Solicitud

In the tubular heat exchangers, the connection between the tube and the tube sheet is usually done by mechanical expansion and thawing. Although these methods can obtain certain tensile strength and airtightness, they are often limited by material and operation conditions, and it is difficult to achieve the desired results. Especially the connection of thin wall, small diameter dissimilar metal tube and tube sheet. For example, titanium, steel, copper - steel and stainless steel - steel and so on, it is very difficult to use these two methods. In addition, mechanical expansion is reliable only at low working temperature and pressure. Otherwise, due to the poor integrity, it may not be enough to maintain the standards and requirements. The release of internal residual stress can easily lead to failure of joint. In addition, thermal cycling and mechanical vibration are also the reasons for failure. Besides the difficulty in operation, fusion welding can not maintain the same welding quality. The quality is also uneven. Therefore, the connection method between tube and tubesheet should seek better technology.
Explosive welding of tube and tube sheet in heat exchanger is a new technology which uses explosive as energy to form a tight and firm welding or connection between them.


Henan Chalco adopts explosive welding technology to weld heat exchanger and pipe sheet, which provides great economic benefits to customers. Especially for dissimilar materials and high temperature and high pressure vessels, explosive welding shows great superiority. Under the condition of small amount of charge, satisfactory quality and technical results have been achieved.
 
The explosive welding technology of Henan Chalco pipe and tubesheet not only inserts the tube into the tubesheet hole, but also keeps a certain gap between the holes. The explosives are arranged in a predetermined manner in the pipe, and the detonators are inserted into them. After installation and detonation of explosives, the outer wall of the pipe is welded with the inner wall of the tube plate hole.
 
 
 
The combination of thick-walled tube and tube sheet as heat exchanger establishes the method of explosive expanding tube and sealing welding. This method has the characteristics of large pull-out force, no porosity during welding, long-term use of heat exchanger under high temperature and high pressure and high reliability. In addition, the tube removal process for thick walled small-diameter pipes is simple and safe, especially the cost saving.
 
As a complete set of equipment, heat exchanger is one of the most typical products, it uses both the sheet metal explosive welding technology and tube explosive welding technology, and the tube and tube explosive welding technology. This technological improvement can be classified into five main advantages:
 
1. Using composite materials instead of ordinary carbon steel to make heat exchangers can significantly improve the service life of equipment, improve the quality of products and ensure normal production.
 
2. replacing pure precious metals with composite materials can save huge amounts of rare metals and reduce the cost of equipment.
 
3. Using explosive plus rolling process instead of pure rolling process to manufacture bimetallic tubes, which can be used as exchanger tube bundles, can obviously improve the heat transfer efficiency.
 
4. Using explosive welding in connection between pipe and tubesheet can improve the reliability of sealing and reduce manual labor compared with mechanical expanding pipe. Compared with thaw welding, the corrosion resistance of the weld can be significantly improved. Because of the expansion effect of explosive welding at the same time, the gap between pipe and tubesheet can be eliminated and the crevice corrosion can be avoided. Especially when bimetal tube sheet is used, explosive welding of tube sheet and tube sheet can be carried out at the same time.
 
5. The application of composite materials not only makes it possible to require different medium corrosion resistance of pipe and shell, but also makes it possible to use the same material for pipe and shell respectively. This not only helps to avoid electrochemical corrosion, but also facilitates the use of welded structure between cylinder and tube sheet without flange connection. 
 

The corresponding material combination of explosive welded pipe and tube sheet
Tube	Tube sheet	Tube	Tube sheet
Aluminum brass	Aluminum brass	70/30 Copper nickel	70/30 Copper nickel
Aluminum brass	Muntz Metal	Stainless steel（TP304）	Stainless steel（TP304）
Aluminum brass	70/30 Copper nickel	mild steel	mild steel
Aluminum brass	90/10 Copper nickel	titanium	titanium
Aluminum brass	Soft steel	titanium	Stainless steel
Aluminum brass	Stainless steel	Aluminum	Aluminum
90/10 Copper nickel	90/10 Copper nickel	Aluminum	Stainless steel
90/10 Copper nickel	70/30 Copper nickel	Copper	Copper
90/10 Copper nickel	Naval brass	Copper	mild steel
90/10 Copper nickel	Soft steel	70/30brass	Muntz metal
70/30 Copper nickel	Naval brass	70/30barss	Naval brass
70/30 Copper nickel	Soft steel	Naval brass	mild steel