20:07 May-04-2009 aldo Engineering Italy, Joined Jan 2009 39
set-up equipment in AC
I have a question on efficiency equipment..
I usually determinate the efficiency equipment with ketos ring following the ASTM E1444 on value of direct corrent (1400A,2500A,3400A) and on numbers of the artifical sub-surface defects (3,5,6)...In ASTM is specified direct corrent..
In most case on my job i use the alternative current to check the surface defects (
especially fatigue crack)..I make the set-up on direct current (ketos ring) but i magnetize in alternative current.. The question is follow:
ASTM does not specific the test for set-up efficiency equipement in alternative current..
Why? If the equipement is efficient with ketos ring (direct current) it is also efficient in alternative current?
Thanks and best regards