DEVELOPMENT OF MATERIAL USED FOR AVIATION APPARATUS AXLE JOURNALS

ＤＥＶＥＬＯＰＭＥＮＴＯＦＭＡＴＥＲＩＡＬＵＳＥＤＦＯＲＡＶＩＡＴＩＯＮＡＰＰＡＲＡＴＵＳＡＸＬＥＪＯＵＲＮＡＬＳ①ＷｕＥｎｘｉ，ＬｉＳｈｅｎ，ＱｉａｎＣｈｏｎｇｌｉａｎｇａｎｄＺｏｕＺｈｉｑｉａｎｇＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｆｏｒＰｏｗｄ...

An advanced Co25W alloy used for producing aviation apparatus axle journals and its technological processes were described. Because highpurity raw materials and consumableelectrode refine technology were used, the content of oxygen and other impurities in the alloy were reduced to 0.011 % and 0.5～1.0 grade respectively. So, the hotworking properties of the alloy was considerably improved. When deformation temperature and crosssection shrinkage ratio of each procedure including forging, hotrolling, rotary forging and wiredrawing were well controlled, the alloy could be drawn into wire of 0.50 mm in diameter. Its Vickers hardness (Hv) of asdrawn alloy was 4 500～5 500 MPa, and it could be improved to more than 7 200 MPa to meet the requirements of axle journals, which was ascribed to age pricipitated Co3W phase in vacuum or H2 atmosphere. The optimum aging temperature was 650 ℃, aging time 8 h. By means of metallography and XRD, microstructure changes in the course of processing, many factors influencing the process properties of the alloy and their choice principles were discussed in details. The influences of aging temperature and time on hardness of CoW alloy and the agehardening mechanism were investigated.