Fatigue-Crack Growth in 20% Cold-Worked Type 316 Stainless Steel at Elevated Temperatures

The fatigue-crack propagation behavior of 20% cold-worked Type 316 stainless steel was characterized over the temperature range 75 to 1300°F (24 to 704°C) using linear-elastic fracture mechanics. It was found that, at a given level of stress intensity factor, increasing the temperature produced a significant increase in the rate of fatigue-crack propagation. At 1000°F, decreasing the cyclic frequency tended to increase the crack growth rate. The data also suggest that, at a given temperature, the crack growth rate is slightly higher when the direction of crack extension is parallel to the rolling direction than when the crack extension is perpendicular to the rolling direction. Comparison with data for solution-annealed Type 316 fatigue-cycled under similar conditions indicates that, at a given temperature, cold working tends to increase the resistance to fatigue-crack propagation.