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Alloy Steel 4140
Material Type
Metal
Material Name
Alloy Steel 4140
Alternative Names
G41400 | 1.7225 | EN19 | 42CrMo4 | AISI 4140 | SCM440
Process Compatibility
CNC Milling, CNC Turning
introduction
Alloy Steel 4140 in CNC Machining
Alloy Steel 4140, also known as chromoly steel, is a versatile low-alloy steel that contains chromium, molybdenum, and manganese.
Alloy Steel 4140 has good machinability in its annealed state, with high ductility for forming using conventional techniques. It can be more challenging to machine in its hardened state. We use high-speed steel or carbide tooling when machining. We ensure adequate cooling and lubrication to manage heat generated and extend tool life. In post-machining, we can apply heat treatment for desired hardness and mechanical properties.
It's weldable, but post-weld heat treatment is needed if welded in a heat-treated condition. The heat treatment involves heating at 845°C followed by quenching. Forging occurs at 926 to 1205°C, and hot working at 816 to 1038°C. Cold working is possible in the annealed condition. Annealing is done at 872°C, and tempering at 205 to 649°C based on desired hardness. Hardening can be achieved through cold working or heating and quenching.
Properties
Properties Table of Alloy Steel 4140
| MECHANICAL PROPERTIES | |
|---|---|
| Ultimate Tensile Strength | 355-370 MPa |
| Yield Strength | 230 MPa |
| Young's Modulus(Elasticity) | 208-216 GPa |
| Elongation at Break | 18-26 % |
| Physical Properties | |
| Corrosion Resistance | Moderate to Poor |
| Magnetism | Semi-Magnetic |
| Weldability | Excellent |
| Thermal Properties | |
| Maximum Service Temperature | 613-650°C |
| Thermal Expansion Coefficient | 11.5-13.5 x 10^-6/°C |
| Thermal Conductivity | 42-48 W/(m·°C) |
| Electrical Properties | |
| Electrical Resistivity | 20-25 μΩ*cm |
TECHNOLOGY OVERVIEW
Basic Knowledge of Alloy Steel 4140
What is Alloy Steel 4140?
Alloy Steel 4140 is a strong and versatile low alloy steel with high strength, toughness, and machinability. Its composition includes carbon, chromium, molybdenum, and manganese. Through heat treatment, it attains impressive strength and good toughness.
It has good wear resistance and the ability to withstand stress. Regarding the 4140 grade designation, 4 indicates it's molybdenum steel with more molybdenum than the 1xxx series. 1 signifies additional chromium compared to 46xx steel. Then, 40 distinguishes it within the 41xx series.
Advantages of Alloy Steel 4140
- High strength and toughness
- Excellent wear resistance
- Superior fatigue strength
- Good machinability
- Heat-treatable for increased hardness
- Versatile applications in automotive, aerospace, and manufacturing industries
Applications of Alloy Steel 4140
- Aircraft components: Landing gear, structural parts
- Automotive parts: Axles, crankshafts, connecting rods
- Oil and gas industry tools: Drilling equipment, downhole components
- Firearms: Gun barrels, receiver components
- General machinery: Gears, shafts, forged parts
FAQ
Machining Alloy Steel 4140 Buying FAQs
4140 alloy steel is not stainless; it is a low-alloy steel with high chromium content but lacks a sufficient amount of nickel to be considered stainless.
4140 steel is generally stronger than most stainless steel, especially in tensile and yield strength.
Disadvantages of 4140 steel include its susceptibility to cracking during welding and its limited weldability compared to other steels. Welding is best done on annealed material, requiring preheating, slow cooling, and subsequent heat treatment.
While 4140 steel has good corrosion resistance due to its chromium content, it can still rust under certain conditions.Proper care, maintenance, and the application of protective measures can help mitigate the risk of rust formation.
Other Materials
Alloy Steel 4340
Alloy Steel 4340 belongs to the AISI 4000 series of steels, a heat-treatable, low-alloy steel with high strength and toughness.
More info about Alloy Steel 4340
Alloy Steel 4130
Alloy steel 4130 is a versatile and widely used material in CNC machining, particularly in the aerospace and automotive industries.
More info about Alloy Steel 4130
Alloy Steel 1215
Alloy Steel 1215 is not a common alloy steel. It is a resulfurized and rephosphorized steel known as free machining steel.
More info about Alloy Steel 1215
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