I would never forge that high a carbon steel that cool. I always start my forging at as high a temp as the steel will support and decend my temps as I get closer to final shape. Then I do a through normalizing and thermo cycle to reduce grain..

Working to cold just forces more cycles imparts greater stress into the steel and invites cracking.

I trust industry numbers explicitly on this sort of thing as they have spend a lot of time and effort to figure it out. Nothing any one of us does in our own shops will be better information that they have allready provided. MP

I will echo what Matt just said. Due to its rather unforgiving nature, I have now spent more lab time with 52100 than any other alloy. I should have released my DVD on this steel last year but I am now going on two years of testing to be sure I get it right. The low temperature forging craze makes this alloy much more complicated than it needs to be. Forging below industrial specs will only make things a lot more miserable to sort out.

After years of observation, I believe baldesmithing would be so much farther ahead if we could just get over this unhealthy and unrealistic obsession with grain size. Or at least completely separate it from the forged blade. Grain size is not something to worry about while forging, unless you wish to totally ignore carbide condition at your own peril. Grain size is best and most easily controlled with heat treatments, not forging. Yes, you can blow the grains during forging if you get deformation out of synch with temperature, but it would take a maximum of two normalizing, or cycling, heats to fix it. On the other hand, repeated low temp cycling with excessive deformation, will totally mess up your carbide condition resulting in heavy segregations that will be very difficult to fix. Homogeneity is the key to maximizing just about any desirable property in steel, and segregation is by definition the opposite of that. Heavy deformation, at improperly low temperatures, lead to segregation issues such as banding, particularly in this alloy. When you have segregated the carbide, enough to see it with the naked eye, the problem with that process is very plain to see.

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I will echo what Matt just said. Due to its rather unforgiving nature, I have now spent more lab time with 52100 than any other alloy. I should have released my DVD on this steel last year but I am now going on two years of testing to be sure I get it right. The low temperature forging craze makes this alloy much more complicated than it needs to be. Forging below industrial specs will only make things a lot more miserable to sort out.

After years of observation, I believe baldesmithing would be so much farther ahead if we could just get over this unhealthy and unrealistic obsession with grain size. Or at least completely separate it from the forged blade. Grain size is not something to worry about while forging, unless you wish to totally ignore carbide condition at your own peril. Grain size is best and most easily controlled with heat treatments, not forging. Yes, you can blow the grains during forging if you get deformation out of synch with temperature, but it would take a maximum of two normalizing, or cycling, heats to fix it. On the other hand, repeated cycling and excessive deformation, will totally mess up your carbide condition resulting in heavy segregations that will be very difficult to fix. Homogeneity is the key to maximizing just about any desirable property in steel, and segregation is by definition the opposite of that. Heavy deformation, at improperly low temperatures, lead to segregation, particularly in this alloy. When you have segregated the carbide, enough to see it with the naked eye, the problem with that process is very plain to see.

I would be interested in that dvd when you get it ready. I appreciate you taking the time t ok explain.

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I would never forge that high a carbon steel that cool. I always start my forging at as high a temp as the steel will support and decend my temps as I get closer to final shape. Then I do a through normalizing and thermo cycle to reduce grain..

Working to cold just forces more cycles imparts greater stress into the steel and invites cracking.

I trust industry numbers explicitly on this sort of thing as they have spend a lot of time and effort to figure it out. Nothing any one of us does in our own shops will be better information that they have allready provided. MP

Thanks for taking the time t ok explain. I will try working it at the higher end of the forging temps and working down.

Another thing Brian. 52100 likes a slower quenchant than parks 50. I believe parks AAA or something similar is a better choice.

Brion

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Another thing Brian. 52100 likes a slower quenchant than parks 50. I believe parks AAA or something similar is a better choice.

Brion

Thank you Brion! I was just about to mention this, as it got by me when I read the post the first time, and then I saw your post. Whenever you see "Cr" in the chemistry of a steel it is time to rethink if you should be using a 7 to 10 second oil. I often see comments about distortion or cracking when quenching an alloy steel in Parks #50 if you aren't careful about X, Y or Z... and this really should be telling us something. I have been using Parks #50 longer than just about any maker aside from Dan Maragni, who told me about it back in the late 90's, and I have never cracked a blade in it. But then I have never used it on a blade made of an alloyed steel designed for an oil quench. I have had numerous metallurgical samples crack when quenched in a 7 second oil and left untempered, but that just reinforces my point.

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Another thing Brian. 52100 likes a slower quenchant than parks 50. I believe parks AAA or something similar is a better choice.

Brion

Thx Brion I appreciate it. It sounds like I need some AAA. Wheres the best place to get 5 gallons? I found some Type A oil from Great Lakes Oil is it equivalent to Parks AAA?

The nice thing about moving to an oil better matched to an alloy steel is that they are much more common, giving you many more choices and less expensive options. Just about any oil on the 11 to 14 second range will work very well, and most are not as difficult to obtain as Heatbath/Park Metallurgical products (i.e. #50 and AAA). The only thing special about Heatbath/Park Metallurgical is the speed of the #50, it is an oil designed to mimic a water quench so that you can quench steels like W1, W2 and 10XX series without the risks posed by water. But oil hardening alloys were designed for oil, so just about any quench oil will do.

Brian, Kevin speaks the truth. Your quench A should work fine for 52100. Also 5160, 80crv2, O1, etc.

Brion

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Whenever you see "Cr" in the chemistry of a steel it is time to rethink if you should be using a 7 to 10 second oil.

Newbie question... is there a certain percentage threshold to look for or just if any chromium is present?

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Brian, Kevin speaks the truth. Your quench A should work fine for 52100. Also 5160, 80crv2, O1, etc.

Brion

I appreciate all the responses. I am going to get some med speed oil.

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I appreciate all the responses. I am going to get some med speed oil.

Any element below .1% is normally a trace element and is of little consequence, except in assessing quality control of the steels production. Cr is normally added for a specific reason and will thus often be of intentional amounts. Once you get up around .5%, you are safely in the oil hardening range, but you are going to see dramatically deeper depths of hardening at .3 and .4. But keep in mind that it is seldom a stand alone thing and there will most likely be other elements interacting with and enhancing the effect. Mn is a big one, and even small amounts of moly along with Cr will have a strong effect. O-1 has a rather low Cr level but in combination with the moly and other additions, it is literally the standard bearer of an oil hardening steel.

Should my med speed oil be heated ?

Check out what I got 130lbs of 52100. Ive got to make a few sets of tongs to get this broke down.