The C53 model is improved to SKD11 Cold die steel , the specifications contained in the Japanese industrial standard (JIS) G4404. It overcomes the SKD11 high temperature tempering hardness and toughness weakness, will replace SKD11 in general and precision mold field.
DC53 heat treatment hardness is higher than SKD11, high temperature (520-530 DEG C) after tempering to 62-63HRC high hardness, strength and wear resistance of DC53 in more than SKD11. Toughness is 2 times that of SKD11, the toughness of DC53 die are more prominent in the cold, made of DC53 very few tools to crack and crack, greatly improving the service life. Less stress after high temperature tempering to reduce the residual stress of wire cutting processing of residual, wire cutting processing of crack and deformation after suppression. Cutting and grinding of more than SKD11, DC53 cutting and grinding is better than that of SKD11, the use of DC53 can increase the life of mould tool and reduce the processing procedures.
1. punching dies, cold forming dies, cold drawing die
2., the punch forming roller
Precision stamping die
The WEDM precision punching die and stamping mould
Plastic deformation tool of difficult machining materials
Mold for cold forging, rolling and deep drawing
High speed punch punch, stainless steel plate
(1) by cutting, grinding is good.
By cutting, grinding are better than the SKD11, so the tool life is longer, compared with the number of working hours.
(2) the advantages in heat treatment
Hardened higher than the SKD11, so it can improve the defects of vacuum heat treatment of hardness.
(3) the advantages of online cutting processing
Through the high temperature tempering can reduce the residual stress and the elimination of residual austenite, can prevent cracking and deformation problems of wedm.
(4) the advantages in surface hardening treatment on
The surface hardening after surface hardness is higher than SKD11, so it can improve the performance of mould.
(5) in the operation of the advantages of repair welding
The preheating and post heating temperature is lower than SKD11, so the repair welding operation is simple.
The workpiece by hardening structure after nitriding surface density, the corrosion resistance and wear resistance of the workpiece increased significantly. 525 C after gas nitriding surface hardness of about 1250HV, 570 DEG C soft nitriding surface hardness of about 950HV.
The density of DC53 die steel
DC53 is slightly heavier than the average density of 7.9g/cm die steel, 3
The chemical composition of DC53 die steel
C Si Mn carbon silicon manganese chromium molybdenum vanadium phosphorus P V Cr Mo
1 0.91 0.32 8 2 0.28 0.0007 DC53
The basic properties of DC53 die steel
DC53 is in SKD11 (Crl2MoV) based on the improvement of the cold working die steel, the conventional heat treatment conditions, almost all of the residual austenite decomposition, it can be omitted in cryogenic treatment, strong hardness still maintained high toughness.Experiment design
DC53 is 1040 DEG C to 530 DEG C to 520 quenching and high temperature tempering, the hardness of HRC is 62 ~ 63, toughness is two times that of Crl2MoV, is commonly used in cold working die steel in the highest, and the cutting and grinding of residual metamorphic layer stress, little residual austenite, carbide fine and uniform distribution. Because the mold stress is complex, some die parts must have some special mechanical properties, according to the standard heat treatment process are often unable to meet the performance requirements of the ideal, need to make appropriate adjustments to the basic characteristics of hardness, toughness and wear resistance by heat treatment, in order to achieve the best working condition. The quenching temperature and mold the tempering temperature is the main technological parameters of heat treatment, this paper focuses on the DC53 characteristics of tempering. Two experimental design
In the experiment, some of the changes of DC53 heat slightly adjusted standard treatment, quenching temperature, tempering temperature of 6 stalls, namely 100 C, 200 c, 300 C, 400 C, 500 C, 600 C. 100 C tempering use 101-2 type drying oven heating, the rest of the SX-25-12 box type resistance furnace heating, tempering temperature of two samples each. The hardness test using the metal Rockwell hardness test, performed at room temperature, using HBRVU-187.5 type Burawoy optical hardness tester. Impact test using 10mm * 10mm * 55mm notched specimens in JB30B impact testing machine, impact energy is 0.3 KN.m or 0.15 KN.m. Experimental results and analysis
The hardness value of each sample from each of 3 different positions of Vickers hardness test, the tempering hardness value, the hardness of the sample values DC53 at 100 to 500 DEG C during tempering, the hardness change little; 400 degrees in the medium temperature tempering hardness after tempering heat treatment, standard the general hardness peak at 520 degrees Celsius; at 600 DEG C after high temperature tempering, the hardness decreased significantly, the average hardness value of HRC is only 52.4, so the tempering temperature should not be too high. ⒉ impact toughness After tempering, wear off the sample surface oxidation decarburization layer, measured at different tempering temperature of the impact value of each sample, the impact of the value of each sample, DC53 tempering at 200 ℃, the average impact Value reached 60 J / cm2 above. Tempering at 500 ℃, the impact toughness is poor, showing some high temperature temper brittleness. Temperatures above 600 ℃ tempering impact toughness, but greatly reduced hardness, reach the use requirements. The experimental results show that the overall tempering stability of DC53 is good, and the hardness and impact value have little change in a certain tempering temperature range. The toughness of tempering decreases sharply at tempering from 400 ℃ to 500 ℃, ℃ tempering, the specimen of high toughness, impact value reached 85 J / cm2, but the sharp decline in hardness. In the production, for some hardness, wear resistance is not too high and toughness requirements of the cold mold can be high temperature tempering; require a higher hardness, but also have higher toughness of the cold die, it is appropriate to adopt Low temperature of about 200 ℃ tempering. Other tempering temperature hardness and impact values can be calculated using appropriate methods (such as interpolation, function approximation, etc.) to predict Then, experimental verification. Intermittent zonal distribution fine carbide in the quenched sample, 200 DEG C after tempering carbide were evenly distributed within the organization, and there is almost no massive carbides, so good toughness. The fracture morphology from 200 DEG C, cleavage fracture microstructure is far less than the quenched specimens, the fracture 5000 times Jin Xiangzhong there are some small and shallow dimples, shows that it has a certain toughness. After tempering, the residual austenite is sufficient, carbides and uniform distribution, the toughness increased. Conclusion
The appropriate adjustment of quenching temperature, tempering hardness at 200 DEG C and impact toughness of DC53 are higher; in the 400 to 500 DEG C when the tempering hardness and toughness decreased greatly; at 600 DEG C when the tempering toughness of high hardness decreased significantly. Precision die and trimming die, cold roll wheel mould, complex shape the appropriate use of low temperature tempering process, so that the die parts of high hardness and high toughness, good abrasion resistance, high strength, can effectively prolong the service life of the mould, to prevent excessive wear, deformation, cracking and other early failure. 3 by the larger impact load of the complex mold can be used to process high low quenching, the impact toughness get high, prevent mold brittle fracture phenomenon, the Japanese industrial standard (JIS) G4404
Japanese brand DC53 is D2 - China improved varieties of type Cr8Mo2SiV, the steel is cold die steel (wear and impact resistance), the toughness of the steel. If the American brand called D2E.