Si含量对Cr8冷作模具钢组织及性能的影响
本文着重研究Cr8冷作模具钢硅含量对其共晶碳化物不均匀度及硬度的影响。共晶碳化物的不均匀度级数对钢的综合性能有着很大的影响，共晶碳化物颗粒度很大并分布不均匀时，钢的塑性显著下降，寿命大大缩减。课题以天工国际公司生产的Cr8冷作模具钢为研究对象，在实验室中模仿日常生产，经电弧炉、LF炉、VD炉得到硅含量不同的实验样本，并对实验样本进行了热处理，在淬火加热箱加热到1050℃进行淬火处理，并在480℃进行回火处理。然后对各样本进行了显微观察，了解各自的组织结构，并且利用软件对图像进行处理，得到了各自共晶碳化物不均匀度的级数，探讨硅含量对金相组织的影响。实验还对样本硬度进行了测试，探讨了硅含量对其硬度的影响。
研究结果表明：随着硅含量的提高，共晶碳化物不均匀级数不断增大，其组织中，合金元素碳化物的偏析越来越严重，当硅含量达到1。5%时，回火温度不足以使碳获得扩散的动能，钢的淬火组织没有得到改善，二次碳化物呈网状分布，严重影响了钢的综合性能，增加其脆性，减少了其寿命。此外，实验还测量了样本的硬度，研究了硅含量对钢硬度的影响。结果显示，随着硅含量的提高，钢的硬度不断加大，这是因为，随着硅含量的增加，其淬火马氏体越来越难以相变，马氏体有着高的硬度，所以随着硅含量的增加，钢的硬度不断增加。
毕业论文关键词：Cr8冷作模具钢；共晶碳化物不均匀度；生产工艺；组织及性能
Abstract Since the 1980s, cold work tool steel into the era of rapid development, Rapid increase in the annual rate of 15 percent, China's mold steel share is low, market development space is very large。 In recent years, China's imports from Japan, the United States and other countries die steel more and more, resulting in increased costs。 Quality die steel demand continues to expand, and the lack of domestic production technology makes no representation quality steel, so the study of the production process has become an important task。 Cr8 cold work die steel with high strength and good wear resistance, and low prices, production process is simple, and therefore is widely recognized in the country, increasing demand, but its stability is difficult to control the quality of the production process It will cause great waste, study its production process and improve its overall performance, has great significance。
This paper focuses on the impact Cr8 cold work die steel silicon content on the unevenness of eutectic carbides and hardness。 Eutectic carbides unevenness series overall performance of the steel has a great impact, and the uneven distribution of eutectic great time, the ductility decreased significantly carbide particle size, life greatly reduced。 Subject to Tiangong International Company's Cr8 cold work tool steel for the study, to imitate in the laboratory daily production by electric arc furnace, LF furnace, VD furnace to give silicon content of different experimental samples and experimental samples were heat-treated, in the quenching tank is heated to 1050 degrees quenching, and tempering at 480 degrees Celsius。 Then each sample was microscopically observed, to understand their organizational structure, and the use of image processing software to obtain their eutectic carbide of the series, investigate the effect of silicon content on the microstructure。 It was also the hardness of the samples were tested to study the effects of silicon content on hardness。
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