The appearance of fake and inferior square tubes often has pitting. Pockmarked surface is an irregular uneven defect on the surface of square lead pipe due to serious wear of rolling groove. Due to the pursuit of profit by fake and shoddy square tube manufacturers,At present, researchers at home and abroad have carried out experimental discussion on the anti adhesion of square tube surface. So far, there is still a lack of research on surface adhesion there is no systematic and perfect theory to guide the preparation of anti adhesion inner surface of pipeline, and there is a lack of operable and low-cost inner surface preparation technology of square pipe. In terms of solid surface adhesion mechanism, based on the solid-liquid interface adhesion work theory and smooth solid surface model, this paper analyzes the spreading process on machined rough surface, studies the dynamic movement characteristics of solid-liquid vapor phase line, directly analyzes the adhesion process, and establishes a line spreading model based on small system energy, It provides theoretical guidance for the preparation of anti adhesion surface of pipeline.Alloy steel: A. low alloy steel (total alloy element content & le; %); b. Medium alloy steel (total alloy element content > ~ %); c. High alloy steel (total alloy element content > %).Mutenz, such as synchronous bending and finishing of the upper side and side of qb square tube. Empty bending can also bend the inner corner of r.t without breaking the tube wall.Section shape classification of large-diameter qb square tube square tube is classified according to section shape: simple section square tube & mdash& mdash; Square tube,EstoliLength of galvanized square pipe, rectangular tube and complex section square tube & mdash& mdash; Flower shaped square pipe, open square pipe, corrugated square pipe, special-shaped square pipe, large-diameter qb square pipe surface treatment classification square pipe is divided according to surface treatment: hot-dip galvanized square pipe, electro galvanized square pipe, oil coated square pipe, acid pickling square pipe, large-diameter qb square pipe purpose classification square pipe is classified according to purpose & mdash& mdash; Square tubes for decoration, machine tool equipment, machinery industry, chemical industry, steel structure, shipbuilding, automobile, steel beam and column, special purpose, large-diameter qb square tube wall thickness classification, large-diameter qb square tube according to wall thickness Classification & mdash& mdash; Super large diameter qb square pipe, large diameter qb square pipe and thin-wall large diameter qb square pipe rectangular pipe are the names of square pipe and QB square pipe, that is, steel pipe with equal side length. It is made of rolled strip steel after process treatment. Generally, the strip steel is unpacked, leveled, crimped and welded to form a round pipe, then rolled into a square pipe from the round pipe, and then cut into the required length. Usually pieces per bag. Qb square pipe, also known as square and rectangular cold-formed hollow section steel, is referred to as square pipe and rectangular pipe, code f and j respectively. The allowable deviation of wall thickness of qb square pipe shall not exceed plus or minus % of nominal wall thickness when the wall thickness is not greater than mm, plus or minus % of wall thickness when the wall thickness is greater than mm, except for the wall thickness of corner and welding joint area.Welding is a synthetic gradient material, mechanical and physical properties between base metals.

In this period, the technology of continuous rolling pipe was not mature.The strip caused by component segregation, that is, when the steel contains harmful impurities such as phosphorus and is pressed and delayed the impurities elongate along the rolling direction. When the steel is cooled below , these impurities become the core of ferrite making the morphology of ferrite distributed in bands,EstoliWhat are the specifications of galvanized round pipe, and then pearlite distributed in bands. This band can be eliminated by electroslag remelting and increasing crystallization speed.The second is the pickling of the square pipe. Both chemical and electrolytic methods are used when pickling the square pipe. These two methods can remove the oxide skin of the square pipe.howSo flat, and the size and thickness are not standardized, it can reflect that this square tube is a poor product& rdquo;Square tube has a wide range of application fields. Its main field is the construction industry, which promotes the development of economic construction. Because the production process of square tube hole is different, the production design of square tube hole is also different. Next I will introduce in detail the types of tube hole design below.Spraying (throwing) derusting spraying (throwing) derusting is that the high-power motor drives the spraying (throwing) blade to rotate at high speed, so that the steel sand, steel shot, iron wire section, minerals and other abrasives can be sprayed (thrown) on the surface of the square tube under the action of centrifugal force which can not only completely remove rust, oxides and dirt, but also the square tube under the violent impact and force of abrasives, It can also achieve the required uniform roughness.

Steel used & mdash& mdash; Such as bridge steel, ship steel, boiler steel,Estoli700 square tube, pressure vessel steel, agricultural machinery steel, etc.Direct material,The reason why the surface of fake and shoddy materials is easy to crack is that its blank is adobe with many air holes. During the cooling process, the adobe has cracks due to the action of thermal stress, and there are cracks after rolling.In order to ensure excellent coating quality, it depends on the quality of the coated surface treatment before construction. After various surface treatments, the coating quality and economic effect are very different.Tool derusting mainly uses tools such as steel wire brush to polish the surface of square pipe, which can remove loose or oxidized scale, rust, welding slag, etc. The derusting of manual tools can reach grade SA and that of power tools can reach grade SA. If the square pipe surface is firmly attached with iron oxide scale, the derusting effect of tools is not ideal and can not reach the anchor depth required by construction.Estoli,Square tubes for low and medium pressure boilers (gb-) are high-quality carbon structural steel hot-rolled and cold drawn (rolled) square tubes for superheated steam tubes, boiling water tubes for low and medium pressure boilers of various structures and superheated steam tubes, large smoke tubes, small smoke tubes and arch brick tubes for locomotive boilers. Square tubes for high-pressure boilers (gb- is a high-quality carbon steel, alloy steel and stainless heat-resistant steel square tube for the heating surface of water tube boilers with high pressure and above. High pressure square tube for chemical fertilizer equipment (GB - is a high-quality carbon structural steel and alloy steel square tube suitable for chemical equipment and pipelines with working temperature of - ~ ℃ and working pressure of ~ mA.When storing QB square pipe, we need to select a suitable place. We need to think about many external factors, such as the corrosivity of steel pipe, etc. Therefore, the place must be clean, dry and ventilated, where harmful gases appear, QB square pipe can not appear, weeds and other sundries should be removed in time, and the outer surface of steel should be kept clean. If there are acid, alkali, salt, etc. in the warehouse, it is easy to react with the steel pipe and corrode the steel pipe, so try to cut it and don't let it. In addition, we can put them into the warehouse for very good retention. According to geographical conditions, there is a sealed warehouse, but the ventilation setting is excellent. The difference between QB square tube and seamless steel tube QB square tube is a kind of high-precision steel tube material after cold drawing or hot rolling treatment. QB square tube is mainly used to produce products of pneumatic or hydraulic components, which can be seamless pipe or welded pipe, because there is no oxide layer on the inner and outer walls of QB square tube, high precision, high finish, cold bending, flaring and flattening without cracks. The chemical composition of QB square tube includes carbon silicon Si, manganese Mn, sulfur s, phosphorus P and chromium CR.The characteristics of square pipe are as follows: the production process of square pipe is simple, the production efficiency is high, the cost is low and the development is fast. The strength of spiral square pipe is generally higher than that of straight seam square pipe. It can produce square pipe with larger pipe diameter with narrow blank, and square pipe with different pipe diameter with blank of the same width. However, compared with straight seam pipe of the same length, the weld length is increased by ~, which will be oriented to the whole country for a long time Individuals and enterprises provide all kinds of square tubes, square rectangular tubes seamless square tubes, galvanized square tubes, galvanized tubes, on-site settlement, honest operation, local offices, long-term cooperation, and low production speed. Therefore, most of the smaller square tubes adopt straight seam welding, and most of the large-diameter square tubes adopt spiral welding.