Analysis of Corresponding Grades and Material Applications for CR12Mo1V1 in Various Countries

CR12Mo1V1 is a commonly used hot work die steel, also commonly referred to as D3 (AISI standard) or 1.2080 (German DIN standard), and JIS: SKD11. It possesses high hardness, wear resistance, cutting performance, and stability, making it suitable for various mold applications. It is primarily used for manufacturing cold work molds, hot work molds, cutting tools, knives, and mold components.                 

After undergoing appropriate heat treatment and tempering processes, Cr12Mo1V1 die steel can achieve a high level of hardness, typically reaching 60-62 HRC, providing excellent wear resistance and cutting performance.

Due to its high hardness and suitable composition, Cr12Mo1V1 die steel exhibits excellent wear resistance, making it particularly suitable for die applications involving long-duration or high-speed processing.

Cr12Mo1V1 mold steel possesses high strength and rigidity, maintaining stable shape and resisting deformation or cracking. It is suitable for manufacturing molds and cutting tools that require strict precision in size and shape.

Due to its high carbon and chromium content, Cr12Mo1V1 die steel exhibits excellent machinability, facilitating easy processing and forming, and is suitable for machining operations such as cutting, milling, and drilling.

Cr12Mo1V1 die steel maintains good stability under high-temperature conditions and exhibits strong thermal fatigue resistance, making it suitable for manufacturing molds and tools that are resistant to high temperatures and thermal cycling.

Application areas of Cr12Mo1V1 die steel:

Stamping die: Due to its high hardness and wear resistance, Cr12Mo1V1 is widely used in the manufacture of stamping dies, such as punching dies and shearing dies.

Cutting tool: Cr12Mo1V1 is suitable for manufacturing cutting tools such as knives, blades, milling cutters, etc., used for metal processing and cutting operations.

Plastic mold: Cr12Mo1V1 has good rigidity and wear resistance, and is commonly used in the manufacture of plastic injection molds, extrusion molds, etc.

Hot work die: Due to its good thermal stability, Cr12Mo1V1 can also be used to manufacture hot work dies, such as hot pressing dies and hot forming dies.

The heat treatment process for Cr12Mo1V1 die steel primarily involves steps such as annealing, solution treatment, quenching, and tempering. Below is a common heat treatment process flow:

1. Annealing: Heat the Cr12Mo1V1 die steel to an annealing temperature of approximately 800-850°C and maintain it for a certain period of time, then slowly cool it down to room temperature. This annealing process helps to eliminate stress, improve cutting performance, and enhance the machinability of the workpiece.

2. Solution treatment: Heat the annealed Cr12Mo1V1 die steel to a solution temperature of approximately 980-1050°C and maintain it for a certain period of time to transform the steel structure into austenite.

3. Quenching: After maintaining at the solution temperature for a certain period of time, rapidly cool the Cr12Mo1V1 die steel to room temperature. Common quenching media include air cooling, oil cooling, or salt bath cooling. Quenching treatment will enable the Cr12Mo1V1 die steel to achieve high hardness and good cutting performance.

4. Tempering: After quenching, heat the Cr12Mo1V1 die steel to an appropriate temperature, typically between 150-550°C, maintain it for a certain period, and finally cool it to room temperature. Tempering helps eliminate the internal stress generated during quenching and enhances the strength, toughness, and wear resistance of the die steel. Cr12Mo1V1 is a widely used high-carbon, high-chromium cold work die steel internationally. It belongs to ledeburitic steel and possesses high hardenability, high wear resistance, good high-temperature oxidation resistance, excellent corrosion resistance after quenching and polishing, and minimal heat treatment deformation.

Cr12mo1v1 mold steel is used for mold parts with higher requirements

chemical composition %

C 1.40-1.60

Si ≤0.60

Mn ≤0.60

Cr 11.00-13.00

Mo 0.70-1.10

V 0.70-1.10

other

Heat treatment process:

Heat treatment process for cr12mo1v1 mold steel

stress relief annealing

After rough machining, the workpiece is heated to a certain temperature, held for 2 hours, cooled to 500°C in the furnace, and then removed from the furnace for air cooling.

quenching

The workpiece is slowly heated to 600°C, held for 20 minutes for the first preheating, then raised to 850°C after temperature equalization and held for another 30 minutes for the second preheating. After that, it is heated to the final temperature, held for 25 to 40 minutes, and then discharged for air cooling.

tempering

Tempering should be carried out immediately after quenching, and it should be done at least twice, with each holding time not less than 2 hours

Note: After quenching, tempering should be carried out promptly to prevent cracking, and surface decarburization should be avoided. Gauges and high-precision molds should undergo cryogenic treatment (-70°C) and high-temperature tempering to reduce workpiece deformation. The high-temperature tempering temperature should be such that the hardness is greater than 58HRC

