How to choose the right steels for making dies and molds?
The common used die steels are
Sweden: Die Steel S136, 8407, DF-2, 718;
To choose different steels has a great impact on the Injection molds. We also need to have a comprehensively consideration, such as adding reinforcement or other modifiers. For example, the glass fiber damage to the mold. Strong acidic plastic materials include PVC, POM, PBT. The weakly acidic plastic materials are PC, PP, PMMA, PA. Highly corrosive plastics are generally require the die steels as S136, 1.2316, 420, etc., and weakly corrosive can use the S136, 1.2316, 420, SKD61, NAK80, PAK90, 718, etc.. The appearance requirements of the product also have a great influence on the selection of tool steel. The transparent parts and surface products requiring mirror polishing require the steels of S136, 1.2316, 718, NAK80, PAK90, 420. Molds with high transparency requirements should use the steels of S136, second choice is 420. However, if you simply meet product requirements without considering production costs, you may not be a good designer. Mold manufacturing costs is also a top priority. Compared with imported 1.2316 and S136, they differs by dozens RMB/kg. If you make the wrong choice, it is difficult for the factory to make a reasonable profit.
Molds with 300,000 to 500,000 shots usually use the tool steels with pre-hardened condition, such as S136H, 1.2316H, 718H, 1.2083H, etc.. Mold below 300,000 shots use tool steel of P20, 1.2738, 1.2311, 1.2711 and so on. For ultra-low requirements of the mold, we can consider S50C, S45C, which directly makes a cavity in the mould.
Cold Work Tool Steel is mainly used to manufacture a die that presses and forms a work piece under cold conditions. Such as: Cold Blanking Die, Cold Stamping Die, Cold Drawing Die, Imprint Die, Cold Extrusion Die, Thread Pressing Die and Powder Pressing Tooling, etc.. Cold Work Tool Steel has a wide range, from various carbon tool steel, alloy tool steel, high speed steel to powder high speed steel and powder high alloy mold steel. Therefore, the recommendation and use classification of cold die steel are complex, that should be selected according to the actual situation.
Hot Work Tool Steel is mainly used to manufacture the dies for pressing the workpiece at high temperature. Such as: hot forging die, hot extrusion die, die casting die, hot upsetting forging die.
The commonly used hot die steel is: alloy die steels with high and medium carbon content, adding Cr, W, Mo, V and other alloy elements; High alloy austenitic heat-resistant die steel is sometimes used for special requirements.
Besides selecting reliable materials, heat treatment should also be fully considered.
The first choice of material origin is TQ1, HP1, USN, USD, H13, SKD61 etc..