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研究了25Cr Mo4钢汽车空心半轴的精锻工艺步骤和显微组织。研究结果表明:通过精密旋锻工艺成形的全空心汽车半轴的材料流动合理,内外表面均比较光滑,变径处过渡平滑,无明显折叠现象。与传统汽车实心半轴相比,精锻的汽车空心半轴每件产品节约材料30%以上;管料经精锻变形后,横截面上晶粒发生扭曲,纵向晶粒变成纤维状;空心半轴热处理后,表面获得了回火马氏体和粒状碳化物,心部的组织为板条马氏体,不仅保证了产品表面的高硬度和良好耐磨性,同时也确保了心部具有较高的强韧性。经检测,旋锻成形的全空心汽车半轴的低载疲劳、高载疲劳和静扭强度等各项指标均达到汽车半轴使用要求。
The precision forging process and microstructure of hollow shaft of 25Cr Mo4 steel were studied. The results show that the material flow of the semi-hollow axle which is formed by the precision swaging technology is reasonable, the inner and outer surfaces are relatively smooth, and the transition of the diameter-reducing place is smooth, with no obvious folding phenomenon. Compared with the traditional semi-solid axle, the forged semi-hollow axle can save more than 30% of the material of each hollow semi-shaft. After the tube material is forged and deformed, the crystal grains in the cross section are distorted and the longitudinal grains become fibrous. Axle heat treatment, the surface was tempered martensite and granular carbide, the heart of the organization of lath martensite, not only to ensure that the product surface hardness and good wear resistance, but also to ensure that the heart has Higher toughness. After testing, the half-shaft of full-hollow car manufactured by swaging has reached the requirements of semi-axle use for all the indexes such as low load fatigue, high load fatigue and static torsional strength.