pre heating of alloy pipe
pre heating of alloy pipe
(OP)
As per B31.3, I understand all P11 materials has to be pre heated. So our client has asked to pre heat even for fit up also. Now the issue I am facing is regarding the small bore. I dont understand how I could preheat to 150 C and do fit up as it will be too hot to handle the fitting being small bore.
I understand pre heating is done to reduce the rate of cooling of weld to reduce the hardness. Hence is there any possibility to waive the requirement during fit up or any alternative method possible for fit. Looking for your comments
I understand pre heating is done to reduce the rate of cooling of weld to reduce the hardness. Hence is there any possibility to waive the requirement during fit up or any alternative method possible for fit. Looking for your comments





RE: pre heating of alloy pipe
The preheat is for the Heat Affected (Weld) Zone ONLY not for the whole pipe.
Their requirement is wrong, but you must be "diplomatic" in how you tell them that fact. Ask THEM to show you where THEIR reference is that THEY read so you can "review it properly" ... Simply but correctly telling them to 'shove it where the reg can't be read" is NOT a diplomatic answer.
RE: pre heating of alloy pipe
RE: pre heating of alloy pipe
RE: pre heating of alloy pipe
RE: pre heating of alloy pipe
thanks
RE: pre heating of alloy pipe
If I was the client, however, I would also require preheating for fit-up. Honestly, you run the risk of cracking without proper preheat, which you may not detect. Why should the client accept that risk? Can you use a mechanical positioner to hold the fitting after preheat?
rp
RE: pre heating of alloy pipe
RE: pre heating of alloy pipe
Ive always considered the 100F drop in sect IX related to procedure qualifications rather than Construction code requirements.
RE: pre heating of alloy pipe
Switch to your tig gloves after the fit if you are using GTAW. Using a gauntlet with a thicker knuckle and a tig finger is a good idea. Thicker gloves aren't impossible with SMAW, though its nice to have that sensitivity that tig gloves provide.
Also, be religious with your interpass temperatures. Get out the temperature crayons, I regularly catch welders in our shop not using temp sticks to monitor interpass temperatures and have to order repair and reworks.
RE: pre heating of alloy pipe