铬、锰对HRB400钢筋力学性能的影响

针对钢中残留铬元素含量高的特点,在试验室条件下分析研究了几组不同Cr、Mn含量试验用钢,铬、锰合金元素含量对HRB400试验钢筋力学性能及显微组织的影响;并利用扫描电镜、电子探针等手段分析了HRB400试验钢筋力学性能与珠光体含量、析出物微观组织的关系。结果表明,在锰含量分别为1.15%、1.25%、1.35%低、中、高锰条件下,随Cr含量的增加,试验钢筋屈服强度、抗拉强度随之提高,微量铬元素起一定的强化作用,从而可减少Mn元素加入量;Cr含量由0.1%增加至0.3%珠光体含量增加,且晶粒度平均在8～9级,钢中有Cr-Fe-Mn复合合金渗碳体和铬碳化物析出;0.125～0.135%Mn,0.20%Cr试验钢筋组织和力学性能达到国标规定的要求;且根据试验结果并结合当前合金元素的价格,吨钢可节约成本约20元。

Effects of Cr and Mn on Mechanical Properties of Steel Bar HRB400

Concerning the phenomenon of high residual Cr in steel bar,the influence of the mass fraction of Cr,Mn alloy elements on the mechanical properties and microstructure of HRB400 test steel bars in laboratory conditions is studied. The relationship between mechanical properties and the content of pearlite, and the microstructure of precipitated particles was also analyzed by transmission electron microscopy. The experimental results are as follows. At low, medium and high Mn content of 1.15% ,1.25% and 1.35% respectively, the yield strength and tensile strength of test steel bars raised with the increase of Cr. Cr played a certain strengthening role,which can reduce Mn addition. The content of pearlite raised with increasinhg Cr from 0.1% to 0.3% ,the average grain size was 8 ~9,Meanwhile,Cr-Fe-Mn composite alloy cementite and Cr carbide have been precipitated from steel. The microstructure and mechanical properties of the reinforced rebar with 0.125% _0.135%Mn,0.20% Cr meet the requirements of international standard. Based on the test results and the current price of alloying elements, the cost per ton of steel can be reduced by about 20 yuan.