The physical properties of cr12mo1v1 die steel include an elastic modulus of MPa and a mass specific heat capacity at constant pressure (Cp) of 461 J/(kg·K). critical temperature

Critical points Ac1, Acm, Ar1, Arcm, Ms

Temperature (approximate value) / 190

Specification for softening of cold extrusion billets

The iron chips are heated with protection at temperature C for 10 hours, then cooled in the furnace to achieve a hardness of 196HBW, which allows for smooth cold extrusion forming

General isothermal spheroidizing annealing specification

×3~4h, cool in the furnace until it reaches ×4~5h isothermal, then remove from the furnace and air cool. Hardness ≤241HBW, eutectic carbide grade ≤3

Optimal isothermal temperature C, duration ≥4 ~5h

Spheroidizing annealing specification

(860±1°C)×2~4h, furnace cooling at a cooling rate of 30°C/h, (740±10°C)×4-6h, slowly cooling to room temperature with the furnace, then air cooling after tapping. Hardness: HBW.

cryogenic treatment

CR12MO1V1 mold steel undergoes deep cryogenic treatment, which enables the precipitation of highly dispersed ultrafine carbides from quenched martensite. After subsequent low-temperature tempering at 200°C, these ultrafine carbides can be transformed into carbides. For martensite without deep cryogenic treatment, only a small amount of carbides precipitate in certain localized areas after low-temperature tempering. 1.2379 mold steel adopts low-temperature chemical heat treatment methods, which maintain high hardness and high wear resistance of the steel while enhancing the adhesion resistance of commonly used low-temperature chemical heat treatment layers such as sub-nitriding, gas nitrocarburizing, and salt bath sulfur-cyanide co-diffusion. All three types of low-temperature chemical heat treatment layers exhibit significant impact adhesion resistance, with salt bath sulfur-cyanide co-diffusion being particularly effective. After gas nitrocarburizing treatment, the service life of steel stainless steel utensils for tensile dies can reach over 30,000 pieces, which is more than 10 times longer than similar molds treated with conventional quenching and tempering processes, plus hardening treatment

To enhance the lifespan of the mold to over 800,000 mold cycles, the pre-hardened steel can be hardened through a process of quenching followed by low-temperature tempering. During quenching, the steel should be preheated for 2-4 hours, then held at a constant temperature for at least 2 hours, and finally cooled in oil to a temperature between 50-100°C before air cooling. After quenching, the hardness can reach 50-52HRC. To prevent cracking, a 200°C low-temperature tempering treatment should be immediately applied. After tempering, the hardness can be maintained above 48HRC

Salt bath vanadizing treatment

The neutral salt bath vanadizing process for cold work die steel can achieve a carbide layer through neutral salt bath vanadizing. Firstly, carbon-vanadium compounds are formed. This layer has a uniform microstructure, good continuity and compactness, uniform thickness, and a dense structure, with high microhardness and high wear resistance. The surface hardness, wear resistance, and adhesion resistance are significantly improved. Secondly, the solubility of VC in austenite is higher than that in ferrite. As the temperature decreases, VC precipitates from ferrite, strengthening the alloy and refining the grain size. The compound layer exhibits high hardness. It belongs to high-carbon high-chromium ledeburitic steel, with a high carbide content of about 20%, often unevenly distributed in stripes or networks, resulting in severe segregation. However, conventional heat treatment is difficult to change the segregation of carbides, which seriously affects the mechanical properties of the steel and the service life of the die. The shape and size of carbides also have a significant impact on the properties of the steel. Especially, large blocky and sharp-angled carbides have a greater fracturing effect on the steel matrix, often becoming the source of fatigue fracture. Therefore, it is necessary to reform the raw material rolled steel by forging to fully crush the eutectic carbides, making them fine and evenly distributed, with a fibrous structure surrounding the cavity or distributed in a non-directional manner, thereby improving the transverse mechanical properties of the steel.

During forging, the steel billet undergoes multiple upsetting and drawing processes from different directions, and is forged using the "two light, one heavy" method. Specifically, the billet is lightly struck at the beginning of forging to prevent fracture, and can be heavily struck at an intermediate temperature of 980~1020°C to ensure the fragmentation of carbides,

The mold steel is not forged, but undergoes a solid solution double refinement treatment [5]. This involves two stages of preheating at around 500 and 800 degrees Celsius, followed by a solid solution treatment at 1100 to 1150 degrees Celsius. After quenching into hot oil for isothermal quenching, it is tempered at 750 degrees Celsius. After machining, it is heated to 960 degrees Celsius, oil-cooled, and then undergoes final heat treatment. This process can also refine carbides, round off edges and corners, and refine grain size.