Heat treatment process of flange pipe fittings
Jan. 08, 2021
1. What is a flange and what is its function?
What is a flange? Many people don’t know what it is when they hear it. Here is a brief introduction
Flanges, gaskets and fasteners are collectively referred to as flange joints. Flange joint is a widely used component in engineering design, involving a wide range of surfaces, and is an indispensable component in pipeline design and pipeline installation valves. It is also used in industrial, thermal engineering, water supply and drainage, heating and ventilation, automatic control and other projects. Common parts.
Forged flanges have three types of sealing surfaces: flat sealing surface, suitable for low pressure and non-toxic media; concave and convex sealing surface, suitable for slightly higher pressure; tongue and groove sealing surface, suitable for flammable, explosive, toxic media and high pressure. The gasket is a ring that can produce plastic deformation and has a certain material strength.
This may be more standard, but fewer people know it. For example, if there is a long-distance pipeline, it needs to connect a section of the pipeline to the entire pipeline, and install valves, sight glasses, expanders, etc. on this pipeline, which can be welded by electric welding, but in the future maintenance Can't be dismantled, right? Therefore, most of these pipelines will choose flange connection for future maintenance and replacement.
The flange ends are welded to the pipeline or connected in other ways, and the latter two opposite flanges are fixed with fasteners (bolts) to form a complete pipeline. Pipes, valves, mirrors, etc. are basically connected in this way.
2. Heat treatment process of flange pipe fittings
After the metal is heated, insulated and cooled, the performance of the metal will change differently, and the performance of the same flange pipe fitting will also be different after heating, such as the superior performance of stainless steel flange pipe fittings obtained by heating and cooling flange pipe fittings . At the same time, the heating process of stainless steel flange pipe fittings is one of the important parameters in the heat treatment process.
In the heat treatment process of flange pipe fittings, the annealing cooling rate is generally very slow, the normalizing cooling rate is faster, and the quenching cooling rate is faster. However, due to the different types of steel, there are also different requirements. When the metal is heated, when the workpiece is exposed to the air, the flange fittings are often oxidized. Decarburization has a great negative effect on the surface properties of steel parts after heat treatment. The flange pipe metal should usually be in a controlled atmosphere or protective atmosphere. Molten salt neutralization and vacuum heating can also be protected by coating or packaging.
In addition, the heating temperature of the flange pipe is one of the important process parameters in the heat treatment process, and the selection and control of the heating temperature is the main issue to ensure the quality of the heat treatment. The heating temperature varies with the metal material and the purpose of the heat treatment, but it is generally heated above the phase transition temperature to obtain a high-temperature structure. Heating is one of the important heat treatment processes. There are many heating methods for the metal heat treatment of flange pipe fittings. The earliest one used carbon as the heat source, and then liquid and gas fuels were used. Nowadays, many manufacturers use electrical applications, which are easy to control and have no environmental pollution.