EN18 is a high tensile **chromium-molybdenum alloy steel** widely used for its **excellent strength**, **shock resistance**, and **toughness**. It can be heat treated to achieve high surface hardness while maintaining core ductility. Commonly used in:

• Defense-grade mechanical parts
• Gears, axles, shafts, and crankshafts
• High-strength fasteners and heavy-duty bolts
• Automotive and aerospace structural components

EN18 offers better hardenability than EN8 and can be nitrided for surface hardness in wear-intensive environments.

Standard Specifications

AISI 4140 is a **chromium-molybdenum alloy steel** known for its **high tensile strength**, **toughness**, and **fatigue resistance**. It is widely used in aerospace, defense, and heavy engineering applications where strength and reliability are critical.

• Aircraft landing gear and structural parts
• Defense vehicle axles, connecting rods, and crankshafts
• Gears, shafts, spindles, and fasteners
• Pressure vessels and tooling applications

The alloy can be heat-treated and offers excellent performance under stress and in impact-prone conditions.

Standard Specifications

AISI 4145 is a **low alloy chromium-molybdenum steel** with enhanced hardenability and strength. It is a close relative of AISI 4140 but with slightly higher carbon content, making it well-suited for heavy-duty applications. It is widely used in:

• Oil & gas drilling equipment (drill collars, subs, and tool joints)
• Military-grade shafts and high-strength fasteners
• Heavy machinery components exposed to stress and impact
• Aircraft landing gear parts

4145 is commonly supplied in the quenched and tempered condition and can be nitrided for surface hardness and wear resistance.

Standard Specifications

709M40 is a **high tensile alloy steel** commonly known as EN19 under BS 970 standards. It offers a combination of **strength, toughness, and wear resistance**, making it ideal for applications in defense, aerospace, and automotive engineering.

• Crankshafts, axles, and high-load gears
• Military-grade shafts and fasteners
• Aircraft structural and drivetrain parts
• Hydraulic components and heavy-duty bolts

The material is suitable for **induction hardening**, and is typically supplied in the **quenched and tempered condition** to improve mechanical properties.

Standard Specifications

AISI 4150 is a **chromium-molybdenum alloy steel** with high hardenability, strength, and fatigue resistance. It offers slightly higher carbon content than AISI 4140, which enhances its ability to achieve high hardness and wear resistance. It is commonly used in:

• Military-grade automotive components
• Aerospace structural parts and landing gear
• Heavy-duty gears, shafts, and fasteners
• Industrial machinery exposed to shock and wear

The steel is often supplied in the quenched and tempered condition and can be further processed with nitriding or surface hardening techniques.

Standard Specifications

41Cr4 is a **low alloy chromium steel** widely used in engineering applications requiring moderate tensile strength and good wear resistance. It is commonly used for parts subjected to mechanical stress and wear, and is known for its good response to heat treatment and case hardening.

• Automotive drive shafts and steering components
• Defense and aerospace-grade shafts and linkages
• Forged parts and machine components
• Transmission gears and fasteners

This steel is known for its good machinability and dimensional stability after hardening.

Standard Specifications

34CrNiMo6 is a **high-strength, low-alloy steel** containing chromium, nickel, and molybdenum. It offers excellent toughness, high fatigue strength, and good hardenability, making it suitable for demanding applications in the **aerospace**, **defense**, and **automotive** industries.

• Aerospace components such as shafts, rotors, and gear parts
• Military-grade structural parts and mechanical fasteners
• Heavy-duty automotive parts and transmission systems
• High-performance crankshafts and connecting rods

It is typically supplied quenched and tempered and can be nitrided or induction hardened for surface strength.

Standard Specifications

AISI 4340 is a **nickel-chromium-molybdenum alloy steel** known for its excellent toughness, high strength, and fatigue resistance. It is commonly used in **aerospace, military, and automotive** industries for parts that undergo high stress and wear.

• Aerospace landing gear, bolts, and shafts
• Military-grade components like rotor shafts and structural parts
• High-performance crankshafts, gears, and fasteners
• Heavy-duty machinery and tooling components

This steel responds well to heat treatment and is commonly used in the quenched and tempered condition.

Standard Specifications

AISI 8620 is a **low-alloy case-hardening steel** with good toughness and core strength. It is widely used for parts that require a tough core and a wear-resistant surface, typically achieved through carburizing and subsequent hardening.

• Gears, camshafts, and crankshafts
• Automotive transmission components
• Defense and aerospace drive systems
• Structural parts requiring high surface hardness

8620 is known for its excellent combination of surface hardness and core ductility after heat treatment.

Standard Specifications

20MnCr5 is a **low-carbon case-hardening steel** with good wear resistance and fatigue strength. It is typically used in the carburized and hardened condition, offering a tough core with a hard outer surface—ideal for components subjected to high loads and friction.

• Gears and gear shafts
• Camshafts and crankshafts
• Pinions and sprockets
• Automotive and aerospace mechanical parts

This steel is well-suited for heat treatment processes like carburizing, followed by quenching and tempering.

