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4140 Steel

4140 Steel is a versatile alloy that is widely used in a variety of industrial and manufacturing applications. Due to its high strength and hardenability, it is particularly well-suited for high-stress applications that require long-lasting durability. It is often used in the manufacturing of gears, shafts, heavy-duty machinery parts, and tooling.

4140 steel

4140 Steel at WMT

4140 Steel – used in the most demanding of applications in several industries.

4140 steel is a low alloy steel composed of chromium, molybdenum, and manganese. This composition gives the steel its high fatigue strength, torsional strength, abrasion resistance, and toughness, making it ideal for a wide range of applications.

Its high fatigue strength allows it to withstand repeated stress without failure, making it suitable for high-stress parts and components. Its torsional strength allows it to resist twisting and turning, making it suitable for shafts and gears. Its abrasion resistance makes it suitable for heavy-duty machinery parts and equipment. Its toughness makes it resistant to impact and wear, making it suitable for high-stress parts and components that require long-lasting durability.

At Wisconsin Metal Tech, we supply AISI 4140 for many applications. Contact us for the most competitive prices. We are committed to providing our customers with high-quality 4140 steel that meets their specific needs and requirements. Our team of experts will work with you to ensure that you get the right product at the right price.

4140 Properties and Specifications

4140 steel is a chromium-, molybdenum-, and manganese-containing low alloy steel. It has high fatigue strength, abrasion and impact resistance, toughness, and torsional strength.

  • 4140 steel hex bar has an unpolished surface with standard tolerance.
  • SAE 4140 grade is low-alloy steel that contains chromium and molybdenum as strengthening agents.
  • Its characteristics include high strength and good machinability and can be heat treated for higher hardness.
  • This steel alloy is very versatile and has good atmospheric corrosion resistance and maintains its strength up to 600º F.
  • Readily machinable.
  • Simple shapes are easily machined following a normalizing treatment while more complex shapes may require annealing.
  • This steel grade’s carbon level may require a structure of coarse lamellar pearlite to coarse spheroidite for optimum machinability.
  • Heat treatment allows for a higher hardness and renders the steel suitable for machining.
  • There are several ways to heat treat a given steel part, Wisconsin Metal Tech’s steel specialists have many years of experience with this process.
  • Forgings may be annealed by transferring parts from forge to a furnace held at a suitable temperature before furnace cooling.
  • This heat treatment is best used for parts with simple shapes.
  • Normalizing heats the 4140 to a temperature above the ferrite to austentite transformation range before cooling it in the air to a temperature below the transformation range.
  • This is often performed as a conditioning treatment before final heat treatment.
  • Hardening results in the formation of martensite after quenching, to produce a greater hardness and tensile strength with some loss of ductility.
  • Should be austenitized at 1500º to 1550º F.
  • Often, tempering is then carried out to relieve stresses from the hardening process and primarily used to bring the 4140 to its required properties.

What is 4140 Steel

4140 steel is a high-strength, low-alloy steel that contains chromium, molybdenum, and manganese. It is known for its toughness, strength, and high hardenability, making it suitable for a wide range of applications. It is often used in the manufacturing of gears, shafts, heavy-duty machinery parts, and tooling. Additionally, it can also be heat-treated to increase its strength and hardness, making it an ideal choice for high-stress applications.

One of the great characteristics of 4140 is that it can be heat-treated to increase its strength and hardness, making it an ideal choice for high-stress applications that require long-lasting durability.

The heat treatment process can be done in a variety of ways, such as quenching and tempering, to achieve the desired properties.

History of 4140 Steel

4140 steel is a high-strength, low-alloy steel that was first developed in the 1920s. The steel was created by adding chromium and molybdenum to improve its hardenability and strength. It was originally used for a variety of industrial applications, such as gears, shafts, and heavy-duty machinery parts.

During World War II, the demand for 4140 steel increased as it was widely used in the manufacturing of weapons and military equipment. After the war, it continued to be used in a variety of industries, including oil and gas, automotive, aerospace, and construction.

In the 1970s, the steel was modified by adding small amounts of other elements such as manganese, nickel and copper which improved its toughness and ductility, making it even more suitable for high-stress applications.

Uses for 4140 Steel

AISI 4140 remains a popular choice for a wide range of industrial and manufacturing applications. Its combination of strength, toughness, and hardenability make it an ideal choice for high-stress parts and components that require long-lasting durability.

Heavy Machinery Gears

AISI 4140 is used in the manufacturing of gears. It is particularly useful in high-stress applications such as in heavy machinery and equipment. The hardenability of 4140 steel makes it resistant to wear and tear, and able to withstand high stress.

High Strength Shafts

4140 steel is also used in the manufacturing of shafts. Its high strength and hardenability make it suitable for shafts that are subject to high stress and wear. Its toughness ensures that it can withstand the high loads and impact forces.

Heavy-Duty Machinery Parts

4140 steel is often used in the manufacturing of heavy-duty machinery parts, such as those found in mining and construction equipment. Its high strength and hardenability make it suitable for parts that are subject to high stress and wear.

For High-stress Tooling

AISI 4140 is used in the manufacturing of tools and dies, due to its excellent machinability and ability to hold a sharp edge. The steel’s high strength and hardenability make it suitable for tools that are subject to high stress and wear.

Automotive Components

AISI 4140 is used in the automotive industry for items such as gears and shafts, due to its excellent strength and hardenability. Its toughness makes it suitable for high-stress parts that are subject to wear and tear.

Aerospace Structural Parts

Popular in the aerospace industry for structural parts, such as landing gear and engine mounts. Its high strength-to-weight ratio and excellent fatigue resistance make it suitable for these high-stress applications.

Construction Equipment

AISI 4140 is typically used in the construction industry for heavy equipment and machinery, such as excavators, bulldozers, and cranes. Its high strength and durability make it suitable for these heavy-duty uses.

For the Defense Industry

4140 steel is also used in the defense industry for weapons and equipment, such as tanks, artillery, and small arms. Its high strength and toughness make it suitable for these high-stress, high-performance applications.