铬含量对新型气阀合金组织和性能的影响

Impact of Chromium Content on Microstructure and Properties of A New Valve Alloy

研究了铬含量对新型气阀合金组织、室温和高温力学性能的影响。结果表明,随着铬含量的增加,合金显微组织中第二相的数量明显增多,晶界处的析出物逐渐粗化,经确认第二相为碳化物Cr_(23)C_6;室温屈服强度和抗拉强度均随着铬含量的增加呈上升趋势,铬质量分数为20%时,室温断后伸长率最高,约为25%;高温屈服强度随铬含量的增加先是变化不大,然后有较为显著的升高;而高温抗拉强度、高温断后伸长率及断面收缩率均随着铬含量的增加先升高后下降;铬质量分数为20%的合金具有较好的综合性能。

The impact of chromium content on microstructure and mechanical properties of a new valve alloy at both room and high temperatures was investigated. It was observed that with the increase in chromium contents the amount of second phase in microstructure of the alloy increased obviously,and the precipitates at grain boundaries tended to become coarser. It was affirmed that the second phase was carbide Cr_（23）C_6. At room temperature,as chromium content increased,so too did the yield strength and tensile strength of the alloy,and the elongation reached as maximum as about 25% when the chromium content was 20% by mass. At high temperature,with the increase in chromium content in the alloy,its yield strength changed a little at first,then increased remarkably,and the tensile strength,elongation,and reduction in area all increased first,and then decreased.The alloy with 20% Cr had better comprehensive properties than others.