How to distinguish hot rolled seamless steel tube and cold drawn seamless pipe by naked eyes

We need to distinguish whether it is hot rolled seamless steel tube or cold drawn seamless steel pipe from its appearance by the following steps:

1. Length: the length of cold drawn seamless pipe is generally shorter than that of hot rolled seamless steel tube. The length of cold drawn seamless pipe can reach up to 9 meters, while that of hot rolled seamless steel tube can reach up to 12.5 meters, and that of heat expansion can reach up to 14 meters.

2. In terms of wall thickness: the thickness of cold drawn seamless pipe is more uniform than that of hot rolled seamless steel tube. The deviation of cold drawn seamless pipe is not nonexistent but very small. For example, the maximum deviation of the wall thickness of 3mm is 0.3mm, while the minimum deviation of the hot rolled seamless steel tube is 0.3mm. Generally, the deviation range of the hot rolled seamless steel tube is 10%. That is to say, the deviation of the wall thickness of 10 mm can reach to plus or minus 1 mm.

3. Appearance: the cold drawn seamless pipe is very beautiful after annealing, while the hot rolled seamless steel tube shows less advantages than the cold drawn seamless pipe, and its appearance is dim.

4. Price: generally, the price of cold drawn seamless pipe is 200-300 higher than that of hot rolled seamless steel tube. The processing of cold drawn seamless pipe is tedious and the processing of hot rolled seamless steel tube is simple.