Accession Number:

ADA106946

Title:

Thresholds for Fatigue Initiation and Propagation and Plastic Work in HY80 and HY130 Steels.

Descriptive Note:

Annual technical rept. 1 Sep 80-31 Aug 81,

Corporate Author:

NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE

Personal Author(s):

• Fine,Morris E.

Report Date:

1981-10-30

Pagination or Media Count:

14.0

Abstract:

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.

Descriptors:

• *STEEL
• *CRACK PROPAGATION
• *FATIGUE(MECHANICS)
• PLASTIC DEFORMATION
• STRESS STRAIN RELATIONS
• MICROSTRUCTURE
• AUSTENITE
• HEAT TREATMENT
• STRAIN RATE
• HARDNESS
• MARTENSITE

Subject Categories:

• Properties of Metals and Alloys
• Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE