Yu-Shoku: V-Toku2 Carbon Steel Clad with Mokume (Copper, Brass, and Stainless Steel), DPS San Mai (.12" x 39-1/4" x 1-1/2")

Product Description for Yu-Shoku: V-Toku2 Carbon Steel Clad with Mokume (Copper, Brass, and Stainless Steel), DPS San Mai (.12" x 39-1/4" x 1-1/2")

Maker: Takefu Special Steel (click to see more by this maker)
Price: $514.31
Item num: 104191
Total length: 39.25 in.
Item weight: 33.20 oz.
Description: This 3mm thick bar of Yu-Shoku is cut to 39-1/4 inches long and is 1-1/2 inches wide.
This bar is pre-laminated V-Toku2 carbon steel core with mokume cladding (forged from copper, brass and stainless steel). DPS (depletion prevention system) adds a thin nickel shim between the core steel and the cladding. The nickel acts as a barrier to stop carbon migration between the carbon steel core and mokume outer layers and creates a particularly dramatic and bold transition line. We recommend not upset forging this material as this can cause delamination.
The V-Toku 2 carbon steel core contains very few impurities and is easy to heat treat. It has good ductility, workability, and is easily forged. Hard and fine carbides are formed by adding Cr (Chromium), W (Tungsten), and V (Vanadium), ensuring tremendous durability and edge holding. The addition of W (Tungsten) brings about high toughness and high strength at elevated temperatures. V (vanadium) ensures fine grain. These effects are even more enhanced with the addition of Cr (Chromium). Although ease of quenching and improved annealing are rarely found together, precise amounts of Mn (manganese) and Cr (chromium) gives this desired effect. Because of the high toughness of V-Toku 2 it can be used at extremely high hardness, Hrc 65 in culinary knives, and 60-61 Hrc in sporting knives. 

V-Toku2 Specs
C CR W V Mn Ni
1.05% .35% 1.25% ≤ 0.2% ≤ 0.4% ≤ 0.25%

Heat Treatment
Forging: Forge at 1010-1065°C/1850-1950°F. Do not forge on edge. Forging at incorrect temperatures can cause delamination. You should anneal after forging.
Annealing: Anneal at 830°C/1526°F. Cooling speed should not exceed 25°C/hr - 77°F/hr
Quenching: Austenitize at 800-840°C/1472-1544°F. Quench in oil (50°C/122°F) or water (25°C/77°F)
Tempering: Temper at 100-200°C (212-392°F) to desired hardness.

Annealed: Hrc 25
Hardened: Hrc 66.5
Sub-Zero: Hrc 67.0

Mastersmith Bill Burke's Heat Treatment Recommendation: After forging, thermal cycle blade a minimum of three times. Anneal at 1526°F, hold 30 minutes, then cool at 77°F per hour to 750°F. then air cool. If desired a sub-critical anneal can be used in place of a full anneal. Soak two hours at 1250°F then cool at 75°F per hour to 750°F, then shut off annealing oven and allow to cool in oven. Austenitize: heat blade to 1350°F, hold 30 minutes, then raise temperature to 1500°F and quench in oil. Hold at temp no more than 10 minutes before quenching. Temper two times for two hours (250°F ~65 Hrc) to bring steel to desired hardness.

Yushoku Heat Treatment Chart

Note: results may vary with hardening method and section size.

Availability: In stock. Usually ships in 1-2 business days