5 inch steel pipe round  a106 grb
Carbon steel seamless steel pipe is a kind of long strip steel. Steel pipe has hollow cross-section and is widely used for conveying fluid, such as oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, the steel pipe has the same bending and torsion strength and lighter weight. It is a kind of economic section steel, which is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffold used in construction.

What is the difference between seam and seamless pipe? ?

Seamless pipe is made by extrusion process i.e molten metal is passed through die to get shape of pipe. ... Seam pipes are made by seam or electric resistant welding process i.e sheet of steel is rolled in a shape of pipe and its sides are welded through electric resistance welding.
What size does steel tubing come in?    
Size Range:
Rectangular tubing from 1.000" x 0.500" x 0.065" wall to 20.000" x 12.000" x 0.625" wall. Round from 0.840" O.D. x 0.109" wall to 16.000" O.D.
What does Schedule 40 mean?  
The pipe schedule refers to the pipe wall thickness. The higher the schedule, the thicker is the pipe wall. For example: 2-inch nominal size steel pipe: schedule 40 has a wall thickness of 0.154 inches and schedule 80 has a wall thickness of 0.218 inches.
How do you determine tube size?     
OD and Nominal Pipe Size
Tubing is measured by the OUTSIDE DIAMETER (O.D.), specified in inches (e.g., 1.250) or fraction of an inch (eg. 1-1/4″). Pipe is usually measured by NOMINAL PIPE SIZE (NPS). Although it is related to the outside diameter, it is significantly different.