Analysis of the technological scheme of the hottes

Analysis of ball valve ball process scheme

Abstract: ball spinning process is an advanced processing method with less and no chips, which is a new branch of pressure processing. It integrates the characteristics of forging, extrusion, ring rolling, stretching, bending and rolling, and has the advantages of less investment and high material utilization rate; Stable quality, saving a lot of processing time

this paper is based on Fuzhou instrument valve factory's exploration of ball processing on the basis of ball valve ball processing technology for many years, combined with new ball processing technology at home and abroad

Fuzhou instrument valve factory plans to establish a ball valve ball processing production line according to the needs of production development. In view of the fact that the factory currently does not have perfect stainless steel ball casting and forging equipment (production equipment that affects the urban environment is not allowed in the urban area), the ball blanks rely on outsourcing processing, which not only costs high, the quality is unstable, but also the delivery time cannot be guaranteed, affecting normal production. Moreover, the blanks obtained by these two methods have the disadvantages of large machining allowance, low material utilization, especially the casting ball has the defects of pores and air leakage, which leads to high product cost and difficult to stabilize quality, which seriously affects the production development of our factory. Therefore, it is imperative to reform the ball processing technology

1. Principle of ball spinning

(2) comparison of ball forming methods

a casting method

this is a traditional processing method, which requires a complete set of smelting, pouring and other equipment, as well as large workshops and more workers, with large investment, many processes, complex production processes, and environmental pollution. Each outdoor lighting measurement method gb/t 15240 (9) workers in four processes have a direct impact on the quality of products, The problem of ball pore leakage cannot be completely solved, but the blank processing allowance is large and the waste is large. It is often found that it is scrapped due to casting defects in the processing process, so that the product cost increases and the quality cannot be guaranteed. This method is not suitable for our factory

b forging method

this is another method adopted by many domestic valve enterprises recently. It has two processing methods: one is to use circular cutting, heating and forging to form a spherical solid blank, and then carry out mechanical processing. The second is to mold the round stainless steel plate on a large press to obtain a hollow hemispherical blank, and then weld it into a sphere blank for machining. This method has a high material utilization rate, but it requires a high-power press, heating furnace and argon arc welding equipment. It is estimated that the investment will need 3million yuan to form productivity, and this method is not suitable for the situation of our factory

c spinning method

metal spinning method is an advanced processing method with less and no chips, which belongs to a new branch of pressure processing. It integrates the process characteristics of forging, extrusion, rolling and rolling. It has high material utilization rate (up to 80-90%), saves a lot of processing time (forming in minutes), and the material strength can be doubled after spinning. During spinning, the spinning wheel contacts with the workpiece in a small area, and the metal material is in the state of two-dimensional or three-dimensional compressive stress, which is easy to deform. Under a small power, a higher unit contact stress (up to 25-35mpa) can be obtained. Therefore, the equipment has a light load and the total power required is small (as small as 1/5-1/4 of the press). Now, it is recognized by the foreign valve industry as an energy-saving ball processing technology scheme, At the same time, it is also suitable for processing other hollow rotating parts

spinning technology has been widely applied and developed at a high speed abroad. The process and equipment are very mature and stable, and the automatic control of mechanical, electrical and hydraulic integration is realized. At present, the spinning technology has also been greatly developed in China, where the income loss caused by fabricated auto parts, consumer goods, medical equipment, packaging and electronic consumer goods has also been reduced, and has entered the stage of promotion and application

2. Technical conditions of spinning ball blank

according to the needs of our factory and in combination with the characteristics of spinning deformation, the following technical conditions are formulated:

(1) material and type of spinning blank: steel pipe or steel plate of 1gr18nr9tr and 2gr13

(2) shape and structure of spinning ball blank:

3. Spinning forming scheme

ball spinning has the same effect due to different blank types. After analysis, two schemes can be used:

(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, clamp it in the spindle chuck of the spinning machine, and rotate with the spindle, The spinning wheel spins the tube blank several times with the help of the hydraulic profiling device, so that it gradually shrinks and closes, forming a semicircular sphere; The second step is to cut off the formed sphere and process the welding groove; The third step is to butt weld the two hemispheres with argon arc welding to form the required hollow sphere blank

advantages of pipe necking spinning method: small need of mold, simple forming process; The disadvantages are: specific pipe making is required, there are welds, and the pipe making cost is high

(2) steel plate general rotation method

this scheme has two ways: the first way is to use the jacking force of tail sequence hydraulic pressure to press the flat circular material tightly on the outer end face of the spherical core mold, rotate together with the main shaft, and use the hydraulic profiling device to gradually shrink and deform the half plate after several times of spinning, and attach it to the core mold to obtain a hollow hemisphere, then cut off the excess burrs and process the welding slope 1 The electronic universal material testing machine has three protection methods, and then the two hemispheres are butt welded with argon arc welding to form the required hollow sphere blank

in the second method, the flat blank is also used for general spinning. The difference is that after spinning into a hemispherical shape, it is also necessary to spin out a section of cylindrical semi-finished products, and then install the semi-finished products into the inner hemispherical core mold, use the tailstock ejector rod with the same diameter to compress, and carry out the same spinning method as the necking of the steel pipe. The cylindrical section is gradually shrunk (closed) to form the other half ball, and the excess metal material of closing is pasted on the ejector rod, Finally, the redundant part is cut off to obtain a required whole hollow ball blank

advantages of this method of steel plate general rotation: it is convenient to make plates and seek sources, and the price is lower than that of pipe making, and it can realize a complete hollow structure sphere. Compared with the scheme before the pipe necking spinning method, the disadvantage is that it requires two core molds, the spinning process is complex, the structure and control of the spinning equipment are complex, and the equipment cost is high. However, from the perspective of economic benefits and product quality, this scheme is still the best scheme

4. Selection of spinning machine tool

warm spinning machine tool is composed of three parts: mechanical, electrical and hydraulic. It is a more advanced medium-sized machine tool with electromechanical hydraulic integration. It is composed of spindle gearbox, hydraulic ejector, tail sequence, roller frame, bed and other parts. In terms of hydraulic transmission, there is a hydraulic station and its hydraulic system, which provides all the power for the machine tool except for the rotation of the spindle. The horizontal direction of the spinning wheel is the spinning profiling control device, including profiling valve, profiling plate, training mechanism and support

in terms of electric control, advanced computer automatic control is adopted to realize the automation of spinning process

5 conclusion

the comparison of the above various processing schemes shows that the ball blank produced by plate spinning is the best scheme, which meets the expectations both in technology and product quality. Therefore, it is necessary to regularly check the temperature, vibration and internal wire effects of electromechanical devices. However, everything has its two sides. The process of flat spinning sphere is complex, and the required spinning equipment structure and automatic control have high requirements, which limits its promotion