Welding Structural Weathering Steels
Welding structural weathering steels is the process of joining together two pieces of metal to form a single structure, usually by using a special welding process. Structural weathering steels are commonly used in building construction, bridge making, and other metal-intensive construction projects due to their high strength and resistance to corrosion. Welding these materials presents unique challenges, as the weathering steels create unique materials that must be understood for best performance.
Weather resistant steels are steel alloys that provide increased levels of corrosion resistance compared to normal steels, due to their special elements. The alloys are composed of iron, manganese, chromium, copper, and nickel. These materials don’t corrode as quickly applying constant cleaning cycles, and therefore can be used for structures that are exposed to harsh conditions such as natural elements, salt air, and high temperatures. Weathering steels can be found in a variety of applications, from wind turbines to industrial facilities.
Selecting the correct method of welding weathering steel is determined by a variety of factors, such as weathering steel thickness, steel grade, and overall environment requirements. To minimize environmental degradation and cracking, due to overheating, the heat input should be as small as possible. It is especially important to use weldments that are compatible with weathering steel, which is generally characterized by higher carbon and manganese compositions in comparison to mild steel. These steels require high joint strength, while also ensuring minimal impact to the environment.
MIG welding is the preferred technique for welding structural weathering steels. This process works with a continuous stream of filler metal being supplied from a metal inert gas (MIG) welding gun. The gun controls the speed of the metal wire, as well as the electric current running through it. Special shielding gases are used for best results, as the process needs to be as clean as possible to ensure high quality welds. The most common shielding gases used are argon and carbon dioxide.
Arc welding is another popular method of welding structural weathering steels, in which an electric arc is used to join together two pieces of metal. This weld process also requires heat input, and should also strive to minimize thermal degradation of the oxidized weathering steel. Most arc weld processes can be performed in both manual and semi-automatic configurations, depending on the type of welding current used.
Welding structural weather steels require attention to detail when selecting appropriate welding techniques and shielding gases. To get the highest quality welds with the least thermal degradation, it is important to have experienced welders and appropriate welding equipment. It is also important to select the right type of weathering steel for the project, as not all grades are suitable for specific applications. Finally, proper post-weld care and maintenance should also be practiced to ensure a long lifespan of the weathering steel structure.
