GB/T 24606-2021
Rolling bearings—Non-destructive testing—Magnetic particle testing (English Version)
- Standard No.
- GB/T 24606-2021
- Language
- Chinese, Available in English version
- Release Date
- 2021
- Published By
- General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
- Latest
- GB/T 24606-2021
- Replace
- GB/T 24606-2009
- Scope
- This document specifies the procedures for wet magnetic particle testing of rolling bearing parts (hereinafter referred to as "parts"). This document is applicable to the magnetic particle inspection of surface and near-surface defects of bearing parts made of ferromagnetic materials (including raw materials, blanks, semi-finished products, finished products, and in-service repair parts).
- Introduction
Core changes in the standard revision
Revision items 2009 version 2021 version Technical significance Magnetic powder particle size Not clearly specified ≤45μm (320 mesh) Increase the detection rate of minor defects Carrier liquid requirements Including formula Performance indexation Enhance operability Contamination control No specific requirements Lamination≤30% Ensure detection stability Test piece standards Basic requirements Add A1/D series Improve sensitivity system
Analysis of key technical requirements
1. Selection of magnetization method
The standard clearly distinguishes the application scenarios of continuous method and residual magnetism method:
- Continuous method: Applicable to parts with complex shapes, allowing composite magnetization (Clause 7.2)
- Residual magnetism method: Magnetization must be performed in steps and demagnetization is required (Clause 7.3)
Application case: tapered roller bearing inspection
The center conductor method (Clause 8.3.1) is combined with the coil method (Clause 8.6) to achieve circumferential and longitudinal dual magnetization. The magnetizing current is calculated according to formula (2): NI=35000/(D+2)
Implementation points
1. Magnetic suspension quality control
The standard establishes a complete quality monitoring chain:
- Preparation stage: Use special carrier fluid according to Clause 6.3.5
- Use stage: Perform water break test (Clause 6.3.7)
- Scrap standard: Contaminant stratification＞30% (Clause 6.3.4)
Analysis of Standard Evolution
2021 version strengthens process control:
- Added upper limit requirements for magnetic powder particle size (Clause 6.3.1)
- Refine the parameters of ultraviolet light source (Clause 6.1.4)
- Introduce a water-based carrier liquid system (Clause 6.3.2.2)
GB/T 24606-2021 Referenced Document
- GB/T 12604.5-2020 Non-destructive testing—Terminology—Magnetic particle testing
- GB/T 15822.2-2005 Non-destructive testing.Magnetic particle testing.Part 2:Detection media
- GB/T 23907-2009 Non-destructive testing.Shims for magnetic particle testing
- GB/T 261-2008 Determination of flash point.Pensky-Martens closed cup method
- GB/T 265-1988 Petroleum products--Determination of kinematic viscosity and calculation of dynamic viscosity
- GB/T 9445-2015 Non-destructive testing.Qualification and certification of NDT personnel
- JB/T 6641-2017 Standard for residual magnetism of rolling bearings and its evaluation method
- JB/T 8290-2011 Non-destructive testing instruments.Magnetic particle flaw detectors
GB/T 24606-2021 history
- 2021 GB/T 24606-2021 Rolling bearings—Non-destructive testing—Magnetic particle testing
- 2009 GB/T 24606-2009 Rolling bearings.Non-destructive testing-Magnetic particle testing