ダイカスト金型鋼に関する研究(第1報) : 金型と試料の残留応力測定

概要

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Surfaces or die steels for die casting were markedly damaged by the repetition of heating and cooling. Heat checking and erosion in the die surfaces were generated and they deteriorated the life and quality of the die. The effects of shot cycles on the residual stresses in the surfaces of die steels for aluminum die casting have been studied and compared with samples for a simulation test. The residual stress in die and samples were measured using the X-ray residual stress method. The stresses before testing in the die and sample surfaces were large compression stresses which are considered to be caused by the surface polishing. Then the stresses on the die changed rapidly to tensile stress with increasing shot cycles up of 100 cycles. However, each stress change curve of the samples showed no change after a few shot cycles. Inflection points in the stress change curves corresponded to crack initiation and unchanged-states agree with crack growth, respectively. It was also found that the stress in the die falls to zero at about 100000 shot cycles. The phenomenon can be attributed to the saturation of crack propagation in the die surfaces and resultant release from the stress.
公益社団法人精密工学会の論文
1989-10-05