Nowadays, many people have used the wrong method in the process of purchasing Full Threaded Stud, which has caused some quality problems in the joint bolts purchased by consumers. So how to identify the authenticity of the hinged bolt?
- Look at this brand. The marking of the box is usually a bolt. Can be divided into 8.8 level, 10.9 level and 12.9 level. Generally speaking, hexagonal bolts have no grade on the hexagonal surface and belong to ordinary grades, while high-strength bolts generally have strength indicators. For example: 8.8, but we should pay attention to the fact that there are too many fake and inferior products, and we should also pay attention to the purchase channels and acceptance.
- High-strength bolts that are not galvanized are usually black. The black outer layer is an oxide layer formed by artificial processing, which is called blackening in the industry. It is an oxidation-resistant protective layer formed by the corrosion of strong alkaline substances on the metal surface. There is also a process called bluing, which has the same function and principle. Therefore, high-strength bolts generally do not rust!
- Since the hexagon holes of the hexagon socket bolts generally require heat treatment before use, the general level of the hexagon socket bolts is relatively high. The material that can increase the hardness after treatment is quenched and tempered steel, which has higher mechanical strength after quenching and tempering. Regarding quenching and tempering, generally high-strength materials are not quenched and tempered at 8.8, and some companies may not quench and temper. When selling them to customers of 12.9 or 10.9, the way to distinguish them is: in the sun, untrained hair is dark, while trained hair is colored. This is the most basic common sense. Simple empirical judgment: throw it on the ground and listen to the sound. The high-intensity sound is very crisp. The sound is strip steel. Stud Manufacturer's scratch test is performed with saw blades and other hard tools. The surface hardness of high-strength bolts is greater than that of ordinary bolts.