Accession Number : AD0695794

Title :   THE STRESS CORROSION RESISTANCE AND FATIGUE CRACK GROWTH RATE OF A HIGH STRENGTH MARTENSITIC STAINLESS STEEL, AFC 77.

Descriptive Note : Research rept.,

Corporate Author : BOEING CO RENTON WASH COMMERCIAL AIRPLANE GROUP

Personal Author(s) : Webster,Donald

Report Date : JUN 1969

Pagination or Media Count : 12

Abstract : The plane-strain corrosion threshold K sub(Iscc) and fatigue crack growth rate have been determined for a high strength martensitic stainless steel, AFC 77, in both conventionally processed and strain-aged conditions. The K sub(Iscc) (in 3.5-percent sodium chloride solution) is markedly affected by both the tempering temperature and the degree of strain aging. The highest K sub(Iscc) of 105 ksi square root of in. was obtained by tempering at 500F and the lowest K sub (Iscc) of 10 ksi square root of in. by tempering at 1100F. Retained austenite raised K sub(Iscc) at tempering temperatures up to 1000F, which was the highest tempering temperature at which austenite could be maintained. Fatigue crack growth rates in both dry air (< 10 percent relative humidity) and 3.5-percent sodium chloride solution were at a maximum for material tempered at 700F. Over the range of stress intensity studied, retained austenite reduced fatigue crack growth rate in salt solution but increased it in dry air. (Author)

Descriptors :   (*STAINLESS STEEL, *STRESS CORROSION), FATIGUE(MECHANICS), CRACK PROPAGATION, CORROSION RESISTANCE, MARTENSITE

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE