JIS SKD-61 Tool Steel Bar - UNS T20813(Die Steel Round Bars)

Product Description

Overview of JIS SKD61 / UNS T20813

JIS SKD61 (standardized under Japanese Industrial Standards) and UNS T20813 are international designators for a premium hot-work tool steel, most commonly known globally as AISI H13.

Characterized by its excellent balance of toughness, resistance to thermal fatigue cracking (heat checking), and high-temperature strength, this grade is the industry standard for demanding hot-work engineering applications.

Technical Specifications & Chemical Composition

The defining feature of SKD61 is its chromium-molybdenum-vanadium ($\text{Cr-Mo-V}$) alloying system, which provides deep air-hardening capabilities and excellent dimensional stability during heat treatment.

Global Cross-Reference Equivalents

When sourcing or substituting material across international projects, SKD61 maps to several major global standards:

• USA (ASTM / AISI / UNS): H13 / UNS T20813

• Germany / Europe (DIN, EN): 1.2344 / X40CrMoV5-1

• United Kingdom (BS): BH13

• France (AFNOR): Z40CDV5

• China (GB): 4Cr5MoSiV1

• Russia (GOST): 4Kh5MFS (45)

Key Mechanical & Physical Properties

• High-Temperature Hardness: Maintains significant structural integrity and wear resistance at elevated operating temperatures up to 500C600C (932F1112F).

• Thermal Shock Resistance: Excellent resistance to cyclical heating and cooling, drastically reducing the risk of premature "heat checking" (surface micro-cracking).

• Machinability: In its supplied spheroidized annealed state (typically $\le$ 229 HBW), it exhibits good machinability and can be readily formed into complex die profiles before final hardening.

• Typical Hardness Post-Heat Treatment: Generally quenched and tempered to an operational hardness range of 46 to 52 HRC, balancing peak toughness with wear resistance.

Common Applications

Because of its structural integrity under extreme thermal and mechanical loads, SKD61 round bars are extensively utilized in:

• Die Casting Dies: Core inserts, ejector pins, nozzles, and shot sleeves for aluminum, magnesium, and zinc die casting.

• Extrusion Tooling: Extrusion dies, die holders, liners, and mandrels for processing aluminum profiles and copper alloys.

• Hot Forging: Forging die inserts, hot punching tools, and hot shear blades.

• Plastic Injection Molding: High-wear molds or tooling components requiring a high polish finish where exceptional core toughness is necessary.