- Product Description
-
718H is a pre-hardened nickel-chromium alloy plastic die steel, where the“H” stands for pre-hardened state. It is based on general purpose P20(3CR2MO) steel, modified by adding about 1% nickel (Ni) , and supplied in the form of flat steel blanks, which have been heat treated at the factory to achieve and use hardness.
The core positioning of 718H is to achieve the perfect balance of hardness, toughness, polishing and processability in the pre-hardening state, and meet the needs of most high-end plastic molds.
I. Core features
Supply in pre-hardened stateThis is its greatest advantage. Ex-factory hardness is usually 30-36 HRC (varies slightly from mill to mill, E. G. 33-38 HRC for Assab 718H) . Mold manufacturers do not need secondary heat treatment, can be directly processed to avoid the risk of heat treatment deformation, greatly shorten the manufacturing cycle.
Excellent polishing performance
718H material uniformity, fine organization, can be polished to a very high level of finish (such as A2-A1 mirror effect, up to # 10000) , meet Zero pairs of appearance requirements of plastic products (such as home appliances, automotive interior, daily necessities production needs) .
Good etching pattern performance
The uniform nature of the material makes it very suitable for etching (textured) processing, clear lines, uniform.
High hardenability & excellent overall toughness
The addition of nickel (Ni) gives it excellent hardenability. Even in the whole section of large mold, can also maintain uniform hardness, strength and toughness, effectively prevent mold cracking, performance consistent.
Good dimensional stability
Because it is prehardened steel and has been heat treated in the steel plant, the internal stress is small, and the size change is small in the processing and subsequent use.
Cost-effective
Compared with high-end mirror steels requiring vacuum heat treatment (e.g. , S136/FS139M) , the cost of 718 h is lower; compared with ordinary P20, its properties (especially polishing and hardenability) are significantly improved. It is the pursuit of“Cheap” and efficient production of the first choice.
Main chemical constituents (typical values)
718H belongs to P20 + NI type steel, the typical chemical composition is as follows:Elemental carbon (c) chromium (CR) manganese (MN) molybdenum (Mo) nickel (Ni)
0.40% ~ 2.00% ~ 1.50% ~ 0.20% ~ 1.00%
Nickel (Ni) : is a key alloying element. It can significantly improve the hardenability and core toughness of steel, and ensure that large-size modules can also obtain uniform hardness and properties, which is the fundamental reason for its superiority over ordinary P20.Typical areas of application
718H is suitable for manufacturing most of the large, long life, high surface quality requirements of plastic mold, in particular:Large injection molds: such as car bumpers, dashboards, interior parts, home appliances shell (TV, air-conditioning) , washing machine rollers and so on.
Bloom moulds with good surface finish for the production of ABS, PP, PS, PC, etc. .
Etch mold: very suitable for surface etch (textured) treatment.
Long-life mold: because of its pre-hard and high toughness characteristics, wear resistance is better than ordinary P20, suitable for the production of hundreds of thousands or even millions of mold times more than the mold.
Die accessories: such as large die set, slider, lifter and so on.
Status of supply and processing
Supply status: flat steel blank in pre-hardening condition with hardness of 30-36hrc (please refer to the actual certificate of Steel Plant) .No heat treatment: the mold manufacturer before and after processing should not need to quenching and other heat treatment.
Nitriding treatment can be carried out: in order to further improve the mold surface wear resistance, anti-occlusion and anti-rust ability, can be completed on the 718H mold nitriding treatment (such as gas nitriding, ion nitriding) , the surface hardness is more than 1000hv, and the service life of the die is prolonged several times.
Points for attention in processing:
Although called“Pre-hard”, but the hardness of the processing tools still have requirements. It is recommended to use high quality carbide cutting tools and to use appropriate cutting speed and feed rate.
Conclusion
718H flat steel blank is the“Mainstay” and“King of performance-price ratio” in plastic mould manufacturing industry. By adding nickel (Ni) element and pre-hardening treatment, the core pain points of“Avoiding heat treatment deformation”, “Ensuring uniform performance of large-scale molds” and“Controlling cost and cycle” in mold manufacturing have been successfully solved.For the vast number of plastic mold applications that do not require extreme corrosion resistance, but pursue high production efficiency, high stability, good appearance and long life, the choice of 718 H is almost an error-free decision. It perfectly balances performance, cycle time and cost and is one of the most reliable and versatile engineering solutions for mold manufacturing.
Product inquiry
Have a question about purchasing a product or solution that you are interested in? Fill in the form and we’ll respond in 7 working days.
Latest Products
1013 Min'an Avenue, Xiang'an District Xiamen City, Fujian Province, China
+86-13225990951
2605949828@qq.com
