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