steel tube

　　After the processing of the carbon steel pipe is complete, there will be some twists and turns, and the reduction of these twists and turns has to rely on the straightening machine to complete. Therefore, almost all the processed carbon steel pipe have to be straightened by the straightener. 　　The meandering of a carbon steel pipe is due to improper adjustment of the rolling mill, residual stress remaining during rolling, and formation of unequal cooling along the section and length of the tube. Therefore, it is not possible to obtain very straight tubes from the rolling mill, as long as the rules of skill conditions are satisfied by the tortuosity of the cold straightened tubes. 　　The fundamental reason for the straightening is to make the carbon steel pipe go through an elastoplastic tortuosity, and the large tortuosity becomes a small degree of tortuosity. Therefore, the steel tube needs to be repeatedly twisted and twisted in the straightener. The degree of repeated twists a...

　　Welding methods of stainless steel plate is following below: 　　 1. Butt joints 　　Butt joints are the most common forms of joints. They can be divided into I-shaped butt joints (not beveled), V-shaped bevel joints, U-shaped bevel joints, X-groove joints and Double U-shaped groove joints and so on. General thickness of 6mm or less, the use of not open groove and leave a certain gap of the double-sided welding; medium thickness and large thickness butt welding of components, in order to ensure penetration, must open the groove. The V-shaped groove is easy to process, but the post-weld part is easily deformed. The X-shaped groove has a symmetrical section of the weld. The deformation and internal stress of the workpiece after welding is smaller than that of the V-shaped groove. Under the same plate thickness condition, the X-shaped slope of the mouth is reduced by 1/2 of the amount of filler metal compared to the V-shaped groove. U-shaped and double U-shaped bevels, with less weld fi...

　　1. Composition: Stainless steel pipe is a kind of nickel-chromium steel, which comes out of carbon and iron, as well as nickel, chromium, manganese and copper. Carbon steel pipe are also called carbon steel pipes. General carbon steel pipes are made of carbon steel or low alloy structural steels such as 16Mn and 5MnV or alloy steels such as 40Cr, 30CrMnSi, 45Mn2, and 40MnB. 　　2.Erosion performance: Because stainless steel pipe contains chromium and nickel elements, these two elements react chemically with oxygen in the air to form an oxide film, thereby protecting the tube from corrosion, so the stainless steel tube has good corrosion resistance. . Carbon steel pipe is very easy to rust. 　　3, Stainless steel pipe surface can be a variety of processing, can be made into a mirror, shiny surface, drawing surface, etc., so the stainless steel tube is generally used for decorative tubes, props, tube products, but carbon steel is mainly used in the industry. 　　4, The price of stainl...

　　 Carbon steel pipe usually lose their load-carrying capacity at temperatures of 450-650°C, causing large deformations, resulting in bending of steel columns and steel beams. As a result, they cannot be used due to excessive deformation, and generally do not protect the carbon steel pipe. The fire resistance limit is about 15 minutes. The length of this time is also related to the speed of the heat absorption of the components. The following describes the different types of carbon steel pipe fire protection measures. 　　1, Outsourcing. The outer cladding is added to the surface of the carbon steel pipe. It can be cast in-situ or sprayed. Cast-in-place solid concrete cladding is usually reinforced with 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 carbon steel pipe at the construction site to form a protective layer. The sand pump can be lime cement or gypsum mortar can also be i...

　　Thick-walled carbon steel pipe processing performance is as follows: 　　1: Thick-walled carbon steel pipe castability (castability): Refers to the ability of a metal material to obtain acceptable castings by casting. Castability mainly includes fluidity, shrinkage and segregation. Liquidity refers to the ability of liquid metal to fill molds. Shrinkage refers to the degree of volume shrinkage when a casting solidifies. Segregation refers to the inhomogeneity of chemical composition and organization within a metal due to successive differences in the crystal during cooling and solidification. . 　　2: Thick-walled carbon steel pipe forgeability: Refers to the ability of a metal material to change shape without cracking during pressure processing. It includes hammer forging, rolling, drawing, extrusion, etc. in hot or cold state. The malleability is mainly related to the chemical composition of the metal material. 　　3: Thick-walled carbon steel pipe Machinability (machinability, ma...

