W1 MS

[guarnera]

Ok. Its Morning, and my brain is not working yet. I need to HT some W1 chisels I'm making. They are 1/8" to 3/8" square W1 stock 3 1/2" long. I'm just HT the working end of them. I want to do a Aus Quench. I think that's what its called, when you quench into salt that is just below Ms and hold for a while and then air cool, and then temper. My question is at what temp is below MS for W1 ( what temp should I quench into ) ? and how long shouls I hold at that Temp. for these small size chisels? Thank You All.

 

Tony G

[Doug Lester]

Can't help you on the actual temperature but when you austemper you hold your steel at just ABOVE the martinsite start point and hold it there until you have formed the percentage of banite that you want to form. The fraction of bainite that is formed depends on the time you hold it in the low temperature salts. A similar process is when you hold the steel at just above the martinsite start point for just about a half minute or so to allow the core of the blade to cool to the same temperature as the surface of the blade. This allow for more complete martinite formation in the core of the blade. That process is called martempering. With the varing compositions of the W series, you may have to contact the supplier to find out what the martinsite starting point is and how long it takes to form particular percentages of bainite in their steel.

 

Doug Lester

[Howard Clark]

Tony the procedure you describe is called "mar-tempering", which I think should be "Mar-quenching". You only hold at the quench temperature long enough for the temp in the whole piece to get to that temperature and stabilize, as Doug said already. Then cool in still air, and it makes martensite during the cooling down to ambient. Ms is around 450f for most simple steels.

[nakedanvil]

Martempering and austempering are two completely different processes, although you both described each of them correctly. Austempering W-1 will only yield a Rockwell in the 30's on the 1/8" parts and will be a total bust on 3/8" thickness. Parts that thick would require an alloy steel like 5160. End quenching adds an unusual variable, never seen that done. Austempering is not used where chisel hardness is the goal. Almost always applied to very thin parts.

 

The question really should be: What are you trying to achieve? Why would you NOT use a "standard" Q&T for a chisel?

Edited July 24, 2009 by nakedanvil

[guarnera]

Martempering and austempering are two completely different processes, although you both described each of them correctly. Austempering W-1 will only yield a Rockwell in the 30's on the 1/8" parts and will be a total bust on 3/8" thickness. Parts that thick would require an alloy steel like 5160. End quenching adds an unusual variable, never seen that done. Austempering is not used where chisel hardness is the goal. Almost always applied to very thin parts.

 

The question really should be: What are you trying to achieve? Why would you NOT use a "standard" Q&T for a chisel?

 

 

 

 

 

Thank you all for your answers. Mar-Tempering is the name I was looking for. I could use a standard Q&T. I've not made up my mind yet. I thought I'd get a tougher tool with the Mar-quench. I might be totally under a misconception ! They are small chisels for working soft steel and copper alloys. Thanks again.

 

Tony G

[kb0fhp]

Thank you all for your answers. Mar-Tempering is the name I was looking for. I could use a standard Q&T. I've not made up my mind yet. I thought I'd get a tougher tool with the Mar-quench. I might be totally under a misconception ! They are small chisels for working soft steel and copper alloys. Thanks again.

 

Tony G

 

 

Martempering or Mar-Quenching is primarily done for controlling distortion while achieving the desired hardness. Martempering can be done on either the 5160 or W1.

[B. Norris]

Thank you all for your answers. Mar-Tempering is the name I was looking for. I could use a standard Q&T. I've not made up my mind yet. I thought I'd get a tougher tool with the Mar-quench. I might be totally under a misconception ! They are small chisels for working soft steel and copper alloys. Thanks again.

 

Tony,

 

Something I read somewhere (would be great if I could remember where) is to quench small tools such as awls, etc. into a block of beeswax. I have made several small items this way, a couple awls and a centerpunch, and it worked very well. I just tempered with a plumbers torch, several times, afterwards. I had quenched a few smaller items into oil but, I had problems with warping a cracking on such small, thin, sections. This has not been an issue, at all, with the beeswax.

 

~Bruce~

[Robert Kobayashi]

1

Edited March 29, 2011 by Robert Kobayashi

[Mike Krall]

Martempering or Mar-Quenching is primarily done for controlling distortion while achieving the desired hardness. Martempering can be done on either the 5160 or W1.

 

Scott,

 

I guess I don't understand Martempering. I thought it wouldn't cool simple steels fast enough to get by the perlite nose to form 100% martensite (or nearly 100%). Would you tell me about what it is I'm not getting, please?

 

Mike