High Speed Steel and WC Particle-Reinforced Composites Produce by Spray Forming

The process of spray forming utilized to fabricate WC particle-reinforced high speed steel composites has been studied. In addition, microstructures and mechanical properties of M2 high speed steel and its composites made by spray forming have been analyzed. The results show that the primary carbides of high speed steel are of two types: MC and MbC. With the increase in flight distance, the morphology of the primary carbides varies from fine fish-bone-like to islandlike and both bending strength and hardness increase. With the increase in volume fraction of WC reinforcement particles,hardness of the composites increases considerably, but bending strength, however, appears to be a decreasing tendency.

MICROSTRUCTURAL CHARACTERISTICS AND MECHANICAL PROPERTIES OF SPRAY FORMED HIGH SPEED STEEL FOR WORK ROLL

The mechanical properties and microstructure characteristics of a high speed steel (HSS) for roll has been studied. As compared with the as-cast HSS, the spray-formed HSS have fine grain and segregation free microstructures. Carbides distribute uniformly. The morphology and types of the carbides in spray-formed HSS are different from those in as-cast HSS. The results of the high temperature tensile experiment show that, as to spray-formed HSS, there is a possibility of superplastic deformation in the range of 780-810℃.

WC Particle High Speed Steel Composites Manufactured by Ultrasonic Spray Forming

The process of manufacturing high speed steel matrix composites reinforced by WC particles was studied. The changes in microstructures and mechanical properties of composites with WC particles were also investigated. The results show that increasing the deposition height can significantly enhance the bending strength and hardness of the alloy, and that the fishbone like carbide ledeburite structure gradually diminishes as the WC particles content increases. It was discovered that the hardness of the composites increases due to the increase of pointlike carbide ledeburite, accompanying the breaking of the fishbone like and the net like carbides. However, the bending strength deteriorates due to excessive WC particles increasing the brittle interfacial phase.

WC_(p)/M42高速钢复合材料的制备与性能

采用粉末冶金法制备了质量分数从0~10%的WC颗粒增强高速钢基复合材料。利用SEM、XRD和万能力学试验机等研究了不同WC质量分数下WC_(p)/M42高速钢复合材料的显微结构和力学性能。结果表明:在温度为1 230℃时,采用真空烧结可获得相对密度超过98.5%的复合材料,其物相组成均为α-Fe、M_(6)C碳化物、M_(7)C_(3)碳化物及少量的M_(2)C碳化物;随着WC添加量的增加,烧结态复合材料的硬度先下降后上升,抗弯强度与冲击韧性均逐步下降;经过1 180℃淬火+560℃回火后,复合材料的硬度随WC添加量的增加而上升,当WC添加量为10%时,硬度达到65.1HRC,相较于烧结态提高了16.4HRC。