What are the national steel-plastic composite pipe brands

1, Tianjin Steel Pipe: Tianjin Steel Pipe Group Co., Ltd, also known as "Tianjin Big Seamless", is located in Tianjin Binhai New Area, is China's energy industry, steel pipe base. 1989 construction, 1992, the success of the hot test, 1996 officially put into production. The main products are petroleum casing, oil pipe and line pipe, high pressure boiler pipe, high pressure gas cylinder pipe, hydraulic support pipe and other kinds of specialized pipes. At the early stage of construction, the company introduced the world's most advanced steelmaking, pipe rolling, pipe processing and direct reduction of iron equipment and technology from Germany, Italy, the United States and Britain, and was equipped with a perfect automation system, which made the company the most technologically advanced and the largest specialized petroleum pipe production plant in China. Since it was put into production, it has always maintained the leading edge in technology and equipment through continuous technological transformation.

Strengthening and enlarging the main business of steel pipe, improving industrial concentration and creating scale advantages. The steelmaking system has three ultra-high-power electric arc furnaces, the tube rolling system has four models and six sets of mills, namely MPM, PQF, ASSEL and REM, and the tube processing system has 26 production lines, with an annual production capacity of up to 3.5 million tons of seamless steel tubes, making it the world's largest single-plant seamless steel tube production plant. It has adjusted its industrial structure to form a high-end, high-quality and high-tech industrial layout, built a number of high-level projects such as copper, stainless steel plate, color coated plate and high-pressure cylinders, developed new industries such as equipment manufacturing, international trade and logistics, and constructed itself into a comprehensive and large-scale enterprise group with the alternating pull and coordinated development of multi-industries. The comprehensive index of economic efficiency has been ranked in the forefront of national key iron and steel enterprises for consecutive years. It ranks 99th among the top 500 Chinese enterprises and 38th among the top 500 manufacturing enterprises.

Improve product quality, enhance the credibility of the enterprise and create brand advantages. Adhering to the marketing and service concept of "conveying true feelings, *** casting brilliant", the company has constructed a perfect marketing process and service guarantee system to provide users with good pre-sale, sale and after-sale services, realizing the transformation from product marketing to brand marketing. The domestic market share of petroleum casing is maintained at about 40%, and the products are exported to nearly 100 countries and regions. Petroleum casing has become "China Famous Brand Product". Seamless steel pipe became "China Famous Brand Export Commodity", and TPCO trademark was recognized as "China Well-known Trademark". Ltd. was established after the asset reorganization of nine subsidiaries belonging to the former Tianjin Youfa Steel Pipe Group Co. The aim is to standardize the business operation, promote the main steel pipe business to enter the capital market, and ultimately realize the rapid take-off of the enterprise. Founded on July 1, 2000 and headquartered in Daqiuzhuang, Tianjin, the largest steel pipe production base in China, Youfa is a large-scale steel pipe manufacturing enterprise integrating the production of straight-seam welded pipes, hot-dip galvanized steel pipes, spiral welded pipes, square and rectangular pipes, steel-plastic composite pipes and other pipe products. At present, it has formed three production bases in Tianjin, Tangshan and Handan, with two branches, seven subsidiaries, more than 6,000 employees, two brands of "Youfa" and "Zhengyinyuan", more than 60 production lines of LSAW pipes, more than 40 hot-dip galvanized steel pipe production lines, 9 production lines of hot-dip galvanized steel pipes and 9 production lines of steel-plastic composite pipes. It has two brands "Youfa" and "ZhengJinyuan", more than 60 LSAW pipe production lines, more than 40 hot-dip galvanized steel pipe production lines, 9 spiral welded pipe production lines and 20 steel-plastic composite pipe production lines, as well as a nationally accredited laboratory and a Tianjin Enterprise Technology Center. Since 2010, the annual increase of steel pipe production and sales volume has exceeded one million tons for four consecutive years. In 2013, the production of various types of steel pipe 8 million tons.

