The manufacture of metal bellows is based on the selection of raw materials, through the main process steps of tube blank manufacturing, bellows forming, shaping, heat treatment, surface treatment, quality inspection, etc., to produce bellows that meet the design requirements.
The bellows is a thin-shell component with complex shapes and extremely high performance requirements. It has many manufacturing processes and complicated processes. Therefore, in the manufacture of bellows, proper process design and implementation are critical. Today, Aoguang and everyone talk about "manufacturing process of metal bellows tube blanks":
Metal bellows tube blanks are divided into two types: seamless tube blanks and seamed tube blanks.
The manufacture of seamless tube blanks is based on different raw materials and is manufactured using different processes. The material processing plant can provide stainless steel thin-walled seamless pipes with a wall thickness of 0.1 to 0.3 mm and an outer diameter of φ10 to 60 mm. This seamless tube has a high surface finish but a large wall thickness tolerance (+/- 0.03 mm) and is generally used to make spiral bellows and ring bellows with less demanding performance. The metal bellows production plant can use various metal plate (belt) materials with a thickness of 0.8~1mm or standard thin-walled pipes with a wall thickness of 0.5~1mm to manufacture corrugated pipe blanks of various specifications through multiple deep drawing or spinning and drawing processes. This process can produce tube blanks with high surface finish, small wall thickness tolerance (<= +/- 0.005 mm) and short length for the manufacture of high requirements bellows.
The manufacture of the seamed blank is generally carried out by selecting the sheet or strip of the required thickness and after the roll is butt welded. The quality of the seamed tube blank depends directly on the quality of the sheet (belt) and the quality of the weld. In general, the wall thickness tolerance is easier to control.
1. Multiple thinning and deep drawing manufacturing process
The multi-thinning and deep drawing manufacturing process is suitable for the manufacture of bellows blanks with a tube blank length of less than 300 mm. The process mainly includes blanking, multiple drawing, multiple heat treatment and multiple thinning and deep drawing.
2. Steel ball spinning and thinning stretching manufacturing process and equipment
The spinning and thinning of the steel ball is a process in which the blank is deepened and thinned by pressing between the punch, the die and the steel ball under high-speed rotation. The high-speed rotation of the punch (or the die) drives the steel ball itself to rotate and rotates at a high speed along the circumference of the blank. When the blank is axially passed on the punch, the material is deformed by the positive force and the tangential force. .
3. Welding tube blank manufacturing process
The method of manufacturing a bellows tube by welding is a process method with high production efficiency, low cost, easy wall thickness control and strong adaptability. It is currently used to manufacture large diameter bellows tube blanks and to manufacture hose blanks. The welding of bellows tube blanks is currently carried out by gas-shielded DC argon arc welding, micro-arc plasma welding and laser welding. The welding thickness is 0.1mm~1mm, and the materials are 1Cr18Ni9Ti, 0Cr18Ni9, 00Cr17Ni14Mo2 and GH169.
4. Manufacture of multi-layer bellows tube blank
Multi-layer bellows have high pressure resistance, small rigidity and large displacement, and are commonly used to manufacture metal expansion joints and bellows for leak-free valves.
Multi-layer bellows for expansion joints generally have an inner diameter of more than φ80 mm. Most of the tube blanks are reserved for the tube blanks, and are welded into the tube blanks of the corresponding layers.
The casing of the multi-layer tube blank can be made according to the requirements of the corrugated tube product for the quality of the interlayer, and the two methods of the hard casing and the soft casing can be adopted. After the finished hard tube blank is cleaned, the inner and outer surfaces are cleaned, and then directly sleeved, and then subjected to solid solution or annealing heat treatment.
This method is difficult to ensure that the interlayer surface is smooth and there is no excess between the layers due to the heat treatment and pickling process. The hard tube blank is first subjected to heat treatment and pickling, and then softened after obtaining a smooth surface quality. The casing under the state can ensure the quality of the interlayer of the bellows product.
