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研究了Fe-Mo-B-CU-C与Fe-Mo-Ni-Cu-C系粉末烧结钢中合金含量、碳加入方式、热处理等温温度对下贝氏体形成的影响,同时对形成的下贝氏体组织形貌进行了比较分析。结果表明:在Fe-Mo—B-Cu—C系中,当B含量在2%,等温热处理温度为350℃时,有较大量针状下贝氏体出现;在Fe-Mo-Ni-Cu-C系中,当碳以石墨粉形式加入时,含镍4%的烧结钢在等温热处理温度200℃及280℃下均获得典型下贝氏体组织;而以镍包石墨方式加入的合金系中,3%、4%的Ni(石墨)试样在等温热处理温度280℃下获得典型下贝氏体组织;以石墨粉形式加入和以镍包石墨形式加入形成的贝氏体显微形貌存在较大差异,前者贝氏体的分布均匀,体积分数较大。
The effects of alloy content, carbon addition method and isothermal isothermal temperature on the formation of lower bainite in Fe-Mo-B-Cu-C and Fe-Mo-Ni-Cu-C powder sintered steels were studied. Bainite morphology was analyzed comparatively. The results show that a large amount of needle-like lower bainite appears in the Fe-Mo-B-Cu-C system when the content of B is 2% and the isothermal heat treatment temperature is 350 ℃. In Fe-Mo-Ni -Cu-C system, when carbon is added in the form of graphite powder, 4% nickel-containing sintered steel obtains isosite lower bainite structure at the isothermal heat treatment temperature of 200 DEG C and 280 DEG C; In the alloy system added, 3%, 4% Ni (graphite) samples obtained a typical lower bainite structure at an isothermal heat treatment temperature of 280 ° C; added as graphite powder and added as nickel-coated graphite There is a large difference in the micro-morphology of the body, the former bainite uniform distribution, larger volume fraction.