"Youfa" brand trademark was recognized as "China Well-known Trademark" by Trademark Bureau of State Administration for Industry and Commerce in March 2008, and "Youfa" brand straight seam welded pipe, hot galvanized steel pipe and spiral welded pipe have been produced continuously. The "Youfa" brand straight seam welded pipe, hot galvanized pipe and spiral welded pipe have been awarded the title of "Tianjin Famous Brand Product" by the Tianjin Municipal Government for many years in a row. For 8 consecutive years, Tianjin Youfa Steel Pipe Group has been ranked among the Top 500 Chinese Enterprises and Top 500 Chinese Manufacturing Industries. In 2013, Tianjin Youfa Steel Pipe Group was ranked 459th among the Top 500 Chinese Enterprises, 243rd among the Top 500 Chinese Manufacturing Industries, 136th among the Top 500 Private Enterprises in China, and 90th among the Top 500 Manufacturing Enterprises in China.

3, JULI:

Zhejiang JULI Special Material Technology Co., Ltd (formerly Zhejiang JULI Stainless Steel Tube Co., Ltd.) was founded in 1987, is located in the center of the "Yangtze River Delta" on the south shore of Lake Taihu - Huzhou City, Zhejiang Province, Zhenxi. The company has the world's advanced level of stainless steel, corrosion-resistant alloys, high-temperature alloys seamless pipe (extrusion, piercing, cold rolling, cold drawing) production line and large, medium and small diameter welded pipe production line, has been committed to industrial piping system to provide safe, reliable and high-performance, corrosion-resistant, pressure-resistant, high-temperature stainless steel pipe and special material solutions.

The company has built a perfect quality assurance system, in the operation of ISO9001: 2000 quality assurance system based on the National Nuclear Security Administration nuclear quality assurance system has been through the implementation of the standard. The company has obtained the "Special Equipment Manufacturing License" issued by the General Administration of Quality Supervision, Inspection and Quarantine in 2004. The company has passed ISO14001:2004 and OHSAS 18001:1999 system certification. The company has also passed the EU Pressurized Equipment Directive PED97/23/EC and the factory certifications of CCS China Classification Society, GL Germanischer Lloyd, BV Bureau Veritas, DNV Det Norske Veritas, ABS American Bureau of Shipping and LR Lloyd's Register.

The company is a national high-tech enterprise and a key leading enterprise in Zhejiang Province, with a provincial R&D center and a post-doctoral research station. The company has always adhered to the enterprise spirit of "hard work, win with quality, trust-based" and the business philosophy of "serving users with mature technology and reliable product quality, contributing to society and developing ourselves", and has a high reputation and popularity among customers and in the society. We have a high reputation and popularity among our customers and in the society. The company has been awarded the honor of "National May 1st Labor Certificate", and has been awarded the titles of "Civilized Unit of Zhejiang Province" and "National Unit of Abiding by Contracts and Keeping Credit". "JiuLi" brand stainless steel pipe was also awarded the "Metallurgical Products Physical Quality Golden Cup Award" by China Iron and Steel Industry Association. Through more than twenty years of unremitting efforts and brand building, "JiuLi" trade name has become "Zhejiang Province, well-known trade name", "JiuLi" trademark for "Chinese The trademark of "Jiuli" is "China Well-known Trademark", and the trademarks of "Jiuli" and "Jiuli" have been registered in more than 50 countries all over the world.

4, Hailiang:

Zhejiang Hailiang Co., Ltd (hereinafter referred to as "Hailiang Co." or "the company") is a sino-foreign joint venture company held by Hailiang Group Co. Since its establishment in 2001, the Company has been committed to the research and development, production, sales and service of high-grade copper products, and is the world's largest producer of copper alloy tubes and one of the world-renowned copper processing enterprises, China's largest exporter of copper tubes and the second-largest producer of copper tubes, and one of the top three manufacturers of precision copper rods and one of the most important producers of copper rods. The company was listed on the Shenzhen Stock Exchange on January 16, 2008, with stock code 002203.

As of December 31, 2012, Hailiang has total assets of 6,435,757,000 yuan, net assets of 2,693,661,600 yuan, asset-liability ratio of 58.15%, and more than 4,000 employees; in 2012, the company achieved operating income of 1 ,034,995.27 million yuan, total profit of 247,087,900 yuan, net profit attributable to shareholders of listed companies was 233,529,200 yuan.

