ASME B18.2.1 is the standard that covers square head bolts, which are also known as carriage bolts. These bolts are designed with a square head and a square neck, providing a secure connection when tightened with a nut. They are commonly used in various applications where a reliable and sturdy fastening solution is needed.

Material: including carbon steel, alloy steel, stainless steel (such as 304, 316, 316L, etc.) and other materials, the specific selection depends on the working environment and application requirements.

Grade: The product grade is different mechanical properties grade (such as 4.8 grade, 8.8 grade, 10.9 grade,A2-70, etc.), these grades reflect the tensile strength, yield strength and other mechanical properties of the bolt. Different grades are suitable for different load bearing requirements and working environments.

Advantage:

Prevention of Rotation: The square neck under the head prevents the bolt from rotating when a nut is tightened, ensuring a secure fit.Versatility: Suitable for a wide range of applications, including construction, automotive, and machinery.Easy Installation: The square head allows for easy installation with a wrench or socket.Corrosion Resistance: Often made from stainless steel (304/316), these bolts offer excellent resistance to rust and corrosion, making them suitable for outdoor use.Load Distribution: The square neck helps distribute the load evenly, reducing the risk of damage to the connected parts.

Scope of 

application

Construction: Used in building structures where a secure connection is required.Automotive Industry: Employed in the assembly of vehicles where a flush finish and secure fastening are needed.Machinery and Equipment: Used in machinery frames and equipment where a secure and adjustable connection is needed.Solar Mounting Systems: Utilized in solar panel mounting systems for securing panels to racks or structures.Furniture and Display Systems: Ideal for use in systems that require frequent assembly and disassembly.Railroad and Automotive Industry: They are essential for fastening tracks, plates, and rail components in the railroad sector, and for engine assembly, chassis construction, and other critical connections in the automotive industry.Marine Applications: Square head bolts made of stainless steel, brass, or bronze are extensively used in marine applications due to their corrosion-resistant properties, ensuring the longevity and reliability of structures, fittings, and equipment exposed to saltwater and harsh marine environments.Historic Restoration: These bolts offer an authentic look in restoration projects or constructions aiming for a traditional or historical aesthetic, helping to maintain the charm of historical buildings.