ThePipingMart Blog Grades SAE/AISI 5155 Alloy Steel (G51550) – Composition, Properties and Uses

SAE/AISI 5155 Alloy Steel (G51550) – Composition, Properties and Uses

SAE / AISI 5155

SAE/AISI 5155 steel is a medium-carbon, chromium and manganese alloy. It is a low-cost steel that can be machined, heat treated, and welded easily. Its high strength makes it great for applications such as springs, fasteners, and automotive components. SAE/AISI 5155 Alloy Steel, also known as UNS G51550, is a high-carbon steel alloy widely used in manufacturing various industrial parts and machinery. With its excellent strength, toughness, and wear resistance, 5155 steel is sought after by engineers and manufacturers worldwide. The composition of this steel includes elements such as chromium, molybdenum, and silicon, which all contribute to its exceptional properties. SAE-AISI 5155 steel is known for its outstanding fatigue resistance, making it ideal for high-stress applications in the automotive, aviation, and construction industries. As such, SAE 5155 and AISI 5155 steels are highly versatile and used for various applications, from springs and gears to heavy-duty components. This blog post will discuss the uses of SAE/AISI 5155, its corrosion resistance, heat resistance, heat treatment methods, machining methods, and welding techniques.

What Forms of AISI 5155 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 5155 Composition

Element Weight %
C  0.51-0.59
Mn  0.70-0.90
P  0.035 (max)
S  0.04 (max)
Si  0.15-0.30
Cr  0.70-0.90

AISI 5155 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 5155 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
Tensile Strength (Mpa) 1158 25 oil quenched, fine grained, tempered at 425°C
Yield Strength (Mpa) 1034
Elongation (%) 15
Reduction in Area (%) 53
Hardness (HB) 335 25 oil quenched, fine grained, tempered at 425°C

AISI 5155 Thermal Properties

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

AISI 5155 Uses

SAE/AISI 5155 steel can be used in a variety of applications due to its strength and flexibility. It is commonly used in automotive components such as axles and drive shafts due to its ability to withstand torsional loading. Additionally, it is used in tools such as wrenches because of its impact resistance and wear resistance properties. It can also be used for springs because it has strong fatigue properties, which allow it to stay elastic even after hundreds or thousands of cycles.

AISI 5155 Uses in Industries

Automotive Industry

AISI 5155, or 55Cr3 or 1.7176, is commonly used in the automotive industry for its high strength and wear resistance properties. It is often used to produce suspension and steering components, such as leaf springs, coil springs, and torsion bars.

Construction Industry

Due to its toughness and ability to withstand heavy loads, AISI 5155 is widely used in the construction industry. It is commonly used to manufacture crane hooks, gears, and other heavy-duty machinery parts.

Aerospace Industry

In the aerospace industry, AISI 5155 is utilized for its high fatigue strength and impact resistance. It often produces aircraft landing gear components, engine parts, and structural elements.

Oil & Gas Industry

The oil and gas industry uses AISI 5155 due to its high tensile strength and corrosion resistance properties. It is often used to produce drilling tools, valves, and other equipment that operates under extreme conditions.

Manufacturing Industry

AISI 5155 has various uses in various manufacturing processes due to its versatility and reliability. It can be found in hand tools, machine parts, and industrial springs due to its ability to withstand heavy loads without deforming or breaking.

AISI 5155 Corrosion Resistance

SAE/AISI 5155 steel has good corrosion resistance when exposed to normal atmospheric conditions. It has excellent pitting resistance. However, it may suffer from intergranular corrosion at elevated temperatures if not properly maintained. To protect against corrosion, it should be stored in a dry place that does not experience large temperature fluctuations or extreme humidity levels. Proper cleaning and maintenance will help ensure that this steel maintains its corrosion-resistant properties over time.

AISI 5155 Heat Resistance

SAE/AISI 5155 steel has good heat resistance when compared to other steels; however, it may suffer from oxidation at temperatures higher than 800°C (1472°F). Therefore, it should not be used for applications that require high temperatures, fire exposure, or extreme environmental conditions, such as chemical plants or refineries where corrosive agents are present.

AISI 5155 Heat Treatment

SAE/AISI 5155 steel can be hardened by heat treatment using either quenching or tempering techniques. Quenching involves heating the material up to 830°C (1526°F) followed by rapid cooling with water or oil baths; this results in higher hardness but lower ductility than tempering techniques, which involve heating the material up to 610°C (1130°F) followed by slow cooling with air or an oven until the desired hardness is achieved without exceeding the maximum hardness limit for the specific grade of material being treated. The most common type of heat treatment for SAE/AISI 5155 steel is quenching and tempering; however, other options are available depending on the application requirements, such as age hardening and case hardening processes, which impart different mechanical properties than those obtained through standard quench-and-temper treatments.

AISI 5155 Machining

Machining operations should always start with soft materials; before beginning any machining operations on SAE/AISI 5155 steel, ensure you anneal it first at around 700°C (1292°F). This will reduce tool wear from excessive cutting forces while increasing surface finish quality since hardened materials can lead to increased vibration during machining operations resulting in poor surface finish quality unless slower feed rates are employed, which increases tool wear even more due to increased cutting forces required for harder materials. Additionally, pre-machining processes such as drilling should always precede turning operations since drilling generates less cutting forces than turning, making them easier on both machine tools and cutting tools alike, thus reducing tool wear while improving surface finish quality during turning operations following drilling steps if they are necessary for your application requirements.

AISI 5155 Welding

Welding operations on SAE / AISI 555 should always begin with proper preheating procedures, especially when welding thicker sections; preheating helps reduce residual stresses caused by thermal expansion differences between welded parts which could cause distortion if not addressed before starting welding operations, so make sure you properly preheat your workpieces before starting any welding work on them otherwise you risk introducing cracks into your welded parts due to thermal shock from sudden temperature changes when starting welding operations without prior preheating procedures being performed first. Furthermore, proper post-weld cooling procedures must also be done after finishing all welding work; these include slow cooling with fans or coolant sprays depending on what type of joint was welded since some joints require slower cooling rates than others, so make sure you take note of these special circumstances before starting any welding work otherwise you risk introducing cracks into your welds due to uneven cooling rates across different parts leading them becoming brittle instead remaining ductile after post weld treatments have been done correctly otherwise.


Overall, SAE/AISI 5555 steel is a versatile material with excellent mechanical properties that make it ideal for various applications such as tools, springs, automotive components, and more. It has good corrosion resistance when exposed to normal atmospheric conditions but may suffer from intergranular corrosion at elevated temperatures if not properly maintained. It has good heat resistance, but higher temperatures may cause oxidation, so it will not hold up well in extreme environmental conditions. Proper heat treatment methods and machining operations will enable it to be formed in various shapes and dimensions, while slow-cooled welds will ensure that it retains its mechanical properties in all; SAE / AISI 555 steel is a great option for various applications due to both its economical price point and extensive mechanical and physical properties.

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