Welding A335-P11 to A106-B with E8018-B2 Electrode 1

[nacer16]

Dear All
I need your help for this matter.

I have to weld A335-P11 (1-1/4 Cr - ½ Mo) to A106B (Carbone Steel).
Construction Code ASME B31.3 (Process Piping)
I have a qualified PQR
Base Metal: A335-P11 to A335-P11 P4.1 as per ASME IX – QW-422
Process welding: SMAW
Filler Metal: E8018-B2 F No 4 A No 3

I Will use a WPS (P4.1 to P1.1) according to ASME IX – QW-424.1
Base Metal(s) Used for Procedure Qualification Coupon:
One metal from P‐No. 4 to any metal from P‐No. 4
Base Metals Qualified:
Any P‐No. 4 metal to any metal assigned P‐No. 4, 3, or 1

My question: Can I use E8018-B2 electrode to weld these dissimilar base metals while AWS D10.8 Table 2 suggest to use E7018 to weld 1-1/4 Cr-0.5Mo (A335-P11) to C-Steel (A106-B).
In the same code
Para. 3.4.2 Joining dissimilar Ferritic Steels. Where dissimilar metals are being welded, the only four possible filler metal composition are:
1. The lower alloy base metal composition,
2. the higher alloy base metal composition,
3. an intermediate composition, or
4. a composition different from any of the first three.
Where both base metals are ferritic , the fourth possibility mentioned above (that of an entirely different alloy) is of special concern for service at elevated temperatures or in corrosive environments. Consistent with the factors listed above, this fourth possibility should normally be considered only where one of the base metals is stainless steel or nickel or copper alloy.

and an other code

API RP 5826.2 Dissimilar Welding
6.2.1 When joining dissimilar ferritic steels (P-1 though P-5), the filler metal shall conform to the nominal chemical composition of either base metal or an intermediate composition. However, when attaching nonpressure parts to pressure parts the filler metal chemical composition shall match the nominal chemical composition of the pressure part.

Below some extracts from ASME II Part. A & C

E8018-B2C

Mn Si P S Ni Cr Mo
0.05–0.12 0.90 0.80 0.03 0.03 . . . 1.00–1.50 0.40–0.65

A 335-P11C

Mn Si P S Ni Cr Mo
0.05–0.15 0.30–0.60 0.50–1.00 0.025 0.025 … 1.00–1.50 0.44–0.65
---------------------------------------------------------------------------------------------------------------------------------------------
E7018C

Mn Si P S Ni Cr Mo V Mn + Ni + Cr + Mo + V
0.15 1.60 0.75 0.035 0.035 0.30 0.20 0.30 0.08 1.75

A106-BC

Mn Si P S Ni Cr Mo V Mn + Ni + Cr + Mo + V
0.30 0.29–1.06 0.10 0.035 0.035 0.40 0.40 0.15 0.08
--------------------------------------------------------------------------------------------------------------------------------------------------

Thanks in advance

And Best wishes from Algeria

 

[metengr]

The E8018 B2 will work just fine for this dissimilar metal weld combination you stated. The selection of filler metal really depends on service conditions and design approach regarding under or overmatched filler metal strength properties in comparison with base materials being joined.

 

[nacer16]

metengr

Thanks alot for your reply.


In fact, I realized that there was confusion in some passages.

Please read.

API RP 582

6.2 Dissimilar Welding

6.2.1 When joining dissimilar ferritic steels (P-1 though P-5), the filler metal shall conform to the nominal chemical composition of either base metal or an intermediate composition. However, when attaching nonpressure parts to pressure parts the filler metal chemical composition shall match the nominal chemical composition of the pressure part.

 

[metengr]

If you are using ASME B31.3, E8018 B2 will be acceptable.

 

[weldstan]

It's also acceptable under API RP582. Your P4 to P4 qualification with "B2" electrodes permits welding of P4 to P1 provided all other essential variables remain the same and you have written a WPS for joining P4 to P1.

 

[denlow60]

Nacer16,

[highlight #FCE94F]My question: Can I use E8018-B2 electrode to weld these dissimilar base metals while AWS D10.8 Table 2 suggest to use E7018 to weld 1-1/4 Cr-0.5Mo (A335-P11) to C-Steel (A106-B).[/highlight]

I have read aws D10.8 and I think you're mistaken it is not tock about E7018 , because here spoken about 1-1/4 Cr-Mo E7018-B2L or E8018-B2 both stick are good to weld P11 to A106b in table 2 .

Denlow

 

[weldstan]

Yes.

 

[gtaw]

The welded joint will only be as strong as the weakest component. The electrode or the welding process selected must meet low hydrogen criteria to mitigate the possibility of hydrogen assisted cracking.

A 7018 SMAW electrode of a filler metal that meets 70ksi would probable work as good as any other filler metal.

Best regards - Al

 

[weldstan]

Because of the low carbon/Mn content of E7018 (typically 0.05%/1.0% today vs 0.08 -0.10%/1.0% in the 1970's) it responds to higher PWHT temps (1300F min for 1 1/4Cr-1/2 Mo per B31.3) to reduce its tensile strength well below 70,000 psi. You need to consider PWHT and its detrimental effect weld tensile strength when using E7018.

 

[birken]

You can use either E8018-B2 or E7018 just like you are using P11 & carbon steel to carry the service. This weld joint will be as strong as the carbon steel is, so better use filler matching to carbon steel instead P11. This is what we had been doing since years. We have qualified procedure of these material with E7018 and PWHT suiting P11 as per B31.3.

Birken