Drinking water pipe with anti-corrosion spiral steel pipe technology

The place or warehouse for spiral steel pipe thermal insulation products shall be clean and well drained away from factories and mines that produce harmful gases or dust. Cut into single pipes. The first batch will send three steel pipes to the first batch of inspection system to check the mechanical properties, chemical composition, melting conditions, surface quality of spiral steel pipes and non-destructive testing of welds, so as to ensure that the steel pipes are qualified in process and can be put into production formally. The production process of spiral steel tube is simple, the production efficiency is high, the cost is low, and the development is rapid. Keep the steel clean in the place where weeds and all sundries are removed. The corrosive materials of steel pipes such as acid, alkali, salt and cement shall not be stacked together in the warehouse. After more than a month, the problem finally appeared. According to the current situation, even the most conservative estimate, 70% of enterprises are in production or limited production, a CISA member, who asked not to be named, told China business daily. When the pipe is under internal pressure, there are usually two main stresses on the pipe wall. The strength of the spiral pipe is generally higher than that of the straight welded pipe. It can be used to produce smaller diameter and narrower diameter pipes, or to produce different diameter pipes with the same width of billet. The gap control device is used to ensure that the gap of the steel pipe with spiral weld meets the welding requirements, and strictly control the pipe diameter, misalignment and gap of the weld. Internal welding and external welding are carried out by single wire or double wire submerged arc welding with Lincoln welder to obtain stable welding specifications. More than a month ago, the European Union decided to conduct a double reverse investigation of China's spiral steel pipes. Since then, the United States has followed. All of these are directly related to the interests of more than 3000 spiral steel tube manufacturers in China. Before that, the region's capacity was designed primarily on the basis of exports. The strength of the spiral pipe is generally higher than that of the straight welded pipe. It can be used to produce smaller diameter and narrower diameter pipes, or to produce different diameter pipes with the same width of billet. But in the same length of straight pipe, the weld length increases by 40-100%, and the productivity decreases. The outer diameter of the spiral steel pipe is indicated by the letter D, followed by the additional outer diameter of the size and wall thickness, such as the outer diameter of 105 spiral steel pipe, the wall thickness of 6mm, the outer diameter of plastic pipe is indicated by d107 * 5, such as de63, other pipes such as reinforced concrete pipe, cast iron pipe and galvanized pipe are indicated by DN in the design drawing, i.e. the design of the nominal diameter is made for the convenience of manufacturing and maintenance A material standard, larger than the nominal diameter, is the specification name of the pipeline (or pipeline).


Corrosion resistant spiral steel pipe


Before delivery, the spiral steel pipe shall be subject to mechanical property test, flattening test and expanding test, and meet the required standards. The quality inspection method of straight seam steel is as follows:


1. Judging from the surface, i.e. visual inspection. The appearance inspection of welding joint is a simple and easy procedure, which is suitable for many kinds of test methods. The important part of test content is mainly to find the defects and size deviation of welding surface. It is usually tested with the naked eye, with standard templates, gauges, magnifiers and other tools. If the surface of the weld is defective, there may be defects in the weld.


2. Physical test method: physical test method is a test method or test method that uses some physical phenomena. Defects in materials or workpieces are usually examined by nondestructive testing. Ultrasonic testing, radiographic testing, through testing, magnetic testing and other non-destructive testing.


3. Strength inspection of pressure vessel: in addition to sealing test, strength test shall also be conducted for pressure vessel. There are two common types of hydrostatic test and pressure test. They all verified the welding tightness of vessels and pipes under pressure. Air pressure test is more sensitive and faster than hydrostatic test, and does not need to drain the tested products, especially for the products with difficult drainage. But this test is more dangerous than hydrostatic testing. During the test, corresponding safety technical measures must be observed to prevent accidents during the test.


4. Air tightness test: there are no dense defects such as cracks, air holes, slag penetration, incomplete penetration and loose structure in the welding container for storing liquid or gas body