GB/T 39082-2020 in English

Interpretation of the core content of the standard

This standard modification adopts the ISO 14271:2017 international standard and establishes a systematic Vickers hardness test specification for resistance spot welding, projection welding and seam welding joints. The main technical features include:

Key Technical Requirements

1. Specimen Preparation Specifications

Based on the differences in weld joint morphology, the standard specifies three sampling schemes:

• Circular welds: Sections in any direction (diameter ratio <1.3)
• Strip welds: Longitudinal sections perpendicular to the welding direction
• Special shapes: Sampling in multiple directions according to application standards

2. Test location selection

The standard recommends two indentation distribution modes:

1. Vertical + horizontal distribution lines: center of weld core + t/4-t/2 from the fitting surface
2. Oblique distribution line: t/4-t/3 from the parent material surface

Implementation points and common problems

Precautions

• Avoid hardness testing at shrinkage holes/fitting surface defects
• Horizontal distribution lines need to be established for different plate thicknesses
• Metallographic corrosion must be performed before microhardness testing

Standard Evolution and Innovation

Compared with the original ISO version, the main improvements of GB/T 39082-2020 include:

• Add test specifications for seam welded joints
• Clarify the principles for selecting test force classification
• Refine the sampling diagrams for different joint types

Test report preparation

The report must contain 9 core information, among which the hardness indentation location diagram and test force value are key quality control points. It is recommended to use the three-dimensional coordinate annotation method to record the indentation location.