In terms of appearance, the difference between seamless steel pipes and welded pipes is that the welded steel pipes have welding bars in the inner cavity, but the seamless ones do not.
I believe that a large number of people still don’t know the difference between
seamless steel pipes and welded steel pipes. Today I will explain it to everyone.
Seamless steel pipe
1. In terms of appearance, the difference between seamless steel pipes and welded pipes is that the welded steel pipes have welding bars in the inner cavity, but the seamless ones do not.
2. The working pressure of seamless steel pipes is higher, and that of welded steel pipes is generally around 10 MPa. Nowadays, welded steel pipes are being seamlessly spliced.
3. Seamless steel pipes are formed in one step during cold rolling. Welded pipes must be welded by electric welding after production. Generally, there are spiral welding and direct welding. Smaller diameter welded pipes mostly use straight seam welding, while large diameter welded pipes mostly use spiral welding. The welding methods of spiral welded pipes and straight seam steel pipes are the same, but straight seam welded pipes inevitably have many T-shaped welds, so there are welding defects. The probability of cracking is also greatly increased, and the weld metal at the T-shaped weld is often in a three-way deformation state, increasing the possibility of cracks. In terms of properties, seamless steel pipes are better, and naturally the price is higher.
Spiral welded pipe
4. Seamless steel pipe is a hollow strip-shaped stainless steel plate, which is often used as a pipeline for transporting fluids, such as crude oil, natural gas, water, liquefied gas, steam, etc. In addition, when the bending and torsional strength are the same , light weight, so it is also widely used to produce mechanical parts and engineering structures. It is also commonly used in the manufacture of various strategic weapons, barrel rifling, bullets, etc.
5. The key is that the forming process is different. Ordinary steel pipes, such as drinking water pipes, are usually welded by bending the sheet metal and then welding. You can find a weld on it; those with larger diameters are usually spiral welded. Seamless steel pipes are generally formed by collecting the molten iron through annular double-slit stock and then undergoing stretching and other processes, so there is no welding. In terms of performance, especially its ability to withstand pressure, it is greatly improved compared to ordinary steel pipes, so it is often used in high-pressure equipment. Such as pipe connections for hydraulic machinery and equipment, etc. The welding position of ordinary steel pipes is its weak point, and the welding quality is a key factor affecting its overall properties. People who live in the north often have the experience of water pipes or heating pipes being frozen and exploded in winter, and the explosion areas are usually welding joints.
