Exterior project technology applies mediumly in motor component rehabilitate and aggrandizement

The heart part that the injury of group of annulus of 1 gas cylinder bushing, piston, piston insults group of annulus of cylinder bushing, piston, piston is engine, also be the place with working very abominable requirement. Baconian rise, the scathing form of group of annulus of gas cylinder bushing, piston, piston has wear away, corrode, acupuncture point corrode, crackle, ablation. (1) the overhaul interval deadline that enrages the injures cylinder bushing wear rate of cylinder bushing to decide engine, normally quantity of the biggest permissible wear is cylinder bushing 0 of internal diameter.

4%~0.

8% . The element such as temperature of the exterior quality of cylinder bushing, quality of fuel, quality of lube, cooling water and working requirement is met to cylinder bushing wear away the influence with very large generation [6] , bring about cylinder bushing to appear wear away, help the loss such as crock and acupuncture point corrode, cause engine rotate speed thereby the flabby, oscillatory aggravate, occurrence noise, happening that risk Bai Yan or risks the state such as black smoke [4, 5] . (2) the requirement of scathing piston work of the piston is abominable, especially coping is to accept the position with mechanical bear and the most serious thermic load. Its basically injure a form to have flaw, rupture, ablation and corrode etc. (3) the accident that the injures piston annulus wear rate of piston annulus decided to engine overhauls cycle, it lights compression ring in high temperature high pressure bear in the condition bend, concussion and wear away, easy happening break off and excessive wear away, make sealed function drops thereby, worsened further engine function [8] . 1.

The structure of lid of scathing air cylinder that 2 air cylinder build is complex, have on its into, aperture of exhaust valve aperture, indicator aperture, relief valve aperture, a powerful person that start, fuel injector aperture, the cooling water accent that interior has a series of irregular figure and enter, exhaust duct, transverse and hang down to respectively with into, vent-pipe and airframe photograph join. Working requirement is more abominable, its bottom (hot) the face is sufferring the high temperature that burns gas, high pressure and corrode action, water interlining also is getting cooling water corrode, and cold, hot not all, get power complex, the other part that the crock covers also tightens bolt because of solid and produce mechanical stress. Its basically injure a form to have: Crock lid crackle, valve base is injured (valve base twist, wear away, crackle) . 1.

The scathing cam tappet of 3 cam tappet is the attrition that invalidation wears away to often appearing in engine deputy one of. Develop to high speed, high-power ceaselessly as engine, the opposite sliding velocity between face of the bedspring force of compressed air distribution mechanism, attrition increases ceaselessly, the lubricant condition between cam tappet is more slashing. Its basically injure a form is the abrade that wear away as a result of adhesive wear and exhaustion and causes and dot corrode. 1.

The scathing crankshaft of 4 crankshaft is one of the most important parts on engine, bear in the job bend, turn round bear and fixed concussion negative charge. The working dependability of crankshaft and life decided the dependability of engine and life greatly. The main form that crankshaft injures has: (1) of journal wear away; (2) brace is sold or main shaft neck and crank arm are linked together crackle of received round horn place, rupture; (3) brace is sold or crackle of position of oily opening of main shaft neck, rupture; (4) corrode what what cause to rupture; (5) slippage of place of built-up crankshaft cylinder bushing; (6) because burn the crankshaft surface crackle that cover with tiles and causes to reach,pull; (7) of crankshaft bend with twist. The form that technology of 2 surfaces project analyses motor component to damage in the application in engine and characteristic can reach the main form of motor component invalidation is: Wear away, corrode wait with exhaustion, they happen at the surface more, perhaps begin from the surface first, raise material surface function to having main effect to extending component service life and play latent capacity so. The aggrandizement method that raises material surface wearability often is from improve the appearance hardness and reduce coefficient of friction two respects begin. Up to now, traditional surface quenchs and cementite quenchs or raise the main measure of component wearability, a large number of component such as crankshaft, piston pin, cam and camshaft are use this kind of technique. Nitrogen of aeriform nitriding, carbon in all ooze, ionic nitrogen is changed etc basically is the exterior hardness that the nitride that uses dispersion to distributing will come to to improve data; The compound layer of the tall hardness that processing of chromium of vanadium of ooze boron, ooze, ooze and deposit carbide, nitride gets and freeboard hardness, have more exceedingly good fight abrasive to wear away ability and fight adhesive wear ability high; Exterior film, if plating chromic layer also is the wearability film of a kind of wide application. Improve attrition condition, the finishing that reduces coefficient of friction but from the wearability that improves data on the other hand. Nitrogen of ooze sulfur, sulfur in all carbon of nitrogen of ooze, sulfur in all ooze, phosphor is changed, graphitization ooze layer is the compound layer that builds anti-friction in metallic surface and metalloid layer, in order to reduce coefficient of friction, avoid friction deputy between direct contact, can prevent consequently adhesion, avoid abrade. Increase material surface fatigue resistance can main method has: High frequency surface quenchs, the hard layer of temper by dipping in water that cementite quenchs, its martensite hardness is tall, exist remains presses stress, it is certain to make fatigue intensity has thereby rise. Gush bolus, surface boils pressure wait for exterior deformation aggrandizement processing is raising exterior hardness, cause while the surface presses stress, still can eliminate exterior flaw, the fatigue strength that can increase material consequently and reduce material the susceptibility to breach. Quench in the surface, it is better that cementite quenchs and bolus of in season of travel of the reentry after nitriding and surface roll the effect that presses processing, especially axial diameter of the axis, the stress such as the tine root of gear is in centrally, boil with the surface it is better to press treatment effect. Increase material surface corrosion resistance can main method has: (1) plating is chromic, because it is in,alkaline, nitric acid, sulfide, carbonate and organic acid Central Africa often are stabilized; (2) nitrogen is changed, because it forms the photograph layer with tall stability in component surface layer, to water, humid air, products of combustion, be opposite especially the sex fighting corrode of nitric acid is very tall; (3) silicon of ooze aluminium, ooze has the good sex that fight corrode to acid; (4) contain chromium nickel radical, cobalt radical has good heat to corrode from layer of fusibility alloy spray, the ability that lights gas to corrode, because formed compact Cr2O3 oxidation film; (5) to steely spare parts, if piston annulus undertakes phosphor,be changed and send blue processing, they can prevent corrode and reduce mechanical wear. A few kinds of commonly used exterior project technologies introduce mainly below. 2.

