Regarding fastener materials, how many types do you know?

Carbon steel has excellent workability, can meet a relatively wide range of strength performance combinations, and has a lower cost compared with other fastener materials.

The mechanical properties of carbon steel are very sensitive to the carbon content, which is usually less than 1.0%. For fasteners, ordinary steel is divided into three types: low carbon steel, medium carbon steel, and alloy steel.

The carbon content of low - carbon steel is usually less than 0.25%, and its strength cannot be improved by heat treatment; it can only be strengthened by cold work hardening. Low - carbon steel is relatively soft and has low strength, but it has excellent ductility and toughness. In addition, it has good workability and weldability, and relatively low production costs. For example, the yield strength of low - carbon materials is 40000 psi, the tensile strength is 60000 - 80000 psi, and the ductility is 25% EL. The most commonly used materials are AISI (American Iron and Steel Institute) standard - specified grades 1006, 1008, 1016, 1018, 1021, and 1022. The grade 1 specified in SAEJ 429 standard and ASTM A 307 grade A are essentially the same, which are standards for the strength grade of low - carbon steel. ASTM A 307 grade B is a special low - carbon steel grade, suitable for low - carbon steel bolts on pipe fittings and flanges. Its performance is basically the same as that of grade A, except that a special maximum tensile strength is specified. This is to ensure that in case of over - tightening during the installation process, the bolt will break before damaging the flange, valve, and pipeline. SAE J 429 grade 2 is a low - carbon steel grade whose strength is improved by cold work hardening.

Medium carbon steels have a carbon content of 0.25 - 0.6% (by mass fraction). The mechanical properties of such steels can be improved through heat treatment methods such as austenitization, quenching, and tempering. Ordinary medium carbon steels have poor hardenability and can only be fully hardened when the cross - section is small. Also, rapid cooling is required during quenching. This means that the final properties of fasteners depend on their specifications. Please note the descriptions of the gradual "degradation" of strength properties with increasing diameter in SAE J 429 Grade 5, ASTM A325, and ASTM A 449. In terms of the ratio of strength to cost, heat - treated medium carbon steel parts have excellent load - bearing capacity, a very low yield - to - tensile ratio, and good toughness. Commonly used materials are several grades specified by the AISI (American Iron and Steel Institute) standards, such as 1030, 1035, 1038, and 1541.

When the manganese content of carbon steel exceeds 1.65%, or the content of silicon or copper exceeds 0.6%, or the chromium content does not exceed 4%, it can be called alloy steel. In addition, when carbon steel is added with components such as aluminum, titanium, vanadium, nickel or other elements with the specified minimum content to meet certain performance requirements, it is also called an alloy. The addition of chromium, nickel, and molybdenum can improve the material strength and ductility of alloy steel after heat treatment.

SAEJ 429 Grade 8, ASTM A 354 Grade BD, ASTM A 490, and ASTM A 193 B7 all belong to common alloy steel fasteners.

Stainless steel is an iron-based alloy steel with a chromium content of over 10.5%. The presence of chromium forms an invisible film on the surface of the steel, which can prevent oxidation and make the material "passivated", or in other words, corrosion-resistant. Adding other elements such as nickel or molybdenum can improve corrosion resistance, strength, and temperature resistance.

Stainless steel can be classified into three types according to its metallographic structure: austenite, martensite, and ferrite. Each type has its own characteristics and is further divided into several grades or types. Moreover, in order to meet the requirements of different corrosion conditions, temperature ranges, strength requirements, weldability, machining cutting performance, cold work hardening, and forming ability, new alloy steels can be further developed by changing the chemical composition.

Carbon steel has excellent workability, can meet a relatively wide range of strength performance combinations, and has a lower cost compared with other fastener materials.

The mechanical properties of carbon steel are very sensitive to the carbon content, which is usually less than 1.0%. For fasteners, ordinary steel is divided into three types: low carbon steel, medium carbon steel, and alloy steel.

The carbon content of low - carbon steel is usually less than 0.25%, and its strength cannot be improved by heat treatment; it can only be strengthened by cold work hardening. Low - carbon steel is relatively soft and has low strength, but it has excellent ductility and toughness. In addition, it has good workability and weldability, and relatively low production costs. For example, the yield strength of low - carbon materials is 40000 psi, the tensile strength is 60000 - 80000 psi, and the ductility is 25% EL. The most commonly used materials are AISI (American Iron and Steel Institute) standard - specified grades 1006, 1008, 1016, 1018, 1021, and 1022. The grade 1 specified in SAEJ 429 standard and ASTM A 307 grade A are essentially the same, which are standards for the strength grade of low - carbon steel. ASTM A 307 grade B is a special low - carbon steel grade, suitable for low - carbon steel bolts on pipe fittings and flanges. Its performance is basically the same as that of grade A, except that a special maximum tensile strength is specified. This is to ensure that in case of over - tightening during the installation process, the bolt will break before damaging the flange, valve, and pipeline. SAE J 429 grade 2 is a low - carbon steel grade whose strength is improved by cold work hardening.

Medium carbon steels have a carbon content of 0.25 - 0.6% (by mass fraction). The mechanical properties of such steels can be improved through heat treatment methods such as austenitization, quenching, and tempering. Ordinary medium carbon steels have poor hardenability and can only be fully hardened when the cross - section is small. Also, rapid cooling is required during quenching. This means that the final properties of fasteners depend on their specifications. Please note the descriptions of the gradual "degradation" of strength properties with increasing diameter in SAE J 429 Grade 5, ASTM A325, and ASTM A 449. In terms of the ratio of strength to cost, heat - treated medium carbon steel parts have excellent load - bearing capacity, a very low yield - to - tensile ratio, and good toughness. Commonly used materials are several grades specified by the AISI (American Iron and Steel Institute) standards, such as 1030, 1035, 1038, and 1541.

When the manganese content of carbon steel exceeds 1.65%, or the content of silicon or copper exceeds 0.6%, or the chromium content does not exceed 4%, it can be called alloy steel. In addition, when carbon steel is added with components such as aluminum, titanium, vanadium, nickel or other elements with the specified minimum content to meet certain performance requirements, it is also called an alloy. The addition of chromium, nickel, and molybdenum can improve the material strength and ductility of alloy steel after heat treatment.

SAEJ 429 Grade 8, ASTM A 354 Grade BD, ASTM A 490, and ASTM A 193 B7 all belong to common alloy steel fasteners.

Stainless steel is an iron-based alloy steel with a chromium content of over 10.5%. The presence of chromium forms an invisible film on the surface of the steel, which can prevent oxidation and make the material "passivated", or in other words, corrosion-resistant. Adding other elements such as nickel or molybdenum can improve corrosion resistance, strength, and temperature resistance.

Stainless steel can be classified into three types according to its metallographic structure: austenite, martensite, and ferrite. Each type has its own characteristics and is further divided into several grades or types. Moreover, in order to meet the requirements of different corrosion conditions, temperature ranges, strength requirements, weldability, machining cutting performance, cold work hardening, and forming ability, new alloy steels can be further developed by changing the chemical composition.