ASTM E2860-12
Standard Test Method for Residual Stress Measurement by X-Ray Diffraction for Bearing Steels

Standard No.

ASTM E2860-12

Release Date

2012

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM E2860-20

Latest

ASTM E2860-20

Scope

This test method covers a procedure for experimentally determining macroscopic residual stress tensor components of quasi-isotropic bearing steel materials by XRD. Here the stress components are represented by the tensor σ_ij as shown in Eq 1 (1, p. 40). The stress strain relationship in any direction of a component is defined by Eq 2 with respect to the azimuth phi(ϕ) and polar angle psi(ψ) defined in Fig. 1 (1, p. 132).

Alternatively, Eq 2 may also be shown in the following arrangement (2, p. 126):

Using XRD and Bragg’s law, interplanar strain measurements are performed for multiple orientations. The orientations are selected based on a modified version of Eq 2, which is dictated by the mode used. Conflicting nomenclature may be found in literature with regard to mode names. For example, what may be referred to as a ψ (psi) diffractometer in Europe may be called a χ (chi) diffractometer in North America. The three modes considered here will be referred to as omega, chi, and modified-chi as described in 9.5.

Omega Mode (Iso Inclination) and Chi Mode (Side Inclination)8212;Interplanar strain measurements are performed at multiple ψ angles along one ϕ azimuth (let ϕ = 0°) (Figs. 2 and 3), reducing Eq 2 to Eq 3. Stress normal to the surface (σ₃₃) is assumed to be insignificant because of the shallow depth of penetration of X-rays at the free surface, reducing Eq 3 to Eq 4. Post-measurement corrections may be applied to account for possible σ₃₃ influences (12.12). Since the σ_ij values will remain constant for a given azimuth, the s₁^{hkl} term is renamed C.

The measured interplanar spacing values are converted to strain using Eq 24, Eq 25, or Eq 26. Eq 4 is used to fit the strain versus sin²ψ data yielding the values σ₁₁, τ₁₃, and C. The measurement can then be repeated for multiple phi angles (for example 0, 45, and 90°) to determine the full stress/strain tensor. The value, σ₁₁, will influence the overall slope of the data, while τ₁₃ is related to the direction and degree of elliptical opening. Fig. 4 shows a simulated d versus sin²ψ profile for the tensor shown. Here the positive 20-MPa τ₁₃ stress results in an elliptical opening in which the positive psi range opens upward and the negative psi range opens downward. A higher τ₁₃ value will cause a larger elliptical opening. A negative 20-MPa τ1.1......

ASTM E2860-12 Referenced Document

• ASTM E1426 Standard Test Method for Determining the Effective Elastic Parameter for X-Ray Diffraction Measurements of Residual Stress
• ASTM E6 Standard Terminology Relating to Methods of Mechanical Testing
• ASTM E7 Standard Terminology Relating to Metallography
• ASTM E915 Standard Test Method for Verifying the Alignment of X-Ray Diffraction Instrumentation for Residual Stress Measurement

ASTM E2860-12 history

• 2020 ASTM E2860-20 Standard Test Method for Residual Stress Measurement by X-Ray Diffraction for Bearing Steels
• 2012 ASTM E2860-12 Standard Test Method for Residual Stress Measurement by X-Ray Diffraction for Bearing Steels