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Up Topic Welding Industry / Technical Discussions / Difficultly in welding medium carbon steel
- - By Harman (*) Date 10-21-2013 15:26
I am trying to weld
1) Hot rolled A572 grade 50 steel
2) Solid rod made of medium carbon steel (ASTM spec: A29) with has C: 0.33%, Mn: 1.52 %, Si:0.48%, Cu:0.16 %, Ni: 0.07 % Cr: 0.05 %

We have tried MIG welding it and also tried welding it using electrodes. I am unable to achieve penetration, any recommendations on what can be done?

Thanks
Parent - - By Lawrence (*****) Date 10-21-2013 17:21
What was your GMAW Data?

*Wire feed speed/amperage?

* Arc Voltage

*Filler Wire Dia. and AWS designation?

*Shield Gas

I'm not going to address material matching and other engineering level issues... Just what it takes in order to get fusion/penetration with GMAW with steel.
Parent - - By Harman (*) Date 10-21-2013 20:21
Settings used were:

Wire speed-  375                                                                             
Arc Voltage-  26 volts
Wire  Size.-   .045
Gas                   90/10 Argon CO2
Machine.       Lincoln power wave 355m
Setting on machine was 5 standard cv welding.

Second Set of Settings
Wire speed-   320
Arc Voltage-   Trim was set at 1.00
Wire size-        .045
Gas-                   90/10 Argon Co2
Machine-        Lincoln power wave 355m
Setting on machine was 19 pulse soft.
Parent - By Lawrence (*****) Date 10-22-2013 22:10
Parameters seem in the ballpark

There may be an unrealistic expectation for root penetration on that flair bevel/groove type joint, if that is what we are talking about..

Al and Brent have touched on it...  I was also thinking about this from the start...

I thought to myself  "what exactly do you mean by no penetration at all?"

Tell us more
Parent - By welderbrent (*****) Date 10-21-2013 19:04
Besides the responses by Lawrence and Al,

Have you double checked the polarity?  While arc blow/magnetism is a strong possibility it is also possible the welder was used with innershield or some other electrode that required DCEN whereas you are trying to weld, or should be, with DCEP.

At first glance, both materials should not be an issue for welding as you mentioned.

But check your electrode, welding parameters, shielding gas, polarity, etc and let us know.

Have a Great Day,  Brent
- - By 803056 (*****) Date 10-21-2013 18:49
Did you check the material for residual magnetic fields?

Has any attempt been made to demagnetize the parts before welding?

Al
Parent - - By Harman (*) Date 10-21-2013 20:35
I didn't check for residual magnetic field, since the weld bead looked pretty good. Is there any way to tell the presence of magnetic field by visual inspections?
Thanks
Parent - - By 803056 (*****) Date 10-21-2013 20:48
If a steel paper clip is hung from a thread and held close to the end of the part, one end of the paper clip will swing toward the end of the material if there is a remnant magnetic field in the part.

A strong magnetic field can deflect the welding arc so you don't get the fusion and penetration you are looking for.

Next; explain what you mean by you can't get penetration.

Al
Parent - - By Harman (*) Date 10-21-2013 21:06
Al,
When I cut a section of the join and do etch test, I can no weld penetration. By no I mean, absoultely nothing.
Parent - By 803056 (*****) Date 10-21-2013 21:12 Edited 10-21-2013 21:15
Are you depositing fillet welds or groove welds?

Is there thick mill scale present or are you welding on "clean" steel?"

Is the arc deflected from the joint as you weld?

Can you post a photo?

I was looking at your welding parameters. It appears you made two separate weld samples. I noticed one setting appeared to be for pulsing and the other appeared to be conventional spray mode although the voltage appears to be somewhat on the low side.

In the pulse mode, what are the average values for arc voltage, current, pulses per second, etc.?

Al
Parent - - By welderbrent (*****) Date 10-21-2013 21:12
UUMMM,

Well...you are not going to get down deep using .045 wire in a flare bevel groove weld.  That will be covered by Z-loss factors for the process and size of material.  Does the job require deep penetration?  To get all the way into the root you would need to prep the round bar and/or backgouge and weld from the opposite side.

If the bead face looks good then I don't see a problem unless you have specs calling for CJP and then you won't get it without added preparation.

Have a Great Day,  Brent
Parent - - By 803056 (*****) Date 10-21-2013 21:18
See, you picked up on the fact that he may be welding a flare bevel. I missed that. If in fact he is welding a flare bevel, you are right about the Z-loss.

Expecting to achieve fusion to the root of a flare groove weld is a common rookie engineering mistake.

Al
Parent - By welderbrent (*****) Date 10-21-2013 21:25
That's the only thing I can come up with when combining all his posts.  But the description lacks enough information to be 100% sure. 

But if that is the joint then it will always show lack of penetration to the root unless one does added preparation.  Even if he opens up the bevel from the first side he will still need to backgouge in order to truly produce a CJP with the welding of the second side. 

I know you know all of that, just filling in for the OP when he reads these last few posts.

Have a Great Day,  Brent
Up Topic Welding Industry / Technical Discussions / Difficultly in welding medium carbon steel

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