Thermal spraying of 1 thermal spraying the law can make the spare parts has wear-resisting not only, be able to bear or endure corrode, be able to bear or endure the different function such as oxidation, high temperature resistant, heat insolation, and can make it has compound property, can protect a part namely, can repair spare parts. Current, in engine, basically use at annulus of coping of crankshaft, piston, piston, air cylinder to cover, the finishing of the spare parts such as exhaust valve, valve base, cam, gear and rehabilitate [6] , watch 1 gave out to use cylinder body of engine of thermal spraying rehabilitate to reach change new economic benefits is comparative, see by the watch, rehabilitate of material of thermal spraying 3Cr13 needs to cost only new 4 of a cost.

2 ％ . Express analysis of economic benefits of 3Cr13 of 1 thermal spraying to be in engine, the spray data that uses at raising wearability of spare parts surface basically has following a few kinds: 1) molybdenum. Molybdenum regards spray as material, its purity needs to be in 99.

95% above. Molybdenum basically regards the gush of piston annulus as the layer, the layer of layer shape molybdenum that it can get having oxide layer and about the hole rate of 10%~15% , ply of its spray layer is commonly 0.

25mm, have good oil storage performance. Molybdenum layer melting point is high (it is 2620 ℃ about) , coefficient of friction low, hardness is tall (HV1070 is controlled) . Wearability is accordingly good, use in place of annulus of the first piston commonly. 2) molybdenum radical alloy. The characteristic of the plasma gush coating of molybdenum radical alloy is tension crock sex good, because it is by the pure molybdenum of low hardness (HV350) comparative with hardness tall (HV700) composition of two-phase of nickel radical alloy. Layer of spray of silk of molybdenum of excel of its thermal stability, wear-resisting function is equivalent to plating chromium, fill time-sharing not quite in lubricant condition especially [10] . 3) chromium radical alloy. The wearability that layer of spray of plasma of chromium radical alloy issues in attrib border condition not only and fight it is as better as function to bite, and still can raise the wearability that deserves to wear stuff, the wearability that can raise cylinder bushing and piston annulus at the same time [11] . Below attrib border and lubricant condition, the piston annulus of this kind of coating is returned than plating chromium more wear-resisting, accordingly, can make the coating material of high speed, middling speed and annulus of piston of low speed engine. 4) pottery and porcelain. Coating of pottery and porcelain is like oxidation chromium and alumina / titanium dioxide hardness is taller (HV1500) , below certain condition, the wear-resisting performance of piston annulus is good, but wear away to cylinder bushing very big however, accordingly, can use below the circumstance of special requirement only. 5) cermet. Cermet is more complex, it is it is with carbide base (like carbonization tungsten) coating, although be below abominable locomotive condition, not only of piston annulus wear away low, of cylinder bushing wear away low also. But cermet is very expensive. In engine, it is gush of pottery and porcelain commonly on working face of annulus of end face of exhaust valve face, piston, piston. 6) nickel radical alloy. Nickel radical alloy has Ni-B-Si and Ni-Cr-B-Si department. Coating of nickel radical alloy is better except wearability outside, still have the very good sex that fight corrode and taller hot rigid. The gush solder that basically is used at engine piston annulus, valve base, valve, cam (also use at repair) , in order to raise the wearability of these spare partses. 7) high-carbon steel and stainless steel. High-carbon steel, if T8 of steel of carbolic element tool is commonly used at repair and aggrandizement engine cast steel, spray of the wire gas blowout of surface of journal of nodular cast iron, report. And because stainless steel is had be able to bear or endure primely corrode sex, hear resistance, and the spray that is used at enraging the surface inside cylinder bushing (blaze gush) , have very good effect. 2.

