Problems Working Tool Steel

[baldinelli]

Hi,

I was working with tool steel for the first time and got a bunch of cracks in the piece I was making. Worked it at a yellow heat. I used a water quench, ???

Any suggestions on working w/ tool steel, or how it differs from mild steel. Also is there a difference between oil and air tool steel?

Thanks for any education sent my way.

Mike
There are no stupid questions, only stupid people who ask them.

[Mike Turner]

Would help if we knew what type of steel you are using.

[baldinelli]

Good question.

Enco Tool Steel No. 409-0017 Carbon content .85 /100 (drill rod)

[Rich Hale]

I don't have an enco catalog in the desk here but my guess uis that enco can give you the heat treat instructions. Some tool steels, and one in particular , M-2 is bad about cracking when being forged. I dont forge that one as it is easier to forge materials like the 0-1 that enco sells. Yes there is a big difference in oil and air hardening steels. If you have a steel and are not sure what to harden in then heat it and let air cool and see if it is hard. If not repeat and use oil. Water is to me a last resort as almost everything I use I oil harden. It would also help if we knew what your intended use is to be. There is a lot to forgeing steel and that is complicated a little with the addition of carbon. However all the high carbon steels I use have information readily availeable for heat treat. Tell us more and maybe we can help more. Good luck.

[roy_tate]

Here is some information from the web site.

Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies
Diameter (Inch): 5/16
Tempering Medium: W-1 Water Hardening
Length (Inch): 36

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I hope this helps those who are experienced with tool steel and will be giving advise.

[Rich Hale]

Thanks Roy that does help a lot. It also tells us that the water was the right thing for B to quench inAccording to the folks that sold it. Being a bit set in my ways I would try oil for a quench before water but that is just me being cautios. No back to the question of why it cracked I really don't know why but I think I can duplicate it if I really want to. If we agree that heating the metal too hot to forge and seeing the little sparklies start is not a good way to work the metal then lets go the other way. A piece that small of a diameter does not retain heat very long, even if you have been working a while and the anvil and hammer are pretty warm. If I bring it from the fire I must start forging reall soon, I think I remember hearing that a piece loses heat at the rate of 10 degrees f per second. May be a bit more for small stock. So if we have the piece to about a temp that a magnet will not stick to it,,that is around 1500f, in ten seconds it will be down 100 degrees f. And remember the anvil, tongs and hammer will take heat from it also. IF I take it out and have to readjust my hold with the tongs and have a couple of steps from the fire to the anvil I can lose a lot of heat. Now I do not have much time left to forge, I can be below forgeing heat before I can get much done to alter the shape. I think if I do all of these things as described I can make the little cracks. To avoid the cracks I would get the correct heat. Use a magnet and see what color the steel is when it no longer sticks to the magnet,,that is the color you want to work with, not a lot brighter and not much darker. Make sure you can get from the fire to the anvil in one motion. Have the hammer ready to work. I hit really fast work on that if you need to watch the color take as many heats as you need to foregg the shape you wish. AFter forgeing bring it up to heat again and let the color go out of it to a black , do this three times to let all the forging tensions go away. Then bring back to non magnetic and right into your quench,,WAter if you like I would try oil. I use oil at between 110 and 120f for this. and I measure the temp. The check with a file and see if it is hard. If a file kind of slides over and does not cut it is hard and needs to be tempered,,follow the data with the steel for that. Or just stick it in an oven for a half hour at 400f and test again with a file, if it cuts it but not easy it will be alright for most things. But would need to know what the use is to be sure. have fun

[evfreek]

Hi Mike. Some pretty good suggestions given above. If the steel you are using is really W1 with 85 points of carbon, a water quench should not crack it, but a piece this small should harden in oil. It is most likely that your problems are related to forging too hot (yellow is too hot) or too cold. I have gotten away with forging simple carbon steel too cold (it just does not move), but I created tiny cracks in S-7. Forging in a narrow range as Rich suggests works great, in my experience. No cracks drawing M-2 (considered difficult) into a graceful taper, but a lot of work. By the way, my highest compliments for using new, known steel rather than starting with unknown junkyard steel.

Here's a tip which I read somewhere which could help a little. I have not tried this out, but it sounds good. Forge to shape without the heat treat. In other words, just let the test piece air cool. Then, lightly grind off the scale and apply the "acid test". Unfortunately, I cannot remember where I read this, and when I search for "acid test" it comes up with tests for gold and drug abuse. Dyed vinegar (?) or something swabbed onto the metal will bring out cracks. Good for beginners, the poster said. Sounds good to me; do the experts have anything to add?

[Rich Hale]

A solid piece of steel without cracks will ring if you tap it with a piece of metal while it is near your ear, may want to do this after you remove scale and the metal is cool. If it rings it is solid if it has a dull sound likely has cracks.

[ThomasPowers]

Note that most manufacturer's heat treat instructions are based on fairly thick cross sections; if you pound out a knifebalde expect to need at least the next quenchent gentler on the scale! So water goes to oil and oil may go to air, etc.

So what were you making?

[attlihammer]

I suspect that you have forged your steel to hot and burnt the surface. this would result in the cracks that you talked of. I have almost entirely worked with recycled materials and as such have never known the content of my steels. the lighting conditions of your forge will greatly affect the apperance of the colour of your steel so in my experiance experimentation is the key. for heat treatment, personly I would produce a series of test peices quenching in oil and water and then drawing different tempers, before testing with a file and then doing impact tests over the edge of the anvil to assess how tough the material is at different tempers (be warned the metal can shatter with some force and send extreemly sharp shards in all directions with some force so protective gear is a must!) I hope this may be of some help.