Chart: Steel Temps

Heat treatment of steel is a science that feels like an art. An good steel can be badly damaged by improper heat treatment. If it is not hardened properly it will deform and not keep an edge. If it’s grain is enlarged, or it is not tempered properly, or if retained austenite is not dealt with it can be easily chipped or broken.

Folks get very emotional about heat treatment and theories (both modern metallurgical and traditional) abound. I am not attempting to cover HEAT TREATMENT, these are ONLY my notes on recommended temperatures for a smattering of steels. I wanted a crib sheet to laminate and put in the shop. Stainless steels are really tweaky a I have no plans to heat treat my own stainless – so no notes are included here on stainless.

For readings on heat treatment, check out the works of John D. Verhoeven and Kevin Cashen’s website. For a more hands-on perspective try books by Wayne Goddard, Jim Hrisoulas, Murray Carter, the American Bladesmith Society, and many other custom bladesmithing books.

I’ve usually noted below where I gleaned the temperatures from – so you can go to the source to get extended or updated info. Please inform me of any misrepresentation in my notes!

All temps are in Fahrenheit. Normalizing and tempering are generally repeated three times each – cooling to holdable temp between times for normalizing – ambient temp between times for tempering. There is generally a “soak at temp” time for normalizing, annealing, and hardening – anything from 5 min to 30 min depending on the steel, the operation, and the temperament of the bladesmith. Tempering time is often 2 hrs for each repetition.

If you can find a specification sheet from the manufacturer of the steel you are using, that should be a better source than these notes – but be aware that steel mill specs are generally for much thicker slabs of steel than a knife blade.

 

 Steel  Forging  Normalizing  Annealing  Hardening  Tempering
 1080 & 1084 – Cashen Blades 2150 – not below 1500 1600, cool in still air 1500, cool to 1200 @ max 50/hr 1500, can oil quench if < 0.25″ thick else water, brine 300 RC 65
350 RC 63-64
400 RC 60-61
450 RC 57-58
 1095 – Cashen Blades 2100 – not below 1500 1575, cool in still air 1475, cool to 1200 @ max 50/hr 1475, can oil quench if < 0.25″ thick else water, brine 300 RC 65
350 RC 63-64
400 RC 62-63
450 RC 61-62
 5160 – Cashen Blades 2200 max – not below 1600 1600, cool in still air 1525, cool rapidly to 1300, then to 1200 @ max 20/hr 1525, quench in oil. Can reach RC 63 ???
 52100 – Cashen Blades 2100 – not below 1700 1625, cool in still air 1460, cool rapidly to 1380, then to 1250 @ max 10/hr 1475 to 1550, quench in oil.  Touchy thermal treatment, carbides, retained austenite. Can reach RC 66 ??? Temper as soon as blade reaches ambient temp from hardening.
 D2 – Crucible Industries ??? 1225, hold 2 hours, cool in still air 1600, hold 2 hours, then to 1000 @ max 25/hr, then air cool. 1150 & soak, then 1425 & soak, then 1825-1875 & soak 30 min, air quench to below 150. 400
 D2 – Goddard – Wonder of Knifemaking ??? ??? 1550-1660 and cool furnace to black @ max 20/hr then turn off furnace and let finish cooling in furnace. 1800-1875 & soak 20 min, then air cool. RC 63-64 450 for RC 59
 D2 – Knife Network ??? ??? ??? 1400-1450 & soak 5-10 min, then 1850 & soak 30 min, quench in warm oil or air. 500 for 2 hrs for RC 60 -or- cryo in dry ice mix, then 400 for 2 hrs
 D2 – Bohler/Uddeholm ??? 1200, hold 2 hours, cool slowly to 930, then air cool 1560, then cool to 1200 @ max 20/hr, then air cool 1110-1290 & soak, then 1870-1920 & soak 30 min, air quench or oil  Cryo (-100 dry ice mix) adds 1 to 3 HC.
Aust F/TemperF/HC/Retain Aust:
1920 800 59 24
1920 900 62 12
1920 1000+ 60- 0
1870 750 59 20
1870 900 60 7
1870 950+ 58- 0
 L6 – Cashen Blades 1800-2000 – not below 1550 1600 then cool in still air 1400 & long soak (1hr?!?), then cool to 1000 @ max 40/hr 1500-1550 & soak 10 to 30 min, then quench in warm agitated oil. RC can be up to 63 Temp/RC
300 63
350 62-63
400 60-61
450 58-59
500 56-57
 O1 – Cashen Blades 1800-1900 – not below 1550 1600 then cool in still air 1400 then cool to 1000 @ max 40/hr, then to ambient 1450-1500 & soak 10 to 30 min, quench in oil. RC up to 65 if fully hardened:
Temp/RC
300 65
350 64-65
400 62-63
450 60-61
500 59-60
 O7 – (tungsten tool steel) 1750-1900 ??? 1500-1550 then cool very slowly 1100-1200 & soak briefly, then 1500-1650 & quench in warm oil Temp/RC
300 66
400 64
500 61
 W2 – Cashen Blades 1800-1900 – not below 1500 1600 then cool in still air 1400 then cool to 1000 @ max 50/hr 1450-1475, water quench – can be quenched in oil if < 0.25″. RC 65-67 ???