Bangdong technogoly provide large diameter seamless steel pipes

September 04, 2018

We supply a full range of Large diameter seamless steel pipe schedules ranging from Sch 5 thru Double Extra Heavy, we deliver Large diameter seamless steel pipe with Exceptional sizes & Quality.

At present, China's large-caliber seamless steel tubes, the main production process for hot-rolled large-diameter seamless steel tubes and hot expanded seamless steel tubes, hot-rolled seamless steel tubes can produce non-GB size, thermal expansion seamless tube is what we often say hot Expanded pipe, a relatively low density but strong contraction of the pipe using the oblique rolling method or drawing method to expand the pipe diameter of a barn finish rolling process. The thickening of steel pipes in a short period of time can produce non-standard and special models of seamless pipes with low cost and high production efficiency. It is the current trend in the field of international pipe rolling.
For GB5310 Steel Pipe with outer diameter greater than or equal to 76 and wall thickness ≥ 14mm, Charpy V-type longitudinal impact test shall be carried out at 20°C; the average value of impact energy of three samples shall not be lower than 40J, allowing one sample The impact energy is lower than the average but not lower than 70% of the average. Outer diameter> 219.1mm, and wall thickness ≥ 25mm steel tube can be used instead of the longitudinal mechanical properties test. The Charpy V-type transverse impact test was conducted at 20°C, and the large-diameter tube was more convenient for the transverse mechanical test.
The standard for Seamless Pipe was first released in May 1998. This standard replaces GB/T17395-1998 "Seamless steel pipe size, shape, weight and allowable deviation" This standard specifies the seamless steel pipe size, shape, weight and allowable deviation. This standard applies to the development of flat-end seamless steel pipe standards for various purposes, select the size, shape, weight and allowable deviations. Compared with GB/T17395-1998, the main changes are as follows:
--- Increased the outer diameter of ordinary steel pipes 232, 267 (267.4), 302, 318.5, 368, 419, 473, 699, 711, 720, 762, 788.5, 813, 864, 914, 965, 1016;
--- Modify the upper limit of the wall thickness of ordinary steel pipe;
--- Modify the theoretical weight per unit length in Table 1 and Table 2;
--- In Table 3, the wall thickness of steel pipes with an outer diameter of 25 or less is increased by 0.5, 0.6, 0.7, 0.8, and 0.9;
--- Increased full-length allowable deviation +150mm level;
--- Change the "ellipticity" to "out-of-roundness" and increase the calculation formula of "out-of-roundness";
--- usually the upper limit of the length range from the original "12000mm" to "12500mm";
--- Modify the allowable deviation of the actual weight and theoretical weight.
Because of its different manufacturing processes, seamless steel tubes are divided into hot rolled (extrusion) seamless steel tubes and cold drawn (rolled) seamless steel tubes. Cold drawn (rolled) tube is divided into two kinds of round tube and shaped tube.