SCM440
Alloy Steel
SCM440 is medium carbon chromium molybdenum alloy steel, which is an alloy steel containing chromium and molybdenum. It has the advantages of stable composition, low harmful elements, high steel purity, small decarburization layer and few surface defects. It is easy to be spheroidized and has low cold cracking rate. It is usually hardened and tempered. The ultimate tensile strength is 850-1000 Mpa. This material achieves a very good balance between strength, toughness and wear resistance. The chromium content of the alloy provides good hardness permeability, and the molybdenum element imparts average hardness and high strength.
SCM440 reacts well in heat treatment and it is easy to process under heat treatment conditions. This material provides many desirable properties such as good strength and wear resistance, excellent toughness, good ductility and resistance to high-temperature stresses.
Chrome alloy structure steel
Purpose
SCM440 are widely used in high toughness alloy structural steel.
Product Features:
1. High strength and toughness.
2. Great property of quenching and can be deep hardened.
3. Less tempering brittleness tendency.
4. Great machining performance under high temperature and nice appearance after machining.
5. Good performance in weld ability.
6. Excellent performance in impact absorption, such as where the hammer may bounce back and has barely any damage caused upon impact.
International Comparison of Materials
| EU EN | INTER ISO | USA AISI | JAPAN JIS | GERMANY DIN | CHINA GB | FRANCE AFNOR |
|---|---|---|---|---|---|---|
| 42CrMoS4 42CrMo4 | 42CrMo4 | 4140 4142 | SCM440 | 42CrMo4 | 42CrMo | 42CD4 42CD4u |
| ITALY UNI | SPAIN UNE | Sweden SS | Finland SFS | Russia GOST | England BS |
|---|---|---|---|---|---|
| 42CrMo4 | 40CrMo41 40CrMo4 F1252 | 2244 | 42CrMo4 | 35KHM 38KHM | 708M40 CFS11 |
**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)
| C(%) | Si(%) | Mn(%) | P(%) | S(%) | Cr(%) | Mo(%) | Ni(%) | Cu(%) |
|---|---|---|---|---|---|---|---|---|
| 0.38-0.43 | 0.15-0.35 | 0.6-0.85 | 0≦0.03 | 0≦0.03 | 0.9-1.2 | 0.15-0.3 | 0≦0.25 | 0≦0.3 |
Conditions of heat treatment
- Annealing: 830℃ Furnace Cooling
- Normalization: 830~880℃ Air Cooling
- Hardening: 830~880℃ Oil Cooling
- Tempering: 530~630℃ Rapid Cooling
Criterion for heat treating conditions revise:
- Ac: 750~790℃
- Ar: 740~690℃
- Ms: 310℃
Mechanical properties
Tensile strength (kgf/mm2): ≧100
Yield strength (kgf/mm2): ≧85
Elongation (%): ≧12
Cross section reduction rate (%): ≧45
Impact value (J/cm2): ≧6
Hardness (Hb) : 285~352
Size Range
| Shape | Size(mm) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Round Bar | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 24 | 25 |
| 26 | 28 | 30 | 32 | 34 | 36 | 38 | 40 | 42 | 44 | 45 | 46 | |
| 48 | 50 | 55 | 60 | 65 | 70 | 75 | 85 | 90 | 95 | 100 | 105 | |
| 110 | 115 | 120 | 130 | 135 | 140 | 145 | 150 | 160 | 170 | 180 | 190 | |
| 200 | 210 | 220 | 230 | 240 | 250 | 260 | 270 | 280 | 290 | 300 | 315 | |
| 325 | 335 | 345 | 355 | 365 | 375 | 385 | 395 | 405 | 415 | 425 | 435 | |
| 445 | 455 | 465 | 475 | 485 | 495 | 505 | 515 | 525 | 535 | 545 | 555 | |
| 565 | 575 | 585 | 595 | 605 | ||||||||
- Steel Application
Gear
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.
Drive Shafts
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.
Bearing Shaft
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.
Cutting Tools
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.
Worm Shafts
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.
Machine Parts
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.