Hailiang's products can be divided into two series: copper pipes and copper rods, encompassing nearly 100 grades and thousands of specifications, which are widely used in air-conditioning and refrigerator refrigeration, construction water pipes, seawater desalination, equipment manufacturing, automobile industry, electronic information, transportation, hardware and machinery, electric power and other industries. The company has made a strategic layout of production and sales for its own copper processing industry globally, with a perfect production and marketing network. With four production bases in Zhejiang, Shanghai, Anhui and Vietnam, Hailiang has accumulated a large number of high-quality and stable customers at home and abroad. The company has business dealings with customers in more than 100 countries and regions around the world. A large number of the company's domestic customers are leading enterprises in the downstream industry, and there are more than 300 domestic and foreign customers. In recent years, the company's copper tube products continue to maintain the leading position in the export of precision copper tube industry, international competitiveness is growing.

Hailiang's technology center is a national enterprise technology center, with CNAS national accredited laboratories, key laboratories of the Ministry of Education, national post-doctoral research stations, provincial enterprise research institutes. The company has strong independent innovation ability, and has made obvious technological breakthroughs in the process, molds and new product development of copper tubes for air conditioning and refrigeration, copper water (gas) tubes and fittings, copper alloy tubes, precision copper rods, etc. The technologies and products developed by the company have won 7 Zhejiang Science and Technology awards, 15 Science and Technology awards of the Nonferrous Metals Industry Association, and a number of other awards such as the International, Industry and Provincial Technical Progress Awards.

5, Xinyuantai:

Xinyuantai Steel Pipe Group Co., Ltd. is located in Cangzhou City Economic Development Zone, 80 kilometers away from Huanghua Port, 180 kilometers away from Tianjin Port, close to the Beijing-Shanghai Railway and the 104, 107 National Highway, the traffic is very convenient.

The group is under the jurisdiction of "Xinyuantai Steel Pipe Group Co, Ltd", "Hebei Litonglian Seamless Steel Pipe Co.", "Cangzhou Xinyuantai Storage & Transportation Co.

The group company has 410,000 square meters of land, one straight seam production line, four spiral steel pipe production lines, one hot rolled seamless steel pipe production line. It mainly produces three major types of steel pipes such as ERW medium straight seam welded steel pipes, double filament double-sided submerged arc welded spiral steel pipes and hot rolled seamless steel pipes. The annual production capacity is 500,000 tons, of which: 200,000 tons of Φ219-2220 spiral welded pipes with wall thickness of 6-20; 100,000 tons of high-quality ERW straight-seam welded pipes with wall thickness of 6-14; 200,000 tons of high-precision hot-rolled seamless steel pipes with wall thickness of 5-35mm in Φ140-273 are produced.

The large-diameter, high-grade welded steel pipe project built by the company in cooperation with Shougang is the fifth subsidiary of the company, the project covers a total area of 500 mu, of which the first phase of the production workshop covers 59,404.5m. It is expected that the first production line will be put into trial operation at the end of 2010. The new project will prepare to build four Φ820, Φ1020, Φ1420, Φ1820 high standard spiral submerged arc welding steel pipe production lines. Our company is the largest steel pipe manufacturer in Cangzhou with the most complete varieties and specifications. It is also one of the few professional steel pipe manufacturers in China that integrates the production of straight seam welded pipe, spiral welded pipe and hot rolled seamless steel pipe.

Xinyuantai Steel Pipe Group has always adhered to the "quality-oriented, integrity is gold" business management philosophy, the company's "seven stars" trademark is China's famous trademark. The company has been assessed by the Administration for Industry and Commerce for many years as a unit of honoring contracts and keeping promises, and has been awarded AAA credit rating by the Agricultural Bank of Hebei Province and the Construction Bank of Hebei Province for many years.

The group has passed ISO 9001:2000 quality management system certification, OHSAS 18001:2001 occupational health and safety management system certification, ISO 14001:2004 environmental management system certification, and obtained the national (pressure) certification.

The Group has passed the ISO 9001:2000 Quality Management System Certification, OHSAS 18001:2001 Occupational Health and Safety Management System Certification, ISO 14001:2004 Environmental Management System Certification, obtained the National Manufacturing License for Special Equipment (Pressure Piping), and obtained the American Petroleum Institute's API 5L, API 5CT products' license for the use of the standard.

