前言毛主席教导我们:“在生产斗争和科学实验范围内,人类总是不断发展的,自然界也总是不断发展的,永远不会停止在一个水平上。因此,人类总得不断地总结经验,有所发现,有所发明,有所创造,有所前进。”近年来,由于生产的发展,硬貭合金得到了广泛地应用。特别是外园表面(如塞规、轧滚、冲头等)和内孔表面(环规、冲模等)和硬貭 Foreword Chairman Mao has taught us: “In the scope of production struggle and scientific experimentation, humankind has always been developing, and nature has always been constantly developing and will never stop at a level. Therefore, humankind has to constantly sum up experience and Discovered, invented, created, and advanced.” In recent years, due to the development of production, hard yttrium alloys have been widely used. In particular, the outer surface (such as plugs, rollers, punches, etc.) and the inner surface (ring gauges, dies, etc.) and hard boring