SKD11 Tool Steel-JIS G4404

SKD11 steel (JIS G4404 standard), as a high-carbon and high-chromium alloy tool steel, has long been recognized as one of the benchmark materials in the field of cold work tool steel due to its excellent wear resistance, excellent hardenability and good toughness.

After optimized heat treatment process, SKD11 can show excellent comprehensive service performance and meet the needs of high-precision and long-life molds. Therefore, it is widely used in the manufacture of various cold working molds (such as punching dies, bending dies, drawing dies, stamping dies) and high-wear-resistant mechanical parts.

SKD11 STEEL CHEMICAL COMPOSITION

Grade	C	Si	Mn	P	S	Cr	Mo	V
SKD11	1.4-1.6	≤0.4	≤0.6	≤0.03	≤0.03	11-13	0.8-1.2	0.2-0.5

Core Element Characteristics

Carbon (C): 1.40~1.60% → High hardness base
Chromium (Cr): 11.0~13.0% → Wear resistance + corrosion resistance
Molybdenum (Mo): 0.80~1.20% → Refined grain + Anti-tempering softening
Vanadium (V): 0.20~0.50% → Improve toughness + wear resistance

Note: High carbon and high chromium form a large amount of (Cr,Fe)₇C₃ type carbides, which give extreme wear resistance.

SKD11 STEEL RELATED STANDARD & EQUIVALENT GRADE

China: Cr12Mo1V1 (GB/T 1299)

USA: D2(AISI/SAE standard)

Europe: 1.2379 (DIN EN ISO 4957)

SKD11 STEEL FORGING

Forging process	Temperature range	Operation requirements
Preheating	750~800℃	Slow heating in stages (≤100℃/h) to avoid thermal stress cracks (especially for large cross-sections)
Initial Forging Temperature	1050~1100℃	Maximum ≤1120℃ (risk of overburning), ensure uniform heat penetration of the material
Final Forging Temperature	≥900℃	Hard requirements! Below 850℃, plasticity drops suddenly, easy to crack (carbide precipitation embrittlement)
Cooling After Forging	Furnace cooling/sand cooling	Immediate annealing (no air cooling!), to prevent cracking caused by spontaneous martensitic phase transformation due to high hardenability

SKD11 STEEL HEAT TREATMENT

SKD11 Steel Spheroidizing Annealing

Purpose: softening structure (facilitating processing) + carbide spheroidization (improving final performance)
Process:
– Heating: 800~830℃ × 2~3h
– Isothermal: 720~750℃ × 4~6h
– Cooling: ≤30℃/h Slowly cool to 500℃ and take out of the furnace
Result:
– Hardness: 192~229 HB
– Structure: spherical pearlite + uniformly distributed carbides (≤ASTM grade 3)

SKD11 Steel Quenching & Tempering

Stage	Key parameters	Micro-transformation mechanism	Performance impact
Quenching	1020~1040℃ × 30min/25mm	Carbide dissolution → Austenite rich in Cr/C	Hardness basis, wear resistance core
Cooling	Oil cooling/gas quenching (≥6bar)	Austenite → Martensite + retained austenite	Insufficient cooling will reduce hardness
Deep cooling	-80~-196℃ × 2h (optional)	Retained austenite → Martensite	Hardness +0.5~1.5HRC, dimensional stability
Tempering	180~530℃ × 2h×2 times	Martensite decarburization + carbide precipitation	Eliminate stress, adjust hardness/toughness

SKD11 steel industrial application

High wear-resistant mold: 1020℃ oil quenching + 180℃×2h tempering → HRC 61-63
Toughness-required mold: 1030℃ gas quenching + 520℃×2h tempering → HRC 57-59 (using secondary hardening)

SKD11 steel advanced process: surface strengthening

Nitriding treatment (520℃×20h): surface hardness ≥HV1100, depth 0.1~0.3mm
PVD coating (TiAlN): friction coefficient ↓40%, life span increased by 3~5 times

SKD11 STEEL PROPERTIES

Properties	Typical values/strong>	Influencing factors
Hardness	HRC 58-63	Quenching temperature/cooling rate
Compressive strength	2500~2800 MPa	Carbide density + matrix strength
Flexural strength	3500~4000 MPa	Impurity content + carbide distribution
Impact toughness	15~25 J/cm² (V-notch)	Tempering temperature (300℃ brittle zone lowest)
Wear resistance	8~12 times of 52100 steel	(Cr,Fe)₇C₃ carbide volume fraction