拖拉机和农用运输车上的零件,如拉杆、拨叉、离合器操纵杆,油门插肖等等,使用不到两个月就断裂了,不仅要换新件,而且在行车中很危险。拖拉机和农用运输车中的此类小零件,都必须经过热处理。而在热处理后,可能会出现淬火裂纹、回火裂纹、磨削裂纹等各种各样的裂纹。故在维修过程中,特别要注意防止有裂纹的零件装机使用。下面介绍两种方法寻找裂纹。一是听敲击声,二是油浸透法。采用此类方法既简单又方便,见效快,同时也比较准确。听敲击声,用锤子轻轻地敲击零件。如听到清脆的金属声,可以认为该零件没有裂纹;反之,若发出浊音,说明该零件有裂 Parts of tractors and agricultural vehicles, such as tie rods, forks, clutch levers, throttle sticks, etc., broke in less than two months, not only for new parts, but also for driving. Such small parts in tractors and agricultural vehicles must be heat treated. After the heat treatment, quench cracking, tempering cracks, grinding cracks and other cracks may occur. Therefore, in the maintenance process, special attention should be paid to prevent cracked parts installed use. Here are two ways to find cracks. First, listen to percussion, the second is oil soaked. Using such methods is simple and convenient, quick, but also more accurate. Listen to the percussion, gently tap the parts with a hammer. If you hear the crisp metal sound, you can think that the parts are not cracked; the other hand, if the issue of dull sound, that the parts are cracked