ThePipingMart Blog Grades AISI 4028 Alloy Steel (UNS G40280) – Composition, Properties and Uses

AISI 4028 Alloy Steel (UNS G40280) – Composition, Properties and Uses

AISI 4028 Steel

AISI (American Iron and Steel Institute) 4028 is a high-carbon steel alloy with 0.42% – 0.50% carbon content, making it one of the most commonly used steel grades in the United States. It’s resistant to corrosion and heat and can be machined with ease, making it an ideal choice for many applications. But what else do you need to know about UNS G40280? Let’s take a closer look at AISI 4028 versatile grade of steel.

AISI 4028 Chemical Composition

Element Content (%)
Iron, Fe 98.07 – 98.67
Manganese, Mn 0.70 – 0.90
Carbon, C 0.25 – 0.30
Molybdenum, Mo 0.20 – 0.30
Silicon, Si 0.15 – 0.35
Sulfur, S 0.035 – 0.050
Phosphorous, P 0.035

AISI 4028 Physical Properties

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

AISI 4028 Mechanical Properties

Properties Metric Imperial
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Elastic modulus 190-210 GPa 27557-30458 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Hardness, Brinell 167 – 212 167 – 212
Hardness, Knoop (converted from Brinell hardness) 212 212
Hardness, Rockwell B (converted from Brinell hardness) 91 91
Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only) 11 11
Hardness, Vickers (converted from Brinell hardness) 199 199
Machinability (annealed and cold drawn. Based on 100 machinability for AISI 1212 steel) 75 75

AISI 4028 Thermal Properties

Properties Metric Imperial
Thermal conductivity (typical steel) 44.5 W/mK 309 BTU in/hr.ft.°F

AISI 4028 Equivalent

  • ASTM A322
  • ASTM A331
  • ASTM A519
  • SAE J404
  • SAE J412
  • SAE J770

AISI 4028 Uses

4028 Alloy Steel is a popular choice for a variety of applications due to its strength, durability, and versatility. It is often used for automotive parts such as axle shafts, crankshafts, gears, and other components. It is also widely used in aerospace and military applications where strength and heat resistance are essential requirements. Additionally, it can be used for industrial tools due to its high wear resistance, as well as agricultural equipment because of its corrosion-resistant properties.

Corrosion Resistance

AISI 4028 has good corrosion resistance when compared with other steels in the same class. It resists oxidation at temperatures up to 815°F (435°C). The alloy also exhibits excellent uniformity of structure when exposed to corrosive environments over time. This makes it ideal for applications operating in harsh conditions or exposed to salt water or other corrosive agents.

Heat Resistance

AISI 4028 has good heat resistance in comparison with other grades of steel in the same class. Its high carbon content helps protect against oxidation at elevated temperatures up to 815°F (435°C). The alloy also maintains good hardness levels when heated above 600°F (316°C), which makes it suitable for use in hot forging operations or high-temperature service applications such as furnace parts or turbine blades.

Heat Treatment

To achieve maximum mechanical properties from AISI 4028 steel, it needs to be heat treated before being put into service. The alloy should be heated slowly until it reaches 1550–1600°F (843–871°C), then held at that temperature before being cooled at a rate no faster than 50°F (10°C) per hour until the desired hardness level is achieved. After cooling, the part should immediately be tempered or quenched depending on the desired mechanical properties needed from the final product.


Due to its relatively low carbon content, AISI 4028 can be machined easily using conventional techniques such as turning and milling without any difficulty or special considerations needed during operation setup, like tool selection or cutting parameters adjustment. As an added bonus, the alloy does not require any post-machining treatments, such as stress relieving after the machining processes are complete.


In conclusion, AISI 4028 is an excellent material for many applications due to its versatility, durability, and strength. With proper heat treatment, it offers good corrosion resistance and machinability while being able to resist oxidation at temperatures up to 815 ° F(435 ° C ) . All these qualities make it an ideal choice for industries ranging from automotive manufacturing all the way through aerospace engineering so if you’re looking for a durable grade of steel with excellent thermal properties, consider giving AISI 4028 a try!

Related Post