Structures and Properties of High-Carbon High Speed Steel by RE-Mg-Ti Compound Modification

摘要

The effects of rare earths（RE）-Mg-Ti compound modification on the structures and properties of high-carbon high speed steel（HSS） were researched.The impact toughness（αk）,the fracture toughness(K1c)and threshold of fatigue crack growth(ΔKth)are tested.The thermal fatigue test is done on a self-straining thermal fatigue tester,the wear test is done on a high temperature wear test machine.The results show that the matrix can be refined by the RE-Mg-Ti compound modification,the eutectic carbides are inclined to spheroidicize and are distributed evenly,the morphology and distribution of eutectic carbides are improved by appropriate RE-Mg-Ti complex modification.After RE-Mg-Ti compound modification,a little effects can be found on the strength,hardness and red hardness,but the fracture toughness(K1c) and threshold of fatigue crack growth(△Kth) are improved in the meantime,the impact toughness （αk） is increased by over one time,and the resistance to thermal fatigue and wear resistance at an elevated temperature are remarkably improved.