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一、前言随着发动机功率与转速的增大,排气阀的工作温度和耐蚀性的要求也相应地提高,排气阀温度可达700～750℃,对排气阀的材料提出了新的要求。目前我国广泛采用的4Cr9Si2,4Cr10Si2Mo等马氏体型阀门钢,已远远满足不了使用要求。汽车工业迫切需要工作温度在700℃以上,具有较好性能的排气阀材料。5Cr 21Ni4Mn9N(即21—4N)钢是一种奥氏体型,较为经济的节镍排气阀材料,在700℃以上具有
I. INTRODUCTION With the increase of engine power and speed, the working temperature and corrosion resistance of the exhaust valve have also been raised accordingly. The temperature of the exhaust valve can reach 700 ~ 750 ℃, and the material of the exhaust valve is proposed to be new Request. At present, widely used in China, such as martensite 4Cr9Si2, 4Cr10Si2Mo valve steel, can not meet the use requirements far. The automotive industry urgently needs exhaust gas valve material with working temperature above 700 ℃ and better performance. 5Cr 21Ni4Mn9N (that is, 21-4N) steel is an austenitic, economical nickel-based exhaust valve material, above 700 ℃ with