Carbon Arc Gougin 321 Stainless plate

[msen]

thread725-172742

Hi everybody,

I have read that topic but could not find any limit for grinding.

I need to cut 45 mm thick 321 stainless steel plate. I will drill a hole of 96 mm outside diameter.

I wonder how much grinding should ı do in order to take away the contaminated material. Is there a calculation, assumption or anybody has experience about this issue?

Thanks in advance.

 

The belief that air-carbon arc gouging imparts carbon into the base metal beyond a superficial surface layer is a persistent misconception. Correct technique of using a low attack angle, followed by grinding to bright metal, will leave no residual carbon. Sorry I cannot provide a citation for the published work I read on this subject a very long time ago.
In any event you should consider plasma arc cutting/gouging; it is much cleaner and quieter.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[weldstan]

As ironic metallurgist said, use plasma arc to cut stainless steel.

 

[metengr]

I would 2nd the above recommendation.

 

[pradipgoswami]

MSEN,
Stainless steels are NEVER cut or gouged by Carbon Arc Gouging. Leave aside the issue of Carbon Buildup, the surface would be full of serrations, which is going to make the grinders life totally miserable. Considering the grinding involved, resulting wastage of time and costly stainless steel materials, fabricators always opt for plasma cutting. In fact Plasma Cutting is the best and only followed option for cutting stainless steel. As regarding drilling holes always opt to portable drilling for smaller dia, never try plasma cut expect for big diameter nozzles.
Thanks

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[CWEng]

Pradip,
I'm afraid you are mistaken. Carbon arc gouging is frequently used on stainless steels. Depending on your power supply, it can be faster than plasma arc gouging, and a skilled gouger can make a relatively smooth surface, so minimum grinding is required. Grinding to bright metal is adequate, as Ironic Metallurgist indicated.

 

[EdStainless]

I have seen good and bad carbon arc gouged SS.
I have also seen heat input damage from improper plasma cutting also.
It all comes down to technique, neither is fool proof and both can work fine.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[Guest102023]

Back in the day we used carbon arc gouging as the first stage finishing of acres of SS hardfacing overlay on hydro turbines. A couple of the guys were real artists, leaving a surface with only about a 1/32" scallop, using very large diameter electrodes. I don't miss the smoke and the noise though.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[pradipgoswami]

Whether it's Carbon Arc Gouging or Plasma Arc Gouging for stainless steel it's the educated call of the fabricator's. From my past shop floor experience with ASME U, U2, N, NPT stamped fabricators, I had observed a great deal of hesitation in application of Carbon Arc Gouging for back gouging in stainless steel welds.
However every engineering shop may follow different practices at their discretion.
Here's some interesting article with good rationales to justify selection of the most appropriate gouging method.
Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
ca.linkedin.com/pub/pradip-goswami/5/985/299