【作者】 张文汉；

【导师】 吴润；

【作者基本信息】 武汉科技大学 ， 材料学， 2007， 硕士

【摘要】 我国重载齿轮钢长期依赖于进口,技术上受制于西方发达国家。经济的发展十分迫切需要开发自己的重载齿轮钢。本文在重载齿轮钢17Cr2Ni2Mo化学成分的基础上,添加V、Nb等微合金化元素,研制出重载齿轮钢G1。并对钢进行了热处理工艺性能的研究,利用电子显微镜观察分析了微合金化元素的作用,最终对其力学性能进行了测试,并与17Cr2Ni2Mo钢进行了对比。试验结果表明,G1钢的奥氏体晶粒长大趋势小于17Cr2Ni2Mo钢:在低于1000℃的奥氏体化温度范围,G1钢的奥氏体晶粒等级为10~11.5级,17Cr2Ni2Mo钢为8.5~10级;在880~940℃保温10小时,G1钢不会发生奥氏体晶粒的异常长大,而17Cr2Ni2Mo钢在940℃奥氏体化时发生了晶粒异常长大。G1钢经900℃淬火+170℃回火后具有优良的力学性能:抗拉强度1365MPa、屈服强度1155MPa、冲击吸收功131焦耳,均高于17Cr2Ni2Mo钢。末端淬火试验表明,两钢的淬透性相当,临界淬透直径约为20mm。热处理工艺试验结果表明,采用渗碳后一次淬火工艺,试验钢能获得合格的显微组织和渗碳层硬度分布,G1钢的渗碳层硬度高于17Cr2Ni2Mo钢;G1钢的热处理变形趋势小于17Cr2Ni2Mo钢。更多还原

【Abstract】 The heavy-load gear steel in our country has been imported from abroad for a long period and technologically controlled by the developed countries. Now it is urgent to make a heavy-load-gear steel for our own industry. A heavy-load gear steel, named G1, was fabricated by means of adding micro-alloying elements such as V, Nb, and so on into another heavy-load gear steel 17Cr2Ni2Mo. The heat treatment procedure and properties of this steel were investigated to figure out effects of micro-alloying elements. The structure and carbonitride precipitation were analyzed through electronic microscope. Compared with steel 17Cr2Ni2Mo, steel G1 has transcended features such as mechanical properties, austenite grain size and heat treatment distortion tendency.The growth tendency of austenite grain in steel G1 is lower than that in steel 17Cr2Ni2Mo. Austenitized at temperature below 1000℃, the austenite grain of steel G1 was graded at 10~11.5 level, and that of steel 17Cr2Ni2Mo at 8.5~10 level. The abnormal growth of austenite grain which occurred in steel 17Cr2Ni2Mo after 10 hours austenitizing at temperature of 880~940℃was not found in steel G1. Excellent mechanical properties are obtained in steel G1 after 900℃quenching and 170℃tempering with the tensile strength of 1365MPa, yield strength of 1155MPa and impact energy of 131J.The hardenability of these two steels is equivalent, with the critical hardenability diameter about 20mm. Qualified carburizing microstructure and satisfied hardness distribution were obtained by a procedure of heat treatment after 910℃carburizing, which was 860℃quenching and 150℃tempering . The hardness of carburized layer in steel G1 is higher than that in steel 17Cr2Ni2Mo. It is noted that the distortion of steel G1 during heat treatment is less than that of steel 17Cr2Ni2Mo.更多还原