How to distinguish true and false galvanized pipes?
How to distinguish true and false hot-dip galvanized seamless steel pipes with naked eyes?Now there is a so-called hot-dip galvanized fluid pipe on the market, also called de-galvanized seamless pipe, which is actually a processed high-frequency welded pipe. The original weld is planed or ground off with special equipment and then galvanized. Now I will share with you how to identify this type of pipe:
(1) Anything that is planed or ground off will leave traces, and some are very obvious;
(2) Hot-dip galvanized seamless steel pipes are all 6 meters, 9 meters or 12 meters in length. Genuine hot-dip galvanized seamless steel pipes are very rare in length because they have to be priced much higher when shipped out of the factory;
(3) Manufacturers of this type of pipe are afraid of taking responsibility, so their quality certificates are all fluid pipes and they dare not say they are seamless steel pipes;
(4) Check whether the wall thickness is uniform. Since seamless steel pipes are made of round steel hot-rolled and perforated, the wall thickness of seamless steel pipes will generally have deviations (with the continuous improvement of technology, the wall thickness deviation of seamless steel pipes is getting smaller and smaller, but there are still some). Although welded pipes have undergone welding rib treatment or heat expansion procedures, since their raw materials are strip steel, their wall thickness is very uniform.
How to identify the authenticity of seamless pipes
The buyers of seamless pipes need to know how to identify the authenticity of seamless pipes. Now, there are many manufacturers producing seamless pipes, and the prices of seamless pipes are also uneven. Among them, there are some manufacturers that sell inferior products as good ones. At this time, I will teach you how to distinguish them!
1. Fake thick-walled seamless steel pipes are prone to folding. Folding is thick, and the wall of thick-walled seamless steel pipes is greatly reduced. Various fold lines are formed on the surface of seamless steel pipes. This defect often runs through the entire longitudinal direction of the product. The reason for the folding is that the fake manufacturers pursue high efficiency, the amount of pressure is too large, and ears are produced. The next rolling will produce folds, and the folded products will crack after bending.
2. Fake thick-walled seamless pipes have pitting. The pitting is due to the fact that the rolling groove seam steel pipe manufacturers want to pursue profits, and the rolling groove rolling is often severely worn, causing irregular uneven defects on the surface of thick-walled seamless steel pipes. Because fake thick-walled pipes are not controlled, they are most excessive.
The surface of the steel pipe is often
3. The surface of the fake thick-walled seamless steel pipe is easy to be rough and easy to stick to steel. These impurities bite the rollers and cause scarring. There are two reasons: ① The material of the fake thick-walled seamless steel pipe is uneven and has many impurities. ② The fake material is easy to cause scarring after the manufacturer's guide equipment is simplified.
4. The fake material has many pores. The adobe produces cracks due to the thermal stress during the cooling process. After rolling, the surface is prone to cracks. The reason is that its blank is adobe, and there are cracks after adobe.
5. The fake thick-walled seamless steel pipe is easy to scratch, and the surface. Deep scratches reduce the strength of the thick-walled seamless steel pipe. Luster, light red or similar to the color of pig iron, there are two reasons. Second, its blank is adobe.
6. The fake thick-walled seamless steel pipe has no metallic luster and is light. There are two reasons. Second, its blank is adobe. The rolling temperature of inferior materials is not standard. They roll in the austenite area of steel. The red or temperature of thick-walled seamless steel pipes is visually inspected. This cannot be similar to the color of pig iron as required, and naturally cannot meet the standard.
How to distinguish hot-dip galvanized steel pipes from the appearance
Do you often worry about whether some pipes are cold-dip galvanized or hot-dip galvanized? Of course, many people will say that it will be clear if they are sent to the quality inspection agency, but I personally think that the traditional inspection method is not only a waste of time and money. Here is a method to distinguish these two types of pipes
1. The difference is as follows:
Appearance: hot-dip galvanizing looks concave and convex and slightly darker; cold-dip galvanizing looks smooth and shiny;
Thickness: hot-dip galvanizing is thick, cold-dip galvanizing is thin;
Inner hole: hot-dip galvanizing inner hole has coating: cold-dip galvanizing inner hole only has coating at both ends;
Corrosion resistance: hot-dip galvanizing is high: cold-dip galvanizing is low;
Marking: hot-dip galvanizing has blue ink printed hoops at both ends, and the whole body has implementation standards and specifications: cold-dip galvanizing has no
2. The price of cold galvanizing is relatively low. This is an empirical thing, but it is an important item to observe whether the galvanized layer is flat and uniform. Another thing is to look at the quality inspection report and the certification documents of the production instructions. If you feel that the documents cannot explain, then I suggest using a hammer or something like that to hit the pipe to see if the galvanized layer will fall off. If it does fall off, then it is most likely cold-galvanized. If you think it is helpful, please forward it to your friends! If you have a more convenient way, you can also leave a message to tell the editor!
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