The impact of CNC lathe cutting on heat treatment workpieces

The inclined bed CNC lathe adopts an inclined structure, and the bed is a hollow structure, which greatly improves the bending and torsional rigidity of the machine tool during operation, and at the same time has high stability. The high rigidity and high stability of the inclined bed CNC lathe provide a strong guarantee for the high precision of machine tool processing.

Inclined bed CNC lathes are mainly used for processing complex rotating parts. It can meet the processing of internal and external circles, step surfaces, cones, spherical surfaces, grooves, threads and complex curved surfaces. It can satisfy the rough and finishing machining of copper, aluminum, iron, stainless steel and other casting and forging blanks.

The inclined bed CNC lathe has good reliability, strong rigidity, high precision, long life and high speed. It can reliably and stably complete the rough, fine and finishing processing of various difficult-to-machine materials. The rotary tower knife is used, which has high positioning accuracy and small deformation during heavy cutting.

The impact of cutting processing on workpiece quality includes surface decarburization, residual stress, machining allowance, surface smoothness, removal of carbon-poor layer, etc. This is when the workpiece is in the tempering, normalizing, and annealed state, and the hardness is lower than 45HRC. However, the effect is not significant and will not constitute a change in the potential function of the workpiece.

Hard machining refers to the processing of hardened steel or workpieces. The higher hardness of 50-65HRC, materials such as bearing steel, high-speed steel, roll steel, general quenched steel and quenched mold steel, has a significant impact on the cutting process. . The factors that cause a certain degree of damage to the surface of the processed workpiece mainly include cutting heat generation and conduction, high-speed friction and wear during the cutting process. The integrity of the surface processed by hard cutting mainly includes the surface structure and its thickness, surface roughness, dimensional accuracy, distribution of residual stress and white layer generation.

The surface hardness of the processed workpiece increases with the decrease of feed amount and cutting amount, and increases with the increase of cutting speed. The higher the hardness of the machined workpiece surface, the greater the depth of the hardened layer. The surface of the workpiece after hard cutting is full of residual compressive stress, while the compressive stress of the workpiece after grinding is mainly concentrated on the surface of the workpiece.

The factor that affects the surface integrity of the workpiece is the hardness of the workpiece. The greater the hardness value of the workpiece, the more beneficial it is to the formation of residual compressive stress. The larger the obtuse radius of the tool used in cutting processing, the greater the value of residual compressive stress; the higher the hardness of the workpiece, the greater the value of residual compressive stress.

The formation of the white layer is another important factor affecting the quality of the surface of the workpiece processed by hard cutting. A kind of tissue structure formed along with the hard cutting process is the white layer. The white layer has common grinding characteristics, namely high hardness, good corrosion resistance and high brittleness. Higher brittleness can easily cause early shedding failure, or even cause the workpiece to crack after being left for a period of time after processing.