BS EN ISO 16946 pdf free download

BS EN ISO 16946-2015 pdf free download.Non-destructive testing 一Ultrasonic testing一 Specification for step wedge calibration block.
BS EN ISO 16946 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 pm.
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 mm;
b) rapid cooling (quenching) in water;
c) tempering by heating to 650 °C for at least 3 h;
d) cooling in still air.
After heat treatment, at least 2 mm shall be removed from all surfaces.
Prior to final machining, the block shall undergo ultrasonic testing to prove that the block is free from internal discontinuities.
For this purpose, an ultrasonic test shall be performed with a longitudinal wave normal-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 from at least two long surfaces to cover the complete volume. The following two acceptance criteria apply:
1) with the probe scanning as shown in Figure 2. the noise level produced by the grain structure shall always be at least 50 dB lower than the amplitude of the fourth back wall echo;
2) no echo arising from any discontinuity in the material shall have an amplitude greater than the grain scatter noise level.
The velocity of longitudinal waves shall be verified as being 5 920 m/s土30 m/s.
8 Marking
The block shall be permanently marked with
a) manufacturer’s trade mark,
b) number of this International Standard, and
c unique serial number.
9 Declaration of conformity
For each block, a declaration shall be issued by the manufacturer stating
a) that the block complies with this International Standard, and
b) the mean value of the measured longitudinal wave velocities, VI.BS EN ISO 16946 pdf download.