The large section of hot forging die steel
In order to make up for 5CrMnMo and 5CrNiMo in large cross section and high temperature thermal stability, thermal fatigue resistance and hardenability of defects in not enough, the development of 45Cr2NiMoVSi (45Cr2), 5Cr2NiMoVSi (5Cr2), 3Cr2MoWVNi, 3Cr2MoVNi (B2) and other large section of hot forging die steel. Compared with 5CrNiMo, 45Cr2 and 5Cr2 contain higher Cr and Mo, and adding a small amount of V, make up high temperature transition region of CCT curve, low temperature transition region were shifted to the right, to improve the hardenability of steel. The section size in die 500*500mm below 970-990 DEG C after quenching, 650 to 680 DEG C after tempering, the hardness is up to HRC36-44. 45Cr2 and 5Cr2 also has two hardening ability, high strength 5CrNiMo steel is their high thermal stability is higher than 50%, 100 to 150 DEG C, the impact toughness is. In addition, the steel thermal wear and thermal fatigue resistance and thermal crack propagation ability is stronger than that of 5CrNiMo. These two kinds of steel used for 12000t mechanical press mold and 16t forging die, die life is the same die made of 5CrNiMo steel several times.
The small hot forging die steel
The above surface temperature up to 600 DEG C and hot forging die, the high temperature performance of 5CrMnMo and 5CrNiMo obviously can not meet the requirements. The high temperature strength of 3Cr2WSV steel is higher, but the toughness and thermal fatigue performance. Therefore, the early development of 2Cr3Mo3VNb, 4Cr3Mo2MnVB (ER8) in carbon chromium high strength heat 3%Cr-3%Mo and 3%Cr-2%Mo type die steel, which is 3Cr3Mo3VNb according to the amount of carbon carbides required for 2Cr3Mo3VNb to make further adjustment of composition. These two kinds of steel added about 3% Mo, which can improve the hardenability and prevent temper brittleness, and can improve the thermal stability of steel. With V and Nb may play a role in grain refinement, reduce overheating sensitivity of steel.Therefore, the hardenability of steel, quenching temperature range, thermal sensitivity is low, with high strength, good thermal stability, good plasticity and toughness, thermal fatigue resistance, thermal wear resistance and other advantages, for the manufacture of stainless steel (2Crl3) such as hot forging, roll forging die and bearing, have good effect.
In addition to the above type 30Cr-30Mo hot die steel, alloy hot carbon in domestic has developed a 5%Cr system for die steel has been widely used in hot forging die, suitable for manufacturing the working temperature of 600 DEG C, the toughness and ductility requirements of high mold. In addition, the steel can also be used for plastic mould steel. The excellent performance of 4Cr5MoV1Si steel has been widely recognized in China, has great application. Many universities, research institutes and mills have spent huge sums of money to do research and production quality improvement work of the steel, and have played their own quality brand.
3 Die Steel
In non-ferrous metal die-casting, 3Cr2W8V die steel was widely used, 5CrNiMo, 5CrMnMo, 3Cr2Mo and other medium carbon low-alloy steel as aluminum zinc alloy die-casting die steel. Thermal fatigue property of 3Cr2W8V is poor, the service life of the die is not high. China has developed several new die steel, such as 4Cr3Mo2MnVNbB (Y4) and 4Cr5Mo2MnVSi (Y10) etc..
4Cr5Mo2MnVSi (Y10), is developed for Aluminum Alloy and die casting mould, compared with 3Cr2W8V steel, thermal fatigue resistance, small deformation, heat treatment of aluminum resistance loss and good performance of the solution has the advantages of steel, die die life is generally made of 3Cr2W8V steel and the service life of more than doubled. The steel can also be used for manufacturing the working temperature at 600 DEG C and hot forging die.
The copper and aluminum hot extrusion die steel
Copper alloy hot extrusion punch die, die length and high temperature copper billet contact mold was harsh working conditions. Making such die with 3Cr2W8V or 4Cr5MoV1Si steel, the service life of the die has been low. China tried to use Austenitic Hot Die steel mold to solve the problem of low service life, but because of poor thermal fatigue performance of steel and has not yet been solved satisfactorily. Under this background, the relevant domestic universities, research institutes and mills has launched a steel can improve the service life of the die. At the same hardness (HRC43), the fracture toughness of 3Cr2W8V steel is 30% higher than. Copper alloy tube made of HD steel extrusion die and bottom punch over the life of 3Cr2W8V steel is doubled, and the punch and die, extrusion die at the end of valve also has a successful application in thermal extrusion bearing ring. Using Y4 steel copper alloy extrusion die bottom die and the punch head, <strong style="font-family: MicroSoft雅黑, "微软 YaHei"; font-size: 14px; text-indent: 32px; white-space: normal;"> Kunshan hot die steel</strong> die life is made of 3Cr2W8V steel die steadily increased more than one times
5. high temperature glass mould steel
Glass mold mold material with high temperature oxidation resistance and thermal fatigue resistance of excellent Naiwang nitrate, good performance of corrosion, high intensity, good polishing performance, and easy to release. This kind of mould commonly used cast iron, alloy cast iron or steel of 3Crl3 stainless steel, the performance is far can not meet the actual needs. To this end, China has developed a code for high temperature glass die steel GY. The steel is Si-Cr-Mo pre hardened steel, has good thermal fatigue resistance, excellent oxidation resistance, glass adhesive temperature excellent thermal performance and high touch. The steel in the pre hardened (about HRC35) processing, good processing performance, especially suitable for glass products in the mold surface quality of manufacturing glass melting or forming high temperature, high demand.