Equivalent Grades: GB 40CrNiMoA, 45CrNiMoVA, JIS SNCM439, and ASTM 4340, 9840. SNCM439 is a kind of refining steel and has the properties of high hardness and toughness. It is often used for the manufacture of screws, gears, shafts, nuts, pistons, the automobile parts required high toughness and so on.
A low alloy steel containing nickel, chromium and molybdenum
SNCM439 is widely used in high toughness alloy structural steel.
International Comparison of Materials
**This comparison table is for reference only. The standards and grades of various countries have slightly different chemical compositions. Please refer to the database for details.**
Chemical Composition(JIS G4051)
Conditions of heat treatment
- Annealing: 820℃ Hot Annealing, 670℃ Cold Annealing
- Normalization: 820~870℃ Air Cooling
- Hardening: 820~870℃ Oil Cooling
- Tempering: 580~680℃ Water Cooling
Criterion for heat treating conditions revise:
- Ac: 730~775℃
- Ar: 710~655℃
- Ms: 285℃
Tensile strength (kgf/mm2): ≧100
Yield strength (kgf/mm2): ≧90
Elongation (%): ≧16
Cross section reduction rate (%): ≧45
Impact value (J/cm2): ≧7
Hardness (Hb) : 293~352
|Round Bar||16, 19, 22, 25, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250.|
- Steel Application
There are many types of gear, such as: spur gear, sprocket, pulley, helical gear, internal gear, rack, straight bevel gear, spiral bevel gear, zero bevel gear, screw gear, worm gear, hypoid gear…etc. A gear should be made by the material which has a high flexural fatigue strength and contact fatigue strength, sufficient hardness, and wear resistance, and toughness.The materials of gear we recommend are as below.
Machine Tool Spindle
A machine may have several spindles. Varieties of spindles include grinding spindle, electric spindle, low-speed spindle, high speed spindle, engraving spindle, milling spindle, turning spindle and more. The spindle should be made by the material with the highest, stability, rigidity and efficiency.The materials of spindle we recommend are as below.
To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or more universal joints, jaw couplings. Therefore, they must use the materials which are strong enough to bear the stress, whilst avoiding too much additional weight as that would in turn increase their inertia.The materials of drive shaft we recommend are as below.
A motor must have an axis which can drive the motor to produce the kinetic energy of equipment or device.The materials of bearing shaft we recommend are as below.
The types of cutting tools are diverse, such as: milling cutter, drill bit, circular saw blade, reamer, PCD (Polycrystalline Diamond) cutting tools, annular cutter, lathe cutting tool, punch cutting tool, etc. The material quality of woodworking cutting tool usually affects the surface performance of machining, efficiency, tool life, and other factors. Therefore, the material of woodworking cutting tool should have the high hardness, wear resistance, sufficient strength, toughness, heat resistance, etc.The materials of cutting tools we recommend are as below.
The friction between worm shaft and worm gear under work causes a lot of heat. High friction and high heat usually wear out the surface of tooth of worm shaft and worm gear. That is why worm shaft should use the materials which have wear resistance and high rigidity.The materials of worm shaft we recommend are as below.
There are three kinds of material type which are used for machining parts, metal material, non-metallic material, and composite. Also, there are two kinds of metal material, ferrous metal and un-ferrous metal. Ferrous metal material which includes steel, cast steel and cast iron has good mechanical properties (such as strength, ductility, toughness, etc.). The ferrous metal material is obtained easily and its price is cheap. Non-ferrous metal material which has the low density has the advantages of thermal conductivity and electric conductivity.The materials of machining parts we recommend are as below.