Note: this has been edited on the temper temperatures. In researching I found two different temper recipes from ASM. The original temper temperatures seemed too high. I am revising the temperatures down to reflect the second set of temperatures I found from ASM that seems to be more in line with what we see in the real world.
I am working on updating the heat treat information I have on my supply site. I thought I might as well post it here also.
Heat Treating 1095
Referencedata: ASM Book: Practical Heat Treating by Boyer
Written byTracy Mickley
www.USAknifemaker.com
1095 is a high carbon steel with .95% carbon (the 95 in1095) and is proven, good quality knife steel with good edge retention. 1095 isconsidered slightly “fussier” about heat treating than say 1080 or 5160. Thisisn’t a deal break at all and really can be mostly ignored. Follow the recipebelow and you shouldn’t have any problem.
Normalizing:Normalize by bringing to 1575F, soak for 5 minutes and allowing to cool instill air. Normalizing steel allows the crystalline structure to be reset andresets the carbides back to uniformity. Steel doesn’t like uneven structure. Ifthe carbides have gotten all bunched up and oversized from forging, the steelwon’t hold an edge as it potentially could. Bar stock from the mill probablyshouldn’t have to be Normalized, especially if it has been annealed. Materialthat has been forged could probably benefit. Basically, heat it in your forgeor oven and let it air cool. Done.
Annealing: Annealby heating to 1475F and cool at a rate no faster than 50F per hour. Generally,most guys heat to temperature in their forge as the last heat of the day, turnoff the forge and let the steel cool in the forge overnight. If you have otherwork you want done, I use a half size trash can full of vermiculite. I heat acouple large bars of scrap steel to add mass/heat. I heat the steel totemperature and put it all in the vermiculite to cool down slowing using thevermiculite as an insulator. Cooling slower in the forge works better butcooking in the vermiculite works fairly well also. Some guys use lime insteadof vermiculite.
Hardening: Heatto 1475F or past non-magnetic which is around 1425F. Generally, in a forge,this means heating it until a magnet doesn’t stick and then “just a little more”to get the extra heat into the steel past non-magnetic. A few minutes at this temperaturewill not grow grain but does allow the carbon to get “into solution”.Overheating steel into the 1550F 1600F range and beyond and soaking it willgrow grain. Simple, heat it to non-magnetic, give it another minute or so toheat a bit more, quench. You will see somewhere, a lot of places in fact, thatthe steel really needs to be cooled off at a high rate, like 1 to 2 seconds andthat is absolutely true. That doesn’t mean you only have 1 second to get fromyour heat source to your quench. Moving a blazing hot piece of steel from heatto oil is where a lot of fires get started. A guy knocks over the oil, dropsthe red hot steel into the oil and instant fire! The steel will retain heat andsurvive a few seconds in the air as you move from heat to quench. Do thissafely and be prepared for a flare up of fire and a large amount of smoke. Alwaysbe prepared for a fire.
Tempering: If youdid everything right quenching, your steel is around 66RC and fragile as glass.If you drop it now, it will shatter. You want to temper it as soon as it getsto room temperature. I have a left a piece of steel overnight untempered andfound it cracked the next day from the stress hardening puts into the steel. It’srare but it happens. Temper twice at 2 hours each allowing the steel to coolback to room temperature between cycles.
(note edited temps below from original post revised data from ASM Heat Treater Guide Practices and Procedures for Iron and Steels.)
· 400F yields approximately 58RC
· 500F yields approximately 57RC which is wheremost will want this steel.
· 600F yields approximately 52RC
Cryo Treatment: Cryotreatment, soaking steel after hardening but before tempering at temperaturesat least minus -90F (dry ice range) to minus -290F (liquid nitrogen range) foreight hours. Most high carbon steels aregenerally not cryo treated as the benefit to carbon steels is usually not assignificant as it is with the newer super stainless steels. Many people willsay a properly heat treated steel should not need any cryo treatment as it only“makes up for a poor heat treat” This sounds good but isn’t necessarily true.Cryo treatment is an industry recognized practice in heat treating and simplywouldn’t exist as an unnecessary expense if wasn’t a legitimate extension ofthe heat treat, quench and temper process. Big business doesn’t waste money onsteps on heat treating it doesn’t need to do. Having said all that, most don’tcryo treat carbon steels but you can if you want. Soak it in liquid nitrogenovernight or even a cooler full of dry ice. You will read about guys usingacetone in dry ice. Acetone is crazy flammable. Avoid it please. Use Kerosene oreven diesel fuel if you feel you need a liquid medium but just putting yourblade under a block of dry is all you need to do. Some guys do one low temperheat at at 300F to 350F sometimes called a “snap temper” to take some of thestress out of a hardened blade before cryo. This lowers the chance of crackingthe blade. I have never had one crack from cryo treating a blade afterquenching but that just means I have been lucky. Eventually I will, it is justa matter of time.
