1045# is widely used in hydraulic fittings (hose tail)

AISI 1045 steel is characterized by good weldability, good machinability, and high strength and impact properties in either the normalized or hot-rolled condition.
AISI 1045 steel has a low through-hardening capability with only sections of around 60 mm in size being recommended as suitable for tempering and through-hardening. However, it can be efficiently flame- or induction-hardened in the normalized or hot rolled condition to obtain surface hardnesses in the range of Rc 54 – Rc 60 based on factors such as section size, type of set up, quenching medium used etc.
AISI 1045 steel lacks suitable alloying elements and hence does not respond to the nitriding process.