the like, thereby obviously improving the production control method for the edge part stamping forming of the high-strength hot-dip galvanized dual-phase steel.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples.

Example one

The embodiment provides a control method for improving the edge forming of cold-rolled hot-galvanized high-strength dual-phase steel, which comprises the following steps:

s1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet;

s2, carrying out hot rolling on the continuous casting billet after conventional heating, and controlling the final rolling temperature to be 880 ℃;

s3, in the process of layer cooling, reducing the cooling speed of the starting layer, controlling the cooling speed at 57 ℃/S and the coiling temperature at 560 ℃;

s4, carrying out cold rolling after conventional pickling, controlling the total rolling reduction rate of the cold rolling to be 50-70%, and controlling the thickness of a cold-rolled sheet coil to be 0.5-2.2 mm;

s5, when annealing is carried out on the continuous galvanizing line, the temperature of the strip steel at the tail section of the heating section is controlled to be 800 ℃, the temperature base of the heat preservation section is controlled to be 795 ℃, the heat preservation time is 60-130S, the temperature of the slow cooling tail section is controlled to be 735 ℃, the slow cooling speed is 1 ℃/S, then the strip steel is rapidly cooled to 460 ℃, and the fast cooling speed is 25 ℃/S;

s6, when hot dip galvanizing is carried out, the temperature of a zinc pot is 460-462 ℃, the galvanizing time is 2-5S, the galvanized steel plate is cooled to 260-300 ℃ after galvanizing, the cooling speed is 8-20 ℃/S, and finally the galvanized steel plate enters a water quenching tank to be cooled to the room temperature;

and S7, finishing, and then entering a trimming process, wherein the control of the clearance of the shear blade is controlled to be 0.28mm, the control of the overlap of the shear blade is controlled to be-0.8 mm, the annealing temperature and the slow cooling temperature are both in the middle upper limit, the clearance of the shear blade is controlled according to the middle lower limit of the range, and the overlap of the shear blade is controlled according to the middle upper limit of the range, otherwise, when the annealing temperature and the slow cooling temperature are both in the middle lower limit, the clearance of the shear blade is controlled according to the middle upper limit of the range, and the overlap of the shear blade.

Example two

S1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet;

s2, carrying out hot rolling on the continuous casting billet after conventional heating, wherein the finish rolling temperature is controlled at 890 ℃;

s3, in the process of layer cooling, reducing the cooling speed of the starting layer, controlling the cooling speed at 55 ℃/S and the coiling temperature at 590 ℃;

s4, carrying out cold rolling after conventional pickling, controlling the total rolling reduction rate of the cold rolling to be 50-70%, and controlling the thickness of a cold-rolled sheet coil to be 0.5-2.2 mm;

s5, when annealing is carried out on the continuous galvanizing line, the temperature of strip steel at the tail section of the heating section is controlled to be 805 ℃, the temperature base of the heat preservation section is controlled to be 800 ℃, the heat preservation time is 60-130S, the temperature of the slow cooling tail section is controlled to be 745 ℃, the slow cooling speed is 0.6 ℃/S, then the strip steel is rapidly cooled to 455 ℃, and the fast cooling speed is 40 ℃/S;

s6, when hot dip galvanizing is carried out, the temperature of a zinc pot is 460-462 ℃, the galvanizing time is 2-5S, the galvanized steel plate is cooled to 260-300 ℃ after galvanizing, the cooling speed is 8-20 ℃/S, and finally the galvanized steel plate enters a water quenching tank to be cooled to the room temperature;

and S7, finishing, and then entering a trimming process, wherein the control of the clearance of the shear blade is controlled to be 0.23mm, the control of the overlap of the shear blade is controlled to be-0.75 mm, the annealing temperature and the slow cooling temperature are both in the middle upper limit, the clearance of the shear blade is controlled according to the middle lower limit of the range, and the overlap of the shear blade is controlled according to the middle upper limit of the range, otherwise, when the annealing temperature and the slow cooling temperature are both in the middle lower limit, the clearance of the shear blade is controlled according to the middle upper limit of the range, and the overlap of the shear blade.

EXAMPLE III

S1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet;

s2, carrying out hot rolling on the continuous casting billet after conventional heating, wherein the finish rolling temperature is controlled at 920 ℃;

s3, in the process of layer cooling, reducing the cooling speed of the starting layer, controlling the cooling speed at 53 ℃/S and the coiling temperature at 580 ℃;

s4, carrying out cold rolling after conventional pickling, controlling the total rolling reduction rate of the cold rolling to be 50-70%, and controlling the thickness of a cold-rolled sheet coil to be 0.5-2.2 mm;

s5, when annealing is carried out on the continuous galvanizing line, controlling the temperature of the strip steel at the tail section of the heating section to be 795 ℃, controlling the temperature base of the heat preservation section to be 790 ℃, keeping the temperature for 60-130S, controlling the temperature at the slow cooling tail section to be 740 ℃, controlling the slow cooling speed to be 0.9 ℃/S, then rapidly cooling to 470 ℃, and controlling the fast cooling speed to be 30 ℃/S;

s6, when hot dip galvanizing is carried out, the temperature of a zinc pot is 460-462 ℃, the galvanizing time is 2-5S, the galvanized steel plate is cooled to 260-300 ℃ after galvanizing, the cooling speed is 8-20 ℃/S, and finally the galvanized steel plate enters a water quenching tank to be cooled to the room temperature;

and S7, finishing, and then entering a trimming process, wherein the control of the clearance of the shear blade is controlled to be 0.28mm, the control of the overlap of the shear blade is controlled to be-0.85 mm, the annealing temperature and the slow cooling temperature are both in the middle upper limit, the clearance of the shear blade is controlled according to the middle lower limit of the range, and the overlap of the shear blade is controlled according to the middle upper limit of the range, otherwise, when the annealing temperature and the slow cooling temperature are both in the middle lower limit, the clearance of the shear blade is controlled according to the middle upper limit of the range, and the overlap of the shear blade.

