温度制度对帘线钢72A表面质量及微观组织的影响

Effect of thermal processing on surface quality and microstructure of LX72A tire cord steel

采用正交实验模拟了不同加热制度下的LX72A钢的表面脱碳实验,结合光学显微观察测定脱碳层深度,研究了预热温度、预热时间、均热温度和均热时间对LX72A钢表面脱碳的影响。在Gleeble-3500热模拟试验机上模拟分析了不同变形温度和吐丝温度对LX72A钢的组织性能影响。结果表明,均热温度对表面脱碳的影响远大于其他因素。变形温度愈高,索氏体化率越高,片层间距愈小,硬度增加。提高吐丝温度有利于索氏体化率的增高以及片层间距的减小,但是当超过900℃,生成了强度更高的屈氏体。

Surface decarburization of LX72 A steel under different heating conditions was simulated by orthogonal test. The effects of preheating temperature,preheating time,soaking temperature and soaking time on surface decarburization of the LX72 A steel were studied via the measurement of decarburization layer depth. Meanwhile,the effects of deformation temperature and laying temperature on the microstructure and mechanical properties of the steel were investigated by simulating the phase transformation process on a Gleeble-3500thermal-mechanical simulator. The results show that the soaking temperature has a much greater effect on the surface decarburization than the other factors. Higher the deformation temperature is,higher the sorbitzing rate is,finer the pearlite lamellar spacing is,finally leading to the increase of hardness. The increasing laying temperature is beneficial to enhancing the sorbitizing rate and decreasing the lamellar spacing,but when the laying temperature is over 900 ℃,the troostite with higher strength appears in the microstructure.