NOS425 Forged Steel Bar 1.2367 / DIEVAR / 8418 / W403 / DH31-S
NOS425, high quality hot work die steels, produced by SUPER
High purity, homogeneous annealing structure, great toughness and
ductility, that is helpful to reduce the risks of die cracks to the
NOS425 is applied for making die casting die, hot extrusion die,
hot forging die, and hot stamping die, which is under the harsh
production condition. It also can be used for making some kind of
plastic mould because of its high mirror polishing performance.
NOS425 is strictly inspected as per standard of NADCA#207-2011, and
other properties also can be tested as customers’ requirement.
Die Steel, Mould Steel
AISI, DIN, JIS, GB
100% UT Passed
Take the advanced melting process for smelting and refining to get
the super purified and homogeneous steels.
Take the advanced 3D forging technology to thinning the structure;
eliminate the internal defect like shrinkage cavity and porosity;
break the big-sized carburization and reduce the band segregation.
It is helpful to reduce the discrepancy in the different directions
of the steel.
Take the advanced Super-fining heat treatment technology to get the
small grain size and homogeneous structure.
Take the strict inspection for each piece of steel products
according to the most advanced standard. Ensure our customers use
the steels with excellent and stable quality.
◆ Chemical Composition (%)
◆ Delivery Condition
EAF+LF+VD+ESR, Forged, Spheroidizing Annealed, Hardness≤200HB,
Black surface or Machined surface, UT 100% Passed
◆ Physical Property (Q+T to be 45HRC)
◆ Mechanical Property (Room temperature, S-T direction)
Tensile Strength (Rm)
Yield Strength (RP0.2)
Reduction of Area(ψ)
◆ Heat Treatment
Heating steels upto 850℃ in protective atmosphere; after soaking,
then have cooling in the furnace at the rate of 10℃/hr; after
temperature comes down to 650℃, finally have air cooling.
Stress Relieving should be done on the die after rough machining,
heating upto 650℃, heat preservation for 2 hours; Slow cooling down
to 500℃, further air cooling.
Refer to Hardening Diagram,
Preheating in two steps as per A: 650℃ and B: 850℃.
In case preheating in three steps, 2nd step B: 820℃, 3rd step use 900℃.
Austenization as per C: 1020-1030℃
Direct cooling as per D, or Sectionalized cooling as per F:500-550℃
Hardening Diagram Tempering Diagram
Refer to Tempering Diagram. Choose the proper tempering temperature
for required hardness.
For die casting mould, temper at least 3 times.
For hot forging die and extrusion die, temper at least 2 times.
After tempering, it must need cooling down to room temperature.
Holding time for tempering is 2 hours min..
Tips: To avoid the temper brittleness, don’t temper in 500-550℃.
Hardness: HRC Residual Austenite %
Tempering Temperature (2h+2h) ℃
1. Holding time means the duration of die steel from total heating
2. During hardening process, steel must be heated to avoid
oxidation or decarburization.
3. Steels need to be tempered immediately when temperature gets
down to be 50-70℃.
4. To get excellent property for the die, the quenching speed
should be as fast as possible,
but should avoid the case of being out of shape or cracks.
If you need more details, please refer to “Heat Treatment Manual”
or consult us.
◆ Quenching Holding Time and Thickness
◆ Product Application
|Industry||Features||Steel Grade Recommendation|
|Die Casting||Die Casting is a kind of metal casting technique. It is
characterized by using the mould cavity to have high pressure on
molten metal. It has the good performance in anti heat cracking,
anti corrosion, anti-crack, red hardness.|
|Hot Extrusion||Before extrusion, heat the metal over temperature of
recrystallization. It has the good strength at high temperature,
high ductility and good toughness, high thermal fatigue resistance
and thermal wear resistance, as well as the anisotropic properties
|Hot forging is a kind of processing under the condition of over the
temperature of recrystalization. It has the good thermal wear
resistance, heat intensity, high ductility and good toughness, high
|Hot Stamping||Hot Stamping is the rapid molding in the mould blank and hardening
heat. It has the good thermal conductivity, hot bending strength,
high toughness and ductility.|
|Injection Molding||Injection molding is a kind of forming process of injection and
molding at the same time. It has the high polishability, good
corrosion resistance, wear resistance, anti-cracking and thermal
|Compression Molding||Compressing Molding is a process of solidifying the thermosetting
plastics through heating and pressing. It is usually used for
plastic molding with reinforced glass fiber. It has the good wear
resistance, strength, hardness and corrosion resistance.|
|Blow Molding||Blow Molding is a process blowing the raw materials in the closed
mould to be the hollow products by gas pressure. It has the medium
strength and wear resistance, good thermal conductivity and
|Extrusion Molding||Extrusion Molding is a kind of process making the heat plasticized
materials to be a specific profile though extrusion. It has the
medium strength, but high demand on corrosion resistance and wear
resistance. Nitridation is generally used for the mould of fiber