Tool steel or 1.4305 stainless steel.

Steel hardened and ground.
Stainless steel ground and kolsterised.

Ball end locating pins are specially designed to ease the locating process. The tendency to jam, caused by the locating hole not being at right angles to the pin or by the pushing force not being parallel to the pin axis, is minimized by the ball-end form (see illustration 1)

A1) Internal thread one side in blind hole
A2) Internal thread both sides in blind holes
A3) Internal thread both sides in through hole