Welding API 5L X70 steel to SA182 F22 2

[lukerobert]

My first post on this forum... A pleasant surprise to find this place. I have a project that requires joining 5/8" thick material of the grades listed above. The first coupon was performed with an E80xx (GTAW) and subsequent passes with e100xx (SMAW) fillers. The coupon failed hardness. Preheat was 500F and interpass was 600F with PWHT 1175F for 4 hrs. Im thinking about going to an e80xx for all passes and hoping to pass tensile. Any thoughts from someone with experience with this combination is appreciated.

 

[metengr]

Yes. The filler metal selection was too high in strength using the 100XX filler metal. You should be using E80XX or ER80S B2 for the entire joint.

 

[stanweld]

With the "B2" filler metal, PWHT at 1250 F is recommended. You haven't defined where hardness failed. P22 HAZ and/or weld metal?

 

[lukerobert]

The sample failed hardness in the HAZ and Cap. So, thinking further into it, it looks like selection of filler and heat are both issues I need to consider. Max PWHT has to be 1175 because that just barely keeps me below the tempering temp of the X70.

 

[metengr]

I am assuming the hardness failed in the F22 side of the weld joint HAZ. If this is the case, here is what you need to do – first, butter the entire F22 side of the weld joint using the ER 80S-D2 filler metal. PWHT the F22 after buttering at 1300 deg F. When this is completed, fit-up and weld the X70 material to the buttered F22 base material using ER80S-D2 for the root and hot pass followed by E8018 B2 to complete the joint with no PWHT.

 

[Guest102023]

We need more information from the get-go. Where and how (hi or low) did hardness fail?

X70 is microalloyed and thus should never experience PWHT. Buttering is a technique for getting around PWHT incompatibility.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[lukerobert]

The following are the hardness readings (Vickers 10kg) in the F22 HAZ from cap to root-295,299,254,257,254.

These are the readings on the X70 HAZ from cap to root- 261,242,196,216,221

 

[metengr]

As I would have expected. The lack of PWHT for the F22 is the critical concern for hardness. Follow what I mentioned above for buttering.

 

[SJones]

According to the initiating post, the coupon had 1175 deg F for 4 hours.

What is the hardness acceptance criterion? Is it 248 HV10? And, do you need to hit Charpy energy criteria too?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[metengr]

According to the initiating post, the coupon had 1175 deg F for 4 hours

The initial PWHT was inadequate.

 

[lukerobert]

We need to maintain NACE criteria which is 250 Vickers as well as Charpy impact. We couldn't PWHT any higher than 1175 because this would surpass the tempering temp of the X70. I like Metenger's idea of the buttering.

 

[SJones]

Indeed, but the X70 still failed!!

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[metengr]

It failed at the cap region only, and this was probably because of weld depostion technique or an interpass temperature problem.