How to Select Filler Rods For Welding Similar & Dissimilar Metals

In case you are working on PV- these answers are to be strictly in line with ASME PV Codes.

However the question asked imply you do not have the relevant WPS (let us forget about hence the PQR and WQR)

Do not carry out welding on boiler parts without access to the correct code of practice for the job. The requested 'ready-reckoner' will be found within them!

A welder will confuse you with all sorts of technical jargon, however, I worked in a food processing plant a few years ago, and had a cracked black iron steam pipe that had to be pressurized in a few hours.

I first ground the valley and then welded it with 7018 stick, then reinforced it with 6013(or 6011, Hey, it's been over five years!).

It held for the year that I worked at that plant!

I don't remember procedure, but if I check my base metal, watch my puddle and my heat I do OK (Translation, nothing I've done has broken yet!).

All I can say is find some scrap pieces and during your breaks practice, practice, practice and practice some more until you get it right, and get a trusted welder friend to evaluate your work. I did, and I wound up doing all the "emergency" fabrication projects in the processing plant. many of these projects should have been weekend jobs, but I learned to adapt.

My dear, the OP is planning to work in pressure vessels.

The so called jargons are necessity here since the equipment costs are in millions of dollars and there are human lives waiting to be compromised due to a single bad welding.

WHOA WHOA, we're talking about welding boiler pressure parts, not a bar b que. OP, might I suggest you speak with some of the senior members at a welding trade school if you're really curious about this? I think that would be a good start. Ask about specs, any possible licenses or certifications for the weld (and welder). Do you have to perform any NDT on the weld afterwards, those sort of things. It seems, unfortunately, that you're getting anecdotal advice here. Thats like NASA going to the moon in the 60's and some guy in his garage is 'recommending' to "just shoot the rocket in that direction..."

DISCLAIMER:

No offense is meant in the direction of any other poster on this thread, or anyone reading this thread, or anyone else, or any baby seals. Mosquitos okay, but not baby seals..

Basically speaking there are 7 classes of filler metals or electrodes which can be used for joining dissimilar steels or their various combinations and the types are given in the bracket.

1. Carbon steel to Carbon steel or up to 1.25 Cr-0.50 Mo (E 7018* or E 7016 for SMAW and ER 70S-2 for TIG process)

2. Carbon - 0.5 Mo to same or up to 1.25 Cr -0.50 Mo (E 7016-A1 or E7018-A1 for SMAW and DIN 8575 - ER SG Mo for TIG process)

3. 1.25 Cr- 0.5 Mo to same or up to 2.25Cr-1.0 Mo (E 8016-B2 or E8018- B2 for SMAW and DIN 8575 - ER SG Cr Mo 1 for TIG process)

4. 2.25 Cr-1.0 Mo to same or up to 5Cr-0.5 Mo (E 9016-B3 or E9018-B3 for SMAW and DIN 8575 - ER SG Cr Mo 2 for TIG process)

5. 5.0 Cr - 0.50 Mo to same or up to 9Cr-1.0 Mo (ER 502-15 type only)

6. 9.0 Cr - 1.0 Mo to same or up to 7Cr-0.50 Mo (E 505-15 type only)

7A. For cyclic services where PWHT is to be used - (Inconnel type 75Ni-16Cr-7Fe)

7B. For non cyclic applications above 430⁰C (310 - 25Cr & 20 Ni or 309 - 25Cr & 12 Ni as an alternative to above)

7C. For non cyclic applications below 430⁰C (310 - 25Cr & 20 Ni or 309 - 25Cr &12 Ni is used).

Type 309 with 20 Cr & 12 Ni is more suitable than type 310 for dissimilar material welding

In your case:

a. for welding SA 210 GrA1 to SA 210 GR A1—

(P1 Gr 1 to P1 Gr.1 -smls. tube - ER 70S-2 for TIG / E7018 for SMAW)

b. for welding SA 213 T11 to SA 213 T22 –

(P4 Gr 1 to P 5A to Gr 1-smls. tube - DIN 8575-ER SG Cr Mo 1 for TIG / E8018- B2 for SMAW )

c. for welding SA 213 T22 to SA 335 P22 --

(P 5A to Gr 1-smls. tube to P 5A to Gr 1 smls pipe -- DIN 8575-ER SG Cr Mo 2 for TIG / E9018- B3 for SMAW)

DIN 8575 ER SG Cr Mo1 (1,25 Cr-0.5Mo) & ER SG Cr Mo2 filler wires (2,25 Cr-0.5Mo) are the nearest available filler metals for TIG process..

Trust above details will help you to plan the welding of various materials.

Sridhar.