Steel pipes are often used in engineering construction. There are many types of steel pipes. Among them, welded steel pipes and galvanized steel pipes are used more frequently. What are the differences between the two? What problems should be paid attention to in construction?
1) The difference between welded steel pipe and galvanized steel pipe
1. Define the difference
Welded steel pipe is to bend the steel strip (or steel plate) before welding, and the seam can be seen on the surface, while the galvanized welded pipe is welded.
Galvanized on the basis of steel pipe. The purpose is to galvanize general steel pipes (black pipes) in order to improve the corrosion resistance of steel pipes.
2. Classification difference
Welded steel pipes are divided into arc welded pipes, high frequency, gas welded pipes, furnace welded pipes, etc. According to the shape of the weld, it can be divided into two types: straight seam and spiral. Galvanized steel pipes are only divided into cold galvanized pipes and hot-dip galvanized pipes. The hot-dip galvanized galvanized layer is thick and the cost of electro-galvanized is low. The price of galvanized steel pipe is much more expensive than that of welded steel pipe.
3. Appearance difference
The surface of galvanized steel pipe usually has a layer of metal material, which is generally very smooth and well-proportioned in color. Because the welded steel pipe is relatively simple and rude in production, its appearance is not good, and some people also call it black pipe. If you want to buy decorative building materials of these two raw materials, people usually prefer galvanized steel pipes.
4. Differences in use
Electric welded steel pipes are commonly used in machinery or oil drilling and mining industries, water and gas pipes, etc. Large-diameter straight seam welded pipes are used for high-pressure oil and gas transportation, etc., and spiral welded pipes are used for oil and gas transportation, pipe piles, bridge piers, etc. The galvanized welded pipe is more suitable for conveying low pressure liquid.
2) Precautions for welded steel pipes
1. First check the raw materials such as steel, and enter the construction site only after the inspection meets the standards.
2. Check whether the welding materials are qualified and stored in accordance with the regulations. Pay attention to see if there is rust on the surface of the welding material. If the steel pipe has been rusted or mildewed, it will not work.
3. The cleaning of the welding area should be managed well, and the welding area should be kept clean and dust-free, and there should be no water, oil, rust and other dirt, and external defects of the weld should be prevented.
4. Select the welding method, try to test the welding first, and then apply the welding principle. In order to avoid welding quality accidents caused by wrong use of welding wire.
5. Look at the groove size before pre-welding. Pay attention to check whether the gap, blunt edge, etc. meet the process requirements.
6. Welders should clean the slag first when repairing the welding work to see if the joints are treated. There should be no oil, rust and other dirt on the groove.