How to identify the true and false hot-dip galvanized seamless steel pipe with naked eyes?
Now there is a so-called hot galvanizing fluid pipe in the market, which is also called de galvanizing seamless pipe. In fact, it is a processed high-frequency welded pipe, which uses special equipment to gouge or grind off the original weld and then galvanize. Now I will take out the identification of this kind of pipe and share with you:
1) All that is planed or ground will leave traces, some of which are still obvious;
2) The hot-dip galvanized seamless steel pipes are 6 meters, 9 meters or 12 meters in length, and the standard hot-dip galvanized seamless steel pipes are very few in length, because the fixed length factory has to add a lot of price;
3) The manufacturer of this kind of pipe is afraid to bear the responsibility. Their quality certificates are all fluid pipes, but they dare not say that they are seamless steel pipes;
4) To see whether the wall thickness is uniform, because the seamless steel pipe is made of round steel by hot rolling and piercing, there will be deviation in the wall thickness of the seamless steel pipe in general (with the continuous improvement of technology, the deviation of the wall thickness of the seamless steel pipe is getting smaller and smaller, but there is still some). Although the welded pipe is processed by welding bars or heat expansion, its wall thickness is very high because its raw material is steel strip Even.
How to distinguish hot and cold galvanized steel pipe from appearance
Do you often worry about whether some pipe fittings are cold galvanized or hot galvanized? Of course, many people will say that it's not clear to send it to the quality inspection authority, but I personally think that the traditional inspection method is not only a waste of time but also a waste of money,
Here is a way to distinguish these two kinds of pipe fittings
1. The differences are as follows:
Appearance: the surface of hot-dip galvanizing is concave and convex, slightly dark; the surface of cold-dip galvanizing is smooth and bright;
Thickness: hot galvanized thick, cold galvanized thin;
Inner hole: hot-dip galvanized inner hole has coating: cold galvanized inner hole only has two ends;
Corrosion resistance: high hot galvanizing, low cold galvanizing;
Identification: both ends of hot-dip galvanizing are provided with hoops printed with blue ink, and the whole body has executive standards and specifications and models: no cold galvanizing.
2. The price of cold galvanizing is relatively low
It's an empirical thing, but it's an important project to observe whether the galvanized layer is even, and also to see the quality
If the test report and the supporting documents of the exit instruction cannot be explained, I suggest knocking with a hammer or something
Hit the pipe to see if the galvanized layer will fall off. If it does, it will be cold plated in nine out of ten cases.
The above is about "how to distinguish the true and false hot-dip galvanized seamless steel pipes with naked eyes?" Jinan Galvanized Pipe Co., Ltd. provides relevant information. For more information, please click the official website http://www.jnlhjscl.com 。