Burrs.
It is called the intake manifold.
Pipe is threaded outside making it a male end, or inside making it a female end. The pipe in this picture is bizarrely called a " short male nipple"
A pipe bending machine is used in a factory to shape large pieces of metal for use in constructing things. This is a good way to get parts made for large projects.
Some cars don't require that metal pipe but if you think you need it, you may be able to find one at a junk yard if not, try the auto parts store.
This is hard to answer with out knowing what type of metal. what the pipe is being used for, the amount of pressure that may be not the pipe.
The base metal is iron - the active metal is zinc (galvanized)
If it is a copper or metal pipe, tap the pipe gentle with a some thing metal (screw driver/small wrench ect...) If the pipe makes a echo sound it is empty, if the pipe has water in it, It will not echo. this also works with pro pain bottles and other metal objects
Corrugated Metal Pipe. CMP
To connect a metal pipe to a PVC pipe using a metal to PVC adapter, the best way is to first ensure that both pipes are clean and free of any debris. Apply primer and cement to the PVC pipe and the adapter, then insert the PVC pipe into the adapter and hold it in place for a few seconds to allow the cement to set. Repeat the same process for the metal pipe and the other end of the adapter. Allow the connection to dry and cure according to the manufacturer's instructions before using the pipes.
By the color
Non-metal
If the pipe is metal try a metal detector. If plastic, get out your shovel.