normalizing 1

[2steelsupplier]

hi guys
i recently purchased 350 tonns of asme sa516 gr70 plate from a european steel mill and the material ha failed charpy inpacts (dismal)we have checked the certs and found the plate was normalized @ 30 min per inch,now from reading your forums i understand that asme says 1 hr per inch,do i have any claim on the mill.
just to give u a background on the testing,we have done pwht testing on coupon plates.
soaking temp-625 c heating rate 50c/hour above 350c
time 495 min cooling rate 50c/hour above 350c,customers requirements are 27j ave,18j min at -48 deg.c.
we are getting 14,13,16,25 etc.
i am now re-normalizing 3 plates to see if this will rectify the problem(is this the right way to go????)

 

[stanweld]

Whereas SA-516 does not specify a minimum soak time at the normalizing temp., your P.O. requirements will dictate any valid claims against the steel manufacturer; by the way, you neglected to state the plates' thickness and whether the vessel is subject to PWHT. I find it hard to believe that you would purchase steel without mill certification of the Client's impact toughness requirements. If that was so, "caveat emptor" let the buyer beware!

On a positive note, renormalizing may very well achieve the required results.

 

[2steelsupplier]

hi ,tnx for the response,the material is half 40mm and half 50 mm,and yes the vessel has 4 x PWHT.we purchased the material from the mill with only short cycle pwht 1hr and planned on doing the long cycle in south africa because of the costs involved (no need to tell me )i have learnt that this was the wrong way to go ,just so you know the mill refused to take on the order with the long cycle pwht .

 

[stanweld]

Wishing you good luck on your renormalizing and tempering efforts. Based on the Charpy values currently obtained (assume includes 4 X PWHT), you have a high probability of success. I have done this a number of times successfully. I have had one failure with the longer PWHT time and you may wish to use a shorter PWHT should the 4X prove a detriment.

 

[weldtek]

2steelsupplier,
I don't understand. Normally, one would purchase material in the Normalized condition, and PWHT the test coupons with the longest anticipated cycle at the highest temperature required for the fabricated component. If its 1 hour then PWHT the test coupons for 1 hour, if it requires multiple cycles then PWHT the test coupons accordingly.
There's no need to PWHT the plate before fabrication, just the test coupons. The cost for 1 hour vs 4 hours would be minimal. The mil may have refused the order with the long PWHT cycle because they weren't comfortable with meeting impacts in that condition.