High precision steel pipe technology

      In recent years, using the technology to produce precision steel tubes have been widely used in domestic hydraulic, pneumatic cylinders, the coal underground stents (pillar), the oil pump pipe, jacks and other manufacturing fields. Promote the application of high precision cold drawn precision steel tubes to save steel, to improve the processing work efficiency, energy conservation, reducing the hydraulic cylinder, cylinder machining equipment investment is important. The technology in November 1991 by the Ministry of Metallurgical Industry, Anhui Science and Technology Commission of experts in December 1992 by the Jiangsu Provincial Science and Technology Commission of experts. The technology is included in the State Science and Technology Commission NSC, (93), to focus on the promotion of national scientific and technological achievements Plan project guidelines issued by the hair into a word 500 No. I4-1-4-21.

Product characteristics of the so-called high-precision cold drawn tube inside diameter size strict accuracy (tolerance range), and external surface finish, roundness, straightness good precision steel tube wall thickness.

 

     After a little honing, the product can be directly used as hydraulic, pneumatic cylinder cylinder tube. Traditional production process of hydraulic, pneumatic cylinder cylinder tube, hot-rolled seamless tubes, boring ─ ─ rolled joint cutting process, the production process, a large number of metal cut into chips wasted, and also consume lot of power. With the development of China's industrial technology, hydraulic cylinder technology has been widely used, according to incomplete statistics, the country each year need all kinds of hydraulic cylinder at about 380 meters, follow the old process technology to produce hydraulic cylinder, has been difficult to adapt production and development needs.

 

     Adoption of new technologies, cold drawn, the production of high precision cold drawn tube ─ ─ hydraulic cylinder compared with the traditional cutting process, has the following characteristics:

 

     (1) the production of high efficiency: the conventional method of production of an inner diameter of 420 mm, 12 m in length of the cylinder tube required 154 hours, cold drawn method produces only 4 minutes.

 

    (2) High rate: due to the the boring rolling head and play the guiding role in the process of cutting, rough pipe due to the dead weight to generate deflection, resulting in rolling head and boring tool easy road, resulting in waste. The genuine rate can only reach about 60%, the production of cold drawn method genuine rate of up to 95%.

 

    (3) high metal utilization: cylinder manufactured using conventional boring method, only 50-70% of the metal utilization. With the drawing of the method of production, the metal is not only not cutting into iron at the end, but can get an extension of 30%, the metal utilization up to 95%.

 

    (4) can improve the mechanical properties of the finished tube metal: by drawing method of production, so that the blanks to obtain more than 30% of the plastic deformation, leaving the metal strength limit of the finished tube due to work hardening greatly improved. Usually up to 60% in the finished tube inner strength limit. Precision cold-drawn tube is a seamless hot-rolled steel, Longitudinal for the blank, after the chemical treatment in a dedicated drawing machine, the design of the mold through a special deformation principle drawing, produce a high-precision tube. Dimensional accuracy of H10 ~ H8, straightness of 0.35 ~ 0.5mm / m, the surface roughness amounted Ra1.6 0.4.

 

      The production process is as follows: feed - visual inspection - Mechanical cleaning - mechanical cleaning - annealing - straightening - tube head the processing - pickling - and - washing - squamous metaplasia - saponification - - Drawing - check - Cut Length - honing - end processing - straightening - final assembly - pressure test - Packing

 

Third, the technical indicators of the technical production of high-precision cold drawn tube main technical indicators have reached or parts exceeded the national standard GB8713 - 88 and the requirements of the international standard ISO4394/I-1980 (E).

 

      Details are as follows: the main technical indicators and standard table project actually achieved GB8713-88 ISO4394 / I bore size tolerances H8 H9 H10 H8 H9 H10 H8 H9 H10 straightness 0.3/1000 A: 0.3/1000 A: 0.5/1000 B: 1/1000: 1/1000 C: 1.5/1000 C: 1.5/1000 thickness deviation of ± 5% wall thickness ± 10% wall thickness ± 10% wall thickness roundness 0.04 no requirement no requirement

 

Product development using high precision cold drawn steel pipe cold drawn precision steel tubes can be used directly as a pneumatic cylinder (Domestic pneumatic components factory in Yantai, Qingdao, Zhaoqing heavy use).

 

     According to the special requirements of the hydraulic cylinder, supporting domestic honing machine to remove phosphide layer and to improve the accuracy of cold drawn pipe, honing the amount is generally only 0.2mm. This pipe was Xuzhou Construction Machinery Group Xuzhou hydraulic Factory high-volume production of hydraulic cylinders (1998 with more than 1,000 tons) and into the international market with its host. Successful technology development oil pump (1200mm bobbin hard piston, 6300mm stroke), replace similar imported pipe, Dagang Oilfield, Dagang Petroleum Machinery Factory (850 tons / 1998) for the introduction of technology and key equipment from the United States built of the API whole barrel pump production line to the standards of their products meet ASTM-A513-84a. Since 1989, the technology has large quantities to the domestic coal machinery factory provides high-precision cold drawn 27SiMn steel pipe.

