ThePipingMart Blog Grades SAE/AISI 4142 Alloy Steel (UNS G41420) – Composition, Properties and Uses

SAE/AISI 4142 Alloy Steel (UNS G41420) – Composition, Properties and Uses

SAE / AISI 4142 Steel

SAE/AISI 4142 steel is a high-quality alloy steel with good mechanical properties and various uses. UNS G41420 has a low carbon content and is often used in applications requiring higher toughness, strength, and wear resistance. SAE/AISI 4142 Alloy Steel (UNS G41420) is a high-quality steel widely used in various industrial applications. With a high carbon content and toughness, this steel has become a popular choice for manufacturing machinery parts, gears, shafts, and other critical components. Its chemical composition includes chromium, molybdenum, and manganese, which provide high strength and resistance to wear and fatigue. Additionally, SAE-AISI 4142 steel offers good weldability and machinability, making it easy to work. Overall, SAE/AISI 4142 Alloy Steel is a durable and reliable material that can handle tough conditions and demands. This blog post will discuss the uses, corrosion resistance, heat resistance, heat treatment, machining, and welding of 4142 Alloy Steel.

What Forms of AISI 4142 is Available at Piping Mart?

  • Nut
  • Bar
  • Bolt
  • Pipe
  • Screw
  • Tubing
  • Valves
  • Washers
  • Flanges
  • Fasteners
  • Electrodes
  • Stud Bolts
  • Sheet Plates
  • Pipe Fittings
  • Forged Fitting
  • Instrumentation Fittings

AISI 4142 Composition

Element Content (%)
Iron, Fe ≥ 96.725
Chromium, Cr 0.80-1.10
Manganese, Mn 0.75-1.10
Carbon, C 0.40-0.45
Silicon, Si 0.15-0.30
Molybdenum, Mo 0.15-0.25
Sulfur, S ≤ 0.040
Phosphorous, P ≤ 0.035

AISI 4142 Physical Properties

Properties Metric Imperial
Density 7.85 g/cm3 0.284 lb/in³

AISI 4142 Mechanical Properties

Properties Metric Imperial
Elastic modulus 190-210 GPa 27557-30458 ksi
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Hardness, Brinell (annealed and cold drawn) 187-229 187-229
Hardness, Knoop (converted from Brinell hardness) 230 230
Hardness, Rockwell B (converted from Brinell hardness) 94 94
Hardness, Rockwell C (converted from Brinell hardness, value below normal HRC range, for comparison purposes only) 15 15
Hardness, Vickers (converted from Brinell hardness) 218 218
Machinability (annealed and cold drawn, based AISI 1212 steel, as on 100 machinability) 65 65

AISI 4142 Thermal Properties

Properties Metric Imperial
Thermal conductivity 42.6 W/mK 296 BTU in/hr.ft².°F

AISI 4142 Equivalent

  • ASTM A322
  • ASTM A331
  • ASTM A505
  • ASTM A519
  • ASTM A547
  • SAE J404
  • SAE J412
  • SAE J770
  • ASTM A29
  • ASTM A372 (VIII)
  • ASTM A711
  • ASTM A752
  • ASTM A829
  • SAE J1397

AISI 4142 Uses

SAE/AISI 4142 steel is commonly used in automotive components such as gearbox housings, shafts, axles, and wheels; it is also used in agricultural equipment parts such as harrows blade holders, cultivator discs, and tines. It can also be used for machine components like camshafts and crankshafts.

AISI 4142 Uses in Industries

Automotive Industry

One of the most common uses of AISI 4142 steel is in the automotive industry. This type of steel is often used to make parts such as gears, shafts, and axles due to its high strength and wear resistance. It is also used in engine components, suspension systems, and other critical parts that require durability and toughness.

Aerospace Industry

AISI 4142 steel is also commonly used in the aerospace industry for its ability to withstand high temperatures and extreme conditions. It is often used to make aircraft landing gear, engine components, and other structural parts that must be strong and durable.

Construction Industry

AISI 4142 steel is often used for structural purposes in the construction industry due to its high yield strength and toughness. It can be found in bridges, buildings, cranes, and other heavy-duty structures that require a strong material capable of withstanding heavy loads.

Machinery Industry

Machinery manufacturers also rely on AISI 4142 steel for its versatility and reliability. Due to its excellent machinability and wear resistance, it can be used to make various machine parts such as gears, shafts, bearings, and couplings.

Tooling Industry

Lastly, AISI 4142 steel is widely used in tooling applications due to its hardness and abrasion resistance properties. It can be found in cutting tools such as drills, reamers, taps, and dies and moulds for plastic injection or die-casting processes.

AISI 4142 Corrosion Resistance

SAE/AISI 4142 steel offers great corrosion resistance due to its high chromium content (13-16%). The chromium forms a passive layer on the surface of the material that prevents corrosion from occurring. The addition of molybdenum (0.7-1%) further enhances the corrosion resistance of this alloy.

AISI 4142 Heat Resistance

SAE / AISI 4142 steel is renowned for its outstanding heat resistance, making it an ideal choice for applications that involve high temperatures. Thanks to its chromium and molybdenum content, this type of steel can maintain its strength even with prolonged exposure to temperatures as high as 600ºC. It has excellent tensile properties, too, so you can be sure the parts created using SAE / AISI 4142 won’t fail under pressure. This allows manufacturers in industries such as aerospace and automotive to create incredibly reliable components while reducing long-term costs associated with repairs or replacements.

AISI 4142 Machining

The machining of SAE / AISI 4142 is a process that requires extreme precision and attention. This hardened steel alloy is commonly used for automotive parts due to its high strength-to-weight ratio, so being able to create complex shapes and features is essential. The machining process consists of operations such as turning, drilling, reaming, broaching, tapping, and threading. Special attention must be given while cutting this alloy in order to achieve desired dimensions without compromising the material’s hardness. Additionally, cooling strategies must be carefully chosen to produce the best results with minimal waste. With the right expertise and equipment, machining SAE/AISI 4142 can be an exact science that yields superior-quality workpieces.

AISI 4142 Welding

Welding the Alloy AISI / SAE 4142 steel can be tricky, as it is considered low weldability. The alloy contains elements such as chromium and molybdenum, making it challenging to join through welding. Choosing a preheat temperature of 210°C or higher is an important step when welding 4142 steel, as this will reduce its risk of cracking while being formed. With the correct preheat temperature and correct welding techniques, 4142 steel can handle tougher applications because of its high fatigue strength rating. By getting these two steps right, welders can enjoy working with a durable alloy with a good machinability factor.


SAE / AISI 4142 steel is an incredibly versatile metal that can be used for numerous applications thanks to its excellent corrosion & heat resistance properties combined with its ease of machinability & weldability capabilities. While care must be taken when welding & machining this material due to its high carbon content preheating prior to welding & stress relief after welding are essential steps in order to prevent any cracking or distortion during these processes respectively, while filler rods must also carefully selected in order to match closely enough with regards regarding hardness & tensile strength levels with this alloy type.

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