The chisels and punches that I am making keep breaking in half or shattering. I quench them. Then I re-heat them to a red heat. I then let it dry. I don't understand why they are busting. I'm using them with hot steel. I use a graphite soap lube for the chisels and punches while forging.

Sounds like you could have a combination of enlarged grain size and stress as well as some inconsistencies in your heat treating methods .

First off what steel are you using ?

What are you quenching in ? Water , brine, peanut oil ?

And why are you re - heating to a red heat after quenching ? after quenching you should temper at say 500 F NOT 1500 F for most simple carbon steel tools.

How about a little more info ...

Jens

I am using "weldable steel" from farm and fleet, A36 from what the other thread said. I am quenching in water. I was told to reheat to a red so that it does not become brittle, so your saying that I should temper in my mom's oven instead???? To like 500. I'll try that and see if it works better.

Might want to think about getting a small toaster oven for about $30. Can probably take to heat and hold easier and will not heat up the house in the summertime. Quite a few here use them with success. Plus you won't stink up the house with smoking oils, etc. Wastes less energy too.

Okay, so I'll see about a toaster. Will post my results. Another bit of info, I've been heating about 3/4 of the tool. And it always breaks almost exactly 7/8in of the way from the bottom. All 5 that have broken.

How about some pictures of the broken punches at the break we need to see the grain structure of the steel. I personally don't use mild steel for punches but can't imagine mild steel breaking being used as a punch A36 is generally .20% to .29% so not much carbon to harden very much. I use almost exclusive H-13 for punches and chisels for hot work and S7 for cold work. I am starting to think you have something different than A36.

A-36 is a very low carbon steel and not suited at all for punches and chisels. For a steel to become hard with heat treat it needs to have a lot higher carbon content than A36. You would be better off useing coil springs from cars and straitening. shapeing and heat treating like the say above. Basically heat it to red and let cool to black three times then heat to non-magnetic and quench in warm oil. then in an oven at 400 for a couple of hours for punches and chisels,,the last step softens the hard steel into a steel that is hard enough to use but should not be brittle. And by the way when they say "weldable" they mean you can weld it with oxy/acet torch, mig, tig or, stick..That does not mean that forge welding is out of the question. Have fun

I'm saying A36 because it's the same stuff as what im using in the other thread, forge weld wont take. And someone said that it is A36.

A-36 is usually remelted scrap and very inconsistent you could say its the goulash of steels - that could be the start of your problems. I'd suggest getting some O -1 or W-1 drill rod from your local machine shop or order it from here- Flat-Stock.com - Tool Steel for Tools, Dies, and Molds: Drill Rod
If you want good tools you need to start with good steel.


Jens

Also when quenching don't stick only part of the tool in the water. Immerse the entire tool! or at least move it up and down so as to not get a sudden transition line---sometimes a cause of breaking in a tool.

do you have a farm well business close around? if you do ask him if he has sucker rod thats good punch I use it also check if any of your horse people they use sucker rod for there arena fenches, and after you hammer the tip use old car oil to quench it dip it slow not fast other was it will get brittle and break.

What exactly is sucker rod?

sucker rod is the pipe that is inside the well casing that sucks water up to your house to your pressure tank

about the use of old motor oil as a quenchant - Click here

all the sucker rod I have used has been 4140.

You don't want to be heat treating the entire length of the tool the same. Heat it, the entire piece, to a good bright white just below sparking and quench it fast. Swirl it around in the water to be sure the water is not being boiled away from the steel and is getting to the surface of the steel and the heat is dissipating. Take it out and emery paper it enough so you can see the surface a quarter inch or so wide all the way down the tool, then put one end of it, the end you will strike, into the fire, or the gas forge, or the flame of your torch. Now watch the surface rainbow. This may take a while, but you will see an iridescent rainbow, like the colors on the surface of a puddle of gasoline, running away from the heat. When you see the blue band nearing the cutting end, quench it again, fast. This should give you a hard business end and a softer shank. If it still breaks you might be using the wrong steel for a tool. I like the old truck or car coil spring suggestion.

Sucker rod is solid, it is not pipe. It is used to manipulate the pump at the bottom of an oil well. They operate similarly to the action of the water pumps found on windmills or the old hand pumps. It is made of something like 4140 but as with any junkyard steel that can vary. Also used sucker may have some nasty stuff on you don't want to breathe. That depends on the well it was pulled from.

"a good bright white just below sparking" is WAY to hot for almost any alloy I have ever worked. Bright orange is more the upper range. Overheating the metal before quenching allows for grain growth and a weaker piece when finished.

To follow up on what Thomas said about over heating certain steels, it helps immensely to get your forge inside so that you can see the colors of the material without "light contamination" from sunlight. Trying to gauge heat temps in bright sunlight is a sure way to over heat the piece.

I am not fond of useing colors to desribe how hot something should be. WE see colors differently and ambient light changes things also,,however a magnet does not see colors. if you heat a piece of medium to high carbon steel to the point that it does not stick to a magnet, note the color and then bring it back to the same color and quench in oil, most steels will harden (if they have enough carbon) If you do not gbring the heat back up after trying the magnet the m agnet and outside air will take too much heat away before you can reach the oil. Have fun

That's what makes horse racing.

It seems like you have plenty of heat treating suggestions, unfortunatly some are better than others. Another possible cause of your tools breaking near the end could be that you are letting them get to hot as you use them and then they may be getting britel as you cool them with your lube or just cooling them in water. This could also explain why they are all breaking near the end. To avoid this cool the tool before it gets to the top of your tempering temp. for a carbon steel this means that the tip on a chisel or punch should never get blue when you are useing it. If you get a chance get someone who has been making some tools for several years to help you make one pay attention to how he heat treats the tool that is the really critical issue unfortunately most beginners are more interested in how he does the forgeing. Then after you memorize the steps get some of the same tool steel to use for yourself.

Good subject,, Did you get you a punch made John..

Oh yeah, I have six right now, that I use. I tossed those away a long time ago.

BTW if using Mum's oven don't say we said it was OK.