 

Five, the prospects for the application of this technology

 

   1) macro-market economic construction steel pipe is one of the important raw materials, known as industrial "vascular said. Precision steel tubes are widely used as mechanical industrial tubes (mainly hydraulic and pneumatic cylinder tube, hydraulic oil pipelines, automotive drive shaft tube and axle casing, bearing steel, belt conveyor roller tube, printing and dyeing roller tube, etc.), oil Geological industrial pipe (oil pump pipe, drill pipe, tubing, casing, drill pipe, etc.), chemical pipe (oil cracking pipe, fertilizer with a high-pressure pipe, chemical equipment and piping tube), boiler and heat exchanger tubes. . With the continuous development of China's economic construction and the technology continues to progress, the scope of application of precision steel tubes will continue to expand, the demand will be growing. According to internal data, the the German Mannesmann production of cold drawn precision tubing in the domestic price of 40,000 yuan / ton, billet tube material, size, quality, open up the international market of precision steel tubes, exports The potential is great. From the raw materials market, China has basically formed the six seamless steel pipe production base in northeast Angang northwest Baotou, North China, Tianjin, Shanghai, east, southwest of Chengdu and Central South Hengyang. Of straight seam welded pipe unit nearly 1,600 sets, since 1986, the introduction of more than 200 sets of 18 sets, the φ219mm more medium and large-diameter longitudinal welded pipes unit which pipe factory in Guangdong Panyu of φ320 unit, Zhangjiakou Ningyuan steel mills φ114 unit , the φ219 unit Xuzhou aura companies, Baoji Steel Pipe Plant φ426 unit, Jinxi Steel Pipe Factory φ508 units, such as the production of oil well pipes, pipelines, mechanical tube and high-end products, will be the reliable production DOM mechanical tube welded pipe billet suppliers. At present, China has no professional precision steel pipe production plant, we can learn from the model and experience of some of the international steel company factories. Japan is a major exporter of a steel tube, steel pipe quality ranking first in the world. Japan's six major steel companies in the production of steel pipes in four (New Japan Iron and Steel, Sumitomo Metal Industries and Nippon Steel Pipe (NKK) and Kawasaki Steel). Nippon Maru Steel Pipe Company is a large, but can not be self-raw steel pipe company, with an annual output of 1,188,000 tons of steel pipes, galvanized pipe products, Pipes, mechanical pipe, standard gas transmission pipes has. Harada Steel Pipe Company in Osaka with an annual output of 12 000 t hydraulic cylinder, precision steel tubes, the main means of production is cold drawn. Katakura steel company headquartered in Osaka has the world's largest 700 tons of cold-drawing machine, built with precision steel tube manufacturing plant in Osaka, Hiroshima and Tokyo, and an annual output of 49,200 t of precision steel tubes.

 

   2) industry demand

 

  (1) engineering hydraulic machinery: hydraulic truck cranes, excavators, bulldozers, forklifts.

 

     (2) coal mine hydraulic support: National production of downhole hydraulic support enterprises 48, high-precision cold drawn tube of the total demand of about 1.2 million meters.

 

     (3) hydropower gate hoist, template machines, especially the Three Gorges Project is a great demand in the next decade.

 

     (4) Construction machinery: aerial work lift machinery, renovation of general building construction can not be separated from the hydraulic machinery.

 

  (5) the Petroleum Geology tube: oil fields in the country each year pump more than 3 million units, the annual consumption of 20-40 million meters of high-precision tubes, but can also use the technical finishing all kinds of drill pipe.

 

  (6) the weapons industry: the military-industrial sector is now spinning method processed guns tube spinning method of production is low and the high cost of production of cold drawing method is more suitable.

 

     (7) bearing industry: the production of rolling bearing seat, round steel raw material, made of slices after stamping. Large bearing race also solid bar emptied to produce metal utilization rate of less than 40%, and an urgent need for high-precision bearing steel thick-walled pipe.

 

    (8) automotive industry: 1995 Drive Shaft with 6000 tons of precision tube axle casing 1 million tons and various pipelines.

 

 (9) The aviation industry: aluminum aircraft landing gear tube and thick-walled steel pipe.

 

  (10) jack Industry: jack manufacturing in China has considerable strength, considerable export prospects. Cylinder jack that all manufacturers use more solid rod material processing, low production efficiency, material waste and the urgent need of high precision cold drawn tube.

 

(11) other areas: a variety of printing and dyeing roller, roller Road roller tube, stainless steel tube, aluminum, copper, shaped tube, and inside and outside the composite tube, and so can be used this technology to produce.