Practical Heating Methods

[Laidbackmofo]

Goodafterning/morning everybody!

I have a simple question with many broad answers, but I haven't found the right one.

Here it is.

How do I heat up Carbon Steel to above 250*f safely?

Restrictions are;

No open flame
Has to plug into a Lincoln 275 DC welding machine
Simple use

I am a supervisor for a Shipfitter shop on a sub-tender and work with High Yield-80 steel. Currently we use "Relient Gear" which is copper wire wrapped in ceramic rings and then covered in braided stainless steel. Which then plugs into a DC welder.
Well, were running out of those loops, and I just found out that "Relient" went out of business a long time ago. I've searched this forum as well as the internet for new methods and manufacturers of resistence pads, and have come up empty. Can someone help me out?

Thank you in advance.
HT2(sw) Stanford.
USS Frank Cable AS-40

[A_DAB_will_do]

Depending on your budget, you should consider looking at induction heating machines. Miller Electric makes them, as do a few other companies. They are not cheap, however induction machines are much faster and more accurate in temperature control than any open flame burner or resistance heater technology.(Induction is faster than resistance heating, but probably has similar temp control accuracy)

Miller's induction machines can come with air cooled blankets suitable for pipe or plate heating up to 400F. They also sell a water cooled system that is capable of PWHT to temperatures exceeding 1000F. You'll have to check the specs on their website for the max temp possible with the water cooled system.

[Matt_Maguire]

They still pre-post heat with boiler work using both radiant heat (like you have) and induction heaters both.

Maybe one of the tube fitters or electricians on the forum will see this and post up.

Good Luck

Matt

[Bob the Welder]

Widely used in the trade. http://www.cooperheat.co.za/

[MoonRise]

Induction heating. Simple to use, no flame, not sure on using a DC275 as the power source though.

http://www.millerwelds.com/products/induction_heating/

http://www.ameritherm.com/aboutinduction.php

The answer(s) may also depend on the size of the object(s) to be heated, as there are also smaller electrical devices that can be usedto heat small(er) parts. Like bearing heaters.

http://www.grainger.com/Grainger/wwg...n_dim_search=1

[nadogail]

Petty Officer Stanford
After my Navy retirement I worked for an industrial shop where we preheated using a Cooper Heat system. Long story short, I rebuilt the burnt out heaters using wire from the Pelican Wire Company www.pelicanwire.com/ I disassembled the old heaters and restrung them with resistance wire from Pelican (www.pelicanwire.com) . Restring heaters is labor intensive but it saved a lot of dollars.

Temperature control can be added relatively inexpensively.

Gail Brownlow, ETC, USN Retired

[Laidbackmofo]

Thank you all very much for the quick response!

A_DAB_will_do and MoonRise both mentioned induction heating. I have looked into this. Its is an amazing approach at heating metal. Sadly though every job on these subs is different in some way. The machinery needed to run and induction heater (from what i've researched) is much to large and used mainly for one type of job in a controlled setting. One of the "higher ups" actually ordered the Miller machine and it is still sittin in the spot that it was dropped off at 6 months ago. Thanks Bob the Welder for that link. I am actually thinking about sending in for a quote.
nadogail, thank you for the link on the pelican wire, I have experienced that labor , and from what i've realized, I can't do that as a permant fix. Mainly becuase of the QA, saying that, everything we use has some type of controls on it. I've tried restringing the Reliant gear with copper from the ET's and well, that was tricky, and my LPO wouldn't buy off on it. Probably a smart move on his part.
Again, thank you all for your info, but it looks like the tried and true way of radiant heating is the route for me. I just hope I can find some more companys that make these type of pads.

Very Respectfully
HT2(sw) Stanford

[nadogail]

In my opinion, NICHROME wire is most probably what you want for heating elements. Copper wire is usually used when conductivity is desired. Better conductivity means less heat. Lower conductivity, higher electrical resistance, gives you more heat.

NICHROME, a nickle chromium alloy) is used for heating elements because it can handle the high temperatures with out burning out (melting under load). Temperature controls for your preheating would be simple to rig using a thermocouple, an off the shelf temperature controler, and a relay.

I am sure Pelican can supply any required certificates for traceability or ISO 2001 purposes.

I have sent you a private message.

[Matt_Maguire]

You can make your own blanket heaters with bronze blocks/flats chained together using cartridge heaters. The heater is inserted/cemented in a hole and can work to temps up to 1600F, they are also made with internal temp sensors. These get cashy fast...

Anyway, check this link to McMaster Carr for small heaters & see if you can make something work... Maybe with a sparky in machinery repair???

http://www.mcmaster.com/#die-cartridge-heaters/=doapma

Matt

[zapster]

If your parts are not that big what about an old oven?

I cook pizza @450...
And with the right plug you would be all set!..

...zap!

[DSW]

I keep thinking about the electric metal drum heaters we used to use for heating water in the winter when I worked for a mason. I know they make some big azz ones. Not sure how hot they get, but I'd guess whoever makes them probably might have something you can use if it's retasked.