CPM D2 - 1/8" x 6" x 36" sheet
Forever raising the bar for themselves, Crucible has taken their well-respected D-2 steel powderized and re-smelted to achieve CPM D2, which has more evenly distributed carbides, adding even better wear resistance to an already impressive steel.
Considered a high carbon steel in this more distributed state, regular D-2 does air-harden which could present difficulties for the amateur maker.
However, when heat treated and ground properly, CPM D2 is a monster in any application, taking everything the user throws at it and then asking for more.
The high carbon and carbide density translate to an edge that forms a burr that is commonly described as eerily sharp no matter the abuse and use.
If there is any downside to this steel is that it may not offer the best corrosion resistance, but when well maintained and cared for, makes a knife worth several lifetimes.
**Knives should be cleaned by washing with soapy water and then either placed into foil pouch or coated with high temperature anti-scale/decarburization compound prior to heat treat if not using Oxygen free heat treat equipment.
***Skipping stages such as pre-heating and equalizing or cryo will result in lower hardness, higher amounts of Retained Austenite (RA), impaired stain resistance or other issues. Ramp AFAP (as fast as possible) between preheating and austenizing temps.
****Clamping flat after quench during cryo or tempering recommended to avoid thermal shock induced warp.
*****Figures represent quenching under positive pressure with aluminum plates and compressed air to at or below 125°F / 50°C--alternative quenching methods may present lower hardness, high RA, or other issues.
Pre-heat/Equalizing Pre-Heat/Equalizing Austenizing temperature Expected Rc (as quenched prior to cryo)
1,200°F / 650°C(hold 10-15minutes)
1,400°F / 760°C (hold 10-15 minutes)
1,850°F / 1065°C Soak 30 minutes - 61Rc (63 after Cryo)
A cryogenic treatment is recommended to convert retained austenite, and can either be done before or after the first temper cycle.
While liquid nitrogen is preferred, a sub zero bath with dry ice and kerosene will suffice for -100°F /
Submerge in sub-zero treatment 1 hour depending on thickness and number of blades.
**A cryogenic treatment can be done immediately done after quench, but it is recommended blades be
clamped flat to avoid thermal shock induced warp--cryo treatment should always be followed by a
Once blade is quenched and near ambient temperature, blades should be tempered accordingly, the
times suggested are to ensure even, consistent temperature.
Figures supplied are as representative of industrial standards.
*If using a small toaster oven or household kitchen oven for tempering, using a blade holding rack made
from kiln furniture, a roasting tray lined with fine sand, or similar large object will help retain thermal
mass to reduce wide swinging temperatures as the device fluctuates trying to maintain temperature.
Note: Final hardness values vary based on initial as-quenched hardness and percentage of conversion to
Martensite. Only reliable testing methods, e.g. calibrated Rockwell hardness tester, can provide actual
hardness values--hardness calibrated files and chisels are relative testing methods and inaccurate for
true hardness value reading.
Temper twice for 2hrs.
Temperature: Hardness (2 hour x2 guideline):
300°F / 149°C 62
400°F / 204°C 61
500°F / 260°C 60
600°F / 316°C 59
**Manufacturers warn against tempering at 800°F / 425°C and above as sensitization will result in
reduction of toughness and corrosion resistance.
***The included Heat Treat Schedule on this page is formulated based upon Industry standards and
data from ASM International, Crucible and other foundry spec sheets, and Kevin Cashen (independent
researcher, ferroalloy metallurgist, and bladesmith of Matherton Forge).
Suggested heat treatment are based on the recommended specifications for use in ovens, high temp
salts, and similarly, properly calibrated equipment; and in line with proper industrial standards for
quenching. Deviation from industry standards for schedules, equipment, quenching mediums; and
hardness testing equipment may result in varied results. The supplied information on this page is on a
generalized scale with the above mentioned standards and methods, which is why soak times and
similar aspects may vary in time length to include a margin for the available heat treating equipment
and steel cross section.