According to the statistics of the steel structure industry, the proportion of stainless steel seamless pipes in the construction steel structure accounts for about 14%. During the “Twelfth Five-Year Plan” period, the output of steel for steel structure in 2015 was about 50 million tons; according to the ratio of 14%, the amount of steel pipe used was about 7 million tons. According to the “13th Five-Year Plan” of the iron and steel industry (“Steel Industry Adjustment and Upgrade Plan (2016~2020)”, China’s steel structure production should reach 100 million tons by 2020, when the steel structure steel pipe is 14 million tons. .

"China's steel structure residential construction sector faces industrialization solutions lacking steel structure system and lack of matching key technologies such as matching enclosure system, fireproof and anti-corrosion technology and high-efficiency assembly connection, lacking bottlenecks such as demonstration of industrialization projects that can be replicated and promoted. Question.” On March 31 this year, Hou Zhaoxin, chief engineer of China Metallurgical Construction Research Institute and director of China Steel Structure Expert Committee, pointed out at a national technical seminar. At the same time, the current real estate control policy is still tightening, 45 cities across the country have issued more than 140 times the order rectification policy, which will have a negative impact on the growth rate of real estate investment. Under the influence of the above two uncertain factors, the author speculates that the application of steel pipe in China's construction steel structure in 2017 is about 8 million tons.

In different building structures, different tubular stainless steel pipes are used in different proportions. In the main building steel pipe structure, the proportion of stainless steel seamless steel pipe is about 25%, the specification is ≤ ф500mm; the amount of straight seam submerged arc welded pipe is about 65%, the specification is ≤ ф800mm; the dosage of high-frequency straight seam welded pipe is about 10%. Specifications ≤ ф219mm; steel grade is generally Q345~Q390. The main body steel structure of the ground is rarely used with a spiral submerged arc welded pipe, so it is omitted here. The form of the steel pipe structure can be divided into four types: grid (shell), truss, frame and concrete-filled steel tube structure.

Stainless steel seamless steel pipes are mainly used in main building space structures in large building steel structures. The steel beam column becomes the main material of the steel structure, and the steel stringer is used as the auxiliary material. For example, the main steel pipe structure of the China Pavilion at the Shanghai World Expo is 4,000 tons, including 1200 tons of seamless steel pipes. The specifications are ф450mm×42mm, ф406mm×35mm, ф299mm×25mm, ф245mm×20mm, ф114mm×10mm. For example, the main structure of the Tianjin Vocational and Technical University Gymnasium is made of ф325mm×12mm seamless steel pipe with a span of 60m, a total length of 78m and a total weight of 1,000 tons.

Hot rolled square rectangular tubes are used in large stadium steel structures. For example, the new building of the Capital Museum and the main building of Guangzhou New Baiyun Airport, the connecting bridge, the fingering corridor and other steel pipe structures, the square tube specifications are F500mm×500mm×22mm, F500mm×500mm×16mm, and the rectangular tube is J500mm×300mm×16mm. . For example, the main truss chord of Guangzhou Zhengjia Commercial Plaza is F450mm×450mm×25mm/35mm; the straight rib is F450mm×450mm×20mm/30mm; the secondary truss chord is J450mm×350mm×16mm/20mm/25mm/35mm; The web is J450mm×350mm×16mm/20mm/25mm/35mm. For another example, the maximum thickness of the hot-rolled square rectangular tube for the steel structure of the Beijing Olympic National Swimming Center (“Water Cube”) is 40 mm, such as J450mm×300mm×40mm. The seamless square rectangular steel tubes used in the construction of the above steel structure were imported from abroad. At present, Panzhihua Steel and Baotou Steel Seamless Steel Tube Plant have developed and mass produced large seamless square rectangular steel tubes with a maximum wall thickness of 35 mm.

Welded pipes are widely used in steel structures. For example, 

the stadium of Guiyang Olympic Sports Center uses a large number of high-frequency straight seam welded pipes, from material Q345, specifications ф114mm×6mm, ф219mm×8mm, to material Q380, specification ф377mm×12mm, up to dozens of varieties. For example, in the China Pavilion of the Shanghai World Expo, the amount of straight seam submerged arc welded pipe is 2,800 tons, the typical specification is ф750mm×35mm, the steel grade Q345B, the single length is about 32m; 9 are welded into one pillar, and 4 pillars are supported close to each other. Ten thousand tons of the "Oriental Crown".

Submerged arc welded pipes (including straight and spiral seams) can be used for concrete filled steel tubular columns, including round columns and square columns. For example, the square tube (concrete) column of Jinan Baihua Lijing Building has a specification of 550mm×550mm×10mm. The square tube (concrete) column of Hangzhou Ruifeng International Business Building has a specification of 600mm×600mm×22mm, and the Dalian International Trade Center is rectangular (concrete). The column size is 1.4m×1.6m, and the rectangular tube (concrete) column of the China Taipei International Financial Center is 2.4m×3.0m.