Welded pipe is a common pipe in gas pipelines, diameter greater than 426mm (or 508mm) welded pipe is generally known as large diameter welded pipe, according to the welding into the pipe way, can be divided into spiral welded pipe and straight seam welded pipe two kinds. Longitudinal welded pipe is hot-rolled coil through the forming machine after forming, so that the steel coil deformation into a smooth cylinder, the use of high-frequency current skin effect and proximity effect or flux layer under the burning arc for welding, so that the edge of the pipe billet heated melting, and in a certain squeezing pressure under the role of fusion, the final cooling and forming. The billet edge melting using high frequency current is known as high frequency longitudinal welded pipe (ERW), and that using electric arc melting is known as longitudinal submerged arc welded pipe (LSAW). The main raw material of LSAW is low carbon steel hot rolled plate coil, hot rolled strip, which is widely used in petroleum, metallurgy, construction, coal, port, machinery and other industries for oil and gas transmission, low pressure water and gas transmission, mining fluid transmission, belt conveyor rollers, automobile transmission shaft and so on.

Welded steel pipe, also known as welded pipe, is a steel pipe made from steel sheets or strips that have been rolled and formed and then welded. Since the 1930s, with the rapid development of continuous rolling of high-quality strip steel production and welding and inspection technology advances, the quality of the weld seam continues to improve, the increasing variety of welded steel pipe specifications, and in more and more areas instead of seamless steel. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the form of the weld seam.

The billet used for welded steel pipe is steel plate or strip steel, which is divided into furnace welded pipe, electric welding (resistance welding) pipe and automatic arc welding pipe due to its different welding process. Because of its different welding forms are divided into straight seam welded pipe and spiral welded pipe two. Because of its end shape is divided into round welded pipe and shaped (square, flat, etc.) welded pipe.

The production process of straight seam welded pipe is simple, with high production efficiency and low cost, and is developing faster. The strength of spiral welded pipe is generally higher than that of LSAW pipe, which can produce larger diameter welded pipe with narrower billets, and can also produce welded pipe of different diameters with the same width of billets. However, compared with the same length of straight seam pipe, the length of the welded seam increases by 30 to 100%, and the production speed is lower. Therefore, most of the smaller diameter welded pipes are straight seam welded, and most of the large diameter welded pipes are spiral welded.

The rust removal and maintenance method of straight seam welded pipe

But the maintenance of straight seam welded pipe equipment has become a headache. The straight seam welded pipe equipment plays a major role in life and work. It is generally required that the surface of straight seam welded pipe fittings reach nearly white level (Sa2.5 practice has proved that the construction process of epoxy, vinyl, phenolic and other anti-corrosion coatings commonly used in straight seam welded pipe fittings. The use of this level of rust removal can remove almost all the oxide, rust and other dirt, anchor depth of 40 to 100μm fully meet the requirements of the adhesion of anti-corrosion layer and steel pipe, while the spray (throw) shot rust removal process available for lower operating costs and stable and reliable quality to achieve nearly white level (Sa2.5 technical conditions. When a certain amount of rust occurs on the LSAW pipe, it is treated in accordance with certain ways and methods of rust removal to ensure the quality and performance of the LSAW pipe, which can be used in different industries and fields to make an important contribution and role in the construction industry.

Rust removal speed of straight seam welded pipes

That is, the total kinetic energy E and the kinetic energy E1 of a single particle of abrasive applied to the steel pipe per unit of time. The rust removal speed speed of the steel pipe depends on the type of abrasive and the discharge of the abrasive. Where: m the amount of abrasive sprayed (thrown); V the speed of abrasive running; m1 the quality of single particle abrasive. m size is related to the abrasive breakage rate, the size of the breakage rate directly affects the interest of the exterior disposal operation and the cost of the descaling equipment. When the equipment is fixed, m is a constant, y is a constant, so E is also a constant, but because of the abrasive broken, m1 change, therefore, should generally choose the loss rate of lower abrasive, which is conducive to improve the speed of cleaning and long blade life.