According to the needs of production development, a factory plans to establish a ball valve sphere processing production line. Since the factory does not currently have complete stainless steel sphere casting and forging equipment (the urban area does not allow production equipment that affects the urban environment), the sphere blanks rely on outsourcing processing , Not only the cost is high, the quality is unstable, but the delivery time cannot be guaranteed, which affects the normal production. In addition, the blanks obtained by these two methods have large machining allowances and low material utilization. In particular, the cast spheres have shortcomings such as capillary air leakage, which leads to high product costs and difficult quality stability, which seriously affects the production and development of our factory. Therefore, it is imperative to reform the sphere processing technology. The editor of Xianji.com will briefly introduce you its processing method.
1. The principle of sphere spinning
1.1 Technical parameters of valve spheres (see Table

1.2. Comparison of sphere forming methods
(1) Casting method
This is a traditional processing method. It requires a complete set of equipment for smelting and pouring. It also requires a larger plant and more workers. It requires a large investment, many processes, complex production processes, and pollutes the environment. Every process The skill level of the workers directly affects the quality of the product. The problem of sphere pore leakage cannot be completely solved, and the rough machining allowance is large, and the waste is large. It is often found that the casting defects make it scrapped during the processing, which will increase the cost of the product. , Quality cannot be guaranteed, this method should not be adopted by our factory.
(2) Forging method
This is another method used by many domestic valve companies at present. It has two processing methods: one is to use round steel to cut and heat forge into a spherical solid blank, and then perform mechanical processing. The second is to mold the stainless steel plate cut into a round shape on a large press to obtain a hollow hemispherical blank, which is then welded into a spherical blank for mechanical processing. This method has a higher material utilization rate, but a high-powered The press, heating furnace, and argon welding equipment are estimated to require an investment of 3 million yuan to form productivity. This method is not suitable for our factory.
(3) Spinning method
The metal spinning method is an advanced processing method with less and no chips. It belongs to a new branch of pressure processing. It combines the technological characteristics of forging, extrusion, rolling and rolling, and has high material utilization (up to 80-90%). ), saving a lot of processing time (1-5 minutes forming), the material strength can be doubled after spinning. Due to the small area contact between the rotating wheel and the workpiece during spinning, the metal material is in a two-way or three-way compressive stress state, which is easy to deform. Under a small power, a higher unit contact stress (up to 25- 35Mpa), therefore, the equipment is light in weight and the total power required is small (less than 1/5 to 1/4 of the press). It is now recognized by the foreign valve industry as an energy-saving spherical processing technology program, and it is also applicable For processing other hollow rotating parts.
Spinning technology has been widely used and developed at a high speed abroad. The technology and equipment are very mature and stable, and the automatic control of the integration of mechanical, electrical and hydraulic is realized. At present, spinning technology has also been greatly developed in my country, and has entered the stage of popularization and practicality.
2. Technical conditions of spinning sphere blank
According to the production needs of our factory and combined with the characteristics of spinning deformation, the following technical conditions are drawn up:
(1) Spinning blank material and type: 1Gr18Nr9Tr, 2Gr13 steel pipe or steel plate;
(2) The shape and structure of the spinning sphere blank (see Figure 1):

3. Spinning scheme
The effect of the sphere spinning is different due to the different blank types selected. After analysis, two solutions are available:
3.1. Steel pipe necking spinning method
This scheme is divided into three steps: the first step is to cut the steel pipe according to the size and clamp it in the spindle chuck of the spinning machine tool to rotate with the spindle. Its diameter is gradually reduced and closed (see Figure 2) to form a semi-circular sphere; the second step is to cut off the formed sphere and process the welding groove; the third step is to weld the two hemispheres with argon solitary welding. The required hollow sphere blank.

The advantages of the steel pipe necking spinning method: no mold is required, and the forming process is relatively simple; the disadvantage is: a specific steel pipe is required, there are welds, and the cost of the steel pipe is higher.