4150 Steel: Uses, Composition, Properties
4150 alloy steel, also known as AISI 4150 or SAE 4150, is a steel alloy with a chemical composition of primarily iron (96.75%–97.67%), carbon (0.48%–0.53%), chromium (0.80%–1.10%), and molybdenum (0.15%–0.25%), among other elements. Its chemical composition makes 4150 steel an ideal material for use in the aerospace, automotive, defense, and oil & gas industries. This article will review 4150 alloy steel and discuss its uses, composition, and properties.
What Is 4150 Alloy Steel?
4150 alloy steel is a steel alloy that contains carbon, chromium, and molybdenum to strengthen the material. Other elements such as: manganese, silicon, sulfur, and phosphorus complete the 4150 alloys. 4150 steel is known for its high tensile and yield strength, hardness, machinability, formability, and wear resistance. While it is commonly known as simply 4150 alloy steel, it is often sold under the name AISI/SAE 4150. To learn more, check out our guide on Carbon Metals.
What Is 4150 Steel Used For?
4150 steel is used for applications that require high strength, hardness, and wear resistance. There are several uses of 4150 steel across several industries. The industries in which 4150 steel is used and its associated applications are shown in the list below:
- Often used in the aerospace industry for parts in jet engines, exhaust ducts, landing gear, and fuel tanks.
- Used for pipelines and structural components in the oil & gas industry.
- Used in the automotive industry to make shafts, gears, and sprockets for engine and transmission applications.
- Firearm barrels and parts for military vehicles and aircraft often make use of 4150 alloy steel.
- Used to create shafts for power transmission applications, axles, gears, sprockets, and spindles.
How Is 4150 Steel Made?
The process of making 4150 steel begins with iron ore that is melted in a blast furnace or electric arc furnace to create pig iron. While held in the furnace, oxygen is injected throughout the molten metal to remove excess carbon and other impurities from the iron. Once the correct carbon concentration is achieved in the molten iron, 4150 alloying elements such as chromium, manganese, and molybdenum, among others, are added. Then, the molten 4150 alloys are cast into ingots, billets, or bars. From there, various forming processes like rolling or extruding can be used to make sheets, plates, wires, bars, and more.
What Is the Chemical Composition of 4150 Steel?
The chemicals that comprise 4150 steel include iron (96.75%–97.67%), carbon (0.48%–0.53%), and chromium (0.80%-1.10%), among other elements. Table 1 below shows the chemical composition of 4150 steel in more detail.
| Element | Chemical Composition (%) |
|---|---|
Element Carbon | Chemical Composition (%) 0.48–0.53 |
Element Chromium | Chemical Composition (%) 0.80–1.10 |
Element Manganese | Chemical Composition (%) 0.75–1.00 |
Element Silicon | Chemical Composition (%) 0.15–0.30 |
Element Molybdenum | Chemical Composition (%) 0.15–0.25 |
Element Sulfur | Chemical Composition (%) 0.04 |
Element Phosphorus | Chemical Composition (%) 0.035 |
Element Iron | Chemical Composition (%) Remainder |
What Is the Carbon Content of 4150 Steel?
The carbon content of 4150 steel can range between 0.48% to 0.53%.
What Are the Properties of 4150 Steel?
4150 steel has several properties that make it desirable for a wide range of applications. The properties of a commonly treated 4150 steel are described in Table 2 below:
| Property | Description |
|---|---|
Property Density | Description 7.85 g/cm3 |
Property Yield Strength | Description 380 MPa |
Property Hardness | Description 197 HB |
Property Magnetic | Description Yes |
Machinability Rating of 4150 Steel
The machinability rating of 4150 steel is 55%. This value is based on annealed and cold-drawn 4150 steel.
What Are the Thermal Properties of 4150 Steel?
The thermal properties of 4150 steel are similar to other 4000 series steel alloys. The thermal properties of 4150 steel are shown in Table 3 below:
| Property | Description |
|---|---|
Property Thermal conductivity | Description 44.5 W/mK |
Property Specific heat | Description 0.475 J/g-°C |
Property Melting point | Description 1,427 °C |
What Are the Common Forms of 4150 Steel Material?
4150 alloy steel, like other types of steel, is available in a variety of shapes that are ideal for different applications. While the different shapes may have different physical characteristics, properties, and microstructures, their chemical compositions are the same. The common forms of 4150 steel alloy are listed below:
Sheet
4150 sheets are thin, flat, and rectangular and have a broader aspect ratio than other shapes like bars. 4150 sheets are made from 4150 ingots or slabs that are heated above the crystallization temperature, rolled into thin plates, and then annealed to add extra strength and malleability. While 4150 sheets and 4150 plates are similar, sheets are thinner and can range anywhere between 0.1 to 6 mm in thickness. Sheets are the most flexible option out of all the 4150 shape offerings but are often only used for lighter applications that are not highly load-demanding.
