What makes a cutting or forming tool last? When it comes to tools like dies and punches, the answer is quite simple – it is the steel that they are made from. Because such tools are worked hard, and face constant friction and impact while shaping metal parts, the choice of the type of steel from which they are made is vital both for cost-effectiveness, as well as efficiency. In the world of tool steels, the choice is, more often than not, between D2 and D3 steels.
D2 and D3 tool steels belong to a group of steels referred to as cold work steel, meaning they are at their best performance at room temperature or slightly higher temperature. Such steels are known for containing high levels of carbon, and of the element chromium, which endow them with remarkable hardness and make them resistant to wear. What sets them apart from each other is the subtle variation in their chemical composition making each one more suitable for certain tasks.
Versatile D2 Steel
Widely available at most D2 tool steel suppliers, D2 steel is the one often referred to as a versatile all-rounder. It is well-known for having an impressive balance of toughness and wear resistance. It can absorb repeated impacts and resist cracking or chipping under stress. This is mainly due to its well-managed composition that enables it to harden uniformly and deeply when properly heat-treated – usually via air quenching.
D2 tool steel is commonly used in shear blades, blanking dies which are used for cutting out flat shapes, and forming dies which are used for shaping and bending metal. Because of the ability of D2 cold work steel to resist abrasion and hold a sharp edge while being able to prevent brittle fractures, makes it a reliable choice of material for situations where the tool may experience moderate shock loads like during long production runs. It is also somewhat easy to shape into complex tool designs for a steel of such hardness.
Hard D3 Steel
On the other hand, D3 steel is the material of choice for when maximum wear resistance and hardness are the top priority. D2 tool steel suppliers often describe D3 steel as containing more carbon than D2 which enables it to acquire greater hardness after undergoing heat treatment. Although D2 is cooled by air (air hardened), D3 is commonly quenched in oil (oil-hardened) to achieve its full potential for hardness. The process of oil quenching gives the steel superior resistance to wear due to abrasion, making it highly durable where there is intense friction.
D3 cold work steel is typically used in tools made for precise cutting of thin materials or lamination dies, certain drawing dies where a material is etched or drawn, and in severe blanking projects. It is best suited for tasks involving highly abrasive materials and require very long production runs without needing regrinding frequently. However, the higher amount of carbon within D3 steel can make it more brittle than the D2 which means it may not be suited for work involving heavy impact. The extreme hardness of D3 can also make it hard to shape or machine.
The Choice
The decision whether to choose D2 or D3 for your business’ dies and punches boils down to a very careful assessment of your application’s specific needs.
D2 would be the ideal choice when you need a steel that is versatile and offers a strong blend of toughness and wear resistance. Any D2 tool steel suppliers can attest that it is a very reliable tool steel for blanking, general-purpose punching, and forming where there are moderate impacts and ease of manufacturing is also a factor.
D3 cold work steel is the optimal choice if you are looking for maximum hardness and wear resistance, and the application only involves minimal shock. It is best for abrasive materials and high volume production where extended tool life between re-grindings is the chief goal.