Welding API 5LX 65.....Preheat, PWHT, Chemistry

By maxmachine1 Date 06-03-2007 13:23 Edited 06-04-2007 07:15

Hi Guys....I Wonder if you can help me with some recommendations for Welding API 5LX 65 with regard to Preheat, PWHT(Temperature, Soak Time), Recommended SAW(Wire,and Flux combination), Recommended FCAW Consumables taking PWHT into account.

thickness Range is 30mm-125mm....Thanks Alot

By 803056

Date 06-04-2007 20:00

API 5LX 65 isn't included in AWS D1.1 as an prequalified base metal.

I didn't find it listed in AWS B2.1 either. I did find API 5L X65 in the API 5L specification and AWS B2.1 in which it is listed as a M1, Group 3 HSLA steel.

API 5L lists the YP as 65 ksi and the UTS as 77 ksi.

The carbon equivalency for welded pipe is around 0.5 using the IIW formula which is on the high side.

I don't see any approved SAW flux and electrodes listed in API 1104 or AWS D1.1 that would produce an UTS of 80 ksi (which would be my first choice). You can try a F7X2-EM13K or F7X2-EM15K and see what you develop for the UTS.

The preheat would be on the order of 320 to 350 degrees F. If you need to do a PWHT, try 1150 degrees F for one hour plus 30 minutes for each 25 mm over 75 mm.

Good luck.

Al

By maxmachine1 Date 06-12-2007 04:30

Thanks alot...I appreciate your help...

By js55

Date 06-12-2007 14:09

A low alloy may be helpful in ensuring you exceed the 77. I think you're gonna need to beat it with a bit of a margin since the Yield/Tensile ratio of the 5L X65 is higher than most fillers. Be conscious of the yield and make sure you get yield data from the lab after mechanical testing.