How to differentiate between erw and seamless Pipes and tubes

Erw and Seamless pipes and tubes are manufactured in different shapes like Square, Round,Rectangle, all Mild steel erw Pipes are have hollow space ,
There is wast difference in erw Pipe and Mild steel seamless Pipe in seamless Pipe as the name suggest there no seam ( no joint ) while in erw pipe the person will find joint on internal side or external side in the whole length
The manufacturing process of erp Pipe in different size  requires electrical process where the coil or sheet is given hot treatment at the edge and folded to make it Square , round  or Rectangle.


Erw products have welded joints through out the length were as seamless Pipes n Tubes go through hot melting process and passes through cooling process so that the required shape is the final out put.


Electric Resistance Welded(ERW) comes in various size the od ranges from 2,3,8 and many more
The wall  thickness also have different range from .5mm to 8 mm. For higher wall thickness special process is required , it find application in play ground  equipment, construction market,
Elevator industry.


Mild Steel Seamless Pipes n Tubes so have different od n wall thickness, this product find application in shipping industry and this seamless hollow Pipe is againg used when ship gets destroyed as country port 
Use of Seamless Pipe n Tube in cnc machining work,gas cylinder

if we take into consideration the american standard of erw pipes and seamless pipe the 2 NB seamless or erw pipes have od of 33.6 and iin schedule 40 the wall thickness is 3.26