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. Defect recording must be done according to the F.B.H. (flat-bottom-hole) method. 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. Such a condition has to be sent to the Lucefin Group’s Technical Department for evaluation.

Acceptance limits

Table 1

Size Category

Single defects

Defects with extension

Max. extension

mm FBH  (1)

FBH  mm 

mm

A

14

10

80

B

10

7

60

C

7

5

40

D

5

3

30

E

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

a

32

16

b

16

8

c

8

4

d

4

2

e

2

1