W.Nr. X40CrMoV5-1 Hot Working Tool Steel Bars / X40CrMoV5-1

Product Description

X40CrMoV5-1 is the standardized chemical alphanumeric designation under the European EN ISO 4957 and German DIN frameworks for premium chromium-molybdenum-vanadium hot-work tool steel. It is identical to Werkstoff number W.Nr. 1.2344, and serves as the direct continental equivalent to the North American AISI H13 and Japanese JIS SKD61.

The notation breaks down exactly as follows:

• X: High-alloy steel status.

• 40: Represents a controlled 0.40% average carbon content to balance baseline toughness with peak hardenability.

• CrMoV5-1: Signifies a primary alloying system of 5% Chromium, paired with 1% Molybdenum and Vanadium additions to provide outstanding red-hardness and resistance to thermal shock.

Technical Specifications & Composition Limits

The strict element parameters for X40CrMoV5-1 ensure deep air-hardening depth and excellent isotropic behavior (uniform structural properties in all directions) when supplied from high-grade or remelted (ESR) heats.

Critical Engineering Benefits of X40CrMoV5-1

• Resistance to Heat Checking: Under intense cyclical temperature shifts (e.g., molten aluminum contacting a cooler die surface), the alloy resists the micro-thermal cracking known as heat checking.

• Secondary Hardening Characteristics: During tempering, the alloy exhibits a secondary hardening peak around 500C550C due to the precipitation of fine sub-microscopic alloy carbides ($\text{VC}$ and $\text{Mo}_2\text{C}$), which prevents the tool from softening prematurely at high operating temperatures.

• High Polishability & Nitriding Capability: It accepts gas, liquid, or plasma nitriding exceptionally well to increase surface hardness up to 1000 HV without sacrificing the high fracture toughness of the underlying core.

Standard Thermal Processing Routine

To achieve the best microstructural balance (tempered martensite with an even distribution of fine carbides), the steel should be processed using precise parameters:

1.Soft Annealing:Delivery State.

Heat uniformly to 820C840C. Soak thoroughly, then slow-cool in the furnace at a maximum rate of 10C20C per hour until reaching 600C. Air cool out of the furnace. Target delivery hardness: $\le$ 229 HBW.

2.Stress Relieving:Pre-Hardening Step.

After intensive rough machining, heat components to 600C650C. Hold for 2 hours to relieve internal machining stresses, then cool slowly inside the furnace to prevent geometric warping.

3.Multi-Stage Preheating:Thermal Protection.

Ramp up the temperature in two stepsfirst to 550C600C, and then to 820C850Callowing the core and surface to equalize. This minimizes thermal stress inside the tooling.

4.Austenitizing (Hardening):Solution Stage.

Elevate to 1020C1050C. Maintain the temperature for 15 to 30 minutes once the core has fully stabilized to cleanly dissolve the primary alloy carbides into the matrix.

5.Quenching:Transformation.

Quench in an oil bath, salt bath (maintained at 500C550C), or via high-pressure nitrogen gas injection inside a vacuum furnace. Vacuum gas quenching is highly preferred to prevent decarburization and surface scaling.

6.Triple Tempering:Final Properties.

As soon as the steel cools down to 50C60C, perform the first tempering cycle at 540C620C for a minimum of 2 hours. A second and third temper are required to transform retained austenite completely. Typical target hardness: 46 to 52 HRC.

Primary Hot-Work Fields of Application

X40CrMoV5-1 round bars are the baseline standard whenever a structural component or industrial tool is exposed to intense thermal fatigue combined with mechanical wear:

• High-Volume Aluminum Extrusion: Specified for extrusion dies, liners, backing blocks, press stems, and mandrels.

• Metal Die Casting: Highly utilized for die cavities, core inserts, sliding blocks, shot sleeves, and distributor nozzles for light alloy casting.

• Hot Forging Operations: Forging die inserts, hot punch components, and ejector mechanisms.

• Heavy Hot-Shearing: Industrial knives and cropping blades for slicing hot steel bars, billets, and strip profiles.