Thresholds for Fatigue Initiation and Propagation and Plastic Work in HY80 and HY130 Steels.
Annual technical rept. 1 Sep 80-31 Aug 81,
NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE
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The effect of tempering temperature on the fatigue crack propagation rate FCPR in the low stress intensity range of HY130 austenitized at 815 C was determined. Four treatments giving the same hardness, R.C. 34, were selected A - 10 hrs at 400 C, B - 5 hrs at 550 C, C - 1 hr at 610 C and D - 14 hr at 650 C. Treatment C, the standard treatment for HY130, gave the highest value of stress intensity threshold, Delta Kth, and the lowest propagation rate at Delta K of 5 MPa square root of m. For HY80 intercritical heat treatments were developed to give desired distributions of ferrite and martensite for measurement of Delta Kth.
- Properties of Metals and Alloys