Thresholds for Fatigue Initiation and Propagation and Plastic Work in HY80 and HY130 Steels.
Abstract
The effect of tempering temperature on the fatigue crack propagation rate (FCPR) in the mid-stress intensity range of HY130 austenitized at 815 C was determined. Three treatments giving the same hardness, R.C. 34, were selected: A - 10 hrs at 400 C, B - 5 hrs at 550 C, and C - 1/4 hr at 650 C. There was little difference in the rates either when the testing was done in air (55% relative humidity) or dry argon. Previously, a ten times larger FCPR was observed in specimens tempered 1 hr at 610 C when the tests were carried out in air rather than dry argon. Changing the tempering furnace from a salt pot to a dry argon tube furnace and water quenching from 610 C rather than air cooling seemed to cure the problem. The threshold for macrofatigue crack propagation was measured in commercially pure iron in both center notch and side notch specimens. Both specimen geometries have the same results, delta k(th) = 6 MN/sq root of m cubed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 16, 1980
- Accession Number
- ADA091345
Entities
People
- Morris E. Fine
Organizations
- Northwestern University