Standard Specifications

17CrNiMo6-7 is a **case hardening steel** with excellent hardenability, strength, toughness, and wear resistance. It is commonly used in applications where high surface hardness and a tough core are required, especially in the **aerospace**, **automotive**, and **defense** industries.

• Gears and transmission components
• High-load shafts and drive train parts
• Heavy-duty mechanical engineering parts
• Bearings and pinions

This steel is best suited for carburizing and subsequent heat treatment for enhanced performance.

Standard Specifications

18CrNiMo7-6 is a **case hardening alloy steel** with high strength, excellent toughness, and good wear resistance. It is widely used in **heavy-duty gears** and **high-stress mechanical components**, especially in **aerospace**, **defense**, and **industrial transmissions**.

• Gear shafts and transmission components
• High-load pinions and drive systems
• Bearings and axles
• Applications requiring high surface hardness and a tough core

It is optimized for carburizing and heat treatment, offering great fatigue resistance even under dynamic loads.

Standard Specifications

16MnCr5 is a **case-hardening steel** with good wear resistance and moderate tensile strength. It is typically used in applications that require a **tough core** and **hardened surface**, making it ideal for **gears, shafts, and other automotive components**.

• Gears and gear shafts
• Steering components
• Transmission parts
• Machine components requiring high surface hardness

This steel is well-suited for carburizing, followed by quenching and tempering.

Standard Specifications

EN39B is a **nickel-chromium-molybdenum case-hardening steel** known for its high core strength and excellent toughness. It is especially suitable for parts requiring **deep case depth and resistance to shock loading**, often used in **aerospace**, **automotive**, and **heavy-duty mechanical** applications.

• Heavy-duty gears
• High-strength shafts
• Axles and pinions
• Rollers and cams

This alloy is ideal for **carburizing and hardening treatments**, resulting in a tough core and hard-wearing surface.

Standard Specifications

EN40B is a **nitriding steel** with good core strength and the ability to develop a hard, wear-resistant surface through nitriding. It is ideal for high-stress applications in **aerospace**, **automotive**, and **engineering** sectors where wear resistance and fatigue strength are critical.

• Crankshafts and camshafts
• Gears and spindles
• Die holders and cylinders
• Valve parts

EN40B is known for forming a hard case without distortion, making it suitable for precision components.

Standard Specifications

4130 is a **low alloy chromium-molybdenum steel** known for its excellent strength-to-weight ratio, weldability, and toughness. It is widely used in **aerospace**, **motorsports**, **oil & gas**, and **structural applications**, particularly where a strong but lightweight material is needed.

• Aircraft tubing and fuselage structures
• Roll cages and race car frames
• Oil drilling components
• Motorcycle frames and industrial tools

It is heat-treatable and performs well under stress and fatigue conditions.

Standard Specifications

4135 is a **chromium-molybdenum alloy steel** known for its **medium hardenability**, strength, and good wear resistance. It is typically used in **gears, crankshafts, and other engine components** due to its ability to withstand moderate to high stress.

• Transmission gears
• Connecting rods
• Crankshafts
• Axles and pins

It offers good mechanical properties in the heat-treated condition and maintains strength while resisting deformation.

Standard Specifications

4320 is a **nickel-chromium-molybdenum low alloy steel** with excellent toughness, ductility, and wear resistance. It is commonly used in **case-hardened components** requiring high surface strength and a tough core, making it ideal for **gears, shafts**, and other high-stress applications.

• Gear sets
• Heavy-duty shafts
• Pinions and couplings
• Aircraft engine parts

Often carburized and hardened to achieve high surface hardness while maintaining a ductile interior core.

Standard Specifications

30CrMoV9 is a **chromium-molybdenum-vanadium alloy steel** known for its **high strength**, **good toughness**, and excellent **heat resistance**. It is commonly used in applications where **resistance to wear, shock, and high temperatures** is essential, such as in **power transmission components**, **tools**, and **aircraft parts**.

• Forged shafts
• Dies and tools
• High-stress machine parts
• Aerospace and defense components

The vanadium content contributes to increased strength and wear resistance, especially after heat treatment.

Standard Specifications

9310 is a **low alloy, nickel-chromium-molybdenum steel** known for its **high core strength**, **toughness**, and **wear resistance**. It is widely used in **aerospace**, **automotive**, and **gear applications**, especially where **case hardening** is required for a hard surface and tough interior.

• Aircraft gears and shafts
• High-performance transmission components
• Pinions and bearing races
• Heavy-duty gears and crankshafts

9310 is often carburized and heat-treated to enhance its performance under high stress and fatigue conditions.

Standard Specifications

EN48A is a **nickel-chromium-molybdenum alloy steel** known for its **toughness**, **high tensile strength**, and **good fatigue resistance**. It is commonly used in the manufacture of **gears, axles**, and other components subjected to heavy stress and shock loading. The material responds well to case hardening and provides a wear-resistant surface with a tough core.

• Automotive gear components
• Crankshafts and camshafts
• Axle shafts and heavy-duty fasteners
• Transmission parts

Typically supplied in the annealed condition but can be heat treated for improved mechanical properties.

Standard Specifications