低碳铝镇静钢在控轧控冷过程中渗碳体析出机理研究

发布时间：2018-04-25 08:18

  本文选题：低碳铝镇静钢 + 深冲性能　； 参考：《华北理工大学》2015年硕士论文

【摘要】：低碳铝镇静钢作为一种典型的冲压用钢,被广泛用于汽车制造业、建筑工业以及包装业等领域,是冶金行业中产量较高、经济效益较好的产品之一。针对唐山某钢铁公司生产的低碳铝镇静钢在冲压成形过程中发生开裂现象,研究了开裂机制,找到导致冲压开裂的主要因素;通过实验室模拟现场生产,调整工艺参数,控制开裂发生;同时,将最理想的工艺用于现场生产,力求解决钢铁厂生产的产品冲压性能不满足要求的问题。采用杯突试验研究钢板深冲性能不足导致开裂的原因,结果表明,钢板韧性较好,其断口呈韧窝状,但是铁素体晶粒交界处有粗大碳化物析出,微裂纹就是在碳化物处萌生,所以条片状的碳化物是导致钢板开裂的主要原因,钢板裂纹的扩展方向与碳化物析出位置一致。在实验室采用Gleeble试验,调整生产工艺,研究不同工艺条件下渗碳体的析出规律与析出机理,结果表明,终轧温度和温降速度对组织中渗碳体析出规律影响最大,终轧温度的升高,铁素体晶粒有逐步长大的趋势,渗碳体析出量也明显增加。当终轧温度一定时,随着温降的降低,铁素体晶粒基本保持不变,渗碳体析出量增加,并出现网状渗碳体。渗碳体的析出量和析出位置都会影响钢板深冲性能,析出量较少且弥散分布的渗碳体对深冲性能影响较小,以此选择最佳终轧温度850℃,温降速度200℃/min。生产最佳工艺是:出炉温度1250℃,粗轧温度范围1100℃~1050℃,精轧前温度在1010℃±30℃,终轧温度850℃±20℃,卷取温度650℃±10℃。最优工艺应用于现场,结果与试验室研究相吻合,渗碳体呈弥散分布,对深冲性能影响最小。
[Abstract]:Low-carbon Al-killed steel, as a typical punching steel, is widely used in automobile manufacturing, construction industry and packaging industry. It is one of the products with higher output and better economic benefit in metallurgical industry. In view of the cracking of low carbon aluminum killed steel produced by Tangshan Iron and Steel Company during stamping forming, the cracking mechanism was studied, the main factors leading to stamping cracking were found, and the process parameters were adjusted by simulating field production in laboratory. At the same time, the most ideal process is used in the field production to solve the problem that the stamping performance of the products produced in the steel plant does not meet the requirements. The causes of cracking caused by insufficient deep drawing properties of steel plate were investigated by cup bursting test. The results show that the steel plate has good toughness and its fracture surface is dimple, but coarse carbides precipitate at the interface of ferrite grains, and microcracks are initiated at carbides. Therefore, the sheet carbide is the main cause of the cracking of the steel plate, and the propagation direction of the crack is consistent with the location of the carbide precipitation. The cementite precipitation law and mechanism under different technological conditions were studied by adjusting the production process by Gleeble test in laboratory. The results showed that the cementite precipitation law was most affected by the final rolling temperature and the temperature drop rate. With the increase of rolling temperature, the ferrite grain tends to grow gradually and the amount of cementite precipitates increases obviously. With the decrease of the temperature drop, the ferrite grain remains unchanged, the amount of cementite precipitates increases, and the net cementite appears when the rolling temperature is fixed. The amount and location of the cementite will affect the deep drawing performance of steel plate. The cementite with less precipitation and dispersion distribution has little effect on the deep drawing property. The optimum rolling temperature is 850 鈩，

本文编号：1800517