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Development of High Performance Sintered Alloy Steels by Metal Injection Molding

金属注射成型高性能烧结合金钢的开发

基本信息

批准号：
04805068
负责人：
MIURA Hideshi
金额：
$ 1.22万
依托单位：
Kumamoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04805068/
关键词：
Metal Injection molding Sintered Alloy Steel Carbon Control Solvent Debinding Mechanical Property High Performance

项目摘要

The purpose of the work is to test the feasibility of using the mental injection molding (MIM) approach to attain the high performance through a new fabrication route. However, there still remains the issue of controlling the carbon content and structure in the final product by the difference of powder type. In this study, MIM process for the 4600 steels has been studied at first by using prealloyed fine powder (particle size : 12mum) contained 0.71wt.% carbon. For the debinding approach, solvent debinding followed by final thermal debinding produced the homogeneous structure and stiff compact enough for handling. The residual carbon content was mainly controlled by changing the fraction of H_2 in gas mixture of H_2 and N_2 during the final thermal debinding. Mechanical properties of the sintered and the heat treated MIM compacts with prealloyed fine powders were inferior to those of the same treated MIM compacts with mixed elemental powders, especially in the ductility. This is due to the insufficient densification of prealloyed fine powder (relative sintered density : 93-94%) and the difference of microstructures.Subsequently, the same experiment has been performed for the Ni-Mo and Cr-Mo steels. For the nearly carbon-free prealloyed Cr-Mo powder, carburization could take place in the debinding by using a carburizing atmosphere such as CO gas and carbon could be restored to the desired level by adjusting the CO concentration in gas mixture of H_2 and CO.The mixed elemental powder was used for the Ni-Mo steels, resulted in the heterogeneous structure by segregation of Ni. However, this tempered steel showed a excellent strength compared to that of the prealloyed powder steel. This seems to be due to the structure consisted of martensite surrounded by a network of tempered martensite. The obtained results indicate the attainability of high performance ferrous materials by the MIM techniques.

这项工作的目的是测试使用金属注射成型（MIM）方法通过新的制造路线获得高性能的可行性。然而，仍然存在通过粉末类型的差异来控制最终产品中的碳含量和结构的问题。在本研究中，首先使用含碳量为 0.71wt.% 的预合金细粉（粒径：12mum）研究了 4600 钢的 MIM 工艺。对于脱脂方法，先进行溶剂脱脂，然后进行最终的热脱脂，产生均匀的结构和足够坚硬的致密性，以便于处理。残余碳含量主要通过改变最终热脱脂过程中H_2和N_2混合气体中H_2的比例来控制。烧结和热处理的预合金细粉MIM压坯的机械性能低于相同处理的混合元素粉末MIM压坯的机械性能，特别是延展性。这是由于预合金细粉致密化不足（相对烧结密度：93-94%）和显微组织的差异所致。随后，对Ni-Mo和Cr-Mo钢进行了相同的实验。对于几乎不含碳的Cr-Mo预合金粉末，在脱脂时使用CO气体等渗碳气氛进行渗碳，通过调节H_2和CO混合气体中的CO浓度可以将碳恢复到所需的水平。混合元素粉末用于Ni-Mo钢，通过Ni的偏析产生异质结构。然而，与预合金粉末钢相比，这种回火钢表现出优异的强度。这似乎是由于该结构由被回火马氏体网络包围的马氏体组成。所得结果表明通过 MIM 技术可以获得高性能黑色金属材料。