What Is D2 Tool Steel?

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D2 tool steel is a high chromium tool steel. Its qualities include high hardenability and high abrasive resistance against wears. To retain good machinability, the grade is offered in annealed conditions. Annealing must be done between 871 - 898 degrees Celsius. After it has been machined, the D2 tool steel needs to be hardened to attain the service properties. It is hardened in a range between 55 and 62 HRC. It makes it outstanding for high-end knife steel, stamping tools, ceramic molds, sheer blades, forming dies, and others.

1. Mechanical Properties – D2 tool steel, found mainly in metric and imperial categories, have different mechanical properties. Hardness for both these types is 769. Hardness Vickers is 748 for both types. Hardness Rockwell C is 62 for both categories as well. The difference appears in the Izod impact unnotched. For the metric type, it is 77.0 J, whereas, for the Imperial type, it is 56.8 ft-lb. Poisson’s ratio for both is between 0.27 – 0.30. Elastic modulus also differs in both categories.

2. Historical fact – D2 tool steel was previously used for making dies in production lines. ...
... Its wide usage and popularity date back to the era of World War II. Back in those days, D2 tool steel was widely used for punching out military airplanes or Vehicle parts. Then, those would be manually assembled. D2 steels were meant for cutting through steels repeatedly without any tear or wear on it. Its excellence in hardness comes from unusually high Chromium content, almost up to 13%.

3. Forging – To forge, D2 tool steel suppliers advise heating uniformly up to 700 degrees Celsius and then heating even more quickly up to 1040 degrees Celsius. It’s is advises not to forge D2 below 925 degrees Celsius. It can be put to reheat to maintain the high temperatures required for forging. After the forging is done, it needs to be annealed within the mandatory conditions mentioned before.

4. Hardening – Hardening of D2 tool steel is a critical procedure, during which it needs to be kept under constant check to avoid overheating. The first phase of heating temperature should be between 750 – 780 degrees Celsius, followed by a higher temperature of heating between 1000 – 1030 degrees Celsius.

5. Benefits of using D2 tool steel – One of the best qualities of D2 tool steel is its resistance to wear or tear even after continuous contact with other metals and abrasive materials. It creates a tough knife that can hold its edge and has extremely high resistance against wearing. Besides the high chromium content, the high carbon content also adds to its robustness. The advantage of high carbon content is that it can easily reach high hardness after heat treatment.

6. Applications – D2 tool steel is popularly used for cupping dies, drawing does, forging dies, flying shears, circular cutters for cold-rolled strips, trimmer dies, thread rolling dies, broaches, plug gauges, cold extrusion dies, ring gauges, master hobs for cold hobbing plastic molds, etc. It is also used for machine knives, milling cutters, cutting and punching tools, etc.