stainless steel bolt,Socket Set bolt
Description：stainless steel bolt--Materials and strength Screws and bolts are made from a wide range of materials, with steel being perhaps the most common, in many varieties.
Materials and strength
Screws and bolts are made from a wide range of materials, with steel being perhaps the most common, in many varieties. Where great resistance to weather or corrosion is required, stainless steel, titanium, brass, bronze, monel or silicon bronze may be used, or a coating such as brass, zinc or chromium applied. Electrolytic action from dissimilar metals can be prevented with aluminium screws for double-glazing tracks, for example. Some types of plastic, such as nylon or Teflon, can be threaded and used for fastening requiring moderate strength and great resistance to corrosion or for the purpose of electrical insulation. Even porcelain and glass can have molded screw threads that are used successfully in applications such as electrical line insulators and canning jars.
The same type of screw or bolt can be made in many different grades of material. For critical high-tensile-strength applications, low-grade bolts may fail, resulting in damage or injury. On SAE-standard bolts, a distinctive pattern of marking is impressed on the heads to allow inspection and validation of the strength of the bolt. However, low-cost counterfeit fasteners may be found with actual strength far less than indicated by the markings. Such inferior fasteners are a danger to life and property when used in aircraft, automobiles, heavy trucks, and similar critical applications. Gradings are indicated as markings, while grade 0 is the lowest, grade 10 is the highest. Here is the sequence of bolt strength and markings, from least to most. Grade 0, 1 and 2 bolts have no markings, grade 3 has 2 radial lines, grade 5 has 3, grade 6 has 4, grade 7 has 5, grade 8 has 6, grade 9 has 7, grade 10 has 8.
In some applications joints are designed so that the screw or bolt will intentionally fail before more expensive components. In this case replacing an existing fastener with a higher strength fastener can result in equipment damage. Thus it is generally good practice to replace fasteners with the same grade originally installed.