Introduction to shaft forging process


The reasonable choice of materials and the requirements of the prescribed heat treatment for drop-forged parts are important to increase the strength and service life of shaft components and, at the same time, have a large impact on the processing of shafts. Shaft components are generally made of 45 steel, with different heat treatment specifications (e.g. normalised, tempered, quenched, etc.) to obtain strength, toughness and resistance to wear, depending on the working conditions.

For medium precision and high speed shaft components, 40Cr and other alloy steels can be used. These steels are tempered and surface quenched to give a high level of overall mechanical performance. Higher precision shafts, sometimes also used bearing steel GCrls and spring steel 65Mn and other materials, they have high anti-wear and fatigue resistance through the quenching and surface quenching treatment.

Die forgings for high speed, heavy load and other conditions of the work of the shaft, can be used 20CrMnTi, 20MnZB, 20Cr and other low-carbon gold-containing steel or 38CrMoAIA nitride steel. The low-carbon alloy steel has high surface hardness, impact toughness and heart strength after carburising and quenching treatment, while the heat treatment deformation is very small. Shaft components are commonly made from round bar stock and forgings, but only certain large, complex shafts are made from castings. Pre-machining of shaft components. Wheel components should be pre-machined before they are cut. Pre-machining includes calibration, cutting and cutting of end faces and drilling of intermediate holes.

Correction: correction of the bending deformation of the bar blank during manufacture, transport and storage, in order to make a uniform machining allowance and feeding clamping. The correction can be carried out on a press. Cutting: When bar stock blanks are used, they should be cut to the required length before turning the outer circle. Cutting is carried out on a sawing machine or on a cutting machine with a thin grinding wheel for high hardness bars. Cutting end face drilling intermediate hole: intermediate hole is the common positioning datum surface for shaft parts processing, in order to get the drilled intermediate hole without skewing, the end face should be cut first and then the intermediate hole should be drilled. Wasteland turning: If the shaft blank is to by forgings or large castings, it is necessary to carry out wasteland turning to reduce the shape error of the foreign surface of the blank, so that the subsequent process of processing the residual view is uniform.

Typical spindle class parts processing process analysis shaft class parts processing process due to its use, structure shape, requirements, production size of different and different. The preparation of process procedures for shafts is a common process work encountered in production.

With the rapid development of our economy and national cause, the demand for large and complex forgings has surged, such as the overall frame of the aircraft, the overall leaf disc of the engine, the large blades and large discs of the gas turbine and gas turbine, etc. Many forgings have a projection area of 3m or more. However, titanium alloys and high-temperature alloys are both large-priced metal materials and difficult to machine and deform.

On the one hand, the mechanical processing performance of such materials is poor; on the other hand, due to the material deformation resistance, high deformation temperature, deformation of the narrow temperature range, generally can only be forged into rough forgings before mechanical processing, thus leading to excessive manufacturing costs, thus in limiting and affecting the use of the material. However, the emergence of hot forging, represented by hot die forging and isothermal forging, has provided an important way to solve the problem of near net forming of difficult to deform materials such as titanium alloys and high temperature alloys, and has provided a new means of producing large and complex forgings.

Both forward and reverse simulations can be summarised as trial and error methods using numerical simulations to verify design results. The basic idea is still the same as the traditional trial-and-error method, except that the means of verification used are different, the modification of unreasonable designs still needs to be proposed by the designer based on experience, and the degree of automation of the design process is still very low. In order to improve the efficiency of the forging process and die design, scholars have conducted a lot of research in recent years on the optimal design of forging processes and dies, and have made great progress.