Study On Wear Performance And Failure Behavior Of High Speed Steel Under High Stress Rolling/Sliding Condition

This study was designed for high speed steel for cold roll，with different carbide as main wear-resistant skeleton. Self-made wear testing machine WM-RS was used to study the wear performance and failure behavior of high speed steel and different sliding ratio on the impact for the failure，and failure behavior and rolling/sliding wear mechanism of high speed steel roll was analyzed by using SEM and TEM. X-ray diffraction was used to measure the content of retained austenite before and after wear，and the electronic microhardness tester was used to analyze microhardness change before and after wear. Further reveals the wear failure mechanism of cold roll with high speed steel，improve the material wear failure theory contains hard points. The results were as follows:1. The typical organization of high tungsten high speed steel after heat treatment is that: tungsten carbide（M6C）and secondary carbide precipitation and acicular martensite and retained austenite. The main constituent elements of the M6C type carbide are iron and tungsten. The typical organization of high molybdenum high speed steel after heat treatment is that: molybdenum carbide（M2C）and twin martensite and retained austenite. The composition of M2C type carbide is given priority to with molybdenum elements.2. Sliding ratio of5.95%，the rockwell hardness and toughness of high tungsten high speed steel and high molybdenum high speed steel are roughly equal and the relative wear resistance is1.25times high molybdenum high speed steel. Along with the increase of wear time, the mass loss of two kinds of high speed steel are approximately linear increase.3. Because in the process of wear work hardening and induced martensite phase transformation occurred, the worn surface microhardness increased.4. The bar strip shape of M2C carbide is more prone to bending fracture than the skeletal shape of M6C carbide. The area fraction of M6C carbide is greater than M2C carbide, so can more effectively hinder dislocation motion. Because the type of M2C carbide in the grid distribution, in the process of wear easily lead to dislocation pile and broken.5. Sliding ratio has significant influence on friction and wear，with the sliding ratio increased，the wear rate increased. Sliding ratio has a significant impact on the amount of retained austenite, with the sliding ratio increased, induce martensitic phase transformation increased and residual austenite decreased.6. Sliding ratio is small (1.13%), the failure of materials main with rolling wear, and the failure form of materials mainly fatigue flake. The sliding rate increases to5.95%, the rolling and sliding wear interaction is the main failure forms, the mainly wear characteristics of materials is plastic deformation, crack and spalling. Sliding ratio increases to10.11%, the main failure forms of materials is sliding wear, the mainly wear characteristics of materials is furrows.