If there is only a single plane weld, the step-by-step back welding shall be adopted from the middle, that is, the arc of the section weld shall be terminated at the section arc.Engaged in square tube, square rectangular tube, seamless square tube, galvanized square tube, galvanized tube, old brand, price advantage and quality guarantee! However the Demander shall cut off the interface pipe when using it. The weight of short length and non fixed length products shall not exceed % of the total delivery. For qb square pipe with theoretical weight greater than kgm, it shall not exceed % of the total delivery. The bending degree of qb square pipe shall not be greater than mm per meter, and the total bending degree shall not be greater than .% of the total length. Galvanized qb square pipe for low-pressure fluid transmission, with standard number of gbt-. Representative materials: QA, qbqb, etc. It is mainly used for conveying water, gas, air, oil and heating hot water or steam, and its purpose is limited to general low pressure fluid.Slema,Square tube flattening test is a kind of test to check the deformation performance of metal tubes (seamless square tubes and rectangular tubes) flattened to the specified size and show their defects. Relevant flattening tests shall be carried out in accordance with relevant provisions of test standards. Requirements for samples samples can be taken from metal pipes with qualified appearance. Generally, sawing is adopted. The inner and outer walls of the pipe shall retain the original surface without any processing. Sample length L & asymp; D (D is the outer diameter of the pipe). When the outer diameter is large, the length l shall not exceed mm. When the outer diameter is less than mm, l = mm. When cutting the sample, the surface of the sample shall not be damaged and the performance of the metal shall not be changed due to heating or cold processing. The edge of the section shall be flattened. The flattening test is a test to check the deformation performance of the metal pipe (seamless square pipe and rectangular pipe) flattened to the specified size and show its defects. Relevant flattening tests shall be carried out in accordance with relevant provisions of test standards. special shaped square pipe is the general name of square pipes with other cross-section shapes except circular pipe. According to the different cross-section shape and size of steel pipe, it can be divided into special-shaped square pipe with equal wall thickness (code D), special-shaped square pipe with unequal wall thickness (code BD) and special-shaped seamless steel pipe with variable diameter (code D) These special-shaped large-diameter qb square tubes are widely used in various structural parts, tools and mechanical parts. Compared with circular tubes, special-shaped tubes generally have large moment of inertia and section modulus and have large bending and torsion resistance, which can greatly reduce the structural weight and save steel. Square tubes are an indispensable part of construction workSuphan Buri,Precision pipe is a seamless pipe with high dimensional accuracy and good surface finish for mechanical structure and hydraulic equipment. The selection of precision seamless mechanical structure or hydraulic equipment can greatly save machining hours, improve material rate and improve product quality. Seamless pipe can be divided into hot rolled pipe and cold rolled pipe according to different productionFunctional index analysis of qb square tube - angular plasticity refers to the power of plastic deformation (permanent deformation) without destruction of qb square tube data under load.Structural stainless steel square pipe (gbt-) is a hot-rolled (extruded, expanded) and cold drawn (rolled) square pipe made of stainless steel for corrosion-resistant pipes, structural parts and parts widely used in chemical, petroleum, light textile, food,SlemaRepresentation of galvanized square pipe, machinery and other industries.

Stage ( & mdash; )Shot blasting and sand blasting are widely used in repair and shipbuilding industry. However whether shot blasting or sand blasting, compressed air is used. Professional square pipe, square rectangular pipe, seamless square pipe, galvanized square pipe, galvanized pipe has high pressure resistance grade, good waterproof performance, fire and high temperature resistance, strong overload capacity, corrosion resistance, radiation protection and long service life. Of course, it is not shot blasting, so it is necessary to use high-speed rotating impeller. In the repair and shipbuilding industry, shot blasting (small steel shot) is mostly used in square pipe pretreatment (rust removal before coating); Sand blasting (mineral sand is used in repair and shipbuilding) is mostly used in formed ships or sections to remove the old paint and rust on the square tube and repaint it. In the repair and shipbuilding industry, the main function of shot blasting and sand blasting is to increase the adhesion of square tube coating paint.Strength refers to the performance of metal materials under static load (excessive plastic deformation or fracture). Since the action modes of load include tension, compression, bending and shear, the strength is also divided into tensile strength, compressive strength, flexural strength and shear strength. There is often a certain between various strengths. Generally,SlemaSquare pipe galvanized square pipe, tensile strength is used as the basic strength indicator. Appropriate sites and warehouses shall be selected. The sites or warehouses for storing steel pipes shall be in clean and unobstructed places, away from factories and mines that produce harmful gas or dust. Weeds and sundries shall be removed on the site to keep the steel pipe clean; In the warehouse, it is not allowed to stack with acid, alkali, salt, cement and other materials that are corrosive to the steel pipe. Different types of steel pipes shall be stacked separately to prevent confusion and corrosion; Large section steel, rail, steel plate, large-diameter steel pipe, forging, etc. can be stacked in the open air; Small and medium-sized section steel, medium diameter steel pipe reinforcement steel wire and steel wire rope can be stored in a well ventilated shed, steel sheets, silicon steel sheets, or thin-walled steel pipes, all kinds of cold-rolled and cold drawn steel pipes and high and corrosive metal products can be stored in the warehouse; The warehouse shall be selected according to geographical conditions, and generally adopts ordinary closed warehouse, that is, the warehouse