A New Look at Thermal Spray Equipment

       Recently, my country has accelerated the pace of equipment development and production. At present, a complete development and production system has been formed. There are more than 20 units engaged in the development and production of thermal spraying equipment, which can produce various types of oxyacetylene flame spraying equipment and spray melting equipment; New arc spraying equipment; complete sets of plasma spraying equipment, spray welding equipment; various special machine tools; thermal spraying air purification equipment, pre-processing and post-processing equipment. There are more than 100 varieties of single machines. The development and production of these products ensure the development of supersonic spraying technology. The more prominent ones are:

1. High-speed flame spraying device

At present, the high-speed flame spraying equipment and supersonic plasma spraying equipment imported from abroad are characterized by high particle flight speed, high bonding strength between coating and substrate, and low porosity. These equipments have been used in aerospace, aviation, metallurgy, chemical industry and electric power Industry plays an important role. However, the above imported equipment is expensive, and the fuel (propane, propylene) is not easy to popularize. In view of the above situation, combined with my country's national conditions, Sichuan Great Wall Spraying Technology Research Institute has successfully developed a high-speed spray gun with oxyacetylene flame as a heat source. Due to the limitation of acetylene pressure, although the particle flight speed cannot reach supersonic speed, it is 4-5 times faster than conventional oxyacetylene flame powder spraying, and 1-2 times higher than atmospheric pressure plasma spraying. Spray metal and alloy powder materials include Al2O3-TiO2-CO-WC and thermoplastic powder materials such as polyethylene and nylon. In addition, Xi'an Jiaotong University and other units have successfully developed a high-speed flame spraying device and started to apply it.

2. High-speed arc spraying device

Because arc spraying has the advantages of high bonding strength, low energy consumption, and low cost, this kind of equipment has been paid more and more attention in China in recent years, and it has been actively used, especially in large-scale long-term protection projects of steel structures and power stations. Boiler piping has played an important role in thermal corrosion. On the basis of ordinary arc spraying, the Armored Forces Engineering College of the National Industry-University-Research Equipment Engineering Center and the Xi'an Second Artillery Engineering College have recently successfully developed a high-speed arc spraying gun with an air velocity of more than 600m/s. Many other indicators are better than ordinary arc spraying, and it is being further promoted and applied.

3. Oxygen-acetylene flame metal powder spraying device

Oxygen-acetylene flame metal powder spraying technology is currently widely used in China, and almost all large enterprises use it as a means of repairing old and reusing waste. Shanghai, Jiangsu, Wuhan, Sichuan and other places have developed and produced various types of spraying and spraying torches, which have been widely used for spraying units. Shanghai Welding, Cutting and Spraying Machinery Factory has recently improved on the basis of the original qht-7/h flame spray gun, using two sets of nozzles and using two heat sources: oxygen-acetylene flame and oxygen-liquefied petroleum gas (household bottled). The use of bottled liquefied petroleum gas as the combustible gas can greatly reduce the cost and bring greater convenience to the spraying operation.

4. Gas detonation spraying device

The 621 Research Institute of the Aerospace Corporation has been developing since the 1960s, and has now installed a complete set of gas explosion spraying equipment, which has sprayed many high-density and high-quality coatings for aerospace, aviation and other military industries. The equipment has reached or is close to foreign countries. similar product level.