Surface weld in AISI 4130 with ERNiCrMo-3 1

[saanu]

Hello Experts ,

We have a application where we need to surface weld a bore of diameter 75 mm length 200 mm AISI 4130 base metal with filler wire diameter 1.2 mm ERNiCrMo-3 .

We preheated the block to get the required pre heat of 149 degrees Celsius as per data sheets available . Process used is MIG welding with a special MIG bore welding torch , current 250 Amps , 26 volts , Argon gas shielding . Job is being auto rotated on a positioner .

Our results were that there was absolutely no bonding between the filler wire and base metal . In fact it looked more like melted wax on glass .

Can you give me suggestions for the same .

Thanks and Regards ,

Saanu

 

[metengr]

Did you qualify a welding procedure specification for this project? Lack of fusion defects like this with an automatic bore welding (Bore Tec) machine can be significant if the original weld parameters are not properly established.

Look at travel speed and wire feed rate and shielding gas. Also your preheat for 4130 should be 180 deg C.

Excerpt from my friends at TWI regarding LOF defects

Welding parameters
It is important to use a sufficiently high current for the arc to penetrate into the joint sidewall and previously deposited weld runs. Consequently, too high a welding speed for the welding current will increase the risk of these imperfections. However, too high a current or too low a welding speed will cause weld pool flooding ahead of the arc resulting in poor or non-uniform penetration.

 

[saanu]

hello Metengr ,

Thank you for the comments . We have resolved the issue . Pre heat temperature the same that is 149 degrees celsius , current 200 amps at 23 volts , argon gas flow 18 lpm . Job rotation speed 1 Rpm . Stopped oscillation of torch for increased weld bead . We just used a stringer bead .

It is doing fine now .

Thanks ,

Saanu

 

[metengr]

Ok, thanks for the feedback.