Help Stop Wasting of Student Welding Materials

[ContractHome]

We use a massive amount of material teaching our welders GTAW welding aon 1" NPS Carbon Steel Socket Welds and Also for Monel 400 NICU Socket Welds. We cut the pipe from the welds to reuse the pipe, but we are told that we must cut one inch away from the welds because the hardened metal from welding would damage the blades in our band DoALL Band Saw (Model C-916M).

Is there away we can treat the metal through some heat treat ment process so that the welded metal will not damage the band saw blades?

Is there an special band saw blades that would not wear- if the blades break or wear to fast it would not be time or cost efficent compared to the price we save on material or would it?



We would like to cut the welds right at the socket couplings so that we can reuse the sockets also.

I am looking for several sugestions to help save us money. Each Monel Socket costs over $100 a piece.

I am open to any suggestions for our welding students.

(See Attachment)

 

[arunmrao]

Why a DoAll machine,you could use a abrasive cut off wheel,it will be fast and cheap. You need to grip the job well before cutting.

Does Monel pose a problem for cutting,use a coarse blade perhaps,it will cut faster. For steel weldments,you may anneal the pieces before cutting on a DoAll.

_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr

 

[ContractHome]

In addition does any one know if these socket couplings would effect the students performance since the sockets are slightly hardened from previous welds?

How would I anneal them- please explain the procedure you would use?

 

[unclesyd]

I would like to say that you have too much weld metal deposited and it's not pretty, my opinion. With a few exceptions all the weld metal needed is to make a equal leg triangle with each leg the length of socket wall.
With a little experience you can tell if the welder is proficient by checking his first pass. have found over the years that there are some very good welders that can't make a satisfactory socket weld.
You can make test coupons from Monel bar bored out to size instead of using actual fittings. When the welder gets the mechanics of the weld process correct and you get a good feeling .,then give them a fitting,

You also may want to checkout a socket weld removal tool like the Wachs linked below.

http://www.ehwachs.com/Industrial-P...l-35/Socket-Weld-Axial-Pneumatic-Kit-214.html

 

[dbooker630]

Try a carbide tipped band saw blade such as the Lenox Tri-Master. DoAll also makes a tungsten carbide set tooth blade. Check with your DoAll rep for specific model numbers. I have good experiences with the Tri-Master on hardened parts or with HAZ's in the 60HRC range.

 

[Guest102023]

I'm surprised I am the first to question the assumption that the steel will be significantly hardened by welding at any appreciable distance from the weld. You should be able to cut as close to the weld toe as you can reach.

If it is Monel, it is not hardenable like steel, but is not as machineable in general. Just google to find a machineability index for it.

 

[ContractHome]

These are students who never welded before in there life and their projects require TX2T fillets but the weld a little over to before doing their final welds. This is their pratice project, not their test project. Thank for the link I will look into it.

 

[tr1ntx]

There's brand of hardened bi-metal blades made in Germany which I've used cutting through welds and they help up well. If you're using standard blades from DoAll, these are sure to be better. Check out McMaster-Carr's site (mcmaster.com), I think I got them from there.

On-line catalog page 2359 is the "About Band Saw Blades" page.

 

[MikeHalloran]

Try Remington Grit-Edge blades.



Mike Halloran
Pembroke Pines, FL, USA

 

[Mr168]

Just my $.02, but if the welders are only at a skill level as shown in your photo, you'd be miles ahead by having them practice on carbon steel fittings, then transitioning them to Monel when they're ready. I would even have them switch to carbon steel filler as well during that transition period. They need to get down the fundamentals and the hand-eye coordination before making the step up to a "specialty" alloy.

 

[arunmrao]

I agree with Mr168,that the students need to be trained with ms plates,rounds etc before graduating to expensive alloy. You will then, not be too concerned about recycling or wastage .

_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr

 

[Jmoore1]

The hardness they are referring to is the martensitic regions formed from the high welding heat and relatively quick cooldown. You can PostWeldHeatTreat the steel to remove this as is VERY common in industry. Anneal by raising the temperature of the metal to the critical temp required for the microstructure formation temperature and a cooldown procedure, pretty easy to do if you have the facilities.

These temperatures and rates are pretty important so you get the right microstructure so you may need to do some research or consult an engineer.

or go with the easy option of using CS :/.

 

[ContractHome]

Mr168,

These students do start off with Carbon Steel and move on to monel latter on. I am sorry to every one for providing a poor example, but my main concern is saving material. When they reach monel the are proficent enough to be tested. I did not have a monel photo to provide.

 

[ContractHome]

Mr. Jmoore1,

What is a CS :/. ?

 

[ContractHome]

Thanks to Everyone for the replies and your options are being considered, but I wanted to know if anyone can comment on:

machining the fittings?

using oxy-acetylene machine?

using plasma cutting machine?

shearing the metal in an iron worker?

 

[Jmoore1]

carbon steel

 

[MikeHalloran]

An iron worker would be useful for cutting plate and bar.
It will crush fittings and pipe before shearing them.

Oxy-acetylene and plasma will cut the pipe easily, but leave a HAZ and a mess of burnt metal around the cut.

Grit-edge bandsaw blades will go through pretty hard stuff, cleanly. You should be able to saw pipe off right next to the weld, maybe partly through the weld if you are careful about the guides. Then you can machine the sockets, e.g. in a lathe. You'll probably need a four jaw chuck, and indicate the ID of the pipe, or maybe the root of the socket, to bore out the old pipe. A good machinist could probably face off the weld and bore the pipe enough to allow collapsing the OD with a chisel without cutting the actual socket very deep.



Mike Halloran
Pembroke Pines, FL, USA

 

[Jmoore1]

could water cut as well

 

[ContractHome]

Yes a iron worker would crush the pipe. I heard that inserts or mandrels where placed in pipe to protect from crushing. The Dies would have to be half-rounds. Has any one seen this type of equipment?

 

[MikeHalloran]

Some ironworkers, I think, have hole stations intended for shearing rounds.
You could support the inside of the pipe with a loose-fitting round that's also sheared, but the pipe will be ovalized.
You could use a tight-fitting round, but then you have to drive the round out of the sheared pipe.
You could use a round as a mandrel, i.e. insert it just short of the shearing plane, but someday it will get sheared, and usually it won't be inserted far enough, so the pipe will be distorted.

Arun's idea, an abrasive chop saw, is probably quicker.



Mike Halloran
Pembroke Pines, FL, USA