Types and characteristics of medical device stamping die materials

The materials for making medical device stamping dies include steel, cemented carbide, steel-bonded cemented carbide, zinc-based alloy, low melting point alloy, aluminum bronze, polymer materials and so on. At present, most of the materials used to make medical device stamping dies are steel. The types of commonly used die working parts are: carbon tool steel, low alloy tool steel, high carbon high chromium or medium chromium tool steel, medium carbon alloy steel, high speed Steel, base steel, cemented carbide, steel bonded cemented carbide, etc.

1. Carbon tool steel

The most commonly used carbon tool steels in moulds are T8A, T10A, etc. The advantages are good processing performance and low price. But the hardenability and red hardness are poor, the heat treatment deformation is large, and the bearing capacity is low.

2. Low alloy tool steel

Low-alloy tool steel is based on carbon tool steel with an appropriate amount of alloying elements. Compared with carbon tool steel, it reduces quenching deformation and cracking tendency, improves the hardenability of steel, and has better wear resistance. Low-alloy steels used to make moulds include CrWMn, 9Mn2V, 7CrSiMnMoV (code CH-1), 6CrNiSiMnMoV (code GD) and so on.

3. High carbon and high chromium tool steel

Commonly used high carbon and high chromium tool steels are Cr12, Cr12MoV, Cr12Mo1V1 (code D2), they have good hardenability, hardenability and wear resistance, heat treatment deformation is very small, for high wear resistance micro-deformation die steel, load The capacity is second only to high-speed steel. However, the segregation of carbides is serious, and repeated upsetting (axial upsetting, radial upsetting) and forging must be carried out to reduce the unevenness of carbides and improve performance.

4. High carbon medium chromium tool steel

The high carbon medium chromium tool steels used for moulds include Cr4W2MoV, Cr6WV, Cr5MoV, etc., which have low chromium content, less eutectic carbides, uniform carbide distribution, small heat treatment deformation, good hardenability and dimensional stability Sex. Compared with high carbon and high chromium steel with relatively serious carbide segregation, the performance has been improved.

5. High-speed steel

High-speed steel has the highest hardness, wear resistance and compressive strength of die steel, and has a high load-bearing capacity. Commonly used in moulds are W18Cr4V (code 8-4-1) and W6Mo5Cr4V2 (code 6-5-4-2, American brand M2) with less tungsten content, and 6W6Mo5Cr4V, which is developed to improve toughness and reduce carbon and vanadium high-speed steel. (Code 6W6 or low carbon M2). High-speed steel also needs modification to improve its carbide distribution.

6. Base steel

A small amount of other elements are added to the basic composition of high-speed steel, and the carbon content is appropriately increased or decreased to improve the performance of the steel. Such steel types are collectively referred to as base steel. They not only have the characteristics of high-speed steel, have a certain degree of wear resistance and hardness, but also have better fatigue strength and toughness than high-speed steel. They are cold-work die steels with high strength and toughness, and the material cost is lower than that of high-speed steel. The commonly used base steels in moulds are 6Cr4W3Mo2VNb (code 65Nb), 7Cr7Mo2V2Si (code LD), 5Cr4Mo3SiMnVAL (code 012AL) ​​and so on.

7. Cemented carbide and steel bonded cemented carbide

The hardness and wear resistance of cemented carbide are higher than any other type of die steel, but the bending strength and toughness are poor. The cemented carbide used as the mould is tungsten-cobalt. For moulds with low impact resistance and high wear resistance, cemented carbide with lower cobalt content can be selected. For high impact moulds, cemented carbide with higher cobalt content can be used.

Steel-bonded cemented carbide is made by adding a small amount of alloying element powder (such as chromium, molybdenum, tungsten, vanadium, etc.) to iron powder as a binder, using titanium carbide or tungsten carbide as the hard phase, and sintering by powder metallurgy. The matrix of steel-bonded cemented carbide is steel, which overcomes the disadvantages of poor toughness and difficult processing of cemented carbide. It can be cut, welded, forged and heat treated. Steel-bonded cemented carbide contains a large amount of carbides. Although the hardness and wear resistance are lower than that of cemented carbide, it is still higher than other steels. The hardness can reach 68~73HRC after quenching and tempering.

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