Hot-dipped zinc-plated steel tubes Product Manuals

I. Product Introduction  
Hot dip galvanized steel pipe product standard name for the “low pressure fluid transmission with hot dip zinc welded steel pipe”, is based on welded steel pipe inside and outside the hot dip zinc, so that the inner and outer walls of the steel pipe at the same time immersed in zinc layer, greatly improving the corrosion resistance of steel pipe, up to about 20 times the ordinary steel pipe. Hot-dip zinc-coated steel pipe is widely used as transportation pipeline or metal structure in fire-fighting engineering, natural gas transportation, petroleum processing industry, water conservancy engineering construction and residential construction. This product is used with reference to the American ASTMA53, British BS1387, national GB/T3091 and enterprise internal control standards, and is not suitable for use in non-neutral environments such as acid, alkali, salt and other exposure. Specifications: DN15-300MM round tube: hot dip galvanized square tube, angle and steel and other profiles processing use: for water, sewage, gas, fire, air, oil, heating steam and other low-pressure fluid transmission and mechanical structures and other use of the production company: Foshan City Sanshui Zhenhong Steel Products Co.

Second

the implementation of standards  
China National Standard GB/T3091-2015 Low Pressure Fluid Conveyance Welded Steel Pipe with Zinc Dip  
Third, series products

V. Connection methods  
(一) Welding connection.  
Pipe cutting and pre-processing 
1, before cutting should be in accordance with the piping diagram first calibration of the outer diameter of the steel pipe, the error of the outer diameter and wall thickness error should be within the allowable range, the processed pipe notch end surface should be perpendicular to the center axis of the pipeline. 
2, pipe cutting should be mechanical methods, pipe cutting surface should be flat without cracks. Concave and convex indentation slag, oxides should be polished smooth. When the pipe end groove processing part of the pipe mouth is not rounded, it should be trimmed to meet the standard requirements. Wall thickness should be uniform, surface dirt, paint, rust, debris, etc. should be removed. 
Table 1:Allowable deviation of inclination angle of cut end surface(mm)

(二) Pipe grooving 
1、Processing steps. 
1) Firstly, set up the cut steel pipe on the grooving machine and the tailstock of the grooving machine. 
2) Measure the level on the steel pipe to make it in horizontal position. 
③Tighten the end face of the steel pipe with the front side of the grooving machine so that the axis of the pipe is perpendicular to the front side of the grooving machine. 
(①Start the grooving machine to roll the ring groove. 
(⑤) stop the machine to measure the depth and width of the groove with vernier calipers, after confirming that the groove size meets the requirements, the grooving machine unloading to take out the steel pipe (longitudinal displacement and angular displacement of the steel pipe is strictly prohibited in the grooving machine rolling groove).

2、Groove requirements: ① The surface from the pipe end to the groove section is smooth without bumps or roll marks. 
(1) the surface of the pipe end to the groove section is flat without bumps and roll marks. 
2) groove garden should be concentric with the pipe wall, groove width and depth should be in line with the requirements of Table 2 (see below): ③ rolling groove machine on the pipe processing molding groove shall not damage the steel pipe zinc layer; ① rolling groove groove groove diameter shall not be greater than the requirements of Table 2 (see below).

Directly weld the square tube by electric welding, simple, convenient and operable, suitable for daily general-purpose connection.

(二) Indirect connection. 
①Find a section of square tube that can fit into the connecting tube, and weld it together with the inner layer of the welding place. If you can not find the applicable pipe, can be close to the size of the connecting pipe size of the square tube cut open, so that its side length is exactly set into the square tube to be welded, and then welded together, so that both beautiful and does not affect the strength. 
② Find a section of square tube, just enough to be connected to the square tube set into the inner layer of the weld and weld it together. If you can't find a suitable pipe, you can find two or four sections of angle iron of comparable size, so that it can just keep the corners of the square tube to be connected, and then weld them together. Improve the strength.

(三) (iii) Screw connection 
Weld two pieces of steel plates with drilled holes on the square tube joints to be connected, and then connect the square tubes with bolts (high-strength or ordinary bolts).

（六）Transportation and Packaging 
(1) Transportation of square tube: when handling or transferring, we should put it carefully and gently, and forbid throwing, dragging, pulling and violent impact, so as to avoid deformation of the square tube, which will affect the normal use and appearance quality. 
(2) Square tube packaging: finished products must be in strict accordance with customer and transportation requirements before leaving the factory coated with anticorrosive agents or other wax-plated packaging, which is an important step to prevent rust and corrosion of the finished tube, in the process of transportation, loading and unloading and transshipment must pay attention to the protection of the packaging can not be damaged to extend the storage period of the finished tube. ③Note: The site or warehouse for keeping steel should be kept in a clean, clean, well-drained, air permeable area, away from the generation of harmful gases or dust, the warehouse shall not be stacked with acid, alkali, salt, cement and other erosive materials on the steel. Different varieties of steel should be stacked separately to prevent misplaced confusion, and often keep the environment hygienic and tidy.

（七）Problem Solving

③ zinc dip square tube surface without scratches, no bubbles, no impurities, no leakage of plating; ④ connection should be smooth, do not allow unevenness, weld phenomenon; square tube connection gap can not be more than 0.5mm, there can not be a difference between the height of the square tube, all square tube is not allowed to have a short material, welding, deformation phenomenon; ⑤ connection should not be skewed, welding, deformation phenomenon; ⑤ connection should not be too large, keep the welding point sharp or no hairline 
⑤ Connections can not be skewed, welding angle needs to be at right angles, diagonal tolerance of 2mm;.