[olek]

Hello,

I did read that plasma cutting do deform the less the pieces if compared with other crude methods.

I wonder if on cast iron it will generate less white hardened iron than cutting disk ?

I am wondering if the process, by immediate ejection of the melted metal, do not allow a less deep heat penetration, or some sort of cooling because air replace the metal.

Do you have some informations ? I will ask one or 2 specialized compagnies I think I will have an answer, unless it is evident in some way.

Gouging electrodes do not burn the metal as much as plasma, I was said.

Regards

Also, gouging electrodes are proposed for iron weld solutions. (Not arcair but I don't know for sure )

I use carbide mill bits for iron but if I want to get rid of a hardened Zone to replace it with FeNi metal what would be the best process ? (Carbide drills will just wear off)

[Otto Nobedder]

Olek,

Perhaps with this question you would do well to post it in French, and allow one of or Quebecois members to translate? I'm having difficulty understanding the question.

Steve

[olek]

Thank you Otto.

Sorry for my limited English. I ask if it may be an option to use a cheap plasma cutter to open cracks in iron.

If it burn the iron , obviously it is not.

Thanks

Isaac

[olek]

I have another question

Is there a difference when using a plasma torch , between pushing, and pulling

Some pro just wrote that it is better to push (to avoid melted metal to jump on the electrode I think he said )

The torch is hold straight at 90 degrees is not it ? an angle is created because of the travel speed that is all, so I do not see where a difference can be when manually cutting, between drag and push (this is for a contact torch)

Thanks

[homeboy]

When cutting a straight cut with a guide I normally drag because it slides easier than pushing. Mine is a drag or contact tip also. When cutting irregular shapes whether flat or profiled just keep the torch at 90 degrees to the work and glide it around keeping the tip as close as possible to the work piece. As for direction it shouldn't matter, just cut in the direction that is most comfortable for better control. I am right handed so I usually cut from right to left when cutting freehand for better visibility. There are some good videos perhaps on You Tube which may help.

[jimcolt]

If using consumables designed (shielded, proper arc length) for drag cutting (for hand cutting) then the best cut quality is achieved with the torch dragging directly on the material and with the torch perpendicular to the material. Whether you push or pull does not matter....whatever is comfortable and provides the most fluidic motion. A drag shield eliminates stiction allowing for smooth motion and smooth cut edges. Jim Colt Hypertherm

[Artie F. Emm]

Cast iron is outside my experience, but I'll jump in to possibly provide some clarity.

Olek, please check me: it sounds like Olek is repairing a crack in cast iron, and asking what method he can use to grind out the crack. He uses the phrase "white hardened iron" (which returns no hits in a google search), seeming to indicate a work hardened or heat affected zone caused by a grinding disk that he'd like to minimize.

Does the "white hardened iron" ring a bell for anyone? Is plasma cutting or arc gouging a good approach to crack repair? Can you manually control these processes enough to remediate a crack? I've only ever heard of drilling the ends of the crack and using a grinding disk.

[olek]

Hello

Thank you for trying to understand me.
Yes grey cast iron when hardened by strong heating have much more embedded carbon molecules, I find "pale iron" or wear resisting iron , but also white iron . on the internet.

That is a state of the metal . A reversible one but I cannot do that process.(the iron part I work on is very large and long)

I just wonder if plasma cutting is creating a smaller HAZ than gouging electrodes.

For my repair I used milling with pneumatic tools so to obtain
. Minimal heat. But I am interested for the bext repair.
The gouging "arcair' electrodes make a U shaped canal very fast.

Best regards

[Fly]

If your talking about repairing a crack I have done that many times. I drill a small hole
at the ends of the crack. I vee the crack some by grinding. I then preheat the casting
& then braze it. It has always worked for me.

Fly

[olek]

I am not equiped for bronzing. And to heat at a sufficient temperature also.

I did read that it was better to keep the boring(s) open. As the part that cracked can be fragile the holes( if no etancheity problems), are relieving stress so they are considered a security.

I did read that on a manual for repairs of large constructions,(bridges) big machinery' as caterpillar and so on pieces under work load stress.

I tested plasma and it is hardening iron as hell, grinding if compared leaves the metal soft enough, no hardening that I could see testing with a file

[nelson]

Are you repairing piano plates? God bless you.