3.Compared grades(based on usage)

4.Heat treatment:

Isothermal annealing:

-   Heat to 880°C, hold at temperature for 1/2 h to 1 h;

-   Furnace cooling to 780°Cand hold at temperature for at least 5 hours;

-   Cool by 10°C/h to 750°C;

-   Cooling in air.

Maximum hardness: 230 HB

Stress relieving:

To be carried out after maching and before the final heat treatment.

-   Heat to 650-700°C, hold for 4÷6 hours;

-   Furnace cooling to 300-350°C;

-   Cooling in air.

Hardening:

-   Initial preheating to 350-450°C;

-   Second preheating to 750-850°C;

-   Heat to hardening temperature in the range 1000-1050°Cand hold at temperature;

-   Cooling in air.

Quenched hardness: 52-56 HRC

Tempering:

In the range 550-630°Cfor at least 3 hours according to hardness requirements and conditions of use.

Tempering must be repeated a second time at a temperature to or 20°Clower than the previous.

    Before tempering, preheat the parts to 200-300°C.

5. About us:

  ◊Establish: Dongguan Circle Four Metal Materials Co., Ltd. was established in 2008 has 5 years manufacturing and exporting professional experience in mould steel, special steel etc.

  ◊Products: We mainly manufacture more than 100 kinds of hot rolling or forging products, such as alloy structural steel, alloy tool steel, carbon structural steel, carbon tool steel, plastic mould steel, hot work steel, cold work steel, spring steel and high speed steel.

  ◊Capacity: 500, 000MT per year.

6. Contact us:

Email: gerrycheng(at)

Skype: gerrycheng2011

Phone No.: 86-13794981366

 Our factory now equiped with large-sized Vertical sawing machines,Horizontal saw machines,Milling machines,Grinding machines,Finish milling.

We do hardness testing of processing for your needs and we also have advanced ultrasonic flaw detection equipment.

Our products have selling to:

Indonesia,Singapore,Japan,Korea,India,Malaysia,Mexico,Brazil,Denmark,Turkey,Germany,Italy,Dubai,the middle east and other regions.