Weathering Steel Shapes are commonly used in structures where savings in weight or added durability is important along with the longer life cycle due to their corrosion resistant properties. A588 is also suitable for many applications in the unpainted condition, including pedestrian bridges, gabion How to Weld Weathering (CORTEN) Steel WELDING Corten, or COR-TEN, is the trademark name for weathering steels manufactured by U.S. Steel Corporation. Weathering steels are a family of low carbon steel alloys that were specifically developed to provide higher strength and more importantly eliminate the need to paint to protect against the elements (rain, snow, humidity, sun, salt, etc.). A242 and A588 
We documented two samples of corten-equivalent weathering steel over the course of 6 months (December 2019-May 2020) to illustrate how the patina forms and changes color over time. The smaller square is 16 GA hot-rolled sheet and the larger square is 18 GA cold-rolled sheet. Weathering Steel A606-4 and A588. Cor-Ten A606 and A588 Weathering Steel, often referred to as Cor-Ten or A606-4 / A588, is a group of steel alloys which were developed to eliminate the need for painting steel and to insure that the steel will form a stable rust-like appearance if exposed to the elements for a prolonged period of time.