Cold Work Tool Steel

Toughness isSKD11twice.The toughness of DC53 isCold Work Tool Steelprominent, therefore, usingDC53 results in very few cracks and chipping, greatly extending its service life.Wire CuttingResidual Stress After Processing，afterHigh-Temperature Temperingreduces residual stress. Therefore, cracks and deformations in large molds and precision molds after wire cutting processing are suppressed.DC53 is a new type of steel improved from SKD11

     Cold Work Tool Steel, its technical specifications are listed in the Japanese Industrial Standard (JIS) G4404. It overcomes the shortcomings of SKD11 in high-temperature tempering hardness and toughness, and will completely replace SKD11 in general and precision mold fields.Introduction

The hardness of DC53 after heat treatment is higher than that of SKD11, reaching a high hardness of 62-63HRC after high-temperature (520-530℃) tempering, and in terms of strength and wear resistance, DC53 exceeds SKD11.

Toughness is

twice that of SKD11, and the toughness of DC53 isprominent, usingCold Work Tool SteelDC53 to manufacture tools results in very few cracks and fractures, greatly extending its service life.The residual stress after wire cutting processing is small, and the residual stress is reduced by high-temperature tempering, suppressing cracks and deformations after wire cutting processing.

Cutting and grinding properties exceed

SKD11, the cutting and grinding properties of DC53 are superior to SKD11, using DC53 can increase tool and mold life and reduce processing steps.DC53 Tool Steel Applications:

Punching Molds, Cold Work Forming Molds, Cold Drawing Molds

1.Forming Rolls, Punches

2.Precision Stamping Molds

Precision Punching Molds for Wire Cutting Processing and Various Stamping Molds

Difficult-to-Process Materials

Plastic Deformation ToolsCold Forging, Deep Drawing, and Wire Drawing Molds

Others

High-Speed Punching Punches, Stainless Steel Plate Punches

Practical Characteristics of DC53 Tool Steel:

DC53 Cold Work Tool Steel

(1) Good machinability and grindability.

Both machinability and grindability are better than

SKD11, so the tool life is longer and processing time is saved.(2) Advantages in Heat Treatment

Quenching hardness can be higher than

SKD11, thus improvingthe shortcomings of insufficient hardness during vacuum heat treatment.(3) Advantages in Wire Cutting ProcessingHigh-temperature tempering can reduce residual stress and eliminate residual austenite, preventing cracking and deformation during wire cutting processing.

(4) Advantages in Surface Hardening Treatment

Surface hardness after surface hardening treatment is higher than

SKD11, thus improving mold performance.

(5) Advantages in Repair Welding OperationsSince both preheating and post-heating temperatures are lower than

SKD11, repair welding operations are simpler.

Nitriding Treatment:SKD11低，所以修补焊接作业较简便。

氮化处理：

After nitriding treatment, the surface of the workpiece obtains a dense hardened layer structure, significantly improving the wear resistance and corrosion resistance of the workpiece.After gas nitriding treatment at 525 ℃, the surface hardness is about 1250 HV, and after soft nitriding treatment at 570 ℃, the surface hardness is about 950 HV.

DC53 mold steel density

DC53 is slightly heavier than ordinary mold steel, with a density of 7.9 g/cm³.

Basic properties of DC53 mold steel

DC53 is improved based on SKD11 (Crl2MoV).Cold Work Tool Steel, under conventional heat treatment conditions,Residual austeniteis almost completely decomposed, and deep cooling treatment can generally be omitted, while still maintaining high toughness under relatively high hardness. Experimental Design

After quenching at 1040 ℃ and high-temperature tempering at 520～530 ℃, the hardness HRC of DC53 can reach 62～63, and the toughness is twice that of Crl2MoV, which is currently the highest among commonly used., its technical specifications are listed in the Japanese Industrial Standard (Moreover, the cutting performance and grinding performance are good, and the residual stress of the electrical machining altered layer is small, Residual austeniteis very few, and the carbides are fine and evenly distributed. 　Due to the complex stress conditions of molds, some working parts of molds need to have some special mechanical properties. If standard heat treatment processes are followed, it is often impossible to achieve the desired working performance requirements. Therefore, it is necessary to make appropriate adjustments to the basic characteristics such as hardness, toughness, and wear resistance through heat treatment to achieve the best working state of the mold. The quenching temperature and tempering temperature are the main process parameters of heat treatment. This article focuses on studying the tempering characteristics of DC53.Experimental Design

