The difference between elbows and bent pipes 2026-07-07

The most basic difference between elbows and bent pipes is that elbows are relatively shorter compared to bent pipes. R=1 to 2 times is an elbow, and any larger multiple is called a bent pipe. Cold bending pipes can be made using ready-made straight pipes and bending machines in the production process, and can be completed in one go without the need for secondary anti-corrosion treatment. But the elbow needs to be customized by the manufacturer, anti-corrosion treatment is required, and the ordering cycle is long. Elbows are more expensive than bent pipes, but their cost-effectiveness is much higher. It is well known that bent pipes without anti-corrosion treatment are prone to damage, but they are widely used in some projects with low requirements due to their low price. The elbow needs to be customized by the manufacturer, with anti-corrosion requirements and a long ordering cycle. Cold bent pipes can be bent using existing straight pipes using a pipe bending machine. A one-time completion does not require secondary anti-corrosion treatment. There is a petroleum standard for the construction process of cold bending pipes, and an enterprise standard for the West East Gas Pipeline. But in open areas, elbows and bends can be used, considering only the cost. Elbows need to be hot bent, while bent ones can be cold bent, although the cost of elbows is high. Sometimes it is necessary to use elbows in narrow areas, such as in stone section pipe trenches, because the curvature radius of elbows is small, usually 6D, while that of elbows is 40D.

Calculation formula for elbow size 2026-07-07

The basic knowledge of elbows requires knowledge of the elbow diameter, bending radius, angle, and some straight sections. According to the angle, there are three most commonly used types: 45 °, 90 °, and 180 °. In addition, other abnormal angle elbows such as 60 ° are also included according to engineering needs. Determining the angle of the elbow requires measuring with tools, and only 180 degrees, 90 degrees, and 45 degrees can be seen. Calculation formula for elbow size: 1. 1.5 times the center height of the elbow=diameter * 1.524, which is actually the diameter * multiple. Round the number after the decimal point of the obtained result to an integer. For example, if the diameter of 219 is 200, the center height is 200 * 1.524=304.8, which is taken as 305; For example, if the diameter of 114 is 100 and the center height is 100 * 1.524=152.4, take 152. The algorithm for calculating the curvature radius of DN100 and above elbows is convenient and fast. 2. Poke height=center height+radius of bend, for example, the poke height of a bend with a diameter of 219 and a diameter of 1.5 times is 305+219/2=305+109.5=414.5 3. Outer arc length=(center height+radius) * 3.14 * 2/360 * degrees, i.e. (punch height) * 3.14 * 2/360 * degrees, from which the outer arc length of a 90 degree elbow can be calculated as=punch height * 3.14/2 4. Inner arc length=(center height radius) * 3.14 * 2/360 * degrees 5. The cutting length of the elbow=elbow center height * 3.14/2 * elbow outer diameter/pipe diameter+(pipe wall thickness * 3)+machining allowance. If using a 180 * 8 pipe for cutting and pushing a 273 elbow, the above formula can be used to calculate: Cutting length=381 * 1.57 * 273/180+24=931.22mm+machining allowance.

Process flow of carbon steel elbow 2026-07-07

The process flow of carbon steel elbow, carbon steel push elbow color process is to use a layer of film to form a specified color. Due to the use of this constantly existing film in the alloy push bend, it neither fades nor requires frequent maintenance like paint. Color alloy push made elbows can also undergo molding treatment, and even at sharp bends, they will not have any adverse effects on the color. This process is closely related to the operating time, and the color will change with different times. The order of color changes is brown, gold, red, purple, and green. One major feature of this process is that its final appearance can reflect the original surface of the material. The process of carbon steel elbow is to immerse the alloy push elbow in a solution tank, preferably containing 250 grams of Cr2O3 per liter or 490 grams of sulfuric acid per liter. The temperature range is 80-85 ℃, and the soaking time depends on the desired color, with a maximum of 25 minutes. After rinsing the alloy elbow with clean cold water, it is then subjected to cathodic treatment at room temperature in a liquid with a concentration of 250 grams/liter of chloric acid and 2.5 grams/liter of phosphoric acid for approximately 10 minutes, with a current density of 0.2~0.4A/dm2.

The selection of carbon steel flanges must meet the design requirements 2026-07-07

When installing a degreasing pipeline, it is not allowed to dismantle the drilling bull's horn pipe section and then degrease it. The selection of carbon steel flanges must meet the design requirements. Tube processing is a combination of processing and metal stamping processing, and a good combination of tube processing technology is a more reasonable and more in line with product requirements. The sealing device for the gate stop valve and reverse screw, with the handwheel turned to the top position and tightened to prevent the medium from leaking out of the packaging. However, this technology is relatively messy, cumbersome to operate, and produces the same quality as the above technology, which is less preferred. Next time. The installation of the pump inlet reducer should be done when the gas accumulation is not adjustable to avoid incorrect installation and cavitation. The high-pressure carbon steel flange is connected to the pipeline flange to form a good connection action. The tubular component is a deep processed product of the pipe machine, which should belong to the scope of the pipe. The pipe can be replaced by the sector processed product and cast, which is lighter than the weight of machined parts and casting structural parts, saving materials; The second is to save hours and low-cost chips compared to cutting processes. Developed by the Shanghai Research Institute of the Chinese Academy of Ceramics, HRA, our company's alumina ceramics have a Rockwell hardness that is higher than that of wear-resistant stainless steel. Especially for small diameter carbon steel pipes, the low price is a major factor determining the reliability and price of the supporting connection method.

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