Bar
4150 bars often come in rectangular and circular varieties but can also come in square, hexagonal, or hollow bars. 4150 bars are made from rolling, extrusion, or casting processes and are often used in machining processes for the fabrication of parts. Bar stock is noticeably stronger than sheets due to its geometry, but also due to various forming processes like hot rolling or cold drawing.
Plate
4150 plates are similar to 4150 sheets but thicker. 4150 plates are created similarly to sheets and are fabricated by rolling steel until the desired thickness is obtained. The plate is then cut to the desired length and width. The thickness of 4150 alloy steel plates ranges between 6 and 25 mm. Welding and plasma cutting are two processes commonly used when fabricating 4150 plates for parts or assemblies.
Hot Rolled
Hot rolling is a process that involves heating a metal above its recrystallization temperature and plastically deforming it by rolling it between two rollers. The process reduces the cross-sectional area of the part and causes atoms to dislocate within the microstructure. The dislocation of atoms results in a stronger and harder metal compared to non-hot-rolled metal. Hot-rolled 4150 steel is commonly available in rectangular and round bars.
Annealed
Annealing is a heat treatment process that involves heating 4150 steel to a temperature higher than its recrystallization temperature and then cooling it to room temperature. Annealing causes the atoms in the 4150 steel’s microstructure to rearrange within the crystal lattice structure and reduces the number of dislocations. As it cools, the material recrystallizes, becomes more ductile, and reduces hardness. Annealed 4150 steel is commonly used in applications that require ductile, but strong materials.
Cold-Drawn
Cold drawing is the process of permanently elongating a material at room temperature to strengthen it. This is normally completed by forcing the material through an extrusion die. Strengthening occurs due to the dislocation of atoms within a material’s crystal lattice structure. Cold drawing is often completed after annealing, but can also be a standalone process to strengthen 4150 steel.
What Are the Equivalents of 4150 Steel?
Many types of steel are equivalent to 4150 steel. Table 4 shows the types of steel that are equivalent to 4150 steel based on the country or region in which the steel is used:
| Country standard | Equivalent grade |
|---|---|
Country standard USA | Equivalent grade AISI/SAE 4150 |
Country standard France | Equivalent grade 50CrMo4 |
Country standard Germany
(W-nr) | Equivalent grade 1.7228 |
Country standard UK | Equivalent grade 708A47 |
Table Credit: https://www.maford.com/SiteContent/Documents///MAFord_2018_Master_Catalog_Material_Conversion_Chart.pdf
What Are the Advantages of Using 4150 Steel?
Using 4150 steel comes with many advantages. The advantages of using 4150 steel are listed and described below:
- Has high tensile strength due to the higher concentrations of molybdenum and chromium in its composition.
- Has high hardness due to its carbon concentration, alloying elements, and heat treatment processes used before the commercial sale. High hardness enables 4150 steel to have higher wear resistance which is ideal for highly abrasive environments.
- 4150 steel is still highly machinable. This makes 4150 alloy steel widely used in a variety of industries and applications. 4150 steel can easily be machined by a CVD-coated carbide tool.
- Has high fatigue resistance which makes it great for applications in which loads are constantly applied and removed. Because of its fatigue resistance, 4150 steel is often used in power transmission applications in the automotive and aerospace industries and barrels for firearms.
What Are the Disadvantages of Using 4150 Steel?
Despite its advantages, using 4150 alloy steel also comes with disadvantages. The disadvantages of 4150 steel are listed below:
- Is costlier than other steels like 4140. This is because there are more involved processes used to create 4150 alloy steel. Additionally, purchasers of 4150 steel often pay a higher premium due to the material’s numerous desirable properties such as high tensile strength, fatigue resistance, hardness, and machinability.
- Like other steels, 4150 is heavy—denser than other metals and alloys like copper, aluminum, and titanium. While 4150 alloy steel is strong, it is not ideal for applications in which product weight is critical.
- 4150 steel, like all ferrous alloys, is susceptible to corrosion without proper surface treatment. Reducing the corrosion potential of 4150 steel may incur higher costs due to the addition of extra processes.
What Is the Difference Between 4150 Steel and 416R Stainless Steel?
4150 alloy steel and 416R steel are two types of steel that are commonly used in the firearms industry. In the industry, 4150 steel is coveted for its thermal stability and abrasion resistance which enables longer life for gun barrels. Whereas 416R steel is a stainless steel alloy formulated specifically for firearm barrels. It is valued for its thermal stability across a wide temperature range and its formability despite its high hardness.
What Is the Difference Between 4150 Steel and 4140 Steel?
4150 steel and 4140 steel are two types of steel that are commonly compared due to their similar properties. Despite their similarities, there are some noticeable differences between the two. The biggest difference between 4150 steel and 4140 steel is that 4150 has higher strength and hardness while 4140 has higher ductility and easier formability. When deciding whether 4150 or 4140 is better for an application, consider the loads that will be experienced by the part and the environment in which the part will be used.
Summary
This article presented 4150 steel, explained what it is, and discussed its composition and properties. To learn more about 4150 steel, contact a Xometry representative.
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