How to classify large-diameter butt-weld elbows by angle?

Large-diameter butt-welding elbows are divided according to the angle of the elbows. There are 45 ° butt-welding elbows, 90 ° butt-welding elbows and 180 ° butt-welding elbows. Other special viewpoint elbows can generally be made according to the customer's drawings Custom processing. The general raw materials of large-diameter butt-welded pipe fittings include: carbon steel, alloy steel and stainless steel. The elbow is divided according to its radius of curvature, which can be divided into long radius butt welding elbow and short radius butt welding elbow.

The radius of curvature of the long radius butt weld elbow is equal to 1.5 times the outer diameter of the pipe, that is R = 1.5D. The radius of curvature of the short radius butt-weld elbow is equal to the outer diameter of the pipe, ie R = 1D. In the formula, D is the diameter of the butt welding elbow, and R is the radius of curvature; if divided by pressure level, there are about 17 kinds, which are the same as the American pipe standard, among which the most commonly used are STD and XS. Large-diameter elbows generally refer to diameters above DN600. Large-diameter elbows include large-diameter straight seam elbows and large-diameter seamless elbows butt-welded elbows. The most commonly used on the market is the butt welding elbow.

Straight seam and seamless in large caliber in addition to raw material equipment skills, and the price is more expensive. Large-diameter elbows can be divided into 45-degree large-diameter elbows according to the viewpoint. There are 90-degree large-diameter elbows, 180-degree large-diameter elbows and other elbows with different viewpoints. According to the raw materials, it can be divided into carbon steel large diameter elbow, stainless steel large diameter elbow, alloy steel large diameter elbow.

According to the radius of curvature, it can be divided into long radius large diameter elbow and short radius large diameter elbow. The main standards for large-diameter elbows are national standard, electric standard, Sinopec standard, marine standard, Japanese standard, American standard, etc. Large-diameter elbows have the advantages of inner wall lubrication, low resistance to heat medium flow, acid and alkali resistance, long service life, and convenient installation.

The threshold of carbon steel elbow skills is very high, currently relying mainly on imports. Judging from the company's skill history, the elbow is more likely to succeed. These skill bottlenecks will inevitably restrict the long-term profitability of the entire industry and the ability to participate in international competition. In order to avoid the erosion of the carbon steel elbow due to heating. The welding current should not be too large, about 20% less than the carbon steel electrode, the arc should not be too long, the interlayer cooling is fast, and the narrow weld bead is suitable.