The means of main be no longer in force of journal of camshaft of engine of rehabilitate of 2 brush plating is wear away or cut, camshaft journal appears previously wear away or cut discarded as useless commonly, after perhaps using the method grinding journal that adds thick plain bearing liner, use, the maintenance that gives an user brings very big trouble. Brush plating technology has facility simple, operation the characteristic with rapid rate of convenient, on the safe side, plating accumulating, use at repair camshaft journal to obtain apparent effect [7] . Watch 2 gave out to use rice of brush plating accept the benefit analysis of axle of Al2O3/Ni rehabilitate engine and connecting rod, brush plating technology can reduce maintenance cost greatly. Express economic benefits of N-Al2O3/Ni of 2 brush plating to analyse 2.

Carborundum of 3 crowded ooze pushs ooze carborundum technology is a carborundum particle squeeze ooze to metallic surface layer directly, in its the surface is shown blame is successive distributing. The main characteristic of this kind of method is craft efficiency of simple, production tall, cost is beardless and cheap, free from contamination, special equipment. Accordingly, it is a kind of new technology that has an outlook very much. Basically use at raising engine to enrage the wearability of annulus of cylinder bushing, piston, particularly right excel in carries engine more effective [8] . 2.

Chromic craft of 4 plating chromic plating basically is used at increasing the wear-resisting caustic of engine spare parts and corrosion resistance, be like crankshaft journal, crosshead journal, chamfer of annulus of piston pin, piston, force plunger of a powerful person of annulus of piston lever, cylinder bushing, piston, gas and chromium of plating of lever of a powerful person, oil pump and sleeve. Current, the commonly used wear-resisting plating chromium in motor component has two kinds, horniness plating chromium and chromium of loose aperture plating [9] . Horniness plating chromium is to show hardness is taller and the shining plating chromic layer of wear-resisting, it is better that it basically is used at lubricant condition, bear below very not big condition, general film ply is 0.

03~0.

3mm, the thickest can achieve 1.

0mm. Chromium of loose aperture plating basically slips with Yu Run undesirable, bear the part with larger load is sold like annulus of engine cylinder bushing, piston, crosshead etc. 2.

5 nitrogen change nitrogen have 3 kinds: (1) common nitrogen is changed, point to infiltration of dinkum nitrogen atomic; (2) soft nitrogen is changed, soft nitrogen of saline bath liquid is changed, the aeriform soft nitrogen in containing medium of gas of atomic of active nitrogen, carbon is changed reach ion soft nitrogen to change (include to add titanium ion nitrogen to change) ; (3) glow ion nitrogen is changed. Current, the most commonly used and what have development outlook most is ionic soft nitrogen is changed and glow ion nitrogen is changed. They basically are used be like,raise engine spare parts the annulus of crankshaft journal, cylinder bushing, piston, camshaft, wearability that waits into tappet of exhaust valve, valve, be able to bear or endure exhaustion and anti-corrosive etc. 2.

6 laser heat the surface quenchs laser heats to quench with Yu Gang and surface of cast-iron spare parts, in order to raise its wearability. Diesel engine of American GM645 series, be hurt to solve what cylinder bushing enrages a mouth to pull and raise its wearability, ever had undertaken to enraging buccal position nitrogen is changed respectively, the induction heats quench and blaze quenchs wait for processing, but because handle very big, temperature tall, appeared to be out of shape badly, produce crackle even, heat with laser finally the surface quenchs processing, obtained favorable result [12] . Laser heats annulus of quenched air cylinder piston already had application in our country, and report is favorable. The characteristic of this method is craft simple, be out of shape very small (if quench to cylinder bushing surface, local temperature can amount to 916 ℃ , other place temperature under 200 ℃ , because this is out of shape very small) . 2.

Bolus of gush of treatment of 7 gush bolus machines a law not to need to change the appearance of component, material, heat treatment, and increase strength easily, especially fatigue intensity, accordingly, there already were a lot of applications in engine, bedspring of a powerful person of axis of Yu Qu of current and main application, connecting rod, gas, rocker reachs transmission gear to wait for place. The aggrandizement layer after classics gush bolus is machined can be amounted to 0.

5~0.

6mm, exterior hardness can amount to HRC40~50 left and right sides. 2.

The 8 cold treatment that press light make the instrument with exterior aggrandizement as light, leng Yaguang machined aborning to receive increasingly wide application, in order to improve the quality of surface layer of its spare parts (the property of deepness of surface roughness, cold strong pitch, cold hard layer, leftover stress and size) . Basically use at enraging surface of lever of conduit of a powerful person of lining of cylinder bushing, piston pin aperture, connecting rod is small copper, gas, a powerful person, camshaft in engine journal of neck, crankshaft, especially crank arm transfers round final precision work, in order to reduces exterior surface roughness and its aggrandizement to present remains to press stress. The place on 3 conclusion put together is narrated, because the working requirement of motor component is complex, attaint often of form of a few kinds of invalidation compound, often not be onefold to the requirement of component surface function. Accordingly, choose exterior aggrandizement method correctly according to the operating mode condition of component and invalidation characteristic only, ability achieves the goal of the service life that prolongs component and managing material. CNC Milling CNC Machining