with roof enclosure, tight doors and windows and ventilation devices; The warehouse is required to pay attention to ventilation in sunny days, close and damp proof in rainy days, and often maintain a suitable storage environment. The principle of reasonable stacking and first in first stacking is to stack according to varieties and specifications under the condition of stable stacking and ensuring safety. Materials of different varieties shall be stacked separately to prevent confusion and mutual corrosion; It is forbidden to store articles that have corrosive effect on steel pipes near the stacking position; The bottom of the stack shall be padded high, firm and flat to prevent the material from moisture or deformation; The same kind of materials shall be stacked according to the warehousing order, so as to facilitate the implementation of the principle of first in, first out; The section steel stacked in the open air must be provided with wooden mats or strip stones. The stacking surface is slightly inclined to facilitate drainage. Pay attention to the straightness of the material placement to prevent bending and deformation; The stacking height shall not exceed m for manual operation, m for mechanical operation, and m for stacking width; A fixed channel shall be reserved between stacks, generally .m, and the access channel is generally ~ om depending on the size of materials and transportation machinery; The bottom of the stack shall be padded up. If the warehouse is cement floor, it can be padded up by .M; If it is muddy ground, it must be padded . ~ .m high. If it is an open site, the cement ground shall be padded with O & middot; ～O· m, . ~ . m higher than the sand and mud surface, the angle steel and channel steel shall be stacked in the open air, i.e. the mouth shall face down, and the I-beam shall be placed vertically. The i-groove surface of the steel pipe shall not face up to avoid ponding and rust. The packaging and protective layer of the protective materials shall be coated with agent or other plating and packaging before leaving the factory, which is an important measure to prevent material corrosion. Attention shall be paid to protection during transportation, loading and unloading and shall not be damaged, The storage period of materials can be extended, the warehouse shall be kept clean and the maintenance of materials shall be strengthened. Before warehousing, materials shall be prevented from being drenched or mixed with impurities. Materials that have been drenched or contaminated shall be wiped according to their properties, such as steel wire brush for high hardness and cloth, cotton and other materials for low hardness; The materials shall be regularly after warehousing. If there is corrosion, the corrosion layer shall be removed; Generally, the steel pipe surface does not need to be coated with oil after being cleaned, but for high-quality steel, alloy steel sheet, thin-walled pipe, alloy steel pipe, etc., the internal and external surfaces need to be coated with anti rust oil before storage; Steel pipes with serious corrosion shall not be kept for a long time after rust removal and shall be used as soon as possible. With the development of economy, all kinds of square tubes, rectangular tubes, seamless square tubes, galvanized square tubes and galvanized tubes have been recognized by the majority of customers for a long time. There are more and more counterfeit products on the market. In order to prevent being deceived when you are in square tubes, you need to know some knowledge about how to judge the authenticity of square tubes: & ldquo; We can judge by observing the surface and flatness of the square tube. If the surface of the square tube is relatively flat, it can reflect that the square tube is good. On the contrary, if the surface is not goodindex,C. electric furnace steel: (a) electric arc furnace steel; (b) Electroslag furnace steel; (c) Induction furnace steel; (d) Vacuum consumable furnace steel; (e) Electron beam furnace steel.Cleaning solvent and emulsion can clean the surface of square tube to remove oil, grease, dust agent and similar organic matter, but it can not remove rust, welding, A. open hearth steel: (a) acid open hearth steel; (b) Alkaline open hearth steel.

There are many ways of ignition, such as arc, electric spark, flame, strong current, high-temperature furnace, laser, high-temperature radiation, microwave, chemical furnace, etc.production costs,Put the pig iron for steelmaking into the steelmaking furnace according to the specified process to obtain steel. The products of steel include ingots, continuous casting billets and various steel castings made of straight square tubes. Generally speaking, steel refers to the steel rolled into various square tubes. Square tube steel belongs to ferrous metal, but steel is not completely equal to ferrous metal.The inclusions in the square tube treated with calcium can be denatured well, and the morphology of sulfide in the rolled stock is also improved.Structural stainless steel square pipe (gbt-) is a hot-rolled (extruded, expanded) and cold drawn (rolled) square pipe made of stainless steel for corrosion-resistant pipes, structural parts and parts widely used in chemical, petroleum, light textile, food, machinery and other industries.Slema,At this time, it shall be welded to the fixed thickness, ground and sandblasted, and repair welding shall be adopted where there are cracks, even if the steel pipe with another large opening can be made up at one time.The surface of fake and inferior square tubes is easy to produce scabs. There are two reasons: the material of fake and inferior square tubes is uneven and there are many impurities. The guide equipment of fake and shoddy material manufacturers is simple and easy to stick to steel. These impurities are easy to scar after biting the roll. special shaped square pipe is the general name of square pipes with other cross-section shapes except circular pipe. According to the different cross-section shape and size of steel pipe, special-shaped square pipe with unequal wall thickness (code BD) and special-shaped seamless steel pipe with variable diameter (code D) These special-shaped large-diameter qb square tubes are widely used in various structural parts, tools and mechanical parts. Compared with circular tubes, special-shaped tubes generally have large moment of inertia and section modulus, and have large bending and torsion resistance which can greatly reduce the structural weight and save steel. Square tubes are an indispensable part of construction work