6, Changbao:

Su Changbao Steel Pipe Joint Stock Company is a professional engaged in a variety of energy pipe production and service providers, is the key manufacturer of domestic oil well tubes and one of the country's key manufacturers of small-diameter alloy high-pressure boiler tubes, China Petroleum Marketing Corporation, "Energy No. 1 network" member units and boilers. It is a member unit of "Energy One Network" of China Petroleum Marketing Corporation and an A-level (excellent) supplier of three leading boiler enterprises. The company's products are used in petroleum, electric power, nuclear power, natural gas and other energy industries, and widely exported to Europe, America, the Middle East, the CIS, Southeast Asia and Africa and other countries and regions.

The company was established as a joint stock limited company on February 2, 2008, and on September 21, 2010, the company was listed on the Shenzhen SME board. Stock code 002478, total share capital of 400.1 million shares after issuance. In the next three years, the company will take advantage of the power of the capital market to complete the layout of the four major energy pipe industry, namely, the oil mining industry pipe, high-pressure boiler pipe for large power stations, natural gas transmission pipe, nuclear power pipe.

The company is located in Changzhou City, Jiangsu Province, which is in the developed area of Yangtze River Delta, and the main factory covers an area of 260,000 square meters, adjacent to Shanghai-Nanjing Expressway and Beijing-Hangzhou Grand Canal, and there is a special railroad line to Shanghai-Nanjing Railway, which makes the transportation very convenient.

The company is equipped with the first set of φ102 hot rolled steel pipe unit for top pipe in China, which introduces CPE process, with an annual production capacity of 180,000 tons; Changzhou Changbao Precision Steel Tube Co., Ltd. which is under the control of the company has the precision cold-drawn and cold-rolled pipe production line, with an annual production capacity of 100,000 tons; Jiangsu Changbao Pleasant Pipe Co., Ltd. which is under the control of the company is equipped with the φ177 hot rolled steel pipe unit, with an annual production capacity of 150,000 tons. The production of oil well pipes, boiler tubes, precision mechanical tubes, geological tubes, marine tubes, petrochemical tubes, structural tubes, pipeline tubes and other varieties to form a series. The production capacity of the main products is 350,000 tons of finished oil well pipes and 100,000 tons of high pressure boiler pipes.

The company has advanced technical equipments, complete technology and testing means. Through ISO9001, 14001, 18001 management system certification, the United States API standard certification, TUV certification, the European Union PED and AD W2000 certification, the Russian GOST certification, with PetroChina "Energy One Network" membership certificate and some of the country's major oilfield supplier access certificate, as well as China's three major power group boiler plant A-grade supplier certificate. We have certificates of PetroChina's "Energy One Network" membership and some major domestic oilfield supplier access certificates, as well as certificates of China's three major power groups' boiler plant's A-class supplier recognition and Shanghai Electric Nuclear Power Equipment Company's qualified supplier recognition.　

7, Yulong:

Beautiful scenery, outstanding people and spirit of the Jiangnan town - Wuxi Yuqi, with a unique location advantages, developed transportation network, perfect infrastructure construction, has bred a large number of outstanding private enterprises.

Jiangsu Yulong Steel Pipe Co., Ltd. is one of the most outstanding new stars in this magical land. Jiangsu Yulong Steel Pipe Co., Ltd, formerly known as Wuxi County High Frequency Welded Pipe Factory, has become the largest spiral submerged arc welded steel pipe production base in East China after thirty years of baptism in the market and getting rid of the systematic constraints of the planned economy, the company covers an area of 320,000 square meters, with a total asset of 700 million yuan, more than 1,000 employees and an annual sales income of more than 3 billion yuan, and it is one of the top 500 private enterprises in China, and the most powerful specialized manufacturer of oil, gas, and petroleum pipes. The company is one of the top 500 private enterprises in China and one of the most powerful manufacturers specializing in the production of steel pipes for oil, natural gas, water transportation and large-scale steel structure. Yulong owns 10 sets of Φ219-Φ2540 SAWH spiral submerged arc welded steel pipe units with an annual production capacity of 400,000 tons; one set of Φ1422 Φ813 SAWL straight-seam submerged arc welded steel pipe units each with an annual production capacity of 250,000 tons; Φ168 Φ508 HFW straight seam high-frequency resistance welded steel pipe two sets, with an annual production capacity of 200,000 tons; 400 × 400 250 × 250 300 × 300 square and rectangular pipe units, each one set, with an annual production capacity of 200,000 tons; Φ920 Φ2020 3PP/3PE/FBE inside and outside the anticorrosion production line two sets, with an annual production capacity of 2.5 million square meters.

