These materials are often referred to as super alloys because of their ability to perform in extremes of temperature or posess extremely high strength qualities as compared to standard fasteners materials. Following are some of the common special proprietary materials that are used for the manufacture of fasteners for special applications.
Plastics are light-weight, non-metallic and non corrosive under normal circumstances. The characteristics of plastics may be further enhanced by chemical and fiber additions to increase strength, hardness, flexibility, temperature and ultra-violet resistance.
They have a chromium content between 15% to 20% and nickel between 5 % to 19 % and offer a higher degree of corrosion resistance than the other two types of stainless steels.