UT SEP 1921/84 STANDARD
This spec is applicable to forged and hot-rolled, raw or processed steel bars in alloyed or non-alloyed steels, in natural state or treated condition. The inspection method for the search of internal defects can be freely chosen by the supplier (instrumentation, 1-4 MHz probes, coupling methods, etc.) as long as the test is carried out on the entire number of pieces. All defects (indications) bigger than the agreed-upon values must be described according to their position, size, extension and have to be reproduced in a drawing.
Acceptance limits
Table 1
Size Category | Single defects, mm (1) | Defects with extension, mm | Max. extension, mm |
А | 14 | 10 | 80 |
Б | 10 | 7 | 60 |
В | 7 | 5 | 40 |
Г | 5 | 3 | 30 |
Д | 3 | 2 | 30 |
(1) The distance between single defects must be min. 50 mm; where the distance is lower, defects must be considered with their extension.
Number of defects on individual pieces
Table 2
Frequency Category | Number of defects | Number of defects with extension |
а | 32 | 16 |
б | 16 | 8 |
в | 8 | 4 |
г | 4 | 2 |
д | 2 | 1 |