ThePipingMart Blog Grades SAE/AISI 6118 Steel Alloy (G61180) – Composition, Properties and Uses

SAE/AISI 6118 Steel Alloy (G61180) – Composition, Properties and Uses

SAE/AISI 6118 Steel Alloy

SAE/AISI 6118 steel is a low-alloy steel that has been used for decades in the automotive and aerospace industries. It offers a combination of good mechanical properties, ductility, and good corrosion resistance. It can be heat-treated and machined with care. When selecting the perfect steel alloy for any project, SAE/AISI 6118 steel is undoubtedly a great option. Also known as UNS G61180, this steel alloy is highly sought after due to its outstanding mechanical properties. What sets SAE 6118 and AISI 6118 apart from other steel alloys is their unique composition, which consists of high amounts of carbon, chromium, and molybdenum. This winning combination infuses the steel with strength, toughness, and wear resistance. Moreover, SAE-AISI 6118 steel is highly versatile and can be used in multiple applications. From heavy-duty machinery to automotive parts, its dependability and reliability have made it a preferred choice for various industries. This blog post will look at the different uses, corrosion resistance, heat resistance, heat treatment, machining, and welding of SAE/AISI 6118 steel alloys.

What Forms of AISI 6118 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 6118 Composition

Element Weight %
C  0.16-0.21
Mn  0.50-0.70
P  0.035 (max)
S  0.04 (max)
Si  0.15-0.30
Cr  0.50-0.70
V  0.10-0.15

AISI 6118 Physical Properties

Quantity Value Unit
Thermal expansion 16 – 17 e-6/K
Thermal conductivity 16 – 16 W/m.K
Specific heat 500 – 500 J/kg.K
Melting temperature 1370 – 1400 °C
Service temperature 0 – 500 °C
Density 8000 – 8000 kg/m3
Resistivity 0.7 – 0.7 Ohm.mm2/m

AISI 6118 Mechanical Properties

Properties  Conditions
T (°C) Treatment
Density (×1000 kg/m3) 7.7-8.03 25
Poisson’s Ratio 0.27-0.30 25
Elastic Modulus (GPa) 190-210 25

AISI 6118 Thermal Properties

Properties Conditions
T (°C) Treatment
Thermal Conductivity (W/m-K) 42.7 100
Specific Heat (J/kg-K) 477 50-100

AISI 6118 Uses

SAE/AISI 6118 is often used in the automotive industry for components such as engine blocks and cylinder heads. It is also used in aerospace applications where strength and weight are important considerations. This material can be found in aircraft engine parts such as turbine blades or housings for hydraulic actuators.

AISI 6118 Uses in Industries

Construction Industry

AISI 6118 steel is commonly used in construction due to its high strength and durability. It is often used to construct buildings, bridges, and other structures that require strong and reliable materials. Its high tensile strength makes it ideal for withstanding heavy loads and harsh weather conditions.

Automotive Industry

The automotive industry also utilizes AISI 6118 steel in the manufacturing of vehicles. This type of steel is commonly used to produce car frames, chassis, and other structural components. Its high strength-to-weight ratio makes it popular for improving fuel efficiency and overall vehicle performance.

Aerospace Industry

In the aerospace industry, AISI 6118 steel is used for aircraft structures such as wings, fuselages, and landing gear. Its ability to withstand extreme temperatures and high stress levels makes it an essential material for ensuring the safety and reliability of aircraft.

Machinery Industry

Many types of machinery, including agricultural equipment, mining machinery, and industrial machinery, rely on AISI 6118 steel for construction. Its toughness and resistance to wear make it suitable for use in heavy-duty equipment that operates under harsh conditions.

Manufacturing Industry

In addition to its uses in specific industries, AISI 6118 steel is widely used in manufacturing processes such as forging, welding, machining, and heat treatment. Its versatility allows it to be formed into different shapes and sizes depending on the needs of a particular project or product.

AISI 6118 Corrosion Resistance

The alloy provides good corrosion resistance when exposed to salt water or other corrosive environments. However, it should not be exposed to alkaline solutions due to its susceptibility to pitting corrosion. The addition of chromium increases its overall corrosion resistance making it an ideal choice for marine applications such as propellers or shafts.

AISI 6118 Heat Resistance

SAE/AISI 6118 steel has excellent high-temperature creep strength making it suitable for applications where elevated temperatures are common. The alloy has a melting point of 1403°C (2550°F), which allows it to resist high temperatures without softening or becoming brittle like other materials would at higher temperatures. This makes it perfect for parts that need to maintain their structural integrity even when exposed to extreme temperatures over long periods of time.

AISI 6118 Heat Treatment

SAE/AISI 6118 can be heat-treated in order to improve its mechanical properties, such as ductility and yield strength. The most common way to do this is through austenitizing followed by quenching and tempering processes at specific temperatures depending on the desired outcome. Heat treating this alloy results in an increase in hardness which can help increase wear resistance but also decreases ductility making it more prone to cracking under stress, so care must be taken during this process.

AISI 6118 Machining

Due to its high strength level, machining this alloy requires slower speeds than other materials such as aluminium or brass alloys but still produces satisfactory results when done correctly using appropriate cutting tools such as carbide tipped tools with positive rake angles and slow feed rates between 0.1 – 0.2mm per revolution along with heavy cutting fluids if necessary.

AISI 6118 Welding

Welding this alloy is possible with the correct process parameters, but care must be taken due to its tendency towards crack formation under stress during welding, so preheating prior to welding is recommended, along with post-weld stress relief processes if necessary. Good joint strength can be achieved by using shielded metal arc welding (SMAW) processes with low hydrogen electrodes, along with manual gas tungsten arc welding (GTAW) using argon shielding gas.


As you can see from the information above, there are many advantages associated with using SAE / AISI 6118 steel alloy, which makes it suitable for many different applications ranging from automotive components such as engine blocks and cylinder heads all the way up through aerospace components like turbine blades or housings for hydraulic actuators due its combination of good mechanical properties, ductility, corrosion resistance, heat resistance, easy machinability, weldability, and ease of heat treatment. All these factors make SAE / AISI6 118 a great choice when looking for a strong, lightweight material that will hold up over time, even when subjected to extreme temperature variations. So if you’re looking for an alloy that will stand up against wear & tear while remaining cost-effective, then look no further than SAE / AISI6118!

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