Comparative example 1

S1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet;

s2, performing hot rolling on the continuous casting billet after conventional heating, wherein the finish rolling temperature is controlled at 960 ℃;

s3, in the process of layer cooling, reducing the cooling speed of the starting layer, controlling the cooling speed at 72 ℃/S and the coiling temperature at 540 ℃;

s4, carrying out cold rolling after conventional pickling, controlling the total rolling reduction rate of the cold rolling to be 50-70%, and controlling the thickness of a cold-rolled sheet coil to be 0.5-2.2 mm;

s5, when annealing is carried out on the continuous galvanizing line, the temperature of band steel at the tail section of a heating section is controlled to be 785 ℃, the temperature base of a heat preservation section is controlled to be 780 ℃, the heat preservation time is 60-130S, the temperature of a slow cooling tail section is controlled to be 720 ℃, the slow cooling speed is 0.9 ℃/S, then the band steel is rapidly cooled to 470 ℃, and the fast cooling speed is 18 ℃/S;

s6, when hot dip galvanizing is carried out, the temperature of a zinc pot is 460-462 ℃, the galvanizing time is 2-5S, the galvanized steel plate is cooled to 260-300 ℃ after galvanizing, the cooling speed is 8-20 ℃/S, and finally the galvanized steel plate enters a water quenching tank to be cooled to the room temperature;

and S7, finishing, and then entering a trimming process, wherein the control of the clearance of the shear blade is controlled to be 0.31mm, the control of the overlap of the shear blade is controlled to be-0.95 mm, the annealing temperature and the slow cooling temperature are both in the middle upper limit, the clearance of the shear blade is controlled according to the middle lower limit of the range, and the overlap of the shear blade is controlled according to the middle upper limit of the range, otherwise, when the annealing temperature and the slow cooling temperature are both in the middle lower limit, the clearance of the shear blade is controlled according to the middle upper limit of the range, and the overlap of the shear blade.

Comparative example No. two

S1, desulfurizing, converter blowing, RH vacuum refining and continuously casting steel meeting the component design of 800 MPa-level C-Si-Mn-Cr series cold-rolled hot-galvanized dual-phase steel to obtain a continuous casting billet;

s2, carrying out hot rolling on the continuous casting billet after conventional heating, wherein the finish rolling temperature is controlled at 970 ℃;

s3, in the process of layer cooling, reducing the cooling speed of the starting layer, controlling the cooling speed at 78 ℃/S and the coiling temperature at 530 ℃;

s4, carrying out cold rolling after conventional pickling, controlling the total rolling reduction rate of the cold rolling to be 50-70%, and controlling the thickness of a cold-rolled sheet coil to be 0.5-2.2 mm;

s5, when annealing is carried out on the continuous galvanizing line, controlling the temperature of band steel at the tail section of a heating section to 775 ℃, controlling the temperature base of a heat preservation section to 785 ℃, keeping the temperature for 60-130S, controlling the temperature at the slow cooling tail section to 725 ℃, controlling the slow cooling speed to 0.9 ℃/S, then rapidly cooling to 470 ℃, and controlling the fast cooling speed to 15 ℃/S;

s6, when hot dip galvanizing is carried out, the temperature of a zinc pot is 460-462 ℃, the galvanizing time is 2-5S, the galvanized steel plate is cooled to 260-300 ℃ after galvanizing, the cooling speed is 8-20 ℃/S, and finally the galvanized steel plate enters a water quenching tank to be cooled to the room temperature;

and S7, finishing, and then entering a trimming process, wherein the control of the clearance of the shear blade is controlled to be 0.32mm, the control of the overlap of the shear blade is controlled to be-0.97 mm, the annealing temperature and the slow cooling temperature are both in the middle upper limit, the clearance of the shear blade is controlled according to the middle lower limit of the range, and the overlap of the shear blade is controlled according to the middle upper limit of the range, otherwise, when the annealing temperature and the slow cooling temperature are both in the middle lower limit, the clearance of the shear blade is controlled according to the middle upper limit of the range, and the overlap of the shear blade.

TABLE 1 Main Hot Rolling Process parameters of the examples

Examples	Final Rolling temperature/. degree.C	Initial layer Cooling Rate/(° C/s)	Coiling temperature/. degree.C
				1	880	57	560
2	890	55	590
				3	920	53	580
Comparative example 1	960	72	540
				Comparative example 2	970	78	530

TABLE 2 Cold Rolling annealing and shearing Process parameters for the examples

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.