20Cr4 alloy structure steel

PRODUCT NAME :Alloy structure steel round bar ( forged ,rolled )
STANDARD:
GB/T3077-1999 EN10083-1 EN10083-3 ISO 683-1
GRADE COMPARISION:

ULTRASONIC STANDARD:
GB/T6402-2008 / SEP921-84. ASTM A388
CHEMICAL COMPOSITION:

MANUFACTURING TECHNIQUE:
EFA+LF+VD(ESR)+ hot forged (hot rolled )
HEAT TREATMENT SPECIFICATION AND MECHANICAL PROPERTIES:

The first time quenching temperature (℃):880;coolant : water / oil  

The second time quenching temperature (℃):780~820;coolant :oil / water 

Tempering temperature (℃):200;coolant : water / air. 

Tensile strength :(σb/MPa):≥835

Yeild strength σs/MPa):≥540 

Elongation (δ5/%):≥10 

Reduction area :(ψ/%):≥40

Impact (Aku2/J):≥47 

DELIVERY CONDITION :ANNEALED
SURFACE : BLACK / GRINDING / PEELING
DIMENSION : mm
Forged round bar :dia 80-550mm
Rolled round bar :dia 16-250mm
Coild rod : dia 5.5-20mm
Wire : dia 0.2-13mm
Rolled flat bar :thickness 5-90× width 44-300mm
Forged flat bar:thickness 120-800×width 120-800
length : forged bar free length 4-5.8M,rolled bar 5.8M. for customers special requirment, the bar length can do 20 meters long.
Tolerance on diameter of forged bar : black surface -0/+5mm, peeled surface -0/+3mm.
REMARK:
Above listed parameters and sepcification only for reference . Specific parameters according to standard. Requirments beyond standard will be negotiate by both sides .
Delivery state:normalized ,annealed, spheroidal annealed, quenched & tempered ,bright bar, cold-drawn, etc. Should be indicated in contract .
Listed specifications are only typical grades; products of required specifications can be developed/produced per international, Chinese or industry standards, or based on agreements with customers.

Used for machine tool gearbox gear ,gear shaft , cam, worm, piston pin, claw clutch etc .