1. Youfa Steel Pipe is a professional welded steel pipe manufacturer with strong comprehensive strength in China. It owns 178 patented technologies, participates in drafting/revising 18 national/industrial standards, and forms four production bases. A large enterprise group integrating the production and sales of straight welded pipe, hot-dip galvanized steel pipe, square rectangular steel pipe, hot-dip galvanized square rectangular steel pipe, plastic-lined composite steel pipe, spiral welded pipe, stainless steel pipe and other products. (CN 10/CNPP brand researcher's professional evaluation) 2. jinzhou area jindi company, founded in 198 1, is a large-scale high-tech listed company focusing on research and development: D, mainly manufacturing high-grade petroleum industrial pipelines and a new generation of green civil pipelines. It has more than 0/00 authorized patents and participated in the formulation and revision of 25 national and industry standards. As a large-scale comprehensive pipeline production and scientific research base, it has an annual production capacity of 6.5438+0.8 million tons of various pipelines, including eight series of products with hundreds of specifications and varieties. 3. Juncheng Pipeline Beijing Juncheng Industry Investment Group was established on 20 10. It is a high-tech enterprise specializing in manufacturing hot-dip galvanized steel pipe, straight welded pipe, square steel pipe, spiral steel pipe, steel-plastic composite pipe and other pipeline products, and is a national steel pipe standard-setting unit. With more than 100 invention patents and a production capacity of more than 5 million tons, it is committed to building an industrial manufacturing enterprise focusing on key projects and making up for the shortage of 10,000 yuan. 4.LIDA Steel Pipe Lida was established in 1992, which is a high-tech enterprise specializing in the production of straight-seam high-frequency welded pipes, galvanized steel pipes and steel-plastic composite pipes. Is a large-scale energy steel pipe manufacturing service provider with a number of independent intellectual property rights and patents. It has 9 sets of high-frequency welded pipes, 7 sets of hot-dip galvanizing line 10 and steel-plastic composite line, with an annual output of 800,000 tons of straight-seam high-frequency welded pipes, 700,000 tons of hot-dip galvanized steel pipes and 70,000 tons of steel-plastic composite pipes. Huaqi, founded in 1993, is a high-tech enterprise under Jinghua Rigang Holding Group. It is a large-scale steel pipe manufacturing enterprise integrating steel pipe R&D, design, manufacture, sales and service. Mainly engaged in Jinghua and Huaqi brand series steel pipes, involving more than ten kinds of pipes such as welded steel pipes, hot-dip galvanized steel pipes and spiral seam submerged arc welded steel pipes. The annual production and sales volume of various steel pipes is 2.3 million tons, and the products sell well in more than 60 countries and regions such as Asia, Europe and the United States.