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白点是钢中细小的內部裂纹。在钢的横向截面上白点呈现为细小弯曲的锯齿状裂纹,在纵向断口上呈现为园形或椭园形的银白色斑点。白点的危害性极大,它不仅使钢的机械性能,尤其是塑性急剧降低,使零件在热处理时容易产生开裂,而且由于白点产生高度的应力集中,使零件在承载时(尤其是在动载负荷下工作时)发生骤然破坏,造成严重的破坏事故。因此,在任何情况下都不允许使用有白点的锻件和用有白点的钢材加工制造机器零件。大部分合金结构钢(主要是含铬、镍、钼、钨、锰等元素的结构钢)和铬轴承钢,都有不同程度产生白点的敏感性,因此,防白点处理是合金结构钢,轴承钢锻造生产工艺中
White spots are tiny internal cracks in steel. In the transverse cross-section of the steel white spots appear as small curved serrated cracks in the longitudinal fracture appears as a circular or oval-shaped silver-white spots. White spots are extremely harmful. Not only does this sharply reduce the mechanical properties of steel, especially its plasticity, it can easily cause cracking of parts during heat treatment, and because of the high concentration of stress caused by white spots, Sudden destruction occurs when working under dynamic load, resulting in serious damage accident. Therefore, it is not permissible to use white forgings and whitened steel for machining of machine parts. Most of the alloy structural steel (mainly containing chromium, nickel, molybdenum, tungsten, manganese and other elements of the structural steel) and chromium bearing steel, have different degrees of white point sensitivity, therefore, anti-white point treatment is alloy steel , Bearing steel forging production process