High hardness values fillet weld

[78500902]

Hello,

I have the following material per Shell's specification (F552) with the below composition:

- 0.13 %C
- 0.51 %Mn
- 2.39 %Cr
- 0.99 %Mo
- 0.006 %V
- 0.11 %Ni
- 0.08 %Cu
- 0.35 %Si
- 0.51% Mn
- 0.0004 %B

We are looking to weld it to S355, fillet weld, although the fabricator is having hardness problems. These are the parameters:

- Preheat 200C
- Position 2F
- Fillet metal GTAW ER70S-3
- Amps 179A
- Volts 11.2V
- Speed 13cm/min
- HI 9.3kJ/cm
- Post heating 250C during 30min + cooling under cover sheet
- No PWHT

Hardness values are 410Hv.

Any ideas to reduce these values? Thank you.

 

[metengr]

The hardness values seem too high for your stated conditions with only 0.13% C in the Cr-Mo material. I would use a bead overlap technique to provide in-situ tempering. Similar to a temper bead but not qualified as a temper bead. I would also use higher heat input, where is your maximum interpass temeprature?