The new shot peening process was applied to meet the different requirements of DBAG and S-Bahn, which were developed separately. These processes enable automated cleaning of the surface of the wheelset as the wheels are ready for NDT. The surface layer of the wheelset is a mixture of a variety of different coatings (eg paint), residues and foreign contaminants. Non-destructive testing requires a clean metal surface.

For this reason, vacuum blasting is an ideal process. The operating plans of the above two companies are also different. Ultrasonic flaw detection requires a partially cleaned metal surface and the surface of an axle used for magnetic particle inspection must be completely clean.

In the conventional shot peening process conditions, there is a need for a shot peening room, but it is not without a problem to arrange this equipment in the wheel lining maintenance process chain, for example, an additional transport path needs to be arranged. The use of a vacuum blast cleaning process provides a multiple choice process that can solve this problem.

1 No blasting "Blast cleaning without blasting" Shot blasting can be inserted directly into the cleaning process chain in the wheel repair and maintenance process chain. This helps reduce operating costs.

In the vacuum blasting process conditions, the air compressor was replaced by an industrial air extractor. It produces a stream of air through negative pressure. In this air stream, shot peening is metered in, carried, and accelerated within a steel lance. The impact on the surface produces the same cleaning effect as under other shot blast conditions. However, due to the effect of the inhalation flow, not only the shot peening but also the contaminants that have been stripped are also sucked away. All the particles flow through a filter screen and are separated on it, so the only clean air is discharged.

In principle, a negative pressure is required for the entire process, so it can only be produced within a closed mechanical system. Even if there are some leaks in the system, dust or steel shots cannot escape into the surrounding environment because atmospheric pressure will only push air into the system. Once this shot peening system is turned on, shot peening will automatically stop. The industrial exhaust or vacuum machine used is fully compliant with the noise standards, so no additional noise interference is generated at the surrounding workplace.

2 Shot blasting in sensitive areas Since it is a closed system, it is possible to perform shot peening without taking comprehensive safety measures. The system does not produce dust without noise. There is no special requirement for labor protection. This makes it possible to use it in the most sensitive area, for example, in a paint shop. It is also possible to carry out shot peening without wearing a mask even in a boiler because fresh air is continuously supplied by suction, according to the suction machine. With different power, the air flow can reach several cubic meters per minute. Dust will not leave the blasting system.

We have used these advantages to develop a shot peening chamber for shot blasting of the entire Berlin metropolitan wheel pair. The entire wheel pair can be placed in it (see and 2). Five automatically controlled spray guns clean the wheel pairs that spin in the shot room. After the wheelsets left the blasting chamber, they could be subjected to magnetic particle inspection. In the 15 months of equipment work, the city subway department performed blast cleaning and non-destructive testing on about 1,400 pairs of wheels. Compared with the obvious improvement, it is precisely because of its good use effect that we plan to produce more such shot blasting equipment this year.

Vacuum Peening Room "Inner Cleanup Wheel Pair Puts Wheelsets Into The Peening Room"

Deutsche Bahn AG uses an ultrasonic flaw detection method. In order to facilitate flaw detection, twenty-six strips of approximately 50 mm in width were shot blasted on the axle (see ), so another solution was developed.

That is, these small movable spray hoods are moved by hydraulic cylinders to their own rotating rails to form a closed system (see). By generating a negative pressure in the spray hood, shot peening starts and a shot peening process is thereby formed. Depending on the number of spray hoods, there will be 2 6 marks left on the axle. This creates conditions for successful ultrasonic flaw detection. Since the equipment was put into use at Deutsche Bahn AG, it had been prepared for the pre-detection clean-up of more than 7,200 pairs of wheeled vehicles in about 10 months.

3 Other advantages From whatever perspective, the vacuum blasting process is economical. On the one hand, vacuum machines are generally cheaper than compressors, so the total investment will be reduced; on the other hand, the necessary inspection costs for pressure vessels and pressure equipment are completely unnecessary. Maintenance of the system is generally limited to replacing, cleaning the filter, and replacing wear parts. In fact, it can also use a variety of commonly used spray material. The consumption of the spray material is very small because no shots are lost in the closed system.

Partial cleaning of the wheelsets Overview of the vacuum blasting equipment for the Berlin S-Bahn Before the air passes through the filter, unconsumed spray material can be recovered and returned to the shot-blasting process. After that, the air will eventually be purified and its work completed. Depending on the specific conditions, the shot peening cycle can be between 5,500 cycles. Under the conditions of the Berlin metro and the use of Deutsche Bahn AG, an inexpensive shot peening can generally complete 68 cleaning cycles. Therefore, if the shot peening quality is required, quality shot peening may also be selected because it can be fully utilized for a long period of time, and the process advantages of vacuum peening can be fully utilized to achieve a good cost/characteristic ratio. In addition, it is also possible to eliminate the need for additional investment in costly labor protection measures and other applications. It is not possible to demonstrate the wide applicability of openwork shot blasting “based on the above two application examples.” After summarizing a great deal of practical experience and developing many different application ranges, examples are as follows: stripping of auto parts or copper conductors; removal of coating on the surface of galvanized sheet or part; cleaning of axles or castings and insulators of railway vehicles Surface; matt finish of glass or high-grade steel; marking of company logos or product serial numbers; roughening as preparation for bonding, welding, and coating processes; deburring and flashing of cast aluminum, stamped, or milled parts Processing operations; polishing of welds, milled parts or castings; shot peening of metal surfaces.

The latest development is the use of vacuum blasting equipment for surface zinc coating at room temperature. That is, using a special zinc powder mixture to spray "a zinc coating layer, it is very attractive as a variety of different rust protection measures. Also, there is often a demand for a specific surface, especially the formation requirements. The need for surface roughness in order to create the necessary conditions for the application of special processes in the field of rust prevention. With the equipment currently used, it has been possible to form a rough depth of approximately 70 m on rolled steel plates.

Zhang Yanru's translation of Yunji School (continued from page 12) The EMU produced by Japan's Sumitomo Light Metal Company runs on the Shinkansen in Japan. Its car floor is welded with FSW/welding technology.

4 Conclusion The FSW welding process is being commercialized in the production of aluminum alloy vehicles around the world. There are several manufacturers of equipment that can provide suitable welding equipment.

Together, they will make the FSW welding process out of the laboratory and use it in the production workshop. This will inevitably make the FSW welding process more widely used in the railway industry.

Wafer Butterfly Valve

Wafer Butterfly Valve

Summary:

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Unique Design:

The disc and the stem are connected without the structure of pin bolts, which guarantees no inner leakage.

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The valve body is coated with epoxy resin without any exposure of iron.

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The epoxy resin and rubber used comply with sanitary standard DVGW

Appling Area:

The valve can be used in water supply and drainage, disposing of polluted water, heat supply, gas, ship industry, metallurgical industry, energy system and textile and so on, especially applicable to those occasions that bi-directional sealing and valve body are easily eroded.

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