Can 40Cr replace P20 die steel
A customer is anxious to use large size P20 round steel, because there is no exact specification, so he asked whether 40Cr can replace P20 die steel? This is a very good question, and then Longtuo Metal will take you to answer the question of whether 40Cr can replace P20 die steel.
P20 die steel is a kind of plastic die steel, including P20H, P20Ni, P20 die steel is mainly used in plastic mold and die casting low melting point metal mold material. P20 die steel has high purity, good machinability and mirror grinding performance, high precision, never deformation, high toughness.
40Cr is a very commonly used alloy structural steel, it is compared with 40 steel, tensile strength, yield strength and hardenability is high, but the weldability is limited, there is a tendency to form cracks, for the more important tempering two parts, 40Cr surface quenching can do load and wear resistance is high, without great impact parts, such as gear, sleeve, shaft, crankshaft and so on.
In the nitriding treatment, 40Cr is also a nitriding steel, the elements contained in it are conducive to nitriding, 40Cr after nitriding treatment can obtain a higher surface hardness, 40Cr modulated nitriding treatment hardness of up to 72-78HRA, converted into Rockwell hardness is 43-55.
P20 die steel can obtain high hardness surface tissue if nitriding treatment, the surface hardness after nitriding reaches 650-700HV (57-60HRC) mold life can reach more than 1 million times, the nitriding layer has dense organization, smooth characteristics, mold release and resistance to wet air and salty liquid corrosion performance.
Some facts that can be obtained through the practice of Longtop metal customers are: most of the APG molds used to be 40Cr, and then gradually replaced by P20 die steel, from the processing performance of P20 die steel is better than 40Cr. From the service life of the mold, the use of P20 die steel is 50,000-100,000 times, and the use of 40Cr is 50,000 times.
The process route of P20 die steel is as follows:
Because the P20 die steel has been pre-hardened, it can be polished and assembled directly after processing. If there is to be transformed into billet after processing and forming, the processing sequence is as follows: material → transformed forging → nodular annealing → milling six sides → pre-hardening (34-42HRC) → mechanical roughing → stress relief annealing → mechanical finishing → polishing → assembly.
40Cr process route is as follows:
Blanking → forging mold → annealing → mechanical roughing → tempering → mechanical finishing → dressing, polishing → Assembly.