Yulong is the director of China Steel Pipe Association, the director of China Cold-Formed Steel Association, the director of China Construction Metal Association, the member of China City Gas Association, the qualified supplier of China Petroleum and Natural Gas Pipeline Bureau, and the first-class qualified supplier of China Petroleum & Chemical Corporation, and "Yulong Brand" square and rectangle pipes are recognized as high-tech products of Jiangsu Province, and "Yulong Brand" square and rectangle pipes are recognized as high-tech products of Jiangsu Province. Yulong brand" square and rectangular pipes are recognized as high-tech products in Jiangsu Province, "Yulong brand" trademark is recognized as China's well-known trademark, the enterprise was named the national contract and trustworthy enterprises.　

8, Lida LIDA:

Tianjin Lida Steel Pipe Group Co., Ltd, formerly known as Tianjin Lida Steel Pipe Factory, was founded in 1993 and restructured as a whole to become Tianjin Lida Steel Pipe Company Limited in July 2006, and reorganized to establish Tianjin Lida Steel Pipe Group Co. Tianjin Lida Steel Pipe Group Co., Ltd. is located in Wangcun Industrial Park, Dasi Town, Xiqing District, Tianjin City, which consists of: Tianjin Jinghai Zhenxing Galvanized Pipe Co.

Tianjin Leader Steel Pipe Group Co., Ltd. has more than 2,000 employees and 300 million yuan of fixed assets. It has 11 high-frequency welded pipe production lines (ф21.3mm-ф340mm), 8 longitudinal shearing lines, 10 hot-dip galvanized steel pipe production lines (ф21.30-ф219.10), and 6 steel-plastic composite pipe production lines (ф21.30-ф219.10), and it has already formed an annual production capacity of nearly 1 million tons of high-frequency welded pipe, and nearly 1 million tons of hot-dipped galvanized steel pipe, and nearly 1 million tons of hot-dipped galvanized steel pipe. The company has formed an annual production capacity of high-frequency welded steel pipe of nearly 1 million tons, hot-dipped galvanized steel pipe of nearly 400,000 tons, steel-plastic composite steel pipe of 30,000 tons, the company has passed the ISO9000 international quality system certification in 2000, and in 2004 to obtain the use of API 5L and API 5CT will be the permit to use the standard in 2010 "Leader" trademark was recognized as "China Well-Known Trademarks" by the State Administration for Industry and Commerce of China. In 2010, the trademark "Leader" was recognized as "China Well-known Trademark" by the State Administration for Industry and Commerce of China.

Products are mainly used in oil and natural gas pipelines, industrial and civil water supply, gas supply, heating, oil supply and construction hardware and other fields; marketing more than 20 provinces and cities, and exported to Europe, North America, Africa, Southeast Asia and other countries and regions, the sales network to form a healthy and stable marketing network based in Beijing and Tianjin as the center, based on North China, facing the whole country, radiating to the world, with excellent quality, reliable reputation, professional thermal insulation and high quality products. With excellent quality, reliable reputation, professional and enthusiastic service, we are trusted by customers at home and abroad.

Lida enterprise was founded nearly twenty years ago. After years of dedicated development and strategic management, Lida has developed into a group of enterprises with Tianjin Lida Steel Pipe Group Co. Has formed an annual sales income of nearly 5 billion yuan, more than 2,000 employees products are mainly used in oil and natural gas pipelines, industrial and civil water supply, gas supply, heating, oil supply and building hardware and other fields; marketing more than 20 provinces and cities, and has been exported to Europe, North America, Africa, Southeast Asia, and Australia and other countries and regions, the marketing network centered on Beijing and Tianjin, based on North China, facing the whole country, radiating globally. The marketing network is centered on Beijing and Tianjin, based on North China, facing the whole country and radiating globally. As early as 2000, the whole series of products have passed the ISO9001:2000 international quality system certification, and in 2004, we obtained the license of API 5L and API 5CT. In 2010, the group invested in Vietnam to set up a wholly-owned holding company, "Vietnam Leader Limited Liability Company", the group realized a faster development and more favorable conditions. In 2010, the Group invested and established a wholly-owned holding company "Vietnam Leader Limited Company" in Vietnam, which has enabled the Group to realize faster development and more favorable to the occupation of overseas markets by our products.　

