Nearly 20 years to develop the methanol washing method, propylene carbonate method, polyethylene glycol dimethyl ether method, compared with pressurized water decarbonization law, they have a high degree of purification, low energy consumption, recycling advantages of high purity carbon dioxide, and selective removal of hydrogen sulfide may, decarburization method is widely used industrially. So, how to prevent surface decarbonization steel pipe products is a problem in the production process should be noted. Foreign imports of wire rod decarburization of 0.02 ~ 0.04mm, wire rod surface can be done without Kobe, Japan, decarbonization, and the average depth of the domestic like product decarburization than 0.05mm. Need to take measures to change the situation. Decarbonization is the result of diffusion on the one hand when the diffusion of oxygen into the decarbonization is steel; hand outward diffusion of carbon steel. Looking at the results from the final decarburization layer can be formed only when the decarbonization rate than the rate of oxidation. When the oxidation rate is large, obvious decarburization phenomenon can not occur, ie after decarburization produce iron from iron oxide skin Jibei. Thus, the relatively weak oxidation atmosphere, the decarburization may be formed deeper. Cause surface decarburization atmosphere is primarily oxygen, water vapor and an oxidizing gas such as carbon dioxide. 

When in contact with the heated oxidizing gas wire surface oxidation and decarburization occurs simultaneously; affinity because the dissolved carbon in the iron and these gases is relatively large, so the carbon off the surface first. These gases are generally packed into the furnace; iron, rust residues and the drawing surface of the wire on the surface of the pipe, will be decomposed into the furnace after heating, the reaction of some of the oxidizing gas. We can purposefully control the furnace atmosphere, so that in reducing the state can effectively avoid surface decarburization.

Posted by: Fran Stow at November 16, 2023 08:23 AM (LvFwa)

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What are the fire protection measures for seamless steel tubes?1. Outer cladding. It is to add an outer cladding on the surface of the seamless steel tube, which can be cast-in-place N08825 Incoloy tube or sprayed. The cast-in-situ molded solid concrete outer cladding is usually strengthened with steel wire mesh or steel bars to limit shrinkage cracks and ensure the strength of the shell. The spraying method can apply a sand pump to the surface of the seamless steel pipe at the construction site to form a layer. The sand pump can be lime cement or gypsum mortar, or can be mixed with perlite or asbestos.

At the same time, the outer cladding can also be made of perlite, asbestos, gypsum or asbestos cement, and light concrete into prefabricated panels, which are fixed on seamless steel pipes with adhesives, nails, and bolts.2. Fill with water. Straight seam steel pipes are steel pipes with welds parallel to the longitudinal direction of the steel pipe. Usually divided into metric welded steel pipes, welded thin-walled pipes, transformer cooling oil pipes, etc. Straight seam welded pipe production process is simple, high production efficiency, low cost and rapid development. The strength of spiral welded pipe is generally higher than that of straight seam welded pipe. It is possible to use narrow blanks to produce welded pipes with larger diameters. It is also possible to use the same width of blanks to produce welded pipes with different pipe diameters. Filling the hollow seamless steel pipe with water is an effective protective measure against fire. This method can keep the seamless steel pipe at a low temperature in the fire, water circulates in the seamless steel pipe, and absorbs the heat of the material itself. The heated water can be recirculated after cooling, or cool water can be introduced through pipes to replace the heated water.

Shield. Precision steel pipe is a kind of high-precision steel pipe material processed by cold drawing or hot rolling. Because the inner and outer walls of the precision steel pipe have no oxide layer, withstand high pressure without leakage, high precision, high finish, cold bending without deformation, flaring, flattening and no crack, etc., it is mainly used to produce products for pneumatic or hydraulic components, such as cylinder Cylinders can be seamless or welded. The seamless steel pipe is installed in the wall or ceiling made of refractory materials, or the components are hidden in the gap between the two walls. As long as a little refractory material is added or not added, the purpose of fire prevention can be achieved. This is a very economical method of fire prevention.4. Expansion materials. The use of seamless steel tube fireproof coating components, this method has the advantages of good fire insulation performance, construction is not limited by the geometric shape of the seamless steel tube, etc., generally do not add auxiliary facilities, and the coating quality is light, and also has a certain decorative effect, It belongs to modern advanced fire prevention technical measures.

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