American AISI/ASTM Carbon Steels
Gene rally speaking, American AISI/ASTM carbon steels are marked with four digital numbers that represent the steel’s grade and chemical composition. The first two digits indicate the steel’s chemical composition percentage, and the last two digits indicate its mechanical or structural properties.
AISI 4140 Steel
AISI 4140 steel is a low alloy steel containing chromium, molybdenum, and manganese. It is widely used across numerous industries and is an excellent material choice due to its toughness, high fatigue strength, and abrasion and impact resistance. Not many grades can match the versatility and usefulness of 4140.
AISI 4140 is not just strong, it is tough too—forging it at a high temperature gives it much higher strength and toughness than a standard grade of steel. AISI 4140 is supported by its heat-treated counterpart—AISI 4140H which is renowned for its hard-wearing properties. It is the most widely used grades of the alloy steel.
AISI 4140 is characterised by good overall strengths, toughness and fatigue strength. Its wear resistance properties are excellent and it can be machined in a variety of ways. It is a versatile steel and has good welding properties, making it useful for a range of applications. It can also be used in a variety of environments.
AISI 1020 Steel
AISI 1020 is a low hardenability and low tensile carbon steel with its relatively low carbon content. It has a very good surface finish, good machinability and excellent weldability. This grade is often supplied in a cold drawn or normalized condition.
AISI 1020 is used in a variety of industries, including automotive, mining and construction. It can be nurtured in a variety of ways and is an economical choice for many applications. It is also relatively easy to machine, with good grinding and turning capabilities.
AISI 1020 is commonly used in moderate strength cold formed applications. It can be welded, although it should not be exposed to temperatures above 350°F (175°C) if welding is necessary. AISI 1020 is used in automotive parts, such as axle shafts, bushings, springs and joints.
AISI 1045 Steel
AISI 1045 is a medium carbon steel which is used to a wide range of applications. It has excellent weldability, good machinability and a high strength-to-weight ratio. AISI 1045 is widely used for parts that require better properties than mild steel but does not justify the costs of an alloy steel. It is used for bolt and pinion gear teeth, gears, shafts, axles and a variety of other critical applications.
AISI 1045 is heat-treated and normalized or quenched and tempered. It has excellent wear resistance, a high fatigue strength and is strong enough for many applications. It has a good machinability rating and its strong mechanical properties make it a good choice for many different applications.
AISI 1018 Steel
AISI 1018 is a low carbon steel that is easy to shape and form. It is often used in a variety of industries, including automotive, construction and manufacturing. It can be readily welded, brazed and soldered. It is composed of a fine-grain structure and is made up of 0.18% carbon, 0.6-0.9% manganese, 0.04% phosphorus, 0.05% sulphur and 0.15-0.3% silicon.
AISI 1018 is one of the most commonly available grades of steel. It is also very easy to machine and can be readily welded. This grade is low cost, yet has a good strength-to-weight ratio. It offers good formability and weldability. AISI 1018 is mostly used in the manufacturing of automobiles, machinery and components.
In conclusion, AISI 4140, 1020, 1045, and 1018 are four of the most popular grades of carbon steel. Each carbon steel grade is unique and has its own specific properties. AISI 4140 is a low alloy steel that is very tough due to its heat-treated properties. AISI 1020 is easy to shape and form and is widely used in many industries. AISI 1045 is a medium carbon steel that offers excellent weldability and machinability, while AISI 1018 is a low cost, yet strong steel that can be used in a variety of applications.
