The reason and function of heat treatment before flange proc

Speaking of flange, we all know that it is a kind of pipe fitting used to connect the pipe end in the pipe. According to the production process of flange, flange is mainly divided into forging, casting, cutting and rolling; according to the manufacturing materials of flange, flange mainly includes carbon steel flange, stainless steel flange, alloy steel flange, etc. However, do you know that the flange needs heat treatment before processing. Do you know why? Next, we will talk about the reason and role of heat treatment before flange processing.

 

The reason and function of heat treatment before flange processing.

 

1. What is the reason for heat treatment before flange processing?

 

(1) The strength, stiffness, surface hardness and corrosion resistance of untreated iron, steel and pig iron are difficult to meet the different needs of our real life. Therefore, people have racked their brains and kept exploring. In addition to the reasonable selection of materials and various forming processes, heat treatment is available. The purpose of heat treatment is to make the metal parts have the required mechanical properties, physical properties and chemical properties, which is an effective means to improve the performance of metal parts.

 

(2) Heat treatment is to endow or improve the performance of the workpiece by changing the internal microstructure of the workpiece or the chemical composition on the surface of the workpiece. Generally, the shape and chemical composition of the workpiece will not be changed. The function of heat treatment is to remove the magnetism produced by steel processing and stabilize the austenite structure; to reduce the natural brightness on the surface of steel materials, because the natural brightness is different from the brightness obtained by polishing; to eliminate the modification phenomenon of carbon steel flange pipe fittings in the process of processing, so as to reduce the hardness to below 220hv, improve the plasticity and toughness, and make the pipe fitting more convenient in installation It can restore the stress and intergranular change of carbon steel flange pipe during the production process, reduce the intergranular corrosion and stress corrosion, and enhance the anti-corrosion ability. ,

 

2. Heat treatment process can be divided into two categories: preparation heat treatment and final heat treatment, especially the preparation heat treatment process is more critical.

 

The purpose of the preparation heat treatment is to improve the machinability, eliminate the internal stress and prepare the metallographic structure for the final heat treatment. The heat treatment process mainly includes annealing, normalizing, quenching and tempering, among which annealing and normalizing are used for hot working blank. The carbon content of carbon steel and alloy steel is more than 0.5%, in order to reduce the hardness and easy to cut, annealing treatment is often used; the carbon content of carbon steel and alloy steel is less than 0.5%, in order to avoid sticking the tool when cutting with low hardness, normalizing treatment is adopted. It should be noted that annealing and normalizing should be arranged after blank manufacturing and before rough machining.