PQR-Hardness Issues on HAZ

By Dinesh.T Date 08-02-2016 02:33

I used the GTAW + SAW for weld the 4130-4130 Pipe(Test Coupon Dia 18" x Thick 1") after PWHT I did not achieve the hardness as per NACE requirements on HAZ. May I know what is the reason behind in this case? Yield Strength-75KSI, Tensile Strength-90KSI, PWHT Temp- 640 Degree Celsius.

By 803056

Date 08-02-2016 04:15

Stress relief performed at a higher temperature (760 C) and cooled slowly may by a solution to your problem.

Al

By jstnjstn Date 08-02-2016 18:15

Hello Dinesh,
Can you provide more information? Did you have an ramp/hold times?

By Dinesh.T Date 08-04-2016 06:00

Preheat - 230⁰C
Inter pass - 320⁰C
Heating & Cooling Rate - 90⁰C/ Hour
Holding Time – 6 hours at 642⁰C (Material Tempering Temperature - 680⁰C)

First three pass - GTAW (wire- Lincoln Ak 10)
Rest - SAW (Wire LA 82 + Flux 812 SRC)

I need to know whether my welding consumable selection wrong, or parameters wrong like (Speed, Feed etc..,)

By jrupert (*)

Date 08-22-2016 17:59

Parameters are only part of successfully passing HAZ hardness on a 4130 qualification. I hate to even say this, but you need to find the right 4130 chemistry for your coupon. The chemistry for 4130 is wide open and there are some grades almost impossible to pass (NACE) based on the micro alloying elements. You should be able to locate this info with some basic research on the net.