Cr6WV Steel Technical Overview

Cr6WV Steel Technical Overview: Cr6WV is a medium-alloy cold work die steel offering reliable overall performance. Key characteristics include minimal deformation after hardening, good hardenability, effective wear resistance, and notable impact toughness.

Compared to Cr12 and Cr12MoV steels, Cr6WV has lower alloy and carbon content. This results in a more uniform carbide distribution, contributing to improved bending strength and impact toughness, especially when oil-quenched from 960°C.

Cr6WV is equivalent to the American A2 steel grade.

1. Cr6WV Steel Chemical Composition (Standard GB/T 1299-77)

The typical chemical composition of Cr6WV steel according to GB/T 1299-77 is as follows:

Chemical Composition (Weight Fraction) / %	Minimum	Maximum
Carbon (C)	1.00	1.15
Silicon (Si)	–	≤0.40
Manganese (Mn)	–	≤0.40
Chromium (Cr)	5.50	7.00
Tungsten (W)	1.10	1.50
Vanadium (V)	0.50	0.70
Phosphorus (P)	–	≤0.030
Sulfur (S)	–	≤0.030

2. Cr6WV Steel Physical Properties

2.1 Critical Temperatures

Approximate critical point temperatures for Cr6WV are:

Critical Point	Temperature (Approximate Value) / °C
Ac1	815
Accm	845
Ar1	625
Arcm	775
Ms	150
Mf	-100

2.2 Linear Expansion Coefficient

Linear expansion coefficients (α) for different temperature ranges:

Temperature / °C	Linear Expansion Coefficient α / × 10⁻⁶ °C⁻¹
100 ~ 250	10.3
250 ~ 350	11.0
350 ~ 600	12.8

3. Cr6WV Steel Heat Treatment

3.1 Forging

Recommended forging parameters:

Item	Heating Temperature / °C	Starting Forging Temperature / °C	Ending Forging Temperature / °C	Cooling Method
Steel Ingot	1100 ~ 1160	1060 ~ 1120	–	–
Steel Billet	–	–	850 ~ 900	Slow cooling after forging

Ensure slow cooling after forging.

3.2 Hardening and Tempering

Standard hardening involves oil quenching, typically from 960°C (though 950°C and 1010°C are used for reference tests). Consider slightly higher quenching temperatures for larger sections (approx. φ30-60mm).

Important: For large or complex parts, use preheating and slow heating to ensure uniformity and minimize the risk of cracking. Temper immediately after quenching to relieve stress.

The relationship between tempering temperature (2 hours) and resulting hardness (HRC) is shown below:

Tempering Temperature / °C	Hardness (HRC) after 950°C Quench	Hardness (HRC) after 1010°C Quench
100	62	63.5
200	57.5	60
300	55	57
400	53.5	56
500	51	56
550	49	56
600	48	55.5
650	47	53

4. Cr6WV Steel Applications

Cr6WV steel’s balance of high strength, wear resistance, and toughness makes it suitable for various demanding applications:

• Gauge blocks and gauges
• Drill sleeves
• Punching dies and punches
• Cold heading dies
• Round rolling dies
• Trimming dies
• Stamping dies
• Thread rolling dies and plates
• Wear-resistant parts
• Integral molds
• Heavy-duty processing tools

For applications like drawing dies (stainless steel) or cold extrusion dies (aluminum, steel), a hardness of 62-64 HRC is often specified. It is also effective for high-volume cold stamping dies (over 1 million pieces) for thin low-carbon steel plates (<1mm).

In essence, Cr6WV provides a versatile and reliable solution for many cold work tooling requirements.