Hardening of T1 during oxy fuel cutting

[tlewis]

I processed 2" T1 Plate through oxy fuel cutting over a water table. We run the water level below the plate to keep dross from freezing to the part. We are experiencing extreme work hardening from the cutting process making machining very difficult. The water level is set to minimize smoke so it splashes back onto the bottom of the plate. Could this water splash back be causing my extreme hardening condition? Would lowering the water level to eliminate splash back make any difference?

Thanks,

[usmcpop]

Could well be. Can you detect any difference in the hardness toward the top of the cut vs. the bottom?

[tlewis]

Not sure of orientation. The component is now part of a weldment. However, that is a good idea for the welder to consider to have the bottom of the flame cut part opposite the machined surface.

[usmcpop]

It could be that the mass of the plate provides somewhat of a a self-quenching action, but it almost has to be worse where some water gets to it. Another thing to consider is just the surface residue from the flame cutting and any corresponding abrasiveness.

P.S. I'm not a welder or engineer, just an enthusiast. But I have a great respect for material properties and the wacko way certain steels can behave. If it were me, I'd tell my wife I need a $250,000. abrasive water jet cutter to do it the right way. :D

[tlewis]

Thanks for your reply, they have started me in a positive direction. I'm just a minion here and have spent the owner broke this past year expanding his operation so the water jet is a non-starter, but I would like one. We run a table with Hi Definition Plasma and OxyFuel as we cut both precision parts down to 1/8" and big ol' parts up to 8" thick, and lot's of them. The water jet wouldn't keep up.

From your handle I take it you either have a child who is a "Devil Dog" or you are a "Devil Dog" who has children? Either way thanks for the Service!

Terry Lewis
U.S. Army Retired

[calweld]

Terry,,,,

If you are in a position, to be buying 2" t-1 steel plate,,,,,, you should also be in a position,,,, to be consulting the manufacturer directly. I suggest, for a purely technical question such as this,,,, that would probably be the best approach.

[HT1]

A call to the manufacturer is in order.. Most people here, myself included would consider t-1 rather hard to start with! Oxy Cutting is going to cause a localized hardening simply because 2 inch of material is going to draw the heat away so quickany splash from the water table will exasperate this, though if you cannot see steam rising from the table, it should be no more of an effect then the air cooling .. let us know what you find out!

P.S. Do you have any scrap pieces. I could make good use of them:rolleyes:

[Pumpkinhead]

.. any splash from the water table will exasperate this,

I seriously doubt water splash will exasperate the hardening, though it appears this phenomenon has exasperated the O.P., hence the query.

[tlewis]

I did follow up with an independent metalurgist as well as two of my suppliers. The suppliers were helpful...not so much! The metalurgist suggested the quenching was not a factor and directed me to further testing which confirmed this T1 was not the best quality. We discovered pockets of hardness throughout the plate. Most likely cause was poor workmanship at the mill in England.
End result we found about .050" of hardening from the oxy-fuel process. Tests on the bottom (water side) of the work piece indicated no significant difference from the opposite side. We did however find variation throughout the entire plate. Most of this variation was found by breaking drill bits that had cruised through the first 1" of material then got stuck in localized pockets of very hard material.

[usmcpop]

Thanks for the update, Terry.

And thank you for your service. My son is the Devil Dog. Lost him in combat in Iraq 4 years ago, sad to say. www.karl.linn.net