Large diameter welded square pipe for low pressure fluid transmission Standard No.: gbt14980-1994. Representative material: grade q235ab. It is mainly used to transport low-pressure fluids such as water, gas sewage, air and heating steam.
Great relationship. Large fillet radius, insufficient blank holder area, easy to produce unstable wrinkles; If the fillet is too small, and the material is not easy to move and transfer inward, which may lead to tensile cracking.
Guapiles.In this period, which is rolled by strip steel after process treatment. Many kinds of materials can form a square tube body. It is used for what purpose and where. Most square tubes are steel tubes, mostly structural square tubes, decorative square tubes and building square tubes. Generally, the strip steel is unpacked, leveled, crimped and welded to form a circular tube, which is rolled into a square tube and then cut to the required length. Usually 50 pieces per bag.
.Performance index analysis of square tube - impact toughness the load acting on the part at a great speed is called impact load, and the ability of metal under impact load is called impact toughness.
Ordinary carbon steel is divided into Q19 Q2 q23 SS400, 20# steel, 45# steel, etc.
The advantages of real bending are small reverse, accurate forming, and as long as the roll shape is accurate, the R of inner corner forming is more accurate. The disadvantage of solid bending is that it has tensile thinning effect. The actual bending will produce tension at the bending point, and the tensile effect will shorten the longitudinal length of the bending line; The metal at the real bend will become thinner due to stretching.
Now in many construction projects, we can see the shadow of q355b square tube, because q355b square tube is quite hard in hardness, stamping, cutting and other processing are based on hardness, which is also the guarantee of mechanical properties. Based on the above, it is very important to test the hardness of q355b square tube.
Carbon steel classified by chemical composition: square tube A. low carbon steel (C & le; 0.25%); b. Medium carbon steel (C & le; 0.25 ~ 0.60%); c. High carbon steel (C & le; 0.60%).
The strength, plasticity and angle discussed later are the machine function indicators of metal under static load. In practice, many mechanical machines are under repeated load, and the whole opportunity is tired in this environment.
Product survey.Square tube is the main type of square tube. It is also very popular in the square tube market. There are many people doing this kind of thing, so there are many in the competition. The future market potential is huge. We should grasp this information well. In addition, we must learn about relevant maintenance and repair!
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 4, these impurities become the core of ferrite, making the morphology of ferrite distributed in bands, and then pearlite distributed in bands. This band can be eliminated by electroslag remelting and increasing crystallization speed.
The square tube is a low-alloy high-strength structural steel with carbon content of 0.1% - 0.25%, and the main alloy elements manganese, silicon, vanadium, niobium and titanium are added; Its total alloy content is 3%. According to the strength, it is divided into four levels: 300, 350, 400 and 450MPa.
Empty bending is the bending moment formed in one direction between the outer roll and the outer wall of the tube blank to bend the strip. Empty bending will compress the bending line, the compression effect will lengthen the bending line longitudinally, and the metal at the bending will accumulate and thicken, which is the compression thickening effect of empty bending.
Quality department.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, the more common piercer is the conical roll piercer. This piercer has high production efficiency, good product quality, large perforation expansion and can wear a variety of steel grades.
Improve the positioning and pre bending steps, if necessary, to ensure that the web hunting problem does not occur when pressing parts. Change the shape of the surface pressure of the material to ensure the quality of the parts and avoid the non movement of the surface shape of the roll gap, resulting in uneven walking feeding.
In order to ensure excellent coating quality, the coating is required to be firmly attached to the surface of the coated object. This depends on the quality of the coating itself; On the other hand, 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.
Guapiles.The q355b square tube protective layer thickness detector is used to measure the actual thickness of the seamless q355b square tube protective layer on site. It is required that the actual thickness of the seamless q355b square tube protective layer of the seamless q355b square tube shall not be lower than the design value. When the requirements are not met, the protective layer of seamless q355b square tube can be chiseled and measured.
The square tube is formed by external control or internal control roller.
Material of square tube: q23 Q345 (16Mn), 20# alloy steel, stainless steel.