Unknown line on round bar surface

[edward995]

why there is a line on the round bar?

 

[EdStainless]

This looks to be hot finished bar. That line is from the hot rolling tooling.
Have you tried to grind or turn a sample to see if it has depth? I doubt that it is a lapp or seam.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

 

[weldstan]

Agree with Ed.

 

Ditto. Not much to see here.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."