低屈强比汽车大梁钢的工艺研究与实践

ANALYSIS AND DISCUSSION ON THE LOW FLEXURAL STRENGTH RATI OF LOW CARBON NIOBIUM MICROALLOY REINRORCED GIRDER

为降低商用重型车架或底盘用钢510L材料的屈强比,对现有的低碳-锰-铌、低碳-锰-钛成分体系的屈强比进行了对比分析研究,确定采用低碳-锰-铌成分体系,并试验了该成分体系下不同冷却模式、不同卷取温度对屈强比的影响。结果表明,随着卷取温度的升高,屈服强度和抗拉强度均有大幅度下降,屈强比明显降低。层流采用后段冷却和两段冷却的模式,相比均匀分散冷却,屈强比有一定的降低,但抗拉强度富余量较小。为综合考虑屈强比和强度富余量指标,层流冷却采用后段+稀疏的冷却方案,效果良好,满足用户的使用要求。

In order to reduce the 510L flexural strength ratio of commercial heavy duty frame or chassis steel,this paper makes a comparative analysis and study on the large-scale production flexural strength ratio under the existing low-carbon manganese-Niobium and low-carbon manganese-Titanium composition system,and determines the adoption of low-carbon manganese-Niobium composition system.The effects of different cooling modes and different coiling temperatures on the flexural strength were tested.The results showed that the yield strength and tensile strength decreased with the increase of coiling temperature,and the flexural strength decreased significantly.Compared with the laminar cooling mode of the back section and the two-section laminar cooling mode,the flexural strength ratio of uniform dispersed cooling is reduced to a certain extent,but the tensile strength surplus is small.In order to balance the flexural strength ratio and strength abundance,laminar cooling is adopted,and the cooling scheme of the back segment+sparse cooling scheme is adopted,which has a good implementation effect and meets the technical and production requirements of users.