TOP SCREW METAL CORP.

Fasteners are hardware device that mechanically joins or affixes two or more objects together. Fasteners can also be used to close a container such as a bag, a box, or an envelope and they may involve keeping together the sides of an opening of flexible material, attaching a lid to a container, etc. Fasteners used in these manners are often temporary, in that they may be fastened and unfastened repeatedly.

Furniture supplied in flat-pack form often uses cam dowels locked by cam locks, also known as conformat fasteners.

Items like a rope, string, wire, cable, chain, or plastic wrap may be used to mechanically join objects; but are not generally categorized as fasteners because they have additional common uses. Likewise, hinges and springs may join objects together, but are ordinarily not considered fasteners because their primary purpose is to allow articulation rather than rigid affixment.

Other alternative methods of joining materials include welding,taping,crimping,soldering, brazing, cementing, or the use of other adhesives. 

There are three major steel fasteners using in industries. Stainless Steel, Carbon Steel and Alloys Steel

Major Grade using in Stainless Steel Fasteners. 200 series 300 series 400 series.

(reference by Wikipedia)