718H P20 steel 
 Sweden ASSAB 718,718 H P20 steel 
 Ingredients% C C: 0.33 Si Si: 0.3 Mn Manganese: 0.8 Cr Chromium: 1.8 Ni Ni: 0.9 Mo Mo: 0.2 
 Factory state: After hardening and tempering to HRC33-37 
 Steel properties: (1) This has been heat-treated steel, even hardness through stable (HB330-370) never made mold deformation. 
 (2) smaller than fancy, the more black surface oxidation has been excluded, so the high utilization ratio, and reduce processing costs. 
 (3) the ultrasonic inspection, hardness and metallurgical structure uniform, mirror-polished and easy to reach. 
 (4) The method used flame hardening in the air, so that part of the vulnerability of local processing to 50-55HRC hard about 5mm depth. 
 (5) is more suited for EDM. 
 ASSAB 718H for the vacuum melting of chromium - nickel - molybdenum alloy steel, hardened and tempered after the factory prior to treatment, have the following advantages: 
 □ deformation and heat treatment without the risk of quench cracking 
 □ without heat treatment costs 
 □ shorten the molding cycle 
 □ reduce the cost of mold making (for example, no distortion correction) 
 □ mold is easy to modify 
 □ can be subjected to nitrogen and flame hardened, the mold surface to enhance the hardness and wear resistance. 
 718H since production has remain high quality, low sulfur level, the factory pre-heat treatment to 36-40HRC so hard steel to have the following characteristics: 
 □ excellent polishing and photo-etching properties 
 □ good processing properties 
 □ high purity and excellent homogeneity 
 □ wear better, longer die life 
 Note: 718H ultrasonic flaw detection has been 100% tested. 
 Large size such as thickness of more than 100mm have been pre-processing, steel milling by the rough surface. About convenience for the users: 
 □ save weight 
 □ has been removed off the surface of the carbon steel layer (black) 
 □ standard size (positive tolerance) 
 □ reduce the amount of machining 
 □ no oxide layer to reduce the amount of machining and tool wear 
 Uses: 
 □ large long-life plastic injection mold, such as home appliances, computer housings and other mold 
 □ high surface finish of the plastic mold 
 □ blow mold 
 □ Because of high hardness, can be used to mold the plastic slide 
 □ forming tools, compressed - braking mode (bending machine model), (depending on production needs may be imposed by flame hardening or nitriding) 
 □ construction and shaft parts