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一、前言奥氏体——贝氏体球铁(下称A-B球铁)是近几年出现的一种新型球铁。它是采用等温处理方法获得的双相组织球铁。其特点是,无论是静强度还是动强度均优于已知各种球铁;其综合机械性能可与某些钢相比,延伸率和冲击值较高,疲劳强度和耐磨性较好,低温冲击韧性也较高。这种材料已引起世界各国的重视,在美国、芬兰等十三个国家已取得了专利权,在汽车、农机、机械制造等行业获得了广泛应用。进口T20型高速柴油汽车在大修过程中拨叉供不应求,价格贵;而国产拨叉质量不过关,在使用中经常发生断裂现象。为分析国产拨叉失效原因,提高拨叉质量,我们从失效分析入手,进行了用A-B球铁代替调质ZG45钢制造汽车拨叉的试验研究,为扩大球铁在汽车制造中的应用开辟了新的途径。
I. INTRODUCTION Austenitic-bainitic ductile iron (hereinafter A-B ductile iron) is a new type of ductile iron that has emerged in recent years. It is an isothermal treatment of biphasic ductile iron obtained. Its characteristics are that both static strength and dynamic strength are better than known all kinds of ductile iron; its mechanical properties can be compared with some of the steel, high elongation and impact value, good fatigue strength and wear resistance, Low temperature impact toughness is also higher. This material has aroused the attention of all countries in the world. It has obtained patent rights in 13 countries such as the United States and Finland, and has been widely used in automobile, agricultural machinery and machinery manufacturing industries. Imported T20 high-speed diesel vehicles fork in the overhaul process in short supply, the price is expensive; but the quality of the domestic fork, however, the use of frequent breakage. In order to analyze the failure reason of domestic shift fork and improve the quality of shift fork, we started with the failure analysis and carried out the experimental study of replacing fork with quenched and tempered ZG45 steel with AB ductile iron, which opened up the application of expanding ductile iron in automobile manufacturing New way.