Hardware Encyclopedia|What do the meanings of the marks on the nuts and bolts?
Bolts and nuts are often marked with numbers, letters, horizontal lines, diagonal lines, points, and so on. There are two common fastener markings: a unique manufacturer identification symbol (such as a letter or a token) and information indicating the strength of the fastener. Such markings vary depending on how the fasteners are made. Alloy steel metric fasteners and stainless steel metric fasteners conforming to ISO standards are shown in the table to the right. UNC threaded fasteners primarily follow ASTM standards. Due to the lack of space, according to ISO 898â€1, small-sized fasteners can be unmarked, such as those with a diameter below M5. Bolts larger than this size must be marked on the head. Editor in charge: Hu Na Gate Valve,Brass flange gate valve,groove type gate valve Chongqing Xingjida Import and Export Trade Co., Ltd. , https://www.xjdvalve.com
