A hex nut is made of grade 2 carbon steel.

 
A zinc plated hex nut will resist rust and corrosion, and it will not tarnish like a bare hex nut. This type of nut is available in a variety of grades and finishes. These hex nuts are often used with carriage bolts and hex bolts made of A307 low carbon steel. In addition to zinc plating, some hex nuts have a PTFE coating, a chemically resistant plastic that has superior properties for long-term performance. These nuts have high tensile strength and high operating pressure, making them ideal for industrial and insulating applications.

A zinc plated hex nut is made of grade 2 carbon steel. The zinc coating acts as an anode, and is also corrosion-resistant. In hot dipped galvanizing, fasteners are immersed in molten zinc to provide corrosion resistance. In mechanical galvanizing, the fastener is tumbled in a chemical bath, but this method does not offer the same corrosion-resistant qualities as hot dipped galvanizing. The chemical treatment process also results in a stud that is clean and free of rust, unlike hot dipped galvanizing, which results in a less dense and cleaner stud. Electroplating is another method for coating hex nuts with a zinc layer.

Another type of zinc plated hex nut is a half lock type. These are a reliable, cost-effective fastener. Because they are made of steel, half lock hex nuts can be tightened with a hand tool or spanner. A half lock hex nut can be tightened from 360 degrees. The hex nut is also available in a plain finish.

Heavy hex nuts are made from AISI 316 grade stainless steel and tested to meet ASTM A194 Grade 8M. They are rated for high-pressure and high-temperature service and have a "7L" grade mark on the side. As a result, these nuts are suitable for stud bolts and other similar applications. So, when you need a hex nut that can withstand high temperatures and pressure, you should consider purchasing one made of stainless steel or carbon steel.