weldability of A106 pipe to A572 plate

By Jan Jensen Date 08-19-2008 16:23

Hello,
ASTM A106 Grade B is a very uncomplicated steel to use and weld. Very low CE value very low Carbon actual values from a certificate: C= 0,09, Mn = 0,55, Cr = 0,11, V= 0,00.
YS= 371N/mm2, TS=461, Elong.= 33%.
Weldability is very good I have been involved in several Welding Procedures without any subsequent problems for the manufacturers.
Remark ! Without any additional specified requirements it will be delivered without impact test.

best regards
Jan Jensen
Denmark

By 803056

Date 08-19-2008 22:19

Both A106 pipe and A572 are listed as prequalified by AWS D1.1. You should have no difficulty weling the two together, but I recommend using a low hydrogen welding process or a low hydrogen type shielded metal arc welding elctrode. Preheat is dependent on the thickness of the thicker material.

Best regards - Al

By ctacker (****)

Date 11-19-2008 18:46

what about A106 grade C at 2" thick?

I'm guessing that at least 225F is needed but don't know for sure.

By 803056

Date 11-20-2008 04:06

Use the alternate method for calculating preheat from the annex of D1.1.

Best regards - Al

By ctacker (****)

Date 11-20-2008 18:26 Edited 11-20-2008 18:50

I'm not sure what to do after figuring the CE and P(cm) can you explain ?

Edit: I think I got it figured for the Hydrogen control method, but having a hard time for the hardness method!

By 803056

Date 11-21-2008 04:49

You have three parameters that have to be determined.

1) Hydrogen Control - H1, H2, H3 - most fabricators can meet H2 using low hydrogen electrodes or a low hydrogen process without any difficulty.
2) Calculate Ce using the equation provided. This will be based on the chemistry of the steel you are welding. Based on the Ce, you will determine what "Susceptibility Group" you fall into, i.e., A, B, C, .... G
3) Determine the degree of restraint, Low, Medium, or High. I'm conservative, I consider the material thickness, rigidity of the structure, and if a circular patch is involved, I go with "High" restraint.

With the information determined above, go to the table XI-2 (I happen to be looking at D1.1-2004) and pick the appropriate preheat from the matrix.

Example: Ce = <.28 and you are in the H2 group - you will be in the Susceptibility group D
The material is 2 inches thick, with a highly restrained joint.
From the table - Left column - go down to "High" restraint and select the row for 2 inches thick material
Move horizontally to the column for group D and you will see the preheat temperature is 300 degrees F

Hope this helps.

I use this method whenever I'm repairing heavy machinery, steel castings, etc. All I need to do is have a sample of the base metal analyized for chemistry and I'm ready to go to work.

Best regards - Al

By ctacker (****)

Date 11-21-2008 15:06

Alot easier than the book made it seem, thanks alot Al.

Carl

By ctacker (****)

Date 11-21-2008 18:01

what if your CE is >.38?
Also the MTR states .37 CE but when its calulated its .47

By 803056

Date 11-21-2008 19:02

There are several carbon equivalency formulas in use and each has its own set of guideline to use.

Did you recalculate the Ce using the formula in the annex? If not, do so. If the Ce is beyond the range listed in the table, you will have to use a different Ce that covers the alloy constituents you are dealing with.

There is another very useful book that will give you some direction regarding preheat and PWHT parameters.
Weldability of Steels
R. D. Stout and W. D. Doty, Welding Research Council 1978

I'm not sure if it is still available from AWS. If it isn't, check Amazon or even Ebay.

Best regards - Al

By ctacker (****)

Date 11-21-2008 19:41

I used the CE formula in the annex, and when I use the formula Pcm(without adding 5 X Boron because there is no boron) I get .23 instead of the .47
going by the zone i'm in, I should be figuring to CE.

I have an MTR for A36 that lists the CE at .43

$220 for a used book on ebay, I will pass on that right now.

Thanks Al

Carl

By 803056

Date 11-24-2008 03:20

Again, the Ce calculated with one equation has little or no bearing on the results obtained by a different equation. Each equation has a set of unique guidelines that are to be applied based on the results obtained from the appropriate Ce equation.

Best regards - Al