What is heavy hex bolt

Heavy hex bolts have thicker heads than standard hex bolts. Some types are threaded all the way up the shaft, while others have a smooth shoulder area. All are designed to be used with hex nuts for a secure fit in construction projects, for repairs, and in automotive applications.

General heavy hex bolts include ASTM A307 specifications, which covers carbon steel bolts and studs ranging from 1/4” through 4” in diameter. This is the most common heavy hex bolt and includes Grades A, B, and C which denote tensile strength, configuration, and its intended use. The ASTM A193 specification covers alloy steel and stainless steel bolt materials for high temperature and high pressure applications.

Heavy hex structural bolts are designed for steel-to-steel structural connections. The ASTM A325 and A490 specifications cover high strength heavy hex structural bolts from 1/2" diameter through 1-1/2" diameter. These bolts are intended for use in structural connections and therefore have shorter thread lengths than standard hex bolts. The A325 and A490 specifications are not intended for general applications.

Heavy hex bolts are required based on a number of different ASTM bolt specifications. In the chemical and petroleum industries, the A193 specification calls for heavy hex bolts and nuts in high heat conditions. The A320 standard covers extremely low temperature conditions and requires the use of heavy hex bolts. Also in ASTM specifications the A307 standard dictates that heavy hex bolts are required in situations where the flanged joints within piping systems are made with cast iron flanges. As well as the standards above, the A490 and A325 specifications call for heavy hex bolts, but with a shorter thread than the others.

Heavy Hex Bolts are designed for use in a variety of high temperature, high strength industrial applications, such as with steel fabrication and general construction. They feature a thicker head than standard or regular hex bolts, and offer a greater bearing surface that distributes the clamping load over a wider area. Heavy hex bolts can be made with a few different materials including low and medium carbon steel, alloy, and stainless steel, and are available plain, hot dipped galvanized, phosphate, zinc or cadmium plated. Some sizes of heavy hex bolts are fully threaded while other sizes offer a smooth shoulder area.

As a national distributor of heavy hex bolts, Goshen Fasteners carries a huge selection of bolt sizes, lengths, materials and finishes, however if you need any assistance fining the heavy hex bolt you need for your application, please contact us now. Our knowledgeable staff is here to help.