1. Material characteristics

H13 hot work die steel is the American standard hot work die steel and electroslag remelting steel. The steel is a hot work die steel with high toughness and toughness commonly used in the world, with high hardenability and thermal crack resistance. The steel contains high carbon and vanadium, good wear resistance, relatively weakened toughness; good heat resistance, good strength and hardness, high wear resistance and toughness at higher temperatures, and at the same time It has excellent comprehensive performance and high tempering resistance.

The forging billet shall be forged on six sides, and the forging ratio shall be greater than 4. Has high hardenability and high toughness; excellent thermal cracking resistance, water cooling in the work environment; moderate wear resistance, can also use carburizing or nitriding process to improve its surface hardness, but slightly less Reduce the thermal cracking resistance; because of its low carbon content, the secondary hardening ability in tempering is poor; it has the ability to resist softening at higher temperatures, but when the temperature is higher than 540 ℃, the hardness drops rapidly; the steel is heat treated The deformation is small, with medium and high workability and medium decarburization resistance.

The maximum service temperature of this steel should not exceed 600℃ and be lower than 3Cr2W8V steel. The thermal strength and thermal stability of the steel are also lower than that of 3Cr2W8V steel, and the impact toughness of the steel is higher than that of 3Cr2W8V steel, and sometimes even more than doubled.

2. the supply status

In quenched and tempered state, the hardness is 185~229HBW.

3. Chemical composition

According to the American standard ASTM681-1986, the chemical composition (mass fraction) of the steel:

C 0.32~0.45%

Si 0.80~1.20%

Mn 0.20~0.50%

Cr 4.75~5.50%

Mo 1.10~1.75%

Ni ≤0.25%

V 0.80~1.20%

P ≤0.03%

S ≤0.03%

4. Corresponding grades

American AISI standard grade H13

China GB standard grade 4Cr5MoVSi

Japan JIS standard brand SKD61

Hitachi (HITACHI) standard grade DAC

NACHI standard grade HDS61

German DIN standard material number 1.2344

Austrian BOHLER standard grade W302

China Taiwan Ronggang (EVERGCREEN) standard grade H13

Swedish UDDEHOLM standard grade ORVAR patented steel

Swedish ASSAB (ASSAB) standard grade 8402/8407

5. thermal processing specifications

The heating temperature is 1110~1160℃, the starting temperature is 1060~1150℃, and the ending temperature is ≥800℃.

6. general annealing specifications

845~880℃x2~4h. Slowly cooled to about 500 ℃, air-cooled out of the furnace.

7. Specification for batch isothermal spheroidizing annealing of blanks

Slowly heating, 850~870℃x3~4h, furnace cooling to 740~760℃x4~5h, then furnace cooling to ≤550℃, out-of-furnace air cooling, hardness ≤229HBW, eutectic carbide grade ≤3.

8. Specification for softening treatment of cold pressed blanks

840~860℃x3~4h, slowly cooling to 600℃ at a cooling rate of 5~10℃/h, and air cooling out of the furnace. The hardness before treatment is less than or equal to 229HBW, and the hardness after treatment is less than or equal to 196HBW.

9. solution treatment + quenching + high temperature tempering pretreatment specification

Solution treatment temperature is 1100~1150℃. High temperature tempering temperature (680±10) ℃, heat preservation for 1h, air cooling out of the furnace. The pretreatment process has a good effect on eliminating the segregation of chemical components and improving the uniformity of the structure.

10. general quenching and tempering specifications

Preheating temperature is 550℃, 850℃, quenching temperature is 1020~1050℃, oil or air cooling hardness is 57~60HRC, tempering temperature is 600℃, tempering twice, hardness is 47~49HRC.

11. Carbide dispersive carburizing (CD carburizing)

Carburize at 930℃x6h, carburizing agent is ethyl acetate or acetone; quench oil at 1000℃, temper at 200℃. Talk about potential control at ψ(C)=0.8%~0.9%, and the carburized layer w(C)=1.8%. The surface hardness is 62~63HRC, the core hardness is 53HRC, and the impact toughness is 49J/cm2.

12. Examples of typical applications

1. Used to make forging dies, hot extrusion dies and precision forging dies with large impact load.

2. Die casting molds for aluminum, copper and their alloys.

3. The service life of H13 steel punch is increased from 2000~3000 times of CrWMn steel punch to 9500~27000 times after CD carburizing.

4. Used for high temperature thermosetting plastic film.