(A) blank shaft parts shaft parts according to the requirements, production type, equipment condition and structure, selection bar, forgings and other rough form. The outer diameter of the shaft or less, generally the main bar; while for the outer diameter of the large difference between the stepped shaft or major axis, often used in forging, which saves material and reduces the workload of the machining, but also improved mechanical properties. Depending on the scale of production, rough forging the way there are two kinds of freedom and die forgings. Small batch production to use more free forging, forging when using a large number of mass production. Material shaft parts (two) shaft parts of different materials should be used depending on the working conditions and the use of different heat treatment requirements and specifications (such as quenching, normalizing, quenching, etc.), in order to obtain a certain strength, toughness and wear resistance. 50 steel shaft parts are commonly used materials, it is cheap after quenching and tempering (or normalized), the get better cutting performance, but also to obtain higher strength and toughness and other mechanical properties, surface hardness after quenching can up to 45 ~ 52HRC. Unhardened surface hardness 28-32HRC 40Cr alloy structural steel suitable for medium accuracy and high speed shaft parts, such steel quenched and quenched with better mechanical properties. GCr15 bearing steel and spring steel 65Mn, after quenching and surface high-frequency hardening, surface hardness up to 50 ~ 58HRC, and have higher fatigue resistance and good wear resistance, can produce high precision axis. Precision machine tool spindle (such as grinding wheel axis, coordinate boring spindle) can be used 38CrMoAIA nitrided steel. This steel is quenched and surface nitriding, not only to get high surface hardness, but also to maintain a softer core, so the impact resistance and toughness. Compared with the case hardening steel, it has a heat deformation small, higher hardness characteristics. No. 50 steel is widely used in machinery manufacturing, good mechanical properties of this steel. But this is a medium carbon steel, hardened performance is not good, 50 gauge steel can be hardened to HRC42 ~ 46. So if you need to surface hardness, and hope to play a 50 gauge steel superior mechanical properties, often the No. 50 carburizing steel surface, so you can get the required surface hardness