Stainless Steel Vs Carbon Steel For Bolts and Screws If you are looking for bolts and screws, you will want to look for a grade of steel that meets ISO standards. Carbon steel is not as good a material as stainless steel, and this grade is commonly used in automotive applications. These steels are non-magnetic when annealed, but become magnetic after cold working. For this reason, dual certified fasteners are available, which comply with the requirements for both the 316 and 316L grades.