Stainless steel welded pipe, which is abbreviated "welded pipe", is a steel pipe made of commonly used steel or steel strips that are crimped and formed by a unit and a mold. The production process of welded steel pipe is pretty simple, its production efficiency is high, category and specification are much, investment of devices is little, but its general strength is lower than seamless steel pipe.

Since the 30th years of the 20th century, with the swift development of high-quality strip continuous rolling production and the advance in welding and testing technology, the quality of the welding gap is constantly increasing. And the variety and specifications of welded pipe are increasing, which make welded pipe replace the seamless pipe in more and more areas such as using pipe in heat-exchange devices, trim pipes, medium and low-pressure fluid pipes, and so on.

Features

On the one hand, a small-caliber stainless steel welded tube is continuously produced online，and the thicker its wall, the more the investment in the unit and welding equipment, and the less economical and practical it is. The thinner its wall, the lower its input-output ratio. On the other hand, the production process decides its strength and weakness. Generally, welded steel pipe has high accuracy, uniform wall thickness, high brightness on the surface of the internal and external pipe(the surface brightness of the steel pipe determined by the surface grade of the steel plate), making size at random. Therefore, it embodies its economy and beauty in high precision and medium and low-pressure applications.

The features of welding

According to the welding technology, it can be divided into automatic welding and manual welding. Automatic welding generally uses submerged arc welding and plasma welding, and manual welding generally uses argon arc welding.

Uses

GB/T12770-2002 (Stainless steel welded steel pipe for mechanical structure). Mainly used in machinery, automobiles, bicycles, furniture, hotel and restaurant decoration, and other mechanical parts and structural parts. Its representative materials are 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
GB/T12771-2008 (Stainless steel welded steel pipe for fluid transportation). Mainly used to transport low-pressure corrosive media. Representative materials are 06Cr19Ni10, 022Cr19Ni10, 06Cr19Ni110Ti, 00Cr17, 0Cr18Ni11Nb, 06Cr17Ni12Mo2, etc.

Perspective demand

With the rapid development of Chinese economic construction, the consumption of stainless steel is continuously increasing, the demand for stainless steel is also expanding, and the market promise is great. The market demand for seamless stainless steel refers to the basic industry, such as petroleum, chemistry industry, power generation, and so on, which their demand accounts for one-three in the consumption of seamless steel pipe, and there is also great demand in the industry of vehicle, ship invention, construction, and environment protection. Stainless steel welded tube is always used for the pipe of heat-exchange devices, fluid, pressure, mechanical structure, and city scenery, and so on, and its consumption per year is about 700 thousand tons. The demand for industrial stainless steel welded pipe is comparatively high, proficient in the production process. The annual consumption of industrial stainless steel welded pipes is about 150 thousand tons, one part of it needs to be imported. From the view of domestic stainless steel pipe products, steel type is mainly austenitic steel; the categories of products are seamless steel pipes including cold drawn pipes, cold rolled pipes, hot extruded pipes, centrifugal cast pipes, spinning pipes; welded pipes include: plasma welding, argon arc welding, submerged arc welding, light velocity welding, and high-frequency welding, etc. All stainless steel pipes that can be manufactured, almost cover the variety specification of the standard from every country. The number of types and specifications of stainless steel-shaped pipe has increased to more than one hundred, and the uses of products involve many areas of industries and people. But generally speaking, in the respect of variety, specification, and number, there is a certain gap between domestic stainless steel and market demand.