GB/T 1499.2-2018中关于维氏硬度判定方法的探讨

Discussion about the Determination Method of Vickers Hardness Subjected to GB/T 1499.2-2018

热轧带肋钢筋新标准GB/T 1499.2-2018于2018年11月1号正式实施,做了较大的改动,其中增加了宏观金相、截面维氏硬度、微观组织检验方法。截面维氏硬度指钢筋横截面边缘测试点与中心测试点的硬度差值(HV-HV0)不大于40时判为合格。存在异议时以微观组织作为仲裁依据。文章通过维氏硬度测试得出数据,对比分析发现,钢筋横截面基圆上存在回火马氏体时,边缘与中心的硬度差值仍有可能小于40,所以不能作为判定是否为热轧带肋钢筋的唯一依据,应要结合宏观金相及微观组织综合判定。

The new national standard GB/T 1499.2-2018 for hot rolled ribbed bars were implemented on November 1,2018.Macrography,Vickers hardness(HV5)of cross section and microstructure were increased.Vickers hardness refers to the difference(HV-HV0)of rebar from edge to centre is less than 40 which will be judged to be qualified.When there are objections,the microstructure shall be taken as the arbitration basis.It is found out by contrast analyses of the data from vickers hardness test that when tempered martensite exists on the base circle of the cross section of steel reinforcement,the hardness difference between the edge and the center may still be less than 40,so it cannot be used as the only basis to determine whether the ribbed steel reinforcement is hot rolled.