ASTM 4140 seamless steel pipe

ASTM 4140 is a material used to manufacture forgings requiring higher strength than 35CrMo steel and a larger quenched and tempered section. This article will talk about theASTM 4140 seamless steel pipe, read on to learn more.

Scope of Application

ASTM 4140 seamless steel pipe is known for its high strength, hardenability, good toughness, minimal deformation during quenching, high creep strength, and lasting strength at high temperatures. It is used in the production of forgings that demand higher strength and larger quenched and tempered sections than those made with 35CrMo steel. Applications include:

Large gears for locomotive traction

Supercharger transmission gears

Rear axles

Connecting rods

Spring clamps under heavy load

Drill pipe joints and fishing tools for oil deep wells below 2000m

Material and Standards

ASTM 4140 is classified as an Alloy Structural Steel under the ASTM A29/A29M Steel Grade standard. The A519 Gr.4140 standard applies to seamless alloy pipes.

Characteristics of Chromoly

Chromoly, specified by the Society of Automotive Engineers (SAE), contains chromium and molybdenum as its alloy elements, hence the name "chromoly" or "cromo." This material is known for its excellent strength-to-weight ratio, weldability, and superior strength and hardness compared to standard 1020 mild seamed and DOM tube steels.

Chemical Composition and Performance

The "4140" designation indicates the chemical composition of the steel. Its performance surpasses that of average seamless steel tubes due to the presence of chromium, enhancing its high temperature, low temperature, and corrosion resistance. The steel requires quenching and tempering and meets high technical standards, making it widely used in industries such as petroleum, chemical, electric power, and boiler manufacturing.

Historical and Modern Uses

4140 chromoly tubing was first used in the aircraft industry and later adopted by race chassis builders for its strength-to-weight ratio. Today, it is used for a variety of applications, including:

- Bicycle frames

- AK-47 receivers

- Tubular chassis

- Suspension parts

- Aircraft parts and airframes

It is commonly utilized for suspension components, cages, tube chassis, and machined parts.