Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-27T03:43:57.496Z Has data issue: false hasContentIssue false

Experimental X-Ray Stress Analysis Procedures for Ultrahigh-Strength Materials

Published online by Cambridge University Press:  06 March 2019

H. R. Woehrle
Affiliation:
Rensselaer Polytechnic Institute Troy, New York
F. P. Reilly III
Affiliation:
Rensselaer Polytechnic Institute Troy, New York
W. J. Barkley III
Affiliation:
Rensselaer Polytechnic Institute Troy, New York
L. A. Jackman
Affiliation:
Rensselaer Polytechnic Institute Troy, New York
W. R. Clough
Affiliation:
Rensselaer Polytechnic Institute Troy, New York
Get access

Abstract

Quite recently there has been commercially developed a series of high-alloy steels, on new compositional bases, which possess 3 very desirable combination of unusually high strength, good ductility, and toughness even at comparatively low temperatures. At the same time, research with mechanical working procedures, combined with optimum heat-treat considerations, have produced with several older, more conventional steels, strength levels of high orders of magnitude. Each of the considered materials is capable of yield strengths approaching or exceeding 300,000 psi, corresponding to elastic strains of about 1%.

This paper is concerned with the development and evaluation of workable X-ray stress analysis procedures to be employed to measure, with a good degree of accuracy, high elastic strains. The materials selected include maraging steels, ausformed steels, and cold-drawn A.I.S.I. 4340 steels.

Of the various possible X-ray techniques which were considered, very satisfactory results were obtained by the use of the two-exposure method. A special fixture was designed and constructed to allow uniaxial straining of test specimens while in the X-ray unit. Imposed strains were measured directly by strain gauges mounted on tbe specimen. Simultaneously, strains were measured by the use of chromium radiation filtered with vanadium foil. The peak resolution obtained was very satisfactory with a peak to background ratio of approximately 4:1 for the {211–121} martensite doublet used to measure the shift in peak location between the normal and oblique exposures. Because of the widths of the peaks involved, it is impossible to precisely specify the angular position of a given peak by inspection of the usual recorded trace. A counting technique, combined with a least-squares curve-fitting procedure involving five points, was very satisfactory for precisely locating positions of maximum intensity, Superior results were obtained when a multiplicative correction factor proposed by Koistinen and Marburger was applied.

Type
Research Article
Copyright
Copyright © International Centre for Diffraction Data 1964

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Christenson, A. L. (ed.), The Measurement of Stress by X-Ray, Society of Automotive Engineers, Information Report TR-182.Google Scholar
2. Pittler, K. and Ansell, G. S., “Precipitation in a Hgh Nkkel Maraging Steel,” Trans. Am. Soc. Metals 57(1) :220246, March 1964.Google Scholar
3. Breyer, N. N. and Folarkowski, N. H., “Cold Drawing of Martensitic Steels to 400,000 psi Tensile Strength,” Trans. Am. Soc. Metals 55(3) :667684, Sept. 1962.Google Scholar
4. Justusson, W. M. and Schmatz, D. J., “Some Observations on the Strength of Martensite Formed from Cold Worked Austenite,” Trans. Am. Soc. Metals 55(3):640653, Sept, 1962.Google Scholar
5. Ogilvie, R. E., Stress Measurements with X-Ray Spectrometer, M.S. Thesis, Massachusetts Institute of Technology, Metallurgy Department, 1952.Google Scholar
6. Maloof, S. R. and Erard, H. R., “A Critical Evaluation of the Norelco High Angle X-Ray Spectrometer for Elastic Strain Measurement,” Rev. Sri. Instr. 23(12):687692, Dec. 1952.Google Scholar
7. Koistinen, D. P. and Marburger, R. E., “X-Ray Measurement of Residual Stresses in Hardened Steels,” Proceedings of the Symposium on Internal Stresses and Fatigue in Metals, 1958, pp. 98-109.Google Scholar
8. Koistinen, D. P. and Marburger, R. E., “A Simplified Procedure for Calculating Peak Position in X-Ray Residual Stress Measurements on Hardened Steels,” Trans. Am. Soc, Metals 51:537555, 1959.Google Scholar