BS ISO 19675:2017 pdf download – Non-destructive testing — Ultrasonic testing — Specification for a calibration block for phased array testing (PAUT)
This document specifies requirements for the dimensions, material and manufacture of a steel block for calibrating ultrasonic test equipment used in ultrasonic testing with the phased array technique.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5577, Non-destructive testing — Ultrasonic testing — Vocabulary
EN 16018, Non-destructive testing — Terminology — Terms used in ultrasonic testing with phased arrays
EN 10025-2, Hot rolled products of structural steels — Part 2: Technical delivery conditions for non-alloy structural steels
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5577 and EN 16018 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Abbreviated terms
ACG angle-corrected gain
FSH full-screen height
RF radio frequency
SDH side-drilled hole
SNR signal- to-noise ratio
TCG time-corrected gain
Blocks shall be manufactured from steel grade S355J0, in accordance with EN 10025-2, or equivalent.
5.2 Pre-machining and heat treatment
5.2.1 Raw blocks
Raw blocks shall be rough-machined to a dimension of 320 mm × 120 mm × 30 mm before heat
5.2.2 Heat treatment
The heat treatment shall consist of:
1) austenitizing at 920 °C for 30 min;
2) rapid cooling (quenching) in water;
3) tempering by heating to 650 °C for 3 h;
4) cooling in still air.
5.2.3 Checking prior to final machining
It is recommended to pre-machine the block to the following dimensions: 305 mm × 101 mm × 26,5 mm.
All external surfaces shall be pre-machined to a roughness value not greater than 1,6 μm R a .
The pre-machined block shall be in accordance with the following.
a) It shall be free from internal discontinuities. For this purpose, an ultrasonic test shall be carried out after heat treatment, with a longitudinal wave straight-beam probe of at least 10 MHz nominal centre frequency and having a transducer size of 10 mm to 15 mm. The block shall be checked on all four long faces to cover the complete volume. With the probe positioned on the largest face of the block, the instrument’s gain shall be set to achieve a grain scatter noise of 10 % of full screen height. No echo shall have an amplitude greater than that of the grain scatter noise;
b) It shall be isotropic for transverse and longitudinal waves proved by velocity measurements in accordance with Annex A (see A.3). Probes shall be located around the mid-position of each of the three faces;
c) It shall present low sound attenuation. NOTE Absolute measurements of attenuation may be difficult to obtain because echo amplitudes depend on many factors. The significance of attenuation can be estimated by simple qualitative tests. Relative attenuation measurements can be made by examining the exponential decay of multiple back wall reflections [a satisfactory attenuation generally is proven by the observation of at least four echoes above of 25 % of FSH when a probe as recommended in 5.2.3 a) is used]. See Figure 1.
5.3 Final machining
5.3.1 Dimensions and surface finish
The dimensions and tolerances of the phased array calibration block shall be determined and recorded in accordance with Annex A (see A.2) and shall be in accordance with Figure 2. All external surfaces shall be machined to a roughness value not greater than 0,8 μm R a
5.3.2 Reference marks
Permanent reference marks shall be engraved on the block in accordance with Figure 3 and Table 1.