SS Overlay on 4130 Steels 1

[KnaT]

Guys,

I want to qualify a new ASME IX procedure for Corrosion Resistant Overlay Welding on AISI 4130(75 Ksi Y.S Min / 95 Ksi Min T.S)base metal using E316L-17 electrodes without using PWHT (Stress Relieving).

Question 1:From the equivalents that I have seen, AISI 4130 steels are said to be matching A 519 which are P-1 materials as per ASME Sec IX. Can I follow that convention or are they closer to P-4 Materials?

Question 2: Is there a compulsion to perform PWHT for these 4130 Co-Mo Alloys?

Question 3: All the previous procedures in my records are with PWHT. I am unable to understand why. Are there chances of failure of the test coupon without the PWHT?

Question 3: Can I get some suggestions for controlling my heat input, current/voltages etc. to ensure minimum amount of resident stresses in the base metal. I just don't want to waste all the testing cost for nothing.

 

[metengr]

Question 1:From the equivalents that I have seen, AISI 4130 steels are said to be matching A 519 which are P-1 materials as per ASME Sec IX. Can I follow that convention or are they closer to P-4 Materials?

You do not need to attempt to assign an equivalent P-No. This material is not listed by ASME B&PV Code, it is unlisted. Just state the material in the WPS as what is being qualified, e.g., 4130

Question 2: Is there a compulsion to perform PWHT for these 4130 Co-Mo Alloys?

It depends on the application. For a weld overlay, you may get by with elevated preheat. Bend and tensile testing will determine if this can be done without PWHT.

Question 3: All the previous procedures in my records are with PWHT. I am unable to understand why. Are there chances of failure of the test coupon without the PWHT?

Because the concern is with the heat affected zone lack of ductility in the 4130 base material.

Question 3: Can I get some suggestions for controlling my heat input, current/voltages etc. to ensure minimum amount of resident stresses in the base metal. I just don't want to waste all the testing cost for nothing.

First off, you are not going to weld 316L weld metal directly on the 4130 base material. This will result in failure due to dilution problems. You will need to qualify the weld overlay using an E309 butter layer followed by the E316 stainless weld metal that will be of sufficient thickness to meet the chemical composition requirements for 316 (no dilution effects with the 309 weld deposit).

Use the same welding parameters as used with the WPS that was qualified with PWHT. Except, increase the preheat to 400 deg F, minimum.

 

[jbeckhou]

@KnaT
API and NACE requirements?

Petrotrim Services

http://www.petrotrim.com

 

[KnaT]

Thanks a lot Metengr. I have noted all of your answers. I have gone through our database for Overlay Procedures, none of which specify E309 butter layer. I have posted another thread with the exact details of Base Material and Preheat, Interpass Temperatures etc. I will appreciate it if you could have a look at that too.

Btw... I have to ensure compliance to NACE MR 0175 and API 6A Requirements.

 

[KnaT]

here is the link to the other thread:

http://www.eng-tips.com/viewthread.cfm?qid=334063