GB/T 5617-2025 PDF English
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GB/T 5617: Historical versions
| Standard ID | USD | BUY PDF | Delivery | Standard Title (Description) | Status |
| GB/T 5617-2025 | 260 | Add to Cart | Auto, 9 seconds. | Determination of surface hardening depth for steel | Valid |
| GB/T 5617-2005 | 125 | Add to Cart | Auto, 9 seconds. | Determination of effective depth of hardening after induction or flame hardening of steel | Valid |
| GB/T 5617-1985 | 199 | Add to Cart | 2 days | Determination of effective depth of hardening after induction or flame hardening of steel | Obsolete |
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GB/T 5617-2025: Determination of surface hardening depth for steel
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT5617-2025GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 25.200 CCS J 36 Replacing GB/T 5617-2005 Determination of Surface Hardening Depth for Steel Issued on: AUGUST 29, 2025 Implemented on: MARCH 1, 2026 Issued by. State Administration for Market Regulation; Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3 1 Scope... 5 2 Normative References... 5 3 Terms and Definitions... 5 4 Symbols and Abbreviated Terms... 6 5 Principle... 6 6 Test Equipment... 7 7 Specimen... 7 8 Test Methods... 9 9 Evaluation of Results... 10 10 Test Report... 11 Appendix A (Normative) Determination of Surface Hardening Depth by Interpolation Method... 13 Bibliography... 15 Determination of Surface Hardening Depth for Steel1 Scope
This Document specifies the test principles, test equipment, specimens, test methods, result evaluation, and test report for the surface hardening depth of steel and the total thickness of surface hardening depth. This Document applies to parts subjected to surface hardening methods such as induction hardening, flame hardening, laser hardening, and electron beam hardening, etc.2 Normative References
The provisions in following documents become the essential provisions of this Document through reference in this Document. For the dated documents, only the versions with the dates indicated are applicable to this Document; for the undated documents, only the latest version (including all the amendments) is applicable to this Document. GB/T 4340.1 Metallic materials - Vickers hardness test - Part 1.Test method GB/T 4340.2 Metallic materials - Vickers hardness test - Part 2.Verification and calibration of testing machines GB/T 7232 Metal heat treatment - Terminology GB/T 18449.1 Metallic materials - Knoop hardness test - Part 1.Test method GB/T 18449.2 Metallic materials - Knoop hardness test - Part 2.Verification and calibration of testing machines3 Terms and Definitions
For the purposes of this Document, the terms and definitions given in GB/T 7232 and the following apply. 3.1 Surface hardening depth; SHD The vertical distance from the workpiece surface to the specified boundary hardness. NOTE. Boundary hardness = A × minimum surface hardness (HV) by the technical requirements. Typically, A = 0.8. 3.2 Total thickness of surface hardening depth; THD The distance from the workpiece surface to the boundary with the same hardness as the substrate. NOTE. The total thickness of surface hardening depth is measured using either hardness or metallography, with metallography being the most commonly used method.4 Symbols and Abbreviated Terms
The symbols and abbreviated terms given in Table 1 apply to this Document.5 Principle
5.1 The hardness gradient curve on a cross section perpendicular to the workpiece surface is used to determine the hardening depth. 5.2 The hardening depth is determined graphically from the hardness distribution curve as a function of distance from the surface. 5.3 When measuring the total thickness of surface hardening depth using the hardness method (detecting hardness changes), a tangent to the hardness distribution curve is drawn in the area where the hardness decreases significantly. The distance from the intersection of this tangent with the core hardness curve to the surface is the total thickness of surface hardening depth (see Figure 1). When measuring using the metallographic method, the distance from the surface to the boundary where no visible change occurs with the matrix structure is the total thickness of surface hardening depth. The test report shall indicate whether the hardness method or metallographic method was used.6 Test Equipment
6.1 The Vickers hardness test shall be conducted. The hardness tester shall be inspected and calibrated in accordance with the provisions of GB/T 4340.2. 6.2 The Knoop hardness test may also be used, with the hardness tester inspected and calibrated in accordance with the provisions of GB/T 18449.2, upon agreement between the parties involved. 6.3 When measuring the total thickness of surface hardening depth after using metallographic methods, the hardened layer shall occupy 1/3 to 2/3 of the microscope's field of view.7 Specimen
7.1 Unless otherwise agreed, the hardened layer depth shall be measured on a cross section of a part that meets the following conditions. a) The test cross section shall be perpendicular to the longitudinal axis of the part. If no longitudinal axis exists, the test may be conducted on a cross section perpendicular to a specific surface of the workpiece by agreement between the parties involved. b) The specimen shall adopt a polished, non-corroded surface. The specimen shall be cut using a gentle technique and secured to ensure a good edge. When grinding and polishing, use appropriate abrasives to remove any surface damage from the cutting and grinding process to avoid affecting the hardness of the test surface and to avoid rounded edges. The test surface shall be polished to a size sufficient to accurately measure the hardness indentation. The lower the test force, the higher the quality of specimen preparation ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
