This work is a study of the manganese influence on the aging behavior of hot rolled and hot dip galvanized low carbon steels. For this, two steels were evaluated, with Mn content ranged between 0.16% and 0.30%. The work was carried out on industrial scale, in order to verify the tendency of results obtained previously on studies performed on laboratory scale. The evaluation of the aging phenomenon was performed in two ways: accelerated aging tests on hot rolled steels and bake hardening tests on cold rolled and galvanized steels. In both tests, it was verified that the increase of the Mn content might be an effective option in the control of aging in aluminum killed steels, within the limits of the process variables used. In agreement with the results of the accelerated aging and bake hardening tests, a higher carbides’ volumetric fraction was observed in the steel with higher Mn content. The steel with higher Mn content presented an approximated mean bake hardening value of 43 MPa and an approximated mean carbides’ volumetric fraction of 0,02. The values related to the steel with lower Mn content was 64 MPa and 1% respectively. This work corroborates with previous studies, which indicates the manganese precipitates as important carbides nucleation sites, reducing the amount of solid solution carbon in the ferritic matrix, resulting in a higher aging resistance.

这项工作是研究锰对热轧和热浸镀锌低碳钢的时效行为的影响。为此，评估了两种钢，Mn含量在0.16％和0.30％之间。为了验证以前在实验室规模的研究中获得的结果的趋势，这项工作是在工业规模上进行的。时效现象的评估有两种方式：对热轧钢进行加速时效测试，对冷轧和镀锌钢进行烘烤硬化测试。在这两个测试中，都证实了在所使用的工艺变量的范围内，增加Mn含量可能是控制铝镇静钢时效的有效选择。与加速老化和烘烤硬化测试的结果一致，锰含量较高的钢中，碳化物的体积分数较高。Mn含量较高的钢的平均烘烤硬化值约为43 MPa，平均碳化物的体积分数约为0.02。与较低Mn含量的钢有关的值分别为64MPa和1％。这项工作与以前的研究相符，后者表明锰沉淀是重要的碳化物成核位点，从而减少了铁素体基体中固溶碳的含量，从而提高了抗老化性。