Title: Experimental conditions and environment effects on thermal fatigue damage accumulation and life of die-casting steel X38CrMoV5 (AISI H11)

Authors: Farid Medjedoub, Gilles Dour, Sabine Le Roux, Pascal Lamesle, Mehdi Salem, Patrick Hairy, Farhad Rezai-Aria

Addresses: Previously with CTIF and Ecole des Mines d'Albi-Carmaux, France; now with Renault Sport, France. ' Tools Surface Investigations Unit, CROMeP, Ecole Mines Albi, Toulouse University, France. ' Tools Surface Investigations Unit, CROMeP, Ecole Mines Albi, Toulouse University, France. ' Tools Surface Investigations Unit, CROMeP, Ecole Mines Albi, Toulouse University, France. ' Tools Surface Investigations Unit, CROMeP, Ecole Mines Albi, Toulouse University, France. ' R&D and Process Optimisation, CTIF, French Technical Centre of Foundry, France. ' Tools Surface Investigations Unit, CROMeP, Ecole Mines Albi, Toulouse University, France

Abstract: Thermal Fatigue (TF) is a life-limiting factor in die-casting dies. The effect of the maximum temperature of thermal cycle, Tmax, and the heating (or heat flux density) of thermal fatigue (X38CrMoV5 AISI H11) at 47 HRC is investigated. Two microscopic and macroscopic heat-checking cells are identified. The microscopic heat checking is limited to the double-layer oxide scales formed on the external surface of TF specimens. An engineering Paris-type law using Kmax, can describe TF surface crack propagation of all tests examined. TF life based on σmax is used to rationalise TF micro- and macroscopic cracking.

Keywords: thermal fatigue; crack initiation; chromium steels; fatigue-oxidation interaction fatigue; fatigue damage accumulation; die casting steel; dies.

DOI: 10.1504/IJMMP.2008.018739

International Journal of Microstructure and Materials Properties, 2008 Vol.3 No.2/3, pp.336 - 349

Available online: 16 Jun 2008 *

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