Welded steel pipe is also called welded pipe, and it is made of steel plate or steel strip after crimp molding. Welded steel pipe production technology is simple with high production efficiency, varieties, wide specifications, less equipment investment, but the general strength is lower than the seamless steel tube. Since the 1930s, with the rapid development of high quality strip steel rolling production and the progress of welding and inspection technology, the weld quality has constantly improved, increasing varieties of welded steel pipe specifications, and in the field of more and more instead of seamless steel tube. Welded steel pipe according to the weld seam can be divided into ERW and spiral welded pipe.
Straight seam welded pipe production technology is simple with high production efficiency, low cost and rapid development. The strength of the spiral welded pipe is generally higher than straight seam welded pipe, and it can use a narrow billet to produce larger diameter welded pipe, and you can also use the same width of billet in the production of different pipe diameter welded pipe. But compared with the same length of straight seam pipe, the weld length will increase by 30 ~ 100%, and the production speed is low.
As a result, a small diameter welded pipe are mostly with straight seam welding, large diameter welded pipe mostly adopts spiral welded.
1. The low pressure fluid conveying usually adopts welded steel pipe (GB/T3092-1993), also known as general welded pipe, commonly known as the black pipe. It is used to transport oil, gas, air, water and heating steam and other general low pressure fluid, etc. Steel tube wall thickness is divided into ordinary steel pipe and increasing pipe; And considering the end of the pipe, it can be divided into steel pipe without thread or the pipe with thread. The specifications of the steel tube can be indicated with diameter (mm), nominal diameter is the approximate inner diameter. Traditionally used in inch such as 11/2. Except for directly used for conveying fluid, the low pressure fluid conveying welded steel pipe can also be used as the original pipe for galvanized welded steel pipe.
2. Low pressure fluid conveying with galvanized welded steel pipe (GB/T3091-1993), also known as galvanized welded steel pipe, commonly known as the white tube. It is used to transport generally low pressure fluid such as oil, gas, air, water and heating steam, warm water, and for other purposes hot dip galvanized welded butt weld or welding steel pipe can be used. Acording to the wall thickness of the steel tube, it can be divided into ordinary galvanized steel pipe and thickening galvanized steel pipe; Considering the pipe end, the galvanized pipe can be divided into galvanized steel pipe without thread and galvanized steel pipe with thread. The specifications of the steel tube can be indicated with diameter (mm), nominal diameter is the approximate inner diameter. Traditionally used in inch such as 11/2.
In the next article, we will keep on talking about the “The Introduction of Welded Steel Tube”.