GB/T 18852-2020
Non-destructive testing—Ultrasonic testing—Reference blocks and test procedures for the characterization of contact probe sound beams

Standard No.

GB/T 18852-2020

Language

Chinese

Release Date

2020

Published By

国家市场监督管理总局、中国国家标准化管理委员会

Lastest

GB/T 18852-2020

Replace

GB/T 18852-2002

Scope

This standard specifies the measurement method for the sound beam characteristics of the sound field inside the workpiece when the probe is in contact with the workpiece to be inspected. Probes include straight probes, oblique probes (refracted longitudinal waves and refracted shear waves), focused probes and dual crystal probes. This standard recommends two metal reference test blocks, which are semicircular step test block (HS test block) and horizontal hole test block (SDH test block). The diameter or side length of the probe element shall not be greater than 25 mm. This standard specifies the measurement guidelines for the sound beam characteristics of probes suitable for testing forged steel, rolled steel, aluminum alloy or titanium alloy products. This standard applies to the frequency range of probes from 1 MHz to 15 MHz. 1 MHz~5 MHz is the most suitable frequency range for the detection of iron and steel products, and 5 MHz~15 MHz is the most suitable frequency range for the detection of fine grain structure products (such as aluminum alloy products). If this standard is applied to testing other than steel products, the testing personnel should pay attention to the fact that the sound velocity of the material is different from that of steel, and the nominal refraction angle of the angle probe is usually designed for testing in steel. This standard gives Snell's law, so that inspectors can calculate the internal refraction angle of other isotropic and fine-grained materials. This standard applies to angle probes, focusing probes and dual crystal probes whose actual refraction angle ranges from 0° to 70°. This standard does not apply to surface wave (Rayleigh) probes. This standard does not involve the use of flat-bottomed hole test blocks to evaluate the equivalent size of imperfections. This standard does not specify acceptance terms, but establishes a technical basis for testing personnel to formulate acceptance terms for probe performance.

GB/T 18852-2020 Referenced Document

• ISO 5577 Non-destructive testing - Ultrasonic testing - Vocabulary
• ISO 7963 Non-destructive testing — Ultrasonic testing — Specification for calibration block No. 2*， 2022-10-05 Update

GB/T 18852-2020 history

• 2020 GB/T 18852-2020 Non-destructive testing—Ultrasonic testing—Reference blocks and test procedures for the characterization of contact probe sound beams
• 2002 GB/T 18852-2002 Ultrasonic non-destructive testing--Reference blocks and test procedures for the characterization of contact search unit beam profiles