SKD4

Other

SKD4

Hot-work tool steel. (JIS G4902; equiv ASTM A681 / DIN 1.2344 / JIS SKD61 / GB 4Cr5MoSiV1). Nominal values—confirm mill certificate.

Chemical Composition (%)

C0.25
CR2
W4.5
V0.2
P0.03
S0.03

Mechanical Properties

Hardness(annealed):≤235 HB;Hardness(hardened):44-50 HRC

Chinese Standard

JIS G4902 SKD4

Equivalent Standards

ASTM A681

Equivalent Grades

DIN 1.2344 / JIS SKD61 / GB 4Cr5MoSiV1

Applications

热作模具钢。,"Bar

Available Forms

Block"

Uses

Tool and die steel for cutting, forming, punching and molding tools. Tungsten/molybdenum (≈5%/0%) give hot hardness and red-hardness for high-speed and hot-work tools. High chromium (≈2.5%) provides wear resistance and secondary hardening. Applied to blanks, punches, extrusion dies, shear blades, plastic-mold and cold-work tooling.

Heat Treatment

Powder/HSS: preheat 800–850 °C, austenitize 1180–1230 °C (salt or vacuum), quench, triple temper 540–570 °C to ≈64–66 HRC.

Precautions

Risk of quench cracking and distortion — use graded preheating, controlled cooling and multiple tempers. Avoid overheating the austenitizing temperature. Machine in the soft annealed condition; allow for dimensional change after heat treatment. Grind with coolant to prevent rehardening cracks.

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