Hardness QB square hardness is a pointer to measure the hardness and softness of metal materials. At present the hardness method is commonly used to measure the hardness in production. It uses the indenter with fixed geometry to measure the hardness value of the metal material surface tested under fixed load according to the degree of hardness.The pipeline is only subject to chemical pickling, which can remove oxide scale, rust and old coating. Sometimes it can be used as the reprocessing after sand blasting. Although chemical cleaning can make the surface reach a certain cleanliness and roughness, its anchor lines are shallow and easy to pollute the surrounding environment. The square tube shall be submitted for acceptance in batches,(& sigma; Su): the large stress before the yield stress of the sample decreases for the first time; Lower yield point (& sigma; SL): the small stress in the yield stage when the initial instantaneous effect is not considered. The calculation formula of yield point is as follows: where: FS -- yield force (constant) in the tensile process of the sample,DobridgeGalvanized square pipe 4, n (Newton) so -- original cross-sectional area of the sample, mm. Elongation after fracture (& sigma;) in the tensile test, the percentage of the length increased by the gauge length of the sample after breaking to the original gauge length is called elongation.The disadvantage of empty bending is that when the upper side and side are synchronously empty bending the forming force is easy to exceed the critical point due to the pressure generated by the upper roll and the lower roll at the same time,DobridgeDn40 hot dip galvanized pipe, and will also affect the stable operation and forming quality of the unit. This is also the different characteristics of qb square tube and round tube empty bending. The concept of square tube: square tube is the pressure processing of ingot resulting in edge instability and concave, billet or square tube Make materials of all shapes, sizes and properties we need.Grimsby,Mechanical engineering, power plants, agricultural and chemical machinery, automobile chassis, airports, boiler construction, highway railings, pressure vessels, oil storage tanks, bridges, heavy transportation machinery and other welded structural parts with high load, etc. Process classification: according to the production process, square tubes are divided into hot-rolled seamless square tubes, cold drawn seamless square tubes, seamless square tubes and qb square tubes.When sand blasting or manual mechanical derusting is used, due to the falling off of the oxide scale of the galvanized square pipe, the metal on the surface of the galvanized square pipe is directly exposed in the air. If a primer is not applied in time, the surface of the galvanized square pipe is easy to rust again, affecting the adhesion of the paint film. I am engaged in all kinds of square tubes, square rectangular tubes, seamless square tubes, galvanized square tubes, galvanized tubes and other materials all year round. I operate in good faith. Welcome to call! As the paint is a time-effective material, the overstock of inventory is easy to expire. Therefore, the main indexes of the paint must be rechecked before use, and the paint can be used only when the results meet the standards.With the progress of the times and the faster and faster economic development, the places where large-diameter seamless square tubes are used are becoming more and more popular

The floating mandrel mill is in its heydayMechanical polishing: after processing, the parts have good levelness, short gloss, dull and rusty. Suitable for processing simple parts, medium and small products.Hardness QB square hardness is a pointer to measure the hardness and softness of metal materials. At present, the hardness method is commonly used to measure the hardness in production. It uses the indenter with fixed geometry to measure the hardness value of the metal material surface tested under fixed load according to the degree of hardness.Recommendation and consultation,B. converter steel: (a) acid converter steel; (b) Basic converter steel. Or (a) bottom blown converter steel; (b) Side blown converter steel; (c) Top blown converter steel.The surface of galvanized square pipe treated by sand blasting, shot blasting or pickling process is relatively clean, and the oxide scale and rust are removed, which improves the adhesion of the coating. When the installation site unconditionally adopts sand blasting and shot blasting, manual and mechanical derusting can be adopted, but the derusting quality level must be reached.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 > %).

. fake and inferior square tubes are easy to fold. Folding is a variety of broken lines formed on the surface of square tubes and this defect often runs through the longitudinal direction of the whole product. The reason for the folding is that the fake and shoddy manufacturers pursue the rate, the reduction is too large, resulting in ears, folding occurs during the next rolling, the folded products will crack after bending, and the strength of the square tube will be greatly reduced.Quotation sheet,It should be noted that the position of the disc from the calibration line can be adjusted according to the reinforcement diameter, and R and R can be equal or different.Strictly feed Si Ca wire quantity to ensure effective & Omega in steel; When (CA) is about .%, the inclusions can be fully denatured without generating more high melting point inclusions.According to smelting classification and furnace type, A. open hearth steel: (a) acid open hearth steel; (b) Alkaline open hearth steel.Dobridge,Brinell hardness (HB), Rockwell hardness (HRC) and Vickers hardness (HV) are commonly used.Cold drawn or cold rolled precision square tube (gb-) is a cold drawn or cold rolled precision square tube with high dimensional accuracy and good surface finish for mechanical structure and hydraulic equipment. The selection of precision square mechanical structure or hydraulic equipment can greatly save machining hours, improve material rate and improve product quality.Ferrous metals refer to iron and iron alloys. Such as steel, pig iron, ferroalloy, cast iron, etc. Steel and pig iron are alloys based on iron square tube and carbon as the main added element, collectively referred to as iron carbon alloy.