Austempering:This is a process of hardening steel into Bainite, something we knife guysgenerally don’t use. We are after Martinsite steel.
I am working on updating the heat treat information I have on my supply site. I thought I might as well post it here also.
Heat Treating 1095
Referencedata: ASM Book: Practical Heat Treating by Boyer
Written byTracy Mickley
www.USAknifemaker.com
1095 is a high carbon steel with .95% carbon (the 95 in1095) and is proven, good quality knife steel with good edge retention. 1095 isconsidered slightly “fussier” about heat treating than say 1080 or 5160. Thisisn’t a deal break at all and really can be mostly ignored. Follow the recipebelow and you shouldn’t have any problem.
Normalizing:Normalize by bringing to 1575F, soak for 5 minutes and allowing to cool instill air. Normalizing steel allows the crystalline structure to be reset andresets the carbides back to uniformity. Steel doesn’t like uneven structure. Ifthe carbides have gotten all bunched up and oversized from forging, the steelwon’t hold an edge as it potentially could. Bar stock from the mill probablyshouldn’t have to be Normalized, especially if it has been annealed. Materialthat has been forged could probably benefit. Basically, heat it in your forgeor oven and let it air cool. Done.
Annealing: Annealby heating to 1475F and cool at a rate no faster than 50F per hour. Generally,most guys heat to temperature in their forge as the last heat of the day, turnoff the forge and let the steel cool in the forge overnight. If you have otherwork you want done, I use a half size trash can full of vermiculite. I heat acouple large bars of scrap steel to add mass/heat. I heat the steel totemperature and put it all in the vermiculite to cool down slowing using thevermiculite as an insulator. Cooling slower in the forge works better butcooking in the vermiculite works fairly well also. Some guys use lime insteadof vermiculite.
Hardening: Heatto 1475F or past non-magnetic which is around 1425F. Generally, in a forge,this means heating it until a magnet doesn’t stick and then “just a little more”to get the extra heat into the steel past non-magnetic. A few minutes at this temperaturewill not grow grain but does allow the carbon to get “into solution”.Overheating steel into the 1550F 1600F range and beyond and soaking it willgrow grain. Simple, heat it to non-magnetic, give it another minute or so toheat a bit more, quench. You will see somewhere, a lot of places in fact, thatthe steel really needs to be cooled off at a high rate, like 1 to 2 seconds andthat is absolutely true. That doesn’t mean you only have 1 second to get fromyour heat source to your quench. Moving a blazing hot piece of steel from heatto oil is where a lot of fires get started. A guy knocks over the oil, dropsthe red hot steel into the oil and instant fire! The steel will retain heat andsurvive a few seconds in the air as you move from heat to quench. Do thissafely and be prepared for a flare up of fire and a large amount of smoke. Alwaysbe prepared for a fire.
Tempering: If youdid everything right quenching, your steel is around 66RC and fragile as glass.If you drop it now, it will shatter. You want to temper it as soon as it getsto room temperature. I have a left a piece of steel overnight untempered andfound it cracked the next day from the stress hardening puts into the steel. It’srare but it happens. Temper twice at 2 hours each allowing the steel to coolback to room temperature between cycles.
(note edited temps below from original post revised data from ASM Heat Treater Guide Practices and Procedures for Iron and Steels.)
· 400F yields approximately 58RC
· 500F yields approximately 57RC which is wheremost will want this steel.
· 600F yields approximately 52RC
Cryo Treatment: Cryotreatment, soaking steel after hardening but before tempering at temperaturesat least minus -90F (dry ice range) to minus -290F (liquid nitrogen range) foreight hours. Most high carbon steels aregenerally not cryo treated as the benefit to carbon steels is usually not assignificant as it is with the newer super stainless steels. Many people willsay a properly heat treated steel should not need any cryo treatment as it only“makes up for a poor heat treat” This sounds good but isn’t necessarily true.Cryo treatment is an industry recognized practice in heat treating and simplywouldn’t exist as an unnecessary expense if wasn’t a legitimate extension ofthe heat treat, quench and temper process. Big business doesn’t waste money onsteps on heat treating it doesn’t need to do. Having said all that, most don’tcryo treat carbon steels but you can if you want. Soak it in liquid nitrogenovernight or even a cooler full of dry ice. You will read about guys usingacetone in dry ice. Acetone is crazy flammable. Avoid it please. Use Kerosene oreven diesel fuel if you feel you need a liquid medium but just putting yourblade under a block of dry is all you need to do. Some guys do one low temperheat at at 300F to 350F sometimes called a “snap temper” to take some of thestress out of a hardened blade before cryo. This lowers the chance of crackingthe blade. I have never had one crack from cryo treating a blade afterquenching but that just means I have been lucky. Eventually I will, it is justa matter of time.
Austempering:This is a process of hardening steel into Bainite, something we knife guysgenerally don’t use. We are after Martinsite steel.
Last edited: