Flame Straightening distorted butt welded joints

By Nallavan Date 03-07-2018 19:51 Edited 03-07-2018 21:21

Dear Experts

Design/Construction Code - AWS D1.1

Flame Straightening distorted butt weld joints by heating and water cooling directly on the affected welds.
Flame Straightening Temperature- 650-660 deg C

Pls advise if allowed or prohibited.If prohibited,why? Pls provide appl code ref.

Material - ABS Grade EH36 x 30mm(thk) x 9M(Length)
Joint Type- Double-V ( 1/3 x 2/3 Bevel )
Weld Process - SAW
Weld Position- 1G

By jwright650 (*****)

Date 03-08-2018 12:17

What are you trying to gain by quenching in water?
It is not advised to use water to rapid quench steel from a temperature of 1200°F. Can you use compressed air instead of water?

By 803056

Date 03-09-2018 05:22

As long as the maximum temperature is not above the lower temperature of transformation; no harm, no foul. The steel noted in the post can only be hardened if it is quenched from a temperature above the transition temperature. Even then, the degree of hardening is very limited due to the low carbon content even if it was fully austenitized and quenched.

Al

By Nallavan Date 03-10-2018 03:13

Dear Sir

It will expedite flame straightening process. I advise shop team to use compressd air and/or allow it to cool naturally but they dont agree with me. That`s why I need to have data/code or spec ref. to prove this incorrect practice. Need Forum members expertise.

By jwright650 (*****)

Date 03-12-2018 11:01

I agree with Al in that 36 grade material will survive with a small amount of hardening, but it isn't a good practice for a shop to get into cooling off with water....I realize that it moves a bit quicker when you quench it with water but it isn't good shop practice, IMHO. At least let the color fade out (1000F) of it before letting the water dance off of it, better yet once it gets down past 500-550F it would be better.

By jinglanh Date 05-05-2018 07:47

so incase after welding surface steel undulary with thk 4mm , How we can apply quenching with air compressor and time to do this ? could u give me other proposal ?