square tubes and thin-walled square tubes according to wall thickness. Gbt6728-200gbt6725-200gbt3094-2000
Classification of wall thickness square tubes are divided into super square tubes, JG 178-200, ASTM A500, JIS g34en10210 or technical agreement.
The raw material for rolling square tube is round tube blank. For a long time, square tube, rectangular tube, seamless square tube, galvanized square tube and galvanized tube have complete products, excellent quality and favorable price. The round tube embryo shall be cut and processed by cutting machine, and the blank with a growth of about 1m shall be brought to the furnace for heating. The billet is sent to the furnace for heating at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature in the furnace is the key problem. After the round tube billet is discharged from the furnace, it should be pierced through the pressure piercer. Generally, good product quality, Rockwell angle (HRC) and Vickers angle (HV) of q355b square tube. Angle is a gauge needle to weigh the soft and hard level of metal data. The angle method is rarely used to determine the internal angle in the current life. It uses the metal data surface tested under the fixed load of the indenter with a certain number and shape to determine its angle value according to the level of the object.
The welded joints of square pipes are subject to on-line continuous ultrasonic automatic flaw detector to ensure the NDT coverage of spiral welds. If there are defects, it will automatically alarm and spray marks. The production will adjust the process parameters at any time to eliminate the defects in time.
.Banded due to improper hot working temperature, that is, when the hot working stop forging temperature is in the phase zone (between, and 40), ferrite precipitates in bands from austenite along the metal flow direction, and the undigested austenite is cut into bands. When it is cooled to a, the banded austenite is transformed into banded pearlite. This can be improved or eliminated by increasing the final rolling temperature, increasing the forging ratio, diffusion annealing and normalizing.
Do a good job in the following aspects to effectively improve the use of square tubes
All seamless q355b square tubes shall be tested for mechanical properties. Mechanical property tests are mainly divided into two categories: tensile test and hardness test.
Functional index analysis of square tube - mechanical function of plastic square tube.
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.
Use classification square tubes are divided into: square tubes for decoration, square tubes for machine tool equipment, square tubes for mechanical industry, square tubes for chemical industry, square tubes for steel structure, square tubes for shipbuilding, square tubes for automobile, square tubes for steel beams and columns, and square tubes for special purposes.
Price.The welding process of square tube is analyzed. The square tube is produced and processed at room temperature with strip steel as raw material. Square pipe can be divided into straight seam welded pipe, square pipe and spiral welded pipe. Due to the different uses of welded pipes, the standards of welded pipes are summarized in turn: galvanized q355b square pipe for low-pressure fluid transportation, and the standard number is gbt3091-2008. Representative materials: Q235A, q235bq345b, air gas, oil and heating hot water or steam, and its purpose is limited to general low pressure fluid.
Material of square tube: q23 Q345 (16Mn), 20# alloy steel, stainless steel.
It must be noted that in the overall process of square tube coating process the cost of surface treatment is still relatively high, so it is very important to select appropriate treatment. Only by selecting the right treatment can the coating quality of square pipe be well guaranteed.
It is mainly caused by the fact that the square pipe body has no cover, the covering protection is not ideal, and there is no support, partly due to the excessive number of stacking layers, and most coastal areas belong to marine climate, with large annual rainfall, high air humidity, ponding in the square pipe and the square pipe. The protection shall be: if the bare pipe or pipe needs to be stored for a long time, it shall be protected with an uncovered object from the beginning of storage to avoid rusting, layer aging, edge warping and other phenomena of the square pipe.
Service first.Mechanical property is an important index to ensure the end use performance (mechanical property) of square pipe, which depends on the chemical composition and heat treatment of steel. In the steel pipe standard, according to different service requirements, the tensile properties (tensile strength, yield strength or yield point, elongation), hardness and toughness indexes, as well as the high and low temperature properties required by users are specified.
According to smelting classification and furnace type, the processing temperature is the key. Professional square tube, square tube, seamless square tube, strict detection, more affordable price and more preferential price. Consultation is welcome. It must be noted that the blank heating should be uniform. Perforation has a great impact on the quality. The perforation temperature of blank varies according to different materials, generally around 1200 ℃.
Skernevice.Hot rolled q355b square tube continuous casting slab or blooming slab is used as raw material, heated by stepping heating furnace and descaled by high-pressure water into roughing mill. Roughing material enters finishing mill after head cutting, tail cutting and then computer rolling. After final rolling, it is rolled into straight hair coil through laminar cooling and coiler. The head and tail of straight hair curl are often tongue shaped and fish tail shaped, with poor accuracy of thickness and width, and there are often defects such as wave shape, hem, tower shape and so on. The coil weight is heavy and the inner diameter of the steel coil is 690mm.
The flattening speed of the sample can be 20 ~ 50mmin.
The standard number of square pipes for transporting flammable and non flammable fluids is gbt97 1 (gbt97 - 199 represents steel for l245-l4 and other pipelines. It is mainly used for transporting flammable and non flammable fluids, low-pressure or high-pressure square pipes, with high requirements.