Which Material Is Used in The Bending Toolings?

What Can Be Selected for the Bbending Die Material?

There are a variety of materials for producing bending machine molds, including steel, cemented carbide, steel-bonded cemented carbide, zinc-based alloy, low-melting alloy, aluminum bronze, and polymer materials. At present, most of the materials used in the manufacture of punching press molds are copper. The types of materials used in the working parts of common bending press molds 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 and cemented carbide, steel-bonded cemented carbide, etc.

The following introduces several material knowledges

First, carbon tool steel

The carbon tool steels used in the bending machine molds are T8A, T10A, etc. The advantages are good process ability and low price. However, the quenching and red hardness are poor, the heat treatment deformation is large, and the bearing capacity is low.

Second, low alloy tool steel

Low alloy tool steel is based on carbon tool steel with an appropriate number of alloying elements. Compared with carbon tool steel, it reduces the tendency of quenching deformation and cracking, improves the quench ability of steel, and has better wear resistance. The low-alloy steels used in the manufacture of bending machine molds are CrWMn, 9Mn2V, 7CrSiMnMoV, etc.

Third, high carbon high chromium tool steel

Commonly used high-carbon and high-chrome tool steels are Cr12, Cr12MoV, and Cr12Mo1V1. They have good burstability, quenching hardness, and wear resistance, and the heat treatment deformation is small. They are high wear-resistant micro-deformation bending machine die steels. Second only to high-speed steel. However, the segregation of the carbide is serious, and repeated upsetting (axial upsetting and radial drawing) must be performed to change the forging to reduce the unevenness of the carbide and improve the performance.

Fourth, high carbon medium chromium tool steel

High-carbon medium-chrome tool steels used for bending machine tools include Cr4W2MoV, Cr6WV, and Cr5MoV. They have low chromium content, low eutectic carbides, uniform carbide distribution, small heat treatment deformation, and good quenching properties. And dimensional stability. Compared with high-carbon high-chromium steel with relatively severe carbide segregation, the performance is improved.

Fifth, high-speed steel

High speed steel has the highest hardness, abrasion resistance and compressive strength among the bending machine molds, and has a high bearing capacity. W18Cr4V and W6Mo5Cr4V with less tungsten content are commonly used in the bending machine mold. High speed steel also needs to be forged to improve its carbide distribution.

Sixth, base steel

Add a small amount of other elements to the basic composition of high-speed steel, and appropriately increase or decrease the carbon content 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 certain wear resistance and hardness, but also have higher fatigue strength and toughness than high-speed steel. But it is lower than high-speed steel. The base steels commonly used in bending machine molds are 6Cr4W3Mo2VNb, 7Cr7Mo2V2Si, 5Cr4Mo3SiMnVAL, etc.

Seventh, cemented carbide and steel cemented carbide

Cemented carbide has higher hardness and wear resistance than any other type of bending die steel, but has poor bending strength and toughness. The cemented carbide used as the mold of the bending machine is tungsten-cobalt. For the bending machine with small impact resistance and high wear resistance, a cemented carbide with a lower cobalt content can be selected. For high-impact bending machine dies, cemented carbide with high cobalt content can be selected.

Steel-bonded cemented carbide is made by adding iron powder with a small amount of alloying element powder as a binder, using titanium carbide or tungsten carbide as a 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 machining of cemented carbide, and 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. After quenching and tempering, the hardness can reach 68 ~ 73HRC.

Eighth, new materials

The materials used for stamping CNC bending machine molds belong to the cold-work bending machine tool steel, which are the most widely used and widely used bending machine tool steels. The main performance requirements are strength, toughness and wear resistance. At present, the development trend of die steel for cold-work press brakes is based on the performance of high-alloy steel D2, which is divided into two major branches. One is to reduce the carbon content and the amount of alloy elements, improve the uniformity of carbide distribution in steel, and improve Toughness of the bending machine mold. Such as 8CrMoVSi of American vanadium alloy steel company, DC53 of Japan Datong Special Steel.

Company and so on. The other is a powder high-speed steel developed with the main purpose of improving wear resistance to adapt to high-speed, automation, and mass production. Such as Germany's 320CrVMo13 and so on.

Selection of Materials for Bending Machine Molds

Although the problem of the deformation of the bending machine mold does not appear much, it still needs to be paid attention to.  It may be related to the error in the production process, or it may be that the hardness of the material of the sheet metal being bent is too high, so that the bending machine mold cannot withstand that strength. Today, I will talk about the selection of the most basic bending machine tool.

A large part of the choice of materials determines the performance of the bending machine mold. The commonly used materials for the bending machine mold are T8 steel, T10 steel, 42CrMo, and Cr12MoV. There is no doubt that Cr12MoV is a good material, the performance is satisfactory, and the process performance is also great, but the price is relatively high. Therefore, the most I have come in contact with is 42CrMo. 42CrMo is a high-strength alloy quenched and tempered steel. It has the characteristics of strong toughness and high strength. What the bending machine mold needs are high strength, high toughness, and excellent wear resistance. Of course, this is just a reference, and the specific choice of materials should be determined according to the product and budget.