EN19

EN19 Alloy Steel Product Overview

EN19, also known as 709M40 or AISI 4140, is a high-strength, low-alloy steel under the BS 970 standard, characterised by its excellent toughness, high tensile strength, and good wear resistance. This chromium-molybdenum steel is widely used for components requiring high strength and fatigue resistance. Typically supplied in the annealed or normalised condition (max 229 HB), it can be heat-treated to achieve hardness levels of 28–32 HRC or higher. EN19 is versatile, offering good machinability and weldability with proper precautions, making it suitable for heavy-duty engineering applications.

Applications

EN19 alloy steel is used in a wide range of engineering and industrial applications requiring high strength and durability:

Automotive and Aerospace:

• Axles, crankshafts, connecting rods, and propeller shafts.
• Landing gear components and high-stress fittings.

Mechanical Engineering:

• Gears, pinions, and spindles.
• High-strength bolts, studs, and couplings.
• Shafts, forgings, and tool holders.

Oil and Gas:

• Drill collars, tool joints, and valve bodies.
• Components for high-pressure pipelines and fittings.

Other Uses:

• Press machine components, such as rams and dies.
• Heavy-duty machinery parts, including sprockets and camshafts.
• Structural components requiring high fatigue resistance.

Chemical Composition

The chemical composition of EN19 ensures its strength, toughness, and hardenability:

• Chromium (Cr): Enhances hardenability, wear resistance, and corrosion resistance.
• Molybdenum (Mo): Improves strength, toughness, and resistance to tempering.
• Manganese (Mn): Contributes to strength and hardenability.
• Carbon (C): Provides hardness and strength while maintaining machinability.

Supply Size

EN19 alloy steel is available in various forms and sizes to meet industrial requirements:

• Round Bars: Diameter 16 mm to 700 mm.
• Flat Bars: Minimum: 10 mm thickness x 80 mm width. Maximum: 500 mm thickness x 2000 mm width.