Accession Number : ADA182295

Title :   Fatigue - Fracture Properties of a Semi-Austenitic PH Stainless Steel,

Corporate Author : MATERIALS RESEARCH LABS ASCOT VALE (AUSTRALIA)

Personal Author(s) : Farrara,R.

Report Date : FEB 1987

Pagination or Media Count : 29

Abstract : Fatigue and fracture toughness properties were determined for STA60 precipitation hardening stainless steel used in the structure of the 105 mm Light Gun. Fatigue properties (S-N crack for initiation and crack growth rate) and fracture toughness were measured on both parent sheet and welded joints for a range of heat treatments including fully re-heat treated and peak aged (450 deg C), overaged as in production (530 deg C), and as-welded joints not re-heat treated. The material was found to be notch sensitive. Fatigue crack growth was much faster, and fracture toughness much lower, in the longitudinal (rolling) direction of sheet because of the presence of nonmetallic stringers in the microstructure. Overaging had little effect on fatigue properties compared with peak ageing, but did achieve a significant improvement in fracture toughness. Weld metal was more resistant to fatigue crack initiationn than parent sheet, but welds not re-heat treated were drastically limited in all three properties because the weld heat-affected zones remained in the soft condition.

Descriptors :   *FATIGUE(MECHANICS), *FRACTURE(MECHANICS), TOUGHNESS, *AUSTENITE, *STAINLESS STEEL, AUSTRALIA, SHEETS, MICROSTRUCTURE, PRODUCTION, CRACKS, RESISTANCE, CRACK PROPAGATION, HEAT TREATMENT, HEAT, WELDS, NOTCH SENSITIVITY, GUNS, ORDNANCE STEEL, MILITARY REQUIREMENTS, FATIGUE(MECHANICS), FRACTOGRAPHY, ROLL BONDING, WELD METAL, WELDED JOINTS

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE