While choosing boiler tubes, pick out the right and good quality tube according to following steps:

Look at the cross-section of the tube. A good quality seamless tube will have a smooth cross-section and will be devoid of bumps and irregularities.

Check the density of the pipe to understand the percentage of impurities in the pipe. If the pipe shows low density, steer clear!

Check the surface of the boiler tube. A good quality boiler tube will have a smooth surface. If you find the surface to be rough and uneven, you can be sure that the quality is not up to the mark.