　　Welded steel pipe: also called welded pipe, which is formed by bending a steel plate or a steel strip and then welded. According to the form of weld, it is divided into lsaw steel pipe and ssaw steel pipe. It is divided into general welded pipe, galvanized welded pipe, blown oxygen welded pipe, wire casing, metric welded pipe, idler pipe, deep well pump pipe, automobile pipe and transformer pipe according to the application. , welded thin-walled tubes, welded shaped tubes and spiral welded tubes. 　　General welded pipe: Generally welded pipe is used to transport low pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steel that is easy to weld. The steel pipe is subjected to experiments such as water pressure, bending and flattening, and has certain requirements on the surface quality. Usually, the delivery length is 4-10 m, and the fixed length (or double rule) is often required for delivery. The specification of the welded pipe is expressed by the ...

　　Polishing performance factors of 304 stainless steel pipe are the following: 　　① Raw surface defects. Such as scratches, pitting, too pickling and so on. 　　② 304 stainless steel pipe material problems. Hardness is too low, polishing is not easy to throw bright (BQ sex is not good), and the hardness is too low, the surface is prone to orange peel deep drawing phenomenon, thus affecting the BQ sex. BQ hardness is relatively good. 　　③ After deep drawing products, the deformation of the surface area will be a great small black spots and ridging, thus affecting the BQ sex. Weldability of different uses of stainless steel welding performance requirements vary. A class of tableware on the welding performance generally do not require, and even part of the pot companies. However, most products require raw material welding performance, such as two types of tableware, mugs, steel pipes, water heaters, drinking fountains and so on...

　　Wrinkling is a type of surface defect that easily occurs when the strain of ferritic stainless steel is large in the forming process. It occurs in the rolling direction of the strip and appears as a narrow convex strip, that is, a surface corrugation. 　　Reducing wrinkles by controlling the production process: 　　(1) Reduce the columnar crystal billet, an increase of equiaxed. Methods are: ① Electromagnetic stirring can promote the columnar crystal to the equiaxed crystal transformation. ② In the process of metal solidification or metal solidification before the application of impulse current to the metal melt, pulse current and due to the interaction of the pulse generated by the magnetic field, so that the solidified metal by strong electromagnetic force and impact force and vibration Dendrites crystallized first break up, forming more crystalline core, so that the solidified tissue has been refined. ③ Control the composition of the front solid-liquid interface coagulation, the ...

　　 Production methods 　　Stainless steel tube according to the production method is divided into two categories of stainless seamless pipe and stainless welded pipe , stainless seamless steel pipe can be divided into hot-rolled tube, cold-rolled tube, cold-drawn tube and extrusion pipe, cold drawing, cold rolling is the second Processing; welded pipe is divided into straight seam welded pipe and spiral welded pipe. 　　Section shape 　　Stainless steel tube by cross-sectional shape can be divided into tube and shaped tube. Shaped tube with rectangular tube, diamond-shaped tube, oval tube, hexagonal tube, all directions and a variety of cross-section asymmetric tube. The profiled tube is widely used in various structural parts, tools and mechanical parts. Compared with the tube, shaped tube generally have a larger moment of inertia and cross-section modulus, a greater bending, torsion ability, can be large greatly reduce the weight of the structure, saving steel. 　 　Tube end shape ...

　　 Production methods 　　Stainless steel tube according to the production method is divided into two categories of stainless seamless pipe and stainless welded pipe , stainless seamless steel pipe can be divided into hot-rolled tube, cold-rolled tube, cold-drawn tube and extrusion pipe, cold drawing, cold rolling is the second Processing; welded pipe is divided into straight seam welded pipe and spiral welded pipe. 　　 Section shape 　　Stainless steel tube by cross-sectional shape can be divided into tube and shaped tube. Shaped tube with rectangular tube, diamond-shaped tube, oval tube, hexagonal tube, all directions and a variety of cross-section asymmetric tube. The profiled tube is widely used in various structural parts, tools and mechanical parts. Compared with the tube, shaped tube generally have a larger moment of inertia and cross-section modulus, a greater bending, torsion ability, can be large greatly reduce the weight of the structure, saving steel. 　　 Tube end shape ...

