Bend TubeThe fundamental difference with elbows is that the same-sized bent pipesElbowCompared to elbows, bends are generally longer, and when the R value is greater than twice the diameter, it is considered a bend. If the R value is between 1 and 2 times the diameter, it is classified as an elbow. In the manufacturing process of bends, cold bending can be achieved by using pipes directly on a bending machine, allowing for the production of bends in one go without the need for secondary anti-corrosion treatment. However, elbows must be custom-made by the manufacturer, require anti-corrosion treatment, and have a longer lead time for ordering.
Bend pipe prices are slightly lower than elbow prices, but their cost-performance ratio is much lower. It's common knowledge that unbonded bend pipes are prone to damage; I won't elaborate. However, due to their low cost, they are widely used in projects with less stringent requirements.
Elbows must be custom-made by manufacturers, requiring corrosion resistance and a longer lead time. Cold bending pipes can be directly formed by pressing the tube into a bending machine, completed in one go, and do not require secondary corrosion protection. There is an oilfield standard for the construction technology of cold-bent pipes, and enterprises have their own standards for the West-to-East Gas Transmission project.
But curved sections and elbow fittings are acceptable for open plots; cost is the only consideration. Cold bending of elbow fittings is feasible, while elbows require hot bending, which naturally makes the elbows more expensive.
In narrow sections, elbows are often required, such as in stone section trenching, as the radius of curvature for elbows is typically smaller at 6D, compared to 40D for bends.
On construction sites for engineering and building projects, deciding between elbows and bends is not just about considering the price and quality of elbows and bends; it also involves thinking about where they will be used, thereby determining whether to choose elbows or bends.
