Structures and properties of high-carbon high speed steel by RE-Mg-Ti compound modification

Abstract

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 (α_k), the fracture toughness (K_1c) and threshold of fatigue crack growth (ΔK_th) 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 unproved 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 (K_1c) and threshold of fatigue crack growth (ΔK_th) are improved in the meantime, the impact toughness (α_k) is increased by over one time, and the resistance to thermal fatigue and wear resistance at an elevated temperature are remarkably improved.

Keywords

high-carbon high speed steel / RE-Mg-Ti / compound modification / thermal fatigue / high temperature wear resistance

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