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ASTM A519 4130 Seamless Pipe

4130 Chromoly

4130 is a Seamless  tubing, and is produced by using a extrusion or rotary piercing process. Chromoly is specified by the “SAE” Society of Automotive Engineers. the Alloy elements of 4130 are chromium and molybdenum,
this is why its often called chromoly  or cromo. Chromoly has an excellent strength to weight ratio, is easily welded and are considerably stronger and harder than standard 1020 mild seamed and DOM tube steels.
The numbers 4130 defines the chemical composition of the steel.

  • 41 means a low alloy steel containing 1 % chromium and 0.2 % molybdenum.
  • 30 means a carbon content of 0.30%.
  • In addition there will be around 0.2-0.5 % silicon, 0.5-1.0 % manganese, and under 0.1 % of each of a dozen or so other elements whose presence is unavoidable.
  • The remaining 97-98 % is iron.
API 5CT GRADE L804130 chromoly tubing  began its first use in the aircraft industry. Race chassis builders began using the tubing for its strength to weight ratio.
4130 tubing is used for anything from bicycle frames, AK-47 receivers, tubular chasis, suspension parts, aircraft parts and air frames etc… Ive used cromo for suspension components, cages / tube chassis and machined parts.

AISI 4130 is a Standard grade Alloy Steel. It is commonly called AISI 4130 Chromium-molybdenum steel. It is composed of (in weight percentage) 0.28-0.33% Carbon (C), 0.40-0.60% Manganese (Mn), 0.035%(max) Phosphorus (P), 0.04%(max) Sulfur (S), 0.15-0.30% Silicon (Si), 0.80-1.10% Chromium (Cr), 0.15-0.25% Molybdenum (Mo), and the base metal Iron (Fe). Other designations of AISI 4130 alloy steel include UNS G41300 and AISI 4130.

Steel is the common name for a large family of iron alloys. Steels can either be cast directly to shape, or into ingots which are reheated and hot worked into a wrought shape by forging, extrusion, rolling, or other processes. Wrought steels are the most common engineering material used, and come in a variety of forms with different finishes and properties. Alloy steels are steels that exceed the element limits for Carbon steels. However, steels containing more than 3.99% chromium are classified differently as stainless and tool steels. Alloy steels also includes steels that contain elements not found in carbon steels such as nickel, chromium (up to 3.99%), cobalt, etc.

The typical elastic modulus of alloy steels at room temperature (25°C) ranges from 190 to 210 GPa. The typical density of alloy steels is about 7.85 g/cm3. The typical tensile strength varies between 758 and 1882 MPa. The wide range of ultimate tensile strength is largely due to different heat treatment conditions.

AISI 4130 steel is a low alloy steel that is used in structural designs that may be found in applications such as aircraft engine mounts or welded tubing. It is well known for its ease of welding and ability to harden in commercial applications. It is commonly referred to as chromium-molybdenum steel.
  1. Composition Specifications

    • AISI 4130 steel is comprised of seven different elements. The weight of each of these elements is measured as a percentage and must stay within the designated range to meet steel standards. The composition must be between 0.28 and 0.33 percent carbon and 0.4 to 0.6 percent manganese. The amount of phosphorous and sulfur must be less than 0.035 and 0.04 percent respectively. The amount of silicon must range between 0.15 and 0.30 percent. Chromium ranges between 0.8 and 1.10 percent while molybdenum must measure between 0.15 and 0.25 percent.

    Mechanical Specifications

      • The mechanical specifications of AISI 4130 steel are standard at 25 degrees Celsius. The density of the material must be between 7700 and 8030 kg per cubic meter while the Poisson ratio must be between 0.27 and 0.30. The elastic modulus ranges between 190 and 210 while the tensile strength and yield strength are 560.5 and 360.6 respectively. Elongation is 28.2 percent and the reduction in area is 55.6 percent. Hardness is rated at 156 and the impact strength is 61.7.

    Thermal and Electric Specifications

      • AISI 4130 is a thermal conductor capable of a rating of 42.7 measured at 100 degrees Celsius. The specific heat it can handle is 477 at 50 to 100 degrees Celsius. The electric resistivity has been measured at 223 when tested at 20 degrees Celsius.

    Heating Specifications

      • AISI 4130 can be heated as a way to harden the material. When hardening is desired, the material should be heated at a minimum of 1600 degrees F. followed by an oil quench. The best results can be obtained when heating occurs between 1650 and 1700 degrees, followed by an oil quench and soak of 1600 degrees. If the material loses too much ductility during this process, the material can be tempered to restore some of the function. Tempering should be conducted at temperatures between 750 and 1050 degrees, depending on the resultant strength desired. The lower temperatures generally result in greater strengths during the tempering process. Heating can also be used to make the material easier to work with. Manipulation heating can be best conducted in a range of 2000 to 1500 degrees.

    Chemistry Data : [top]


    0.28 - 0.33


    0.8 - 1.1


    0.7 - 0.9


    0.15 - 0.25


    0.035 max


    0.15 - 0.35


    0.04 max













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