OT - Steelwork

Re: OT - Steelwork

John Lucas

>Mark

I've never done anything to my tool rests after welding. You are actually softening them from the heat unless you quench them in water while they are still bright red. If in doubt put them in the oven and let them set at 450 degrees for 1/2 our per quarter of an inch.

I would have to dig through my notes to find the specs on how hard the steel is when you buy it. It's soft but easily hard enough to avoid damage from turning tools. I've use the same round one on my Mini lathe for about 6 years and I've never touched it with a file. I have to hit my cast iron tools rests about once a week with a file.

Re: OT - Yup *LINK*

DaveZ

>Here ya go


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Re: OT - Steelwork

Mark Mandell - Gone Round In Jersey

>Thanks, John. You may be thing of annealing. Normalizing is different and yields a harder steel (but not "hardened") and is done by heating to a higher temp over about 3/4 hr., oven soaking at the higher temp for about 1/2 hour per inch of thickness, and then removal to air cool. The metal is not quenched. The idea is to relieve internal stress in the metal caused by the welding/forming, and is usually done before hardening.

I seem to remember that the temp setting is 1,500 F, but can't confirm it, yet. I'll be using a smaller (16") jewelry kiln to heat the item.

Mark

Re: OT - Yup

Mark Mandell - Gone Round In Jersey

>Thanks, Dave.

Seems like 1500 for 1/2 hour is the trick.

Mark

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Re: OT - Yup

John Lucas

>Mark

I had forgotten about normalizing. It has been too many years since that class. I looked up the info I have and they say that normalizing should be done at a higher temperature than the critical temperature for heat treating. One book says 30 degrees. The work should "soak" at this temperature for 1 hour per inch of thickness. Remove from furnace and allow to sit in the air and cool.

Interesting. Thanks for asking this question. I love to learn. It would seem to me that this would get the metal back to or near it's original state. If a harder surface was required I would guess you would have to harden it from this state. Does that sound correct to you? My metal expert is on vacation now so I can't call and ask.

Re: When we normalized, the piece cooled in mica.

Al Crandall

>We let it cool for about 24 hours before doing anything with it. The mica really slowed down the rate of cooling. Hardened die sections were normalized prior to being welded so that they wouldn't crack at the weld joint. Then they were rehardened and tempered. I always wince when guys weld hard steel to soft steel to make their own tooling.

Re: OT - Yup

Mark Mandell - Gone Round In Jersey

>That's the deal, John. Now critical temp for heat treating seems to be 1450-1500, I'm thinking that if I lift the temp slowly to 1550-1600, hold for 45 min, then remove and let air cool, I should come out without hard spots round the weld to create cracks. Biggest difference between annealing and normalizing is that annealing uses a very slow cooling, often in the furnace, rate of like 40* per hour, whereas normalizing gets a bit hotter, but then is allowed to cool in open air without control of the rate.

Mark

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A little trick

andrew j

>One trick that I was taught is to use a magnet to tell when it has reached the "right" temperature, as the steel will no longer be magnetic over that temperature. This is handy when you don't have any other means of accurately measuring temperature. Let it cool slowly to anneal.

Hope this helps

Andrew

Re: OT - Yup

John Lucas

>Mark

I did read last night that some places use cover the piece with lime to slow the cooling during normalizing. I guess that's similar to what Al said. I remember my blacksmithing instructor saying something about using sand to slow the cooling after annealing.

I don't have an oven but wondered if you could heat to the non magnetic and then go a little lighter in color to get to this same normalizing temperature. When my metals guy gets back I'll ask. He'll be able to tell my how the Blacksmiths do it.