　　Talking about seamless steel pipe , flaring and flattening would be here. And which kind of factor would associate with this production process? Today, we’ve listed them here for our customers. 　　First of all, carbon content of the steel would be one of the affecting factor. The lower of the carbon content in steel pipeline, with the low sulfur and phosphorus content, we will have perfect quality for the steel tubes. 　　For ferrite based alloy steel pipe, if the chromium content ranges from 11%~30%, we will get a body centered cubic crystal structure. Thus, this kind of steel with high heat conductivity, thermal expansion coefficient is small, good oxidation resistance and so on. 　　Of course, the secondary refining technology ( AOD or VOD ) can be used to make carbon, nitrogen, gap elements are greatly reduced, thus making this kind of steel is widely used. 　　For more detailed information, welcome to have a discussion here.

　　In recent years, the demand for steel products by automobile and real estate enterprises has been large, which has greatly increased the demand for steel products, which has driven the development of the steel market. The steel pipe industry is one of the important basic industries in the national economy. Due to the continuous improvement of the living standards of our people and the increasingly good overall economic development, China's steel pipe market has developed rapidly. The demand for the Chinese steel pipe market will continue to increase steadily in the future. 　　Precision seamless steel tubes have the following features: 　　1. Light weight, weight is only 1/5 of the square steel. 　　2. Corrosion resistance, acid resistance, alkali resistance, salt resistance, atmospheric corrosion resistance, high temperature resistance, impact resistance, fatigue resistance, no regular maintenance. Their effective service life can reach more than 15 years. 　　3. The tensile str...

　　No matter seamless steel pipe or welded pipeline, we should have check methods for the final products in order to guarantee the quality. Here are three main points for the tube’s inspection process. 　　There is no cracks, lack of fusion, porosity, slag and spatter for the welded joint’s surface. As these drawbacks would finally have big influence for the good quality of a steel tube. Pipeline design temperature is below -29 degrees, fan ruler of hardened stainless steel and alloy steel pipes tend to be larger weld surface, without undercut. 　　Nondestructive test is necessary on the pipe’s surface. Different steel pipe with various functions should take different pressure taking. Thus, magnetic iron pipe should be used in magnetic particle testing; non-ferromagnetic steel should be used in penetration testing. 　　Ray inspection and ultrasonic testing. Ray inspection and ultrasonic testing is the main target of the butt joint pressure pipe and pipe fittings for butt joints. 　　 ht...

　　N80-1 non-tempered seamless casing is produced by hot rolling of medium carbon-manganese V steel, and controlled final rolling temperature > phase change point Ar3 is equivalent to normalizing treatment. The production method of N80-1 non-tempered seamless casing has the advantages of low cost, saving heat treatment resources and shortening the delivery period. However, the process control of N80-1 non-tempered seamless casing is very complicated (such as deformation, deformation rate, cooling rate and other performance factors can not be artificially controlled), coupled with the lack of effective process control technology, making the performance control of this product has been not stable, the performance is not stable in the range of 552-758MPa, and the impact toughness is often lower than the longitudinal 27J or the lateral 14J (API 5CT standard requirements), which seriously affects the material yield and use security. The development of N80-1 non-tempered seamless casing wa...

　　The difference between hot rolling and cold rolling seamless steel pipe. 　　1. Cold-rolled steel allows partial buckling of the section, so that the bearing capacity of the bar after buckling can be fully utilized; and the hot-rolled steel does not allow local buckling of the section. 　　2. The causes of residual stresses in hot-rolled and cold-rolled steels are different, so the distribution on the cross-section is also very different. The residual stress distribution on the section of the cold-formed thin-walled steel is curved, while the residual stress distribution on the section of the hot-striped steel or welded steel is a film type. 　　3. The free torsional stiffness of hot-rolled steel is higher than that of cold-rolled steel, so the torsional performance of hot-rolled steel is better than that of cold-rolled steel. 　　Cold-rolled seamless steel pipe is divided into general steel pipe, low and medium pressure boiler pipe, high pressure boiler pipe, alloy steel pipe, stain...