DIN 1.2358 Tool Steel | 60CrMoV18-5

DIN 1.2358 steel, also known as 60CrMoV18-5, is a medium-carbon chromium-molybdenum-vanadium alloy cold work tool steel under the German standard system.

Featuring “moderate load + impact resistance + dimensional stability,” DIN 1.2358 steel is gradually replacing traditional high-carbon, high-chromium steels (such as D2/DIN 1.2379), meeting wear resistance requirements while addressing the weakness of high-carbon, high-chromium steels in terms of insufficient toughness and susceptibility to cracking.

DIN1.2358 steel is widely used in cold-working molds, precision cutting tools and wear-resistant mechanical parts.

1.2358 STEEL CHEMICAL COMPOSITION

Grade	C	Si	Mn	P	S	Cr	Mo	V
1.2358/60CrMoV18-5	0.58-0.62	0.2-0.5	0.7-0.9	≤0.03	≤0.03	4.3-4.7	0.4-0.6	0.2-0.3

Core Element Characteristics

Carbon: 0.58–0.62%（It forms carbides with Cr, Mo, and V, ensuring hardness and wear resistance after quenching; the medium carbon content avoids excessive reduction in toughness.）
Chromium: 4.3–4.7%（Improve hardenability: Ensure uniform hardness of large cross-section parts; form Cr₂₃C₆ carbides, enhancing wear resistance and corrosion resistance (limited rust prevention).）
Molybdenum: 0.4–0.6% (Optimize toughness and thermal stability: suppress temper brittleness and improve hardness retention at high temperatures; synergistically enhance hardenability with Cr.)
Vanadium:0.2-0.3%(Refining grain size: Forming VC carbides (extremely high hardness), significantly improving wear resistance and red hardness; reducing heat treatment deformation.)

1.2358 Steel Physical Properties

Density (ρ): 7.85 g/cm³
Thermal Conductivity (λ): 28~32 W/(m·℃)
Coefficient of Thermal Expansion (α): 11.9 μm/(m·℃)
Resistivity (ρ): 0.22~0.26 μΩ·m
Curie Temperature: ≈730℃

1.2358 Steel Processing Properties

Forging Properties: Good. Forging temperature: 850~1050℃. Avoid forging below 800℃ (prone to cracking). Slow cooling and timely annealing after forging are recommended.
Machining Properties: Good machinability in the annealed state (hardness ≤240 HB). Can be machined using high-speed steel or cemented carbide tools; no special tools required.
Welding Properties: Moderate. Preheating to 200~300℃ is required before welding. Slow cooling and immediate tempering after welding (to relieve welding stress) are recommended to prevent cracking.
Heat Treatment Properties: Excellent hardenability. Oil/air cooling is sufficient for section thickness ≤100mm, resulting in uniform hardness. Good tempering stability; low residual austenite content and dimensional stability after multiple temperings.

1.2358 STEEL HEAT TREATMENT

1.2358 Steel Softening Annealing

Purpose: To reduce hardness, improve machinability, and eliminate forging/rolling stress;
Process: Hold at 820~860℃ for 2~4 hours (adjust according to section thickness), furnace cool to 770℃, then control the cooling rate to ≤10℃/h, and finally air cool to 650℃;
Result: Hardness ≤240 HB, easily machinable by turning, milling, drilling, etc.

1.2358 Steel Quenching

Preheating: 600~750℃, hold for 1~2 hours (reduce thermal stress and avoid cracking);
Austenitization: 950~970℃, hold for 2~3 hours (ensure full dissolution of alloying elements; excessively high temperatures can lead to coarse grains and decreased toughness);
Cooling methods: Oil cooling (recommended, good hardenability and minimal deformation), air cooling (suitable for thin-section parts), hot bath quenching (salt bath/alkali bath, minimal deformation);
Results: Hardness after quenching is 62~64 HRC, with residual austenite and internal stress, requiring immediate tempering.

1.2358 Steel Tempering

Core requirements: Complete within 24 hours after quenching, with at least two tempering cycles (cooling to room temperature after each tempering) to ensure full transformation of residual austenite;
Properties corresponding to different tempering temperatures (key selection criteria):

Tempering Temperature	Tempering Times	Holding Time	Final Hardness	Applicable Scenarios
180~200℃	2 times	≥2h / time	58~60 HRC	High wear resistance requirements (stamping dies, cutting tools)
250℃	2 times	≥2h / time	55~57 HRC	Medium wear resistance + high toughness (bending dies, stretching dies)
300℃	2 times	≥2h / time	52~54 HRC	High impact requirements (cold extrusion dies, thick plate stamping dies)
350℃	2 times	≥2h / time	49~51 HRC	Wear resistance + fatigue resistance (mechanical parts, gears)

Comparison With Similar Types of Steel

Grade	Core Advantages	Core Disadvantages	Conclusion
Cr12MoV	Extremely high wear resistance	Poor toughness, prone to cracking	1.2358 has better toughness, suitable for impact conditions; Cr12MoV is suitable for low-impact, high-wear-resistance applications.
D2/1.2379	Better wear resistance and red hardness	Moderate toughness, slightly poor hardenability	D2 steel has stronger wear resistance, but 1.2358 has better impact resistance and machinability.
H13	Good thermal stability (for hot-working dies)	Slightly inferior cold-working wear resistance	H13 is suitable for hot-working dies, 1.2358 is more suitable for cold-working applications.
1.2358	Balanced toughness, wear resistance, and machinability	Extreme wear resistance is not as good as D2/Cr12	Best overall performance, suitable for most "balanced" cold-working applications.