Machining analysis of thin-walled stainless steel tubes in the machinery industry ----------- in the machinery industry, due to poor rigidity, thin-walled workpieces are easy to produce vibration and deformation in the turning process, and their geometric tolerance and dimensional tolerance can not be guaranteed. If the solution is not appropriate, it will even make the machining impossible.

1. Proposal of processing problems

The machining of thin-walled parts is a thorny problem in turning. The reason is that the rigidity of thin-walled parts is poor, the strength is weak, and it is very easy to deform in machining, which increases the shape and position error of parts, and it is not easy to ensure the machining quality of parts.

Therefore, strict requirements are put forward for the clamping of thin-walled parts, the rational selection of cutting tools and the selection of cutting parameters in turning.

Machining analysis of thin wall stainless steel pipe in machinery industry

The thin-wall stainless steel pipe we process is the nozzle thermal shock proof sleeve on a product. This workpiece belongs to large-diameter thin-wall workpiece. The outer diameter of the pipe is 292mm. The material is z2cnd17-12 nitrogen control stainless steel. The wall thickness is required to be 4mm. The total length of the workpiece exceeds 550mm (with clamping allowance), the roundness is required to be 0.05mm, and all surface roughness values RA = 6.3 μ m. This determines that the accuracy coefficient of this workpiece is very high.

2. Formulation of processing technology

(1) Increase the process chuck to lengthen the length from 550mm to 610mm of the finished product

(2) Divide processing stages:

① Rough machining stage. Rough turning and rough boring are used to remove the allowance. During rough machining, the back feed and feed can be larger; During finishing, the back feed is generally 0.2 ~ 0.5mm, the feed is generally 0.1 ~ 0.2mm/r or even less, and the cutting speed is 6 ~ 120m / min. during finishing, the cutting speed shall be as high as possible, but not too high.

② Semi processing stage. Prepare for the finishing of the main surface, complete the processing of some secondary surfaces, and adopt semi finishing machining to achieve the necessary accuracy and machining allowance before finishing. If the pipe is clamped on the chuck with excessive force, it will deform the thin-walled parts and cause the roundness error of the parts. If the chuck is not clamped tightly, the parts may become loose and scrapped during turning. We adopt clamping during rough turning and loosening during fine turning to control the deformation of parts. In the semi finishing stage, the back draft is smaller, so that the internal stress of thin-walled stainless steel pipe is released and the deformation of finishing is reduced.