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1.7227, DIN 42CrMoS4, AISI 4140

AISI 4140 Steel Material Properties

AISI 4140 steel is a low alloy medium carbon steel that contains chromium, molybdenum, and manganese.


    AISI 4140 steel is a low alloy medium carbon steel that contains chromium, molybdenum, and manganese.

    AISI 4140 Steel Material Properties

    AISI 4140 steel is a low alloy medium carbon steel that contains chromium, molybdenum, and manganese.

    It is highly regarded in many industries due to its exceptional mechanical properties, such as high strength, fatigue resistance, and hardness. This makes it an ideal choice for manufacturing machine components like shafts, gears, and bolts, as well as automotive parts.

    Its impressive combination of strength, ductility, and shock resistance means it can withstand harsh industrial environments where stress and strain are common.

    AISI 4140 steel is a versatile and reliable material for use in demanding applications.

    AISI 4140 steel Specification

    The UNS Number of AISI 4140 Steel is UNS G41400. AISI 4140 steel material specifications are:

    1. ASTM A 193: Grade B7, B7M,

    2. ASTM A29, A 322, A331, A506, A513, A519, S646, A 752: Grade 4140,

    3. SAE J404: Grade 4140,

    4. EN 10250: Grade 42CrMo4 (1.7225),

    5. BS 970: Grade 42CrMo 4, 7.DIN 17200: Grade 42CrMo4 (1.7225)

    AISI 4140 steel Equivalent material

    AISI 4140 is part of the 41xx series of SAE steels and has several equivalent materials available on the market today. Some of these include:

    1. Grade 42CrMo4 (1.7225)

    2. JIS G4105- Grade SCM440

    3. AS 1444-Grade 4140

    4. ASTM A29, A 322, A331, A506, A513, A519, S646, A 752: Grade 4140

    Each of these equivalent materials has its own unique set of chemical compositions, mechanical properties, and intended applications. Knowing these alternatives allows engineers and manufacturers to select the most suitable material for their specific needs. This ensures that their products have the desired characteristics such as strength, ductility, and toughness.

    4140 steel meaning




    means that aisi 4140 steel is Molybdenum as main alloying


    Means added Chromium for alloying.


    Grade designation.

    AISI 4140 Chemical Compositions



















    AISI 4140 steel is a versatile and reliable material that can be quenched and tempered to achieve high strength and toughness. It is commonly used for highly stressed components in vehicle construction, as well as for mechanical engineering applications where quenching and surface hardening are required.

    The tensile strength of AISI 4140 steel is typically around 95 Ksi (655 MPa), while the minimum yield strength is 60.2 Ksi (415 MPa). The hardness of the steel varies depending on the temperature at which it is treated for toughness, generally ranging from 217 HB to 241 HB.

    AISI 4140 steel is an excellent choice for demanding applications where strength, toughness, and hardness are required. Its versatility and reliability make it a popular choice among engineers and manufacturers alike.



    Tensile Strength

    95 Ksi(655 Mpa)

    Yield Strength

    60.2 Ksi(415 Mpa)





    Melting Points


    AISI 4140 Heat Treatment

    AISI 4140 steel is a high-quality material that offers good mechanical properties when quenched and tempered. It is commonly used for construction parts in automotive and vehicle manufacturing due to its reliable strength and fatigue resistance.

    To achieve the desired strength and toughness, AISI 4140 steel undergoes a tempering process that involves hardening and subsequent tempering of the material. The heat treatment can be precisely controlled to adjust the relationship between hardness and toughness.

    The hardening process involves heating the steel between 820°C and 860°C before rapidly cooling it in an oil bath or water. The subsequent tempering temperature depends on the desired strength, and the steel must be tempered as soon as possible after hardening to avoid cracking. A tempering treatment in a temperature range of 540°C to 680°C with subsequent air cooling is recommended.

    Different heat treatments can also be applied to AISI 4140 steel, such as annealing at 800°C to 850°C with furnace cooling, normalizing at 870°C to 900°C with still air cooling, and quenching at 820°C to 860°C followed by water quenching. Tempering is usually performed at a temperature range of 540°C to 980°C, soaking for one hour per inch thickness followed by still air cooling.

    AISI 4140 Steel Welding

    When welding AISI 4140 steel, preheating the material is crucial to ensure successful joining of two pieces. Proper preheating helps prevent cracking and ensures the weld is strong and durable.

    AISI 4140 steel can be welded using various methods including Stick welding, TIG welding, and MIG welding. Each method requires different techniques and equipment, but all can produce a good quality weld if properly performed.

    The selection of the welding method depends on several factors such as the thickness of the material, the type of joint, and the required strength of the weld. It is important to choose the appropriate welding method that best suits the specific application and follow proper welding procedures to ensure a high-quality weld.

    AISI 4140 Steel Uses

    AISI 4140 steel is a versatile material that is commonly used in mechanical engineering for a wide range of applications. Some examples include:

    · Machine components

    · Axles

    · Steering knuckles

    · Connecting rods

    · Crankshafts

    · Transmission shafts

    · Pinions

    · Gears

    · Drums

    · Base plates

    · Body parts

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