1.Specification of aisi 4340

       Round bar 

Diameter(mm)

Length (mm)

10~300

2000~5800

         Plate

Thickness(mm)  

Width (mm)       

Length (mm)    

20~70

105~610

2000~5800

The specification can be customised!

2.Chemical compositon of aisi 4340

NO.

C

Mn

Si

Cr

Mo

Ni

P

S

aisi 4340

0.38~0.43

0.60~0.80

0.15~0.35

0.70~0.90

0.20~0.30

1.65~2.00

≤0.035

≤0.040

3. Mechanical properties of aisi 4340

Tensile str. (N/mm2)

Yield point (N/mm2)

                Elongation (%)

              Hardness

               980

835

                          12

269 

4.Heat treatment of aisi 4340

1. Forging:Heat slowly and uniformly to 1000°C. After forging cool slowly.

2. Annealing: 780-800`C slow cooling

5.Characteristic of aisi 4340

(1)Good purity and homogeneity.

(2) Good machinability (Roughing, grinding and drilling).

(3) Good dimensional stability during heat treatment.

(4) Excellent preparation for nitriding, both ionic and gaseous, induction hardening to increase the mechanical properties.

6.Application of aisi 4340

(1)It is widely used in high-strength forgings, such as traction gear, supercharger drive gear,  rear axle, the load of connecting rod, spring clip; 

(2)It also manufactured tool joints and finish tools which used for oil wells below 2000m deep.

Hot work tool steel

DIN

1.2344,1.2343,1.2365,1.2581,1.2367,1.2713 etc.

AISI

H13,H11,H10,H21, etc.

JIS

SKD61,SKD6,SKD5,SKT4 etc.

Cold work tool steel

DIN

1.2601,1.2379,1.2080,1.2363,1.2842,1.2419,1.2510,1.2550,1.2767 etc.

AISI

D2,D3,D5,D6,D8,A2,O2,O1 etc.

JIS

SKD1,SKD11, SKS3 etc.

Plastic mould steel

DIN

1.2083,1.2311, 1.2316,1.2738 etc.

AISI

P20, P20+Ni, 420 etc.

JIS

NAK80

High speed tool steel

DIN

1.3355,1.3343

AISI

T1,M2,M35,M42

JIS

SKH2,SKH51

Structural alloy steel

DIN

1.7225,1.6511,1.7035,1.7220

AISI

4,140,434,051,404,130

JIS

SCM440