Fabrication Of T15M High Speed Steel By Powder Metallurgy And Researching Its Properties

High-speed steel (HSS) is high carbon alloy ledeburite steel. It is important tool materials due to the fact that it offers a high wear resistance and high hardness. High-speed steel has special structure and properties, make it plays an irreplace role in special steel industry. But the high-speed steel which was produced by the traditional process has problems like coarse microstructure and composition segregation.In this thesis, T15M high speed steel and T15M-4NSiC high speed steel fabricated by means of powder metallurgy are studied. Powder metallurgy can solve problems like coarse microstructure and composition segregation effectively. To find better heat treatment process for T15M high speed steel, heat treatment processes was studied. And the mechanical property, wear mechanism and inoxidizability of T15M high speed steel and T15M-4NSiC high speed steel were also studied. The influence of SiC was also studied. The main studies are as follows:The optimized heat treatment processing of T15M high speed steel is quenching at1326℃and tempering at540℃three times. In this case, the hardness is high (68.53HRC), produced a rounded or globular form of carbide, most of the retained austenite translated into tempered martensite.(The volume fraction of retained austenite was3.46%).The addition of sic helped to significantly improve red hardness and abrasion performance, but reduced the impact toughness and bending properties, the impact toughness dropped as much as48.7%. At high temperature, a layer of oxides produced on the surface, to prevent further oxidation. Sic was oxidized to SiO2at high temperature to prevent further oxidation.