大吨位万能试验机的大小V型齿状夹头和平齿夹头,是该机的主要件。从使用情况看,它承受拉压应力甚大,齿部直接夹住各种测力试样,应具有高而均匀的硬度、强度和极好的韧性,并能承受冲击力等特点。夹头材料为GCr15轴承钢,结构如图1所示。前一段时期,成批夹头在试验机总成校车时,发生明显的断裂、坏齿事故,严重影响产品出厂。经探伤检查和金相分析,发现其基体存在较严重的网状碳化物组织。针对这一问题,我们从生产流程的锻造、正火、球化、热处理各道 Large-tonnage universal testing machine size V-shaped tooth-shaped chuck and flat tooth chuck, is the main piece of the machine. From the use of view, it is subject to tension and compression stress is very large, the tooth directly clamping a variety of load test specimens, should have high and uniform hardness, strength and excellent toughness, and can withstand the impact of such characteristics. Chuck material GCr15 bearing steel, the structure shown in Figure 1. Some time ago, batch chucks in the test machine assembly school bus, there was a clear fracture, bad tooth accident, seriously affecting the product factory. After flaw detection and metallographic analysis, found that the matrix there is more serious mesh carbide organization. In response to this problem, we from the production process forging, normalizing, balling, heat treatment of all