9, Huaqi:

Jinghua Innovation Group Co., Ltd. was approved by the State Administration for Industry and Commerce in January 2003, and formally registered in February 2003, with a registered capital of 580 million yuan and more than 5,000 employees. Under the jurisdiction of wholly-owned and holding enterprises are: Hengshui Jinghua Tube Manufacturing Company Limited, Tangshan Jinghua Tube Manufacturing Company Limited, Guangzhou Jinghua Tube Manufacturing Company Limited, Chengdu Pengzhou Jinghua Tube Manufacturing Company Limited, Laiwu Jinghua Tube Manufacturing Company Limited, Jilin Jinghua Tube Manufacturing Company Limited, Zhengzhou Jinghua Tube Manufacturing Company Limited, Hengshui Jinghua Real Estate Development Company Limited, Hengshui Jinghua Chemical Industry Company Limited, Beijing Qinghewan Rural Sports Club Co. Ltd. is one of the top ten private enterprises in Hebei Province.

The group takes steel pipe manufacturing as its main business, with a production capacity of 5 million tons, ranking among the front ranks of peers in terms of scale and variety. The company's main product "Huaqi" brand series of steel pipe, involving straight seam welded pipe, hot-dip galvanized steel pipe, spiral submerged arc welded steel pipe, oil pipeline steel pipe, oil casing, oil pipe, FBE petroleum anticorrosive steel pipe, 3PE petroleum anticorrosive steel pipe, and so on more than ten kinds of categories. The products are exported to Asia, Europe, Africa and more than ten countries and regions, the products can be in accordance with the national standard, American standard, British standard, Japanese standard, German standard, oil and gas, chemical industry, fire and other industry standards for the production of steel pipe to the X80 steel grade; covering GB/T 9711-2011 PSL1, GB/T 9711-2011 PSL2, API 5L, 5CT, ASTM A53, EN10217, EN10219, SY/T 5037 and other pipeline steel standards of most varieties and specifications, applicable to oil, natural gas, shipbuilding, chemical industry, environmental protection, water conservancy, electricity, steel structure, construction and other fields.

The Group has always adhered to the business purpose of "survival by quality and development by reputation", which has been recognized and praised by our customers. Huaqi" brand steel pipe produced by the group has passed GB/T19001-2000 quality management system certification, GB/T24001-2004 environmental management system certification, GB/T28001-2001 occupational health and safety management system certification and API product quality certification, and has been awarded the "Hebei Famous Brand". It has been awarded the honors of "Hebei Famous Brand", "Socially Recognized Satisfactory Product", "China Recognized Famous Brand Product" and so on.

10, Pearl River PCK:

Pearl River Steel Pipe is China's largest manufacturer and exporter of LSAW pipes, listed on the main board of the Hong Kong Stock Exchange in 2010 (stock code: 01938.HK), with six production bases located in Panyu, Guangzhou, Zhuhai, Jiangyin, Jiangsu, Lianyungang, Saudi Arabia and Dubai.

Currently, Pearl River Steel Pipe has been ranked No. 1 in the country for 10 consecutive years in terms of the output of LSAW pipes, taking the leading position in the industry. In addition, Pearl River Steel Pipe is currently the only company in China that simultaneously holds the "China Metallurgical Products Physical Quality Golden Cup Award", "National Torch Plan Key High-Tech Enterprise" and "Nationally Recognized Enterprise Technology Center "It is the only welded pipe manufacturer with three national honors at the same time, and is the main drafting unit of the national standard of LSAW steel pipe. At the same time, Pearl River Steel Pipe has a post-doctoral research station and academician workstation, which constantly improves the quality of products and expands the applicable fields of products.

Steel pipe (Steel pipe) is used for conveying fluids and powdery solids, exchanging heat energy, manufacturing mechanical parts and containers, and is also a kind of economic steel.

The development of steel pipe production technology began with the rise of the bicycle manufacturing industry, the development of oil in the early 19th century, the manufacture of ships, boilers and aircraft during the two world wars, the manufacture of coal-fired boilers after the Second World War, the development of the chemical industry, as well as oil and gas drilling and transportation, etc., have been strongly driven by the development of the steel pipe industry in terms of varieties, output and quality.

Steel pipe can be divided into two main categories according to the production method: seamless steel pipe and seamed steel pipe, seamed steel pipe referred to as straight seam steel pipe.