Heat treatment and quenching and tempering is to improve the comprehensive mechanical properties of the fastener and to meet the tensile strength and yield ratio specified by the product. The quenching and tempering heat treatment process has strict requirements on raw materials, furnace temperature control, furnace atmosphere control, and quenching medium. The main control defects are carbon segregation of the core of the material, surface decarburization during material and annealing, cold cracking, quenching cracking and deformation in quenching and tempering.
Bolt heat treatment process: feeding → cleaning → heating → quenching → cleaning → tempering → coloring → offline.
About 80% of the fastener companies surveyed have heat treatment equipment, and most of the heat treatment process lines in Taiwan are used; the process line equipment is a continuous belt belt furnace with atmosphere protection, and the atmosphere, temperature and process parameters are controlled by computer.
The problems are that the quenching medium lacks the cooling performance measurement, the carbon potential control is unstable, and the furnace temperature test cycle is too long, which may cause heat treatment defects.
A fastener is a general term for a type of mechanical part that is used to securely join two or more parts (or components) as a whole. It is also called a standard part on the market. It usually consists of the following 12 types of parts: 1. Stud Bolts: A type of fastener consisting of a head and a screw (a cylinder with an external thread), which is to be fitted with a nut for fastening the two The parts of the through hole.
This type of connection is called a bolted connection. If the nut is unscrewed from the L-Bolts, the two parts can be separated, so the bolt connection is a detachable connection. 2. Stud: A type of fastener that has no head and only has threads on both ends. When connecting, one end must be screwed into the part with the internally threaded hole, the other end is passed through the part with the through hole, and then the nut is screwed, even if the two parts are fastened together as a whole. This type of connection is called a stud connection and is also a detachable connection. It is mainly used in the case where one of the connected parts has a large thickness, requires a compact structure, or is frequently used for disassembly, and should not be bolted. 3. Screw: It is also a kind of fastener consisting of two parts, head and screw. It can be divided into three categories according to the purpose: machine screw, set screw and special purpose screw. The machine screw is mainly used for a tightly threaded part and a tight connection with a part with a through hole. No need for a nut fit (this type of connection is called a screw connection and is also a detachable connection; Fitted with a nut for a secure connection between two parts with through holes.) The set screw is primarily used to secure the relative position between the two parts. Special purpose screws such as eyebolts are used for lifting parts.