Traditionally, refrigeration pipes for air-conditioning products use copper pipes. China's aluminum resources are relatively abundant, and the aluminum industry is also more developed. Therefore, aluminum substitutes for copper for air-conditioning and refrigeration lines has become a general trend. Calculated only in China's air-conditioning market, the annual sales volume of 50 million units means that there will be nearly 2 billion yuan of copper-aluminum connecting pipe market capacity each year. At the same time, it will also reduce the amount of copper used for 50,000 tons. After more than one year, Qingdao Haiqing Machinery General Factory adopted thin-wall copper-aluminum pipe welding technology to produce a new type of copper-aluminum air conditioning connecting pipe. After the product was put into the market, because its sales price was reduced by half compared with copper tubes, plus its performance, service life, and ease of installation were all superior to those of pure copper tubes, it quickly won the favor of air conditioner manufacturers, and its products were in short supply. At present, most domestic air-conditioning companies have applied this technology product, and air-conditioning companies in South Korea and Japan have begun to use this technology product. At the same time, its product quality has withstood the market inspection. Since it was put into production in 2004, it has put nearly 6 million sets of copper-aluminum air-conditioning connecting pipes on the market, with a passing rate of 100%.