Threaded Rod DIN 975:

A threaded rod Din 975, also known as a stud, is a relatively long rod that is thread on both ends; the thread may extend along the complete length of the rod. They are designed to be used in tension. Thread bars in bar stock form is often called all-thread. Moreover Threaded bars featuring a white color code are the strongest. The second-strongest color code is red, which is made of A4 stainless steel. The third-strongest color code for threaded fasteners is green, which is made of A2 stainless steel. Coming in fourth and five is yellow and unmarked, respectively.

General:

With respect to shape, stud bolts a.k.a. studs are categorized into three basic types: “fully threaded stud bolts”, “tap end stud bolts”, and “double end stud bolts”. Each of these studs have different application. As name suggests, fully threaded studs have full body coverage with threads for full engagement of the matings nuts or similar parts. Tap end studs have threads at extreme ends of the body with unequal thread engagement length, while double end stud bolts have equal thread length at both ends. Generally Apart from these there are stud bolts for flanges which are fully threaded studs with chamfered ends. And double end studs with reduced shank for special bolting applications. For studs that are not completely threaded, there are two types of studs: full-bodied studs, and undercut studs. Full-bodied studs have a shank equal to the major diameter of the thread. Undercut studs have a shank equal to the pitch diameter of the screw thread. Undercut studs are designed to better distribute axial stresses. In a full-bodied stud the stresses are greater in the threads than in the shank. Thus Undercut studs (rolled thread) are also stronger because the metal is “rolled” up to the major diameter, not removed. Because this preserves the grain of the steel, and in some cases even enhances it. Full bodied studs (cut thread) are weaker because metal is removed to create the thread, disturbing the grain of the steel.