BS EN ISO 16946:2015 pdf download – Non-destructive testing — Ultrasonic testing — Specification for step wedge calibration block.
1 Scope This International Standard specifies the dimensions, material, and manufacture of a step wedge steel block for the calibration of ultrasonic instruments. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. 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 inspection — Vocabulary EN 1330-4, Non-destructive testing — Terminology — Part 4: Terms used in ultrasonic testing 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 1330-4 apply. 4 Dimensions The dimensions of the block are given in Figure 1. The tolerances are ±0,1 mm for length and width of the block and −0,02 mm for the step thickness. All external surfaces shall be machined to an Ra value not greater than 0,8 µm.
5 Alternative dimensions In the event of a different size of calibration block being required which is not described in this International Standard, the principles embodied in the design and manufacture of a calibration block to the requirements of this International Standard shall be applied to such a block. The tolerances are ±0,1 mm for length and width of the block and −0,02 mm for the step thickness up to 12,5 mm and −0,1 mm for larger thickness. 6 Material The calibration block shall be made from steel of grade S355J0 in accordance with EN 10025-2 or from equivalent steel grade. 7 Preparation Blocks shall be rough-machined to a plan parallel plate, which is at least 3 mm larger at all sides than the dimensions of the finalised step block. In order to obtain a fine grain structure and good homogeneity, the block shall be heat treated as follows: a) maintain at 920 °C for 30 min; b) rapid cooling (quenching) in water; c) tempering by heating to 650 °C for at least 3 h; d) cooling in still air.