Welding procedure 2

[fakhfakh]

Dear Sirs,

Would you please inform me about the recommanded filler metal and any eventual preheat and/or PWHT for welding C45 steel bar with structural steel Fe 430b. (fillet weld)

Thank you

 

[metengr]

Please provide more information;

1. Composition of the bar and structural steel

2. Thickness of each

 

[fakhfakh]

Dear Mr. Metengr,

Please find below the requested informations:
C45 C /0,42-0,50 Si/0,40 Mn/0,50-0,80 P/0,45 S/0,45 - Cr/0,40 Mo/0,10 Ni/0,40
Rp/310 - 565 (Mpa) Rm/580 - 1050 (Mpa) -


Fe 430b equivalent to S275JR (EN10025):

C/0.22 Mn/1.5 P/0.045 S/0.045 N/0.009
Rp/275 (Mpa) Rm/410-560 (Mpa)

Thickness C45: 50mm
Thickness Fe430b: 16mm
(Fillet weld with SMAW process)

Best regards

 

[metengr]

Thank you for the information. The preheat requirements for the fillet weld will be dictated by the thicker and higher strength C45 material. Since you are joining to a lower strength structural steel, I would use an E70XX H4 series filler metal. You should use LOW HYDROGEN electrodes for this job.

The minimum preheat temperature should be 450 deg F, with a maximum interpass temperature of 650 deg F. If you keep the fillet weld throat less than 3/8" - NO PWHT.

 

[fakhfakh]

Thank you very much.

I have started this morning by using E8018C3 electrode with preheat temperature up to 150°C without PWHT.

What do you think?

 

[metengr]

The E8018 C3 is ok. The preheat is lower than I would use. Did you use E8018 C3 H4 - low hydrogen? If not, you need to post bake that weld joint at 232 deg C for 2 hours.


Also, perform a wet fluorescent MT, just to make sure.

 

[fakhfakh]

Thank you for your prompt support.

We have used E8018-C3-H4-R
The problem is that the joint is very long and discontinuous and access is very tight. The C45 bar welded is for an overhead crane rail.

The PWHT is impossible.

Best regards

 

[Carburize]

On a non welding related issue. One of the worse features for in-service fatigue crack initation in overhead crane ways are fillet welds.

 

[PAN]

metengr & fakhfakh,

I used to see a paper about preheating steels. If we increase electrode diameter, the preheating temperature will be decreased. Please comment.

 

[fakhfakh]

Diameter of electrodes used up to now 4mm.

I'll perform some PT or MT as recommanded by Mr. metenger to be sure for eventual crack.

Best Regards

 

[metengr]

PAN;
The increase in electrode diameter increases the heat input (Joules/inch) during welding. However, the increased heat input during welding does not necessarily reduce the initial effects of restraint in the weld joint, formation of a hardened HAZ, and hydrogen diffusivity into surrounding base metal that the benefits of a weld preheat would provide.

Most of the calculations related to the threshold for preheat temperature factor in chemical composition, strength of the base metals and thickness of the weld joint.