GB/T 11344-2021
Non-destructive testing—Ultrasonic thickness measurement (English Version)
- Standard No.
- GB/T 11344-2021
- 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 11344-2021
- Replace
- GB/T 11344-2008
- Scope
- This document specifies ultrasonic thickness measurements for contact method impulse sound measurements. This document applies to ultrasonic thickness measurements of metallic and non-metallic materials.
- Introduction
Analysis of the core content of the standard
Technical elements GB/T11344-2008 GB/T11344-2021 Technological evolution Measurement method Only the contact pulse echo method is specified New requirements for penetration ultrasonic thickness measurement Expand the detection capability of high attenuation materials Calibration system Appendix A is the specification for step test blocks Changed to the sound velocity table for common materials (Appendix A) Strengthen the data support for material properties Uncertainty Not systematically specified Add Appendix D Factors affecting measurement accuracy Establish a quantitative evaluation system
Key points for the implementation of key technologies
Instrument selection matrix
Application scenarios Recommended instrument type Accuracy range Conventional thickness measurement (＞3mm) Digital direct reading ultrasonic thickness gauge ±0.1mm Thin plate/coating measurement High frequency thickness gauge with A-scan (≥10MHz) ±0.01mm High temperature environment (＞60℃) Special high temperature probe + thermal insulation coupling agent Floating depending on working conditions
Typical problem solutions
Measurement of coated materials
When there is a tightly bonded coating on the substrate surface, the standard recommends method 3 (multiple echo method):
- Use a single crystal probe to obtain the 1st to nth bottom echoes
- Calculate the echo spacing ΔT=(Tn-T1)/(n-1)
- Thickness d=v·ΔT/2, automatically exclude the influence of coating
Note: When the difference between the sound velocity of coating and substrate is greater than 15%, separate calibration is required
Background analysis of standard revision
The 2021 version of the standard mainly responds to the following technical development needs:
- ISO16809:2017 non-equivalent adoption to enhance international compatibility
- Adapt to the detection needs of new composite materials and additively manufactured parts
- Strengthen the normative requirements for corrosion monitoring of in-service equipment
GB/T 11344-2021 Referenced Document
- GB/T 12604.1 Non-destructive testing—Terminology—Ultrasonic testing
- GB/T 20737 Non-destructive testing-General terms and definitions
- GB/T 36439 Non-destructive testing.Certification and qualification of aerospace non-destructive testing personnel
- GB/T 9445 Qualification and certification of non-destructive testing personnel*， 2024-09-29 Update
GB/T 11344-2021 history
- 2021 GB/T 11344-2021 Non-destructive testing—Ultrasonic thickness measurement
- 2008 GB/T 11344-2008 Non-destructive testing.Practice for measuring thickness by ultrasonic pulse-echo contact method
- 1989 GB/T 11344-1989 Measuring thickness by ultrasonic pulse-echo contact method