剥皮压光研磨圆钢

　　Cr12

　　Carbon C: 2.00 ~ 2.30 Si: ≤0.40 Manganese Mn: ≤0.40 Sulfur S: ≤0.030 Phosphorus P: ≤0.030 Chromium Cr: 11.50 ~ 13.00 Nickel Ni: Permissible residual content ≤0.25 Copper Cu: permissible residual content ≤0.30 Cobalt Co: 1.00 or less

　　Cr12 is an alloy tool steel with good hardenability and good wear resistance. It is mainly used for cold stamping dies and punches, cold cutting scissors, drill sleeves, gauges, wire drawing dies, embossing dies, wire rolling plates, drawing dies and thread rolling dies with low impact load and high wear resistance.

　　GB/T 1299-2000

　　Scope of application

　　It is a widely used cold working die steel with high strength, good hardenability and good wear resistance, but poor impact toughness. Mainly used for bearing less impact load, requiring high wear-resistant cold die and punch, cold cutting scissors, drill sleeve, gauge, wire drawing die, stamping die, rolling plate, drawing die and thread rolling die.

　　Cr12 die steel belongs to high carbon and high chromium letenite steel, and is also a widely used cold working die steel. The steel has good hardenability, wear resistance and hot workability. Carbides are well distributed in steel and can be used to manufacture various cold working molds with complex shapes and heavy working conditions. Such as cold stamping punch, thread rolling die, wire drawing die, material die, metallurgical powder die, woodworking cutting tools, cold cutting scissors drill sleeve and gauge and other tools. In the development, after repeated exploration and testing, we have formulated a reasonable smelting process and special ingot mold and forging process, so that the material organization is uniform, in addition to the standard material processing, bold innovation, the use of double-tool chip new technology, greatly improve the efficiency, shorten the cycle, reduce the cost.[1]

　　1. Vacuum degassing refining treatment of pure steel.

　　2. Spheroidizing annealing softening treatment, good cutting performance.

　　3. Strengthening elements vanadium, molybdenum special addition, wear resistance is extremely excellent.

　　use

　　1. The thickness is not more than 2MM thin sheet, efficient blanking die, punching die and stamping die.

　　2. Various scissors, inlaid blades, woodworking blades.

　　3. Thread rolling die and wear-resistant slider.

　　4. Cold heading mold, thermosetting resin molding mold.

　　5. Stretch forming die, cold extrusion die.

　　Supply status

　　Make way? State, hardness 269-271HBW, indentation diameter 3.7 ~4.1mm[2]

　　EDITOR

　　Chinese GB standard Cr12. German DIN standard material number 1.2080. German D1N standard x210Cr12. British BS standard BD3. French AFN0R standard z200Cr12. Italian UNI standard X210cr13KU/x250cr12I

　　Mechanical property

　　Hardness: Annealed,269 ~ 271HB, indentation diameter 3.7 ~ 4.1mm; Quenched,≥58HRC

　　Heat treatment

　　Metallography structure: tempered martensite + undissolved carbide + residual austenite.

　　Delivery condition: Steel is delivered in annealed condition.

　　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 a secondary hardening phenomenon, tempering not less than 2 times, each 2h, tempering can be air cooled or oil cold, high temperature quenching before the best 2 times preheating, at high temperature heating, need to take protective measures to prevent oxidation.

　　temper

　　EDITOR

　　Recommendation specification

　　Application Heating temperature /℃ Tempering time /h tempering times Hardness (HRC)

　　Stress relief and tissue stabilization 180~200 2 1 60~62

　　Stress relief and hardness reduction 320~350 2 1 57~58

　　Cr12 quenching

　　Hardening temperature /℃ hardness of cooling medium

　　950~980 Oil 59~63

　　Treatment technology

　　Cold work die steel is mainly used for metal or non-metal materials punching, drawing, bending, cold extrusion, cold heading, wire rolling, bending and other processes. Therefore, the mold is required to have high strength, high wear resistance and enough toughness to ensure its service life. Cr12 steel has been widely used in mass production as a general cold working die, and its heat treatment methods are usually two: one hardening method (low quenching + low return) and two hardening method (high quenching + high return).

　　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, the cold stamping mold with high hardness and wear resistance is required, and the low temperature tempering is used, and the hardness after tempering can reach HRC60 or more. For stamping dies requiring higher hardness and certain toughness, 250~270 degrees of tempering can be used, and the hardness after tempering can reach HRC58 ~ 60. For the mold with higher impact toughness, 520 degrees of 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 number of residual austenite in the steel after quenching, so the hardness is low (HRC42 ~ 45), through multiple (3 ~ 5) high temperature tempering, the residual austenite into martensite to produce secondary hardening. The hardness can be increased to HRC59 ~ 64. mainly suitable for mold parts requiring red hardness, the disadvantage is that the impact toughness is poor, affecting the multi-impact life, so it is not suitable for cold mold.

　　Because the one-time hardening method uses 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 grinding heat in the subsequent processing and affect the service life.

　　Therefore, it is preferred to use medium temperature quenching + high temperature tempering method, that is, quenching about 1050 degrees, and the hardness after quenching is HRC63. Then use 500 ~ 520 high temperature tempering. Because the hardness after secondary hardening and tempering can reach HRC60 or more, 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 toughness. Moreover, due to the advantages of sufficient stress relief after high temperature tempering, not easy to crack during subsequent wire cutting and discharge machining, not easy to anneal during grinding, and titanium plating on the surface, it has been applied in production to some extent.

　　Typical example

　　EDITOR

　　1) The steel can be used for silicon steel cold stamping dies, for drawing and punching dies requiring high wear resistance and simple shape under dynamic load conditions

　　2) It is widely used to make cold working molds with complex shapes, impact and high wear resistance, such as silicon steel cold stamping dies, thread rolling dies, and pull-out dies.

　　3) It is used to make the concave touch requiring wear resistance in the drawing die, and the recommended hardness is 62 ~64HRC.

　　4) When used for the punch of aluminum cold extrusion die, the recommended hardness is 60 ~62HRC.

　　5) Used to make bending die requirements? Wear-resistant, complex shape punch, die, insert, make punch, die recommended hardness of 60 ~64HRC.

　　6) For forming carbon mass fraction of 0.5%~0.80% of the steel plate, hardness of 37 ~42HRC, the service life of up to 220.000 times

　　7) For the production of cold heading truck bolt concave die, parts size of 8.9mm × 9.0mm concentric cylinder, service life is only 0.1 to 0.2 thousand times

　　8) For thermosetting plastic molding die, requiring high mushroom resistance, high strength mold

　　9) For the wear-resistant brick forming die after boron + quenching + tempering, compared with the original Q235 steel carbon die, the service life is increased by 5-6 times, the process is simple, and the economic benefits are significant

　　10) Cr12 steel edge punch solid boron chromium total, the number of convex edge up to L60.000 ~ L70.000 times. The conventional quenching process is only 60.000 to 80.000 times, and the boron treatment is only 70.000 to 10.000 times

　　11) After vanadium composite treatment of Cr12 steel wire rolling plate, the service life of the mold is increased to 17 thousand pieces

　　12) The hexagon die of Cr12 steel cold heading hexagon head bolt, after vanadium composite treatment, the service life of the die is increased by l0 times.