正火温度对G115钢组织及室温强度的影响

Effect of normalizing temperature on microstructure and room temperature strength of G115 steel

对G115钢进行1065~1120℃不同温度的正火处理,研究其显微组织和室温拉伸性能。结果表明：正火温度由1065℃升至1075℃时,抗拉强度由802.91 MPa降至741.15 MPa;正火温度由1075℃升至1105℃时,抗拉强度出现一个“平台”,约为798.97 MPa;当正火温度由1105℃升至1120℃时,抗拉强度降至745.13 MPa,屈服强度的变化规律与抗拉强度相似;随正火温度由1065℃升至1095℃,G115钢原奥氏体平均晶粒尺寸由38.40μm减小至34.45μm左右,在1075℃至1095℃亦出现个“平台”;当温度升至1120℃时,原奥氏体平均晶粒尺寸为67.64μm。不同正火温度试样均发现较多的富W和Fe元素的Laves相。

Microstructure and room temperature tensile strength of G115 steel after normalizing treatment at 1065-1120℃ were studied by means of scanning electron microscopy and tensile test. The results show that the tensile strength of the steel decreases from 802.91 MPa to 741.15 MPa when the normalizing temperature increases from 1065℃ to 1075 ℃. When the normalizing temperature increases to 1105℃ , the tensile strength keeps at 798.97 MPa and decreases to 745. 13 MPa when the normalizing temperature increases to 1120℃, and the change law of yield strength is similar to tensile strength. With the normalizing temperature increasing from 1065℃ to 1095℃, the prior austenite grain （PAG） size of the steel decreases from 38.40 μm to 34.45 μm, and increases obviously to 67.64μm at 1120℃. Laves phases with rich tungsten and iron are also observed in the steel after normalizing treatment at different temperatures.