1、外文资料Mechanical face work qualityThe machine parts destruction, always starts generally from the surface layer.The product performance, in particular its reliability and the durability, are decided to a great extent by the components surface layer quality.Studies the machine-finishing surface quality
2、 the goal is in order to grasp in the machine-finishing each craft factor to process the surface quality influence the rule, in order to utilize these rules to control the processing process, finally achieved the improvement surface quality, enhances the product operational performance the goal.Just
3、 processed between the friction vice-two faying surface, the initial stage in the surface roughness peak department contact, the actual contacted area far was only smaller than the theory contacted area, in the peak department which contacted mutually has the extremely big unit stress, caused the ac
4、tual contacted area place to have the plastic deformation, the elastic deformation and the peak department between shearing failure, caused the serious attrition.The components wear may divide into three stages generally, the initial period attrition stage, the normal wear stage and the fierce attri
5、tion stage.The surface roughness the influence which wears to the components surface is very big.Said generally the surface roughness value is smaller, its wearability is better.But the surface roughness value too is small, the lubricating oil not easy to store up, between the contact face easy to h
6、ave the molecular cementation, wears instead increases.Therefore, contact face roughness has a best value, its value and components working condition related, when work load enlarge, the initial period wearing capacity increases, the surface roughness best value also enlarges.The processing surface
7、hammer-harden makes the friction subtabulation surface layer metal the microhardness to enhance, therefore may cause the wear resistant enhancement generally.But is not the hammer-harden degree will be higher, the resistance to wear is higher, this is because the excessive hammer-harden will cause t
8、he metal organization to be excessively loose, even will appear the crack and surface layer metal flaking, will cause the resistance to wear to drop.After metal the fatigue failure which is produced the alternating load function often occurs in the components surface and under the superficial chilli
9、ng level, therefore the components surface quality is very big to the fatigue strength influence.Under the alternating load function, the surface roughness saddle spot easy to set up stresses the centralism, produces the fatigue cracking.The surface roughness value is bigger, the superficial grain m
10、ark is deeper, the grain bottom radius is smaller, anti-fatigue failure bottom ability is worse.The residue stress is very big to the components fatigue strength influence.The surface layer remaining tensile stress will make the fatigue cracking to expand, acceleration fatigue failure; But the surfa
11、ce layer residual stress can prevent the fatigue cracking the expansion, delays the fatigue failure the productionThe surface chilling is accompanied by the residual stress generally the production, may prevent the crack has and prevents to have the crack expansion, to enhances the fatigue strength
12、to be advantageous.The components corrosion resistance is decided to a great extent by the surface roughness.The surface roughness value is bigger, then in the saddle accumulates the corrodent to be more.The corrosion resistance is worse.The surface layer remaining tensile stress can have the stress
13、 corrosion dehiscence, reduces the components the resistance to wear, but the remaining compressed stress can prevent the stress corrosion dehiscence.The surface roughness value size will affect the mating surface the coordinate quality.Regarding the gap coordination, roughness value congress caused
14、 the attrition enlarge, the gap to increase, destroyed the request coordinate nature.Regarding the full coordination, in the assembly process a part of superficial raised peak has been pushed evenly, the actual full quantity has reduced, reduced the coordination joint strength.The cutting tool is op
15、posite when makes the feed motion in the work piece, in the processing surface has left behind the layer of cutting residual area, when its shape the cutting tool geometry shape duplicate reflects.Reduces to feed quantity, the host angle of deflection, the vice-angle of deflection as well as increas
16、es the knife point circular arc radius, may reduce the residual area the altitude.In addition, suitably increases the cutting tool the front rake reduces when the cutting the plastic deformation degree, the production which chooses the lubricant reasonably and improves the cutting tool sharpening quality to reduce when cutting the plastic deformation and the suppression built-up edge, the scale punctures, also is reduces the surface roughness value the effective act
