Cr12Mo1V1 Tool Steel Technical Overview

Cr12Mo1V1 Tool Steel Technical Overview: Cr12Mo1V1 is a high-carbon, high-chromium alloy tool steel classified as a cold work die steel offering high wear resistance and toughness. Due to the presence of hard eutectic carbides, which are fundamental to its wear performance, it’s often referred to as a Ledeburite steel.

A key feature of Cr12Mo1V1 is its composition, specifically the higher levels of Molybdenum (Mo) and Vanadium (V) compared to the older Cr12MoV grade. This enhanced alloying refines the steel’s microstructure and grain size, directly improving performance characteristics.

1. Cr12Mo1V1 Tool Steel Chemical Composition (Reference Standard: GB/T 1299)

The typical chemical composition (% mass fraction) is:

• Carbon (C):40 – 1.60%
• Silicon (Si):≤0.60%
• Manganese (Mn):≤0.60%
• Chromium (Cr): 0 – 13.0%
• Molybdenum (Mo):70 – 1.20%
• Vanadium (V):50 – 1.10%
• Phosphorus (P):≤0.030%
• Sulfur (S):≤0.030%
• Cobalt (Co):≤1.10%

Note the significantly higher Vanadium range than Cr12MoV, contributing to its property enhancements.

2. Performance Advantages

Cr12Mo1V1 delivers superior overall performance compared to Cr12MoV, primarily seen as higher wear resistance and improved toughness. The increased Mo and V content promotes finer, more uniformly distributed carbide particles. These carbides are crucial for resisting abrasive wear. The refined microstructure also improves the steel’s resistance to cracking and chipping under operational stress.

In practice, its equivalent grade D2 has shown significantly longer service life (reports suggest 5-6 times) than Cr12MoV in applications like thread rolling wheels and cold stamping dies.

3. Cr12Mo1V1 Tool Steel Heat Treatment

3.1 Supply Condition: Typically supplied annealed for good machinability (Hardness ≤255 HBW).

3.2 Hardening:  It requires quenching. Common austenitizing temperatures are in the 1030-1050°C range. Quenching methods (air, oil, salt bath) depend on section size and distortion control needs.

3.3 Tempering: Essential after quenching to reduce brittleness and achieve the target balance of hardness and toughness.

• Lower temperature tempering (e.g., 190-210°C, often performed twice) can achieve high hardness (around 59 HRC).
• Secondary hardening is performed at higher temperatures (e.g., around 500-530°C, often double tempering similar to SKD11 practices), potentially improving toughness while maintaining high hardness.

3.4 Optimization: For optimal performance, the specific heat treatment cycle must be tailored to the tool’s geometry, size, and final properties.

4. International Equivalents

Common equivalent grades in other standards include:

• USA (ASTM/UNS): D2 / T30402
• Japan (JIS): SKD11
• Germany (DIN): 1.2379 / X155CrVMo12-1

5. Cr12Mo1V1 Tool Steel Applications

Due to its excellent properties, Cr12Mo1V1 is widely used for demanding cold work tools and dies requiring high wear resistance and dimensional stability:

• Dies: Intricate punching dies, blanking dies (incl. for silicone steel), trimming dies, flanging dies, wire drawing dies, cold extrusion dies, deep drawing dies, thread rolling plates/dies, cold forging dies, hemming dies.
• Tools: Cold cutting shears, circular saws, standard tools, gauges.
• Molds: Wear-resistant plastic molding dies, especially large, complex, high-precision types and those for thermosetting plastics.

6. Summary

Cr12Mo1V1 represents a significant improvement over earlier high-carbon, high-chromium steels like Cr12MoV. Its balanced composition results in a refined microstructure, providing an excellent combination of high wear resistance, good toughness, and reliable dimensional stability during heat treatment. While grades like D2 might offer slightly higher initial hardness, Cr12Mo1V1 (and SKD11) often provide a better overall balance, particularly regarding toughness, making it less prone to chipping. This makes Cr12Mo1V1 a preferred material for a broad range of demanding cold work applications. Remember that proper, application-specific heat treatment is critical to realizing the full potential of this steel.