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Differences Between Cold Forging and Hot Forging of Carbon Steel Flanges

Apr. 14, 2020

Forging flange is a disc-shaped part, the most common in pipeline engineering, flanges are used in pairs. In pipeline engineering, stainless steel flanges are mainly used for pipeline connections. In the pipelines that need to be connected, install a piece of the flange, low-pressure pipelines can use wire flanges, and welding flanges for pressures above 4 kg. Add sealing points between the two flanges, and then tighten with bolts. Different pressure flanges have different thicknesses and use different bolts. When the water pump and valve are connected to the pipeline, some parts of this equipment are also made into corresponding flange shapes, also called flange connection. Any connecting parts that are bolted on both sides and closed at the same time are generally called "flanges". For example, the connection of ventilation pipes, this type of part can be called "flange parts". But this connection is only a part of the equipment, such as the connection between the flange and the water pump, it is not easy to call the water pump "flange parts". Smaller ones, such as valves, can be called "flange parts". The main purposes are: connecting the pipeline and maintaining the sealing performance of the pipeline; facilitating the replacement of a section of the pipeline; facilitating the disassembly of the pipeline to check the condition of the pipeline; facilitating the closure of a pipeline. But do you know the difference between cold forging and hot forging? Carbon steel forged flange factory introduces you to:

The cold forging of the flange is a small change in the dimension of the flange during low-temperature casting. When casting below 700 ℃, there is little scale formation and there is no decarburization on the surface. Therefore, as long as the deformation energy is within the forming energy range, cold forging is simple and obtains good scale accuracy and surface finish. As long as the temperature and lubrication are controlled, warm forging below 700 ° C can also obtain good accuracy. The collective term for plastic processing such as cold die forging, cold extrusion, and cold heading.

Cold forging is a forming process below the recrystallization temperature of the material, which is casting below the recovery temperature. In production, it is customary to call the casting without heating the blank as cold forging. Most cold forging materials are aluminum and some alloys, copper and some alloys, low carbon steel, medium carbon steel, and low alloy structural steel with low deformation resistance and good plasticity at room temperature. Cold forgings have good surface quality and high dimensional accuracy and can replace some cutting processes. Cold forging can strengthen the metal and improve the strength of the flange.

Forging Flange

Forging Flange

The development of cold forging technology is mainly to develop high value-added products and reduce production costs. Together, it is constantly immersing or replacing in the fields of cutting, powder metallurgy, casting, hot forging, sheet forming technology, etc. The combination of processes constitutes a composite process.

The hot forging of the flange is: during hot forging because the deformation energy and deformation resistance are very small, it can cast a large flange with a messy shape. To obtain high-precision flanges, hot forging can be used in the temperature range of 900-1000 ℃. In addition, pay attention to improving the working environment of hot forging. Forging dies life (hot forging 2-5 thousand, warm forging 1-2 thousand, cold forging 20,000-50,000) is shorter than other temperature range casting, but it has a large degree of freedom and low cost.

The purpose of hot forging flanges is mainly to reduce the deformation resistance of metals, so reducing the forging pressure required for the deformation of bad materials so that the tonnage of forging equipment is greatly reduced; the cast structure of the steel ingot for flanges is changed, and it is After recrystallization, the coarse as-cast arrangement becomes a new arrangement of fine grains, and the defects of the as-cast structure are reduced to improve the mechanical properties of the steel.