ASTM A519 AISI 4140 Tubes

A519 Gr.4140 standards applicated in the seamless alloy pipe.

ASTM A519 carbon and alloy steel mechanical tubing

Chromoly is specified by the “SAE” Society of Automotive Engineers. the Alloy elements of 4140 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 4140 defines the chemical composition of the steel.

Its performance is much higher than the average of seamless steel tubes, because the steel contains Cr more inside, alloy seamless pipe, its high temperature, low temperature resistance, corrosion resistance is smaller than other seamless.

Especially, it need to do the quenched & tempered and has a high technical requirements. so alloy tube in the petroleum, chemical, electric power, boiler and other industries use more widely.

Chemical composition (%)

Grade C Mn P≤ S≤ Si Cr Mo
4140 0.38-0.43 0.75-1.00 0.040 0.050 0.15-0.35 0.80-1.10 0.15-0.25
Mechanical properties (Mpa)
Grade Condition MPa Tenslle Point Yield Point Elongation
4140 SR ≥689 ≥855 ≥10%
A ≥414 ≥552 ≥25%
N ≥621 ≥855 ≥20%

4140 chromoly tubing began its first use in the aircraft industry. Race chassis builders began using the tubing for its strength to weight ratio.

4140 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 4140 is a Standard grade Alloy Steel. It is commonly called AISI 4140 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 4140 alloy steel include UNS G41400 and AISI 4140.

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 4140 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.

ASTM A519 AISI 4140 Tubes

Application Of 4140 & 4140 Pipe & Pipe Fittings

4140 steel alloy is famous for its strength property when it is used for heat treatment. The importance of this steel is in aircraft manufacturing companies and welding purpose. It has features of both chromium and molybdenum steel alloys.

Types of ASTM A519 AISI 4140 Tubes
  • ASTM A519 AISI 4140 Superheater Tubes
  • ASTM A519 AISI 4140 Seamless Tubing
  • Alloy Steel ASTM A519 AISI 4140 Carbon Tubes
  • ASTM A519 AISI 4140 Plain End Tubes
  • Carbon Steel ASTM A519 Superheater Tubes
  • ASTM A519 AISI 4140 Carbon Tubes
  • ASTM A519 AISI 4140 Square Tubing
  • ASTM A519 AISI 4140 Single Random Tube
  • ASTM A519 Seamless Tubing Exporter
  • ASTM A519 AISI 4140 Polish Seamless Tubes
  • Carbon Steel ASTM A519 AISI 4140 Polish Tubes
  • ASTM A519 AISI 4140 Mechanical Tubes
  • CS ASTM A519 AISI 4140 Cold Drawn Tubes
  • ASTM A519 AISI 4140 Beveled End Tube
  • ASTM A519 AISI 4140 Mechanical Tubing
  • ASTM A519 AISI 4140 Tubing Supplier
  • Alloy Steel AISI 4140 Round Tubes
  • ASTM A519 AISI 4140 Double Random Tubes
  • CS AISI 4140 Cold Drawn Tube
  • ASTM A519 AISI 4140 Rectangular Tubes

Packing and Marking

Alloy steel specification, Standard and identification

Alloy Steel pipe contains substantial quantities of elements other than carbon such as nickel, chromium, silicon, manganese, tungsten, molybdenum, vanadium and limited amounts of other commonly accepted elements such as manganese, sulfur, silicon, and phosphorous.


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The most important and desired changes in alloy steel are:

Alloy steels are made by combining carbon steel with one or several alloying elements, such as manganese, silicon, nickel, titanium, copper, chromium and aluminum. These metals are added to produce specific properties that are not found in regular carbon steel. The elements are added in varying proportions (or combinations) making the material take on different aspects such as increased hardness, increased corrosion resistance, increased strength, improved formability (ductility); the weldability can also change.

  • Increased hardenability.
  • Increased corrosion resistance.
  • Retention of hardness and strength.

Nearly all alloy steels require heat treatment in order to bring out their best properties.

Alloying Elements & Their Effects

  • Chromium – Adds hardness. Increased toughness and wear resistance.
  • Cobalt – Used in making cutting tools; improved Hot Hardness (or Red Hardness).
  • Manganese – Increases surface hardness. Improves resistance to strain, hammering & shocks.
  • Molybdenum – Increases strength. Improves resistance to shock and heat.
  • Nickel – Increases strength & toughness. Improves corrosion resistance.
  • Tungsten – Adds hardness and improves grain structure. Provides improved heat resistance.
  • Vanadium – Increases strength, toughness and shock resistance. Improved corrosion resistance.
  • Chromium-Vanadium – Greatly improved tensile strength. It is hard but easy to bend and cut.
ASTM A335 P11 alloy pipe


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