AISI O2 • DIN 1.2842 • JIS SKS31 Steel

What is O2 steel?

AISI O2 steel also can be called JIS SKS31 and DIN 1.2842 steel. It is the better type compare with the O1 tool steel. Its content of carbon, chromium and tungsten has been raised. So it has a higher hardenability characteristic, the deformation is small during the quenching. It is a low alloy tool steel which is better than carbon steel at the point of the mechanical property. It has high hardness and wearing resistance. Because of the certain account of vanadium element, the crystal grain is smaller then decrease the overheating sensitivity of the steel. At the meantime, the carbide is getting smaller and the distribution is uniformity. O2 Steel chemical composition and heat treatment as below.

O2 Steel Grade Equivalent Chart

StandardGB/T 1299-2000ASTM A681-08EN ISO 4957-1999ISO 4957: 1999

O2 Steel Chemical Composition

GB/T 1299-20009Mn2V
ASTM A681-08O20.85-0.951.40-1.80≤0.030≤0.030≤0.50≤0.50≤0.30≤0.30-
EN ISO 4957-199990MnCrV8/1.28420.85-0.951.80-2.20≤0.030≤0.0300.10-0.400.20-0.500.05-0.20--
ISO 4957: 199990MnCrV80.85-0.951.80-2.20--0.10-0.400.20-0.500.05-0.20--

1.2842 Steel Physical Properties

Properties T (°C)
Density7.66 x 1000 kg/m³25

1.2842 Steel Mechanical Properties

Properties T (°C)
Poisson's ratio0.27-0.3025
Elastic modulus27557-30458 ksi25

1.2842 Steel Characteristics

  1. The processibility is good and the size after heat treatment is stable.
  2. High wearing resistance.
  3. The deformation is small and even without it during the processing
  4. The toughness is not good.
Steel Packing

O2 Steel Heat Treatment

Spheroidizing Annealing

1.2842 steel usually be processing with spheroidizing annealing at the same temperature. After forging, heat the mold base up to 760℃-780℃. And then keep the temperature for 2h-4h, furnace cooling to 680℃-700℃, stay the temperature for 5h-6h. Finally, make it air cooling after the temperature is about 500℃ for furnace cooling.

Quenching and Tempering

The temperature of quenching is 800℃-840℃. And the small mold base usually uses the method of oil quenching. The tempering stability is not good. It usually needs a low temperature that is about 160℃-170℃ to tempering. And the time is about 2 hours.

Steel Transportation

O2 Steel Application

It is the stand of the USA, it is oil quenching hardening tool steel. It is widely used due to good processability and wearing resistance. But its toughness and decay resistance are not good. And its application as below.

  1. It is used to make the fittings of blanking die with high hardness. And the width is smaller than 3mm.
  2. The precision template with good wearing resistance and small deformation.
  3. Knives, screw tap, screw die, reamer bit and etc.
  4. Be used to make the mold base with high strength, wearing resistance.

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