Cr12 Hardware Tool Steel Bar

Cr12 is an alloy tool steel with good hardenability and good wear resistance. It is mainly used for cold punching dies and punches, cold cutting scissors, drill sleeves, gauges that bear less impact load and require high wear resistance. , Wire drawing die, stamping die, thread rolling board, drawing die and thread rolling die, etc.

Cr12 die steel belongs to high carbon and high chromium ledeburite steel, and it is also a widely used cold work die steel. The steel has good hardenability, wear resistance, and hot workability. Carbides are well distributed in steel and can be used It is used to manufacture various cold work molds with complex shapes and heavy working conditions, such as cold die punches, thread rolling dies, wire drawing dies, material molds, metallurgical powder molds, woodworking cutting tools, cold cutting scissors drill sleeves, gauges and other tools. In our research and development, after repeated exploration and testing, we have formulated a reasonable smelting process and a special ingot mold and forging process to achieve a uniform and consistent material structure. In addition, we have boldly innovated the standard material processing and adopted the new technology of double-knife chipping. The efficiency is greatly improved, the cycle is shortened, and the cost is reduced.

Chemical composition:(Wt %)

Mechanical Properties:

Equivalment Grade:

Heat treatment:

Metallographic structure: tempered martensite + undissolved carbide + retained austenite.

Quenching temperature: Cr12 quenching 950～1000℃ oil quenching, secondary tempering 550℃

High temperature quenching 1100-1150℃, low temperature quenching 960-1050℃, tempering 550-650℃, the former has secondary hardening phenomenon, tempering is not less than 2 times, each 2h, after tempering, it can be air-cooled or oil-cooled, high temperature It is best to preheat twice before quenching. When heating at high temperature, protective measures should be taken to prevent oxidation.

Processing Suggestion:

Cold work die steel is mainly used in the processes of punching, stretching, bending, cold extrusion, cold heading, thread rolling, and bending of metal or non-metal materials. Therefore, the mold is required to have high strength, high wear resistance and sufficient toughness to ensure its service life. As a general-purpose cold work die, Cr12 steel is widely used in mass production, and there are usually two heat treatment methods: primary hardening (low quenching + low recovery) and secondary hardening (high quenching + high recovery).

The quenching temperature of the one-time hardening method is 1020～1040 degrees, and the tempering temperature can be selected according to the requirements of the mold. Generally, cold stamping dies that require high hardness and wear resistance are tempered at a low temperature of 160 to 180 degrees, and the hardness can reach HRC60 or more after tempering. . For stamping dies that require higher hardness and a certain degree of toughness, 250-270 degree tempering can be used, and the hardness can reach HRC58-60 after tempering. For molds with higher impact and toughness, 520 degrees high temperature tempering can be used, and the hardness after tempering is HRC55-57.

The quenching temperature of the secondary hardness method is 1080 ~ 1120 degrees. Because there is a large amount of retained austenite in the steel after quenching, the hardness is low (HRC 42 ~ 45). After multiple (3 ~ 5 times) high temperature tempering, the residual The transformation of austenite into martensite produces secondary hardening. The hardness can be increased to HRC59~64, which is mainly suitable for mold parts that require red hardness. The disadvantage is that the impact toughness is poor, which affects the multi-stroke life, so it is not suitable for cold work molds.

Because the one-time hardening method adopts low temperature tempering, although the hardness can reach HRC60 or more, the tempering temperature is low, the stress relief after quenching is not sufficient, and it is easy to reduce the surface hardness of the workpiece due to the grinding heat in the subsequent processing and affect the service life .

Therefore, the medium temperature quenching + high temperature tempering method is preferred, that is, the quenching is about 1050 degrees, and the hardness after quenching is HRC63. Then use 500-520 high temperature tempering. Since the hardness of the secondary hardening and tempering can reach above HRC60, the quenching temperature of this process is lower than that of the secondary hardening method, and the strength of the mold after heat treatment is higher, and it has a certain degree of toughness. Moreover, due to the sufficient stress relief after high temperature tempering, the following advantages of wire-cutting electric discharge machining are not easy to crack, not easy to anneal during grinding, and the surface can be plated with titanium, etc., which have certain applications in production.

Application:

1. The steel can be used for silicon steel cold punching dies, and used for drawing and punching dies that require high wear resistance and simple shapes under dynamic load conditions.
2. It is widely used to make cold work dies with complex shapes, impact resistance, and high wear resistance, such as silicon steel cold punching dies, thread rolling dies, wire drawing dies, etc.
3. It is used to make concave molds that require wear resistance in deep drawing dies. The recommended hardness is 62~64HRC.
4. When used for the punch of aluminum cold extrusion die, the recommended hardness is 60~62HRC.
5. It is used to make convex molds, concave molds, and inserts that require high wear resistance and complex shapes in bending molds. When making convex molds and concave molds, it is recommended that the hardness is 60~64HRC.
6. The elastic steel plate with a mass fraction of 0.5% to 0.80% for forming carbon, with a hardness of 37 to 42HRC, and a service life of up to 220,000 times
7. It is used to make the die for cold-headed truck compartment bolts, the part size is 8.9mm×9.0mm concentric cylinder, and the service life is only 10,000 to 20,000 times
8. Used for thermosetting plastic molding molds, which require high resistance to mushrooms and high strength molds
9. The wear-resistant brick forming mold used for boron + quenching + tempering, compared with the original Q235 steel carbon mold, the service life is 5-6 times longer, the process is simple, and the economic benefits are significant
10. After the solid boron and chromium of the Cr12 steel edge punch die, the number of convex mouldings is as high as 160,000 to 170,000 times. The conventional quenching process only has 6,000 to 8,000 times, and the boron treatment is only 7,000 to 10,000 times.
11. After Cr12 steel rolling plate vanadium composite treatment, the service life of the mold is increased to 17 thousand pieces
12. Cr12 steel cold heading hexagonal head bolts, after the vanadium compound treatment, the service life of the mold is increased by 10 times.

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