OH255
 
Identification

 

Designation by Standards
Brand Name Ravne No. Mat. No. DIN EN AISI
OH255 255 - - - -

 

Chemical Composition

 

Chemical Composition in Weight %
C Si Mn Cr Mo Ni V W Others
1.00 1.10 0.30 8.00 2.70 - 0.30 - -

 

General Information

Description
High alloyed cold work tool steel. High hardness and wear resistance with good thoughness.

Applications
Cutting dies, thread rolling tools, roamers, shearing blades, rolls for cold rolling.

 

Properties

Physical properties (avarage values) at ambient temperature:
Modulus of elasticity [103 x N/mm2]: 210
Density [g/cm3]: 7.73

Coefficient of Linear Thermal Expansion 10-6 oC-1
20-100 'C 20-200 'C 20-300 'C 20-400 'C 20-500 'C 20-600 'C 20-700 'C 20-800 'C
11.2 12.3 12.9 13.2 13.4 13.7 13.8 14.0

Continuous Cooling Transformation (CCT) Diagram

 

Heat Treatment

Soft Annealing
Heat to 820-860 'C, cool slowly in furnace. This will produce a maximum Brinell hardness of 250.

Stress Relieving
Stress relieving to remove machining stresses should be carried out by heating to 650 'C, holding for one hour at heat, followed by air cooling. This operation is performed to reduce distortion during heat treatment.

Hardening
Harden from a temperature of 1040-1080 'C followed by oil or air quenching. Hardness after quenching is min. 60 HRC.

Tempering
Tempering temperature: Please see the diagram bellow.

Tempering Temperature ( 'C) vs. Hardness (HRC)
200 'C 300 'C 400 'C 500 'C 520 'C 540 'C 560 'C 580 'C 600 'C
60 58 59 62 62 61 58 53 50

Effect of Tempering Temperature on Hardness

 

Workability


Forging
Hot forming temperature: 1050-900 'C.

Machinability
No data.