In the experiment, slight changes were made to the heat treatment specifications of DC53, adjusting the quenching temperature appropriately, and the tempering temperature was taken at 6 levels, namely 100 ℃, 200 ℃, 300 ℃, 400 ℃, 500 ℃, and 600 ℃. The 100 ℃ tempering used a 101-2 type drying oven for heating, while the others used an SX-25-12 typebox-type resistance furnacefor heating, with two samples taken at each tempering temperature.Hardness testing used metal 　Rockwell hardness testing, conducted at room temperature, usingHBRVU-187.5 type Brinell optical hardness tester. The impact test used 10mm×10mm×55mm notched samples, conducted on a JB30B impact testing machine, with impact energy of 0.3 KN.m or 0.15 KN.m. Experimental Results and Analysis1. Hardness Value For each sample, hardness was measured at 3 different points, obtaining hardness values at each tempering temperature. The comprehensive hardness values of each sample showed that DC53 had little variation in hardness when tempered at 100～500 ℃; the hardness was slightly higher during tempering at 400 ℃, and the peak hardness after standard heat treatment tempering is generally around 520 ℃; after high-temperature tempering at 600 ℃, the hardness significantly decreased, with an average HRC hardness value of only 52.4, so the tempering temperature should not be too high. 2. Impact Toughness After tempering, the oxidized decarburized layer on the surface of the samples was ground off, and the impact values of each sample at different tempering temperatures were measured. The comprehensive impact values showed that DC53 achieved an average impact value of over 60 J/cm² when tempered at 200 ℃. At 500 ℃ tempering, the impact toughness was poor, showing some high-temperature tempering brittleness. Tempering above 600 ℃ showed good impact toughness, but the hardness significantly decreased, failing to meet usage requirements. The experimental results indicate that DC53 has good overall tempering stability, with little variation in hardness and impact values within a certain tempering temperature range; toughness significantly decreases during tempering at 400～500 ℃, showing tempering brittleness; at 600 ℃ tempering, the toughness of the samples is very high, with impact values reaching 85 J/cm², but the hardness significantly decreases. In production, for some cold work molds with lower hardness and wear resistance requirements but higher toughness requirements, high-temperature tempering can be used; for cold work molds with higher hardness requirements and also needing high toughness, low-temperature tempering around 200 ℃ is recommended. The hardness and impact values at other tempering temperatures can be predicted using suitable calculation methods (such as interpolation, function approximation, etc.) and then verified by experiments. In the quenched state samples, carbides are distributed in a discontinuous fine band, and after tempering at 200 ℃, carbides are uniformly distributed, with almost no large block carbides present in the structure, thus ensuring good toughness. From the fracture morphology, the cleavage steps of the fracture in the 200 ℃ tempered structure are far fewer than those in the quenched state samples, and the fracture at 5000 times metallography shows some small and shallow ductile dimples, indicating a certain level of toughness. After tempering, the residual austenite transforms sufficiently, and the carbides are fine and evenly distributed, which increases toughness.

Conclusion 1. After appropriately adjusting the quenching temperature, DC53 has high hardness and impact toughness when tempered at 200 ℃; at 400～500 ℃ tempering, the hardness is high, but toughness significantly decreases; at 600 ℃ tempering, the impact toughness is very high, but the hardness significantly decreases. 2. Complex-shaped precision punching dies, finishing dies, cold-rolled rollers, and other molds should adopt low-temperature tempering processes to ensure that the working parts of the molds achieve high hardness, high toughness, good wear resistance, and high strength, effectively extending the mold's lifespan and preventing excessive wear, deformation, cracking, and other early failure phenomena. 3. Complex molds subjected to high impact loads can adopt low quenching and high tempering processes to achieve higher impact toughness and prevent brittle fracture of the molds.

⒈适当调整淬火温度后，DC53在200℃回火时硬度和冲击韧性都较高；在400～500℃ 回火时硬度较高，韧性大幅度下降；在600℃ 回火时冲击韧性很高，硬度显著下降． 　⒉形状复杂的精密冲模、修整模、冷轧辊轮等工模具宜采用低温回火工艺，以使模具工作零件获得高硬度、高韧性、耐磨性好、强度高，可有效延长模具寿命，防止过度磨损、变形、开裂等早期失效现象． 　⒊受冲击载荷较大的复杂模具可采用低淬高回工艺，以得到较高的冲击韧性，防止模具产生脆性断裂现象