Process to improve fatigue strength of micro alloy steels, forged parts made from the process and an apparatus to execute the process

A forged part made from vanadium micro alloy steels said part having improved grain size and structure, obtained through a process of forging that comprises a step of improving grain size, said improved grain structure being a pearlite structure, said improved grain size being between ASTM 6-8, and said step comprising:

• austenitising said parts by heating them to a first temperature which is in the range between 900-1050° C., maintaining said parts at that temperature for a soaking period in order to allow said part to attain homogenized temperature, and cooling said parts to room temperature.

An apparatus to make a forged part from vanadium micro alloy steels, said apparatus comprising at least a grain size refinement station wherein steps of austenitising, soaking and cooling of said forged part are carried out.

A process to improve fatigue strength of forged parts made from vanadium micro alloy steels, said process having a step of refining the grain size, said step of refining the grain size in turn comprising:

• austenitising said parts by heating them to a first temperature which is in the range between 900-1050° C., maintaining said parts at that temperature for a soaking period in order to allow said part to attain homogenized temperature, and cooling said parts to room temperature, wherein said soaking period is 30 to 60 minutes, and wherein said cooling is applied by still or forced air cooling methods.