Engine cylinder liners and piston rings are a pair of friction pairs that operate under high temperature, high pressure, alternating loads, and corrosion. The long-term work in the complex and changing conditions, the result is the wear and deformation of the cylinder liner, affecting the engine's power, economy and service life. Careful analysis of the causes of wear and deformation of the cylinder liner is of great importance for improving the economical efficiency of the engine.
First, the cause of the cylinder liner wear analysis cylinder liner working environment is very bad, causing a lot of wear and tear. Normal wear is usually allowed due to construction reasons, but improper use and maintenance can cause abnormal wear.
1, the cause of structural wear and tear
1) The lubrication conditions are not good, making the upper part of the cylinder sleeve seriously worn. The upper part of the cylinder liner is adjacent to the combustion chamber. The temperature is high and the lubrication conditions are poor. Fresh air and unevaporated fuel scour and dilute, exacerbating the deterioration of the upper condition, and making the cylinders dry friction or semi-dry friction, which is the cause of serious wear on the upper part of the cylinder.
2) The upper part is under pressure, making the cylinder wear heavy and light. The piston ring is pressed against the cylinder wall by its own elastic force and back pressure. The larger the positive pressure is, the more difficult it is for the lubricant film to form and maintain, and the mechanical wear is increased. During the power stroke, as the piston descends, the positive pressure gradually decreases and the cylinder wear becomes heavy and light.
3) The surface of the cylinder is corroded by mineral acids and organic acids. The combustible mixture in the cylinder burns, generates water vapor and acidic oxides. They dissolve in water to generate mineral acids. Together with the organic acids produced in the combustion, the surface of the cylinder is corroded. Corrosion substances are gradually scraped by the piston ring during friction. Loss of cylinder liner deformation.
4) Into the mechanical impurities, so that the central cylinder wear increased. Dust in the air, impurities in the lubricating oil, etc., cause abrasive wear between the piston and the cylinder wall. Dust or impurities accompany the reciprocating motion of the piston in the cylinder, and the wear of the middle of the cylinder is exacerbated due to the maximum speed of movement in the middle of the cylinder.
2, the use of improper wear and tear
1) Lubricating oil filter has poor filtering effect. If the lubricating oil filter does not work properly, the lubricating oil will not be effectively filtered, and the lubricating oil containing a large amount of hard particles will inevitably make the wear of the inner cylinder bore intensify.
2) Air filter filtration efficiency is low. The role of the air filter is to remove the dust and sand contained in the air entering the cylinder to reduce the wear of parts such as cylinders, pistons and piston rings. Experiments show that if the engine is not equipped with air filters, the cylinder wear will increase 6-8 times. The air filter is not cleaned and maintained for a long time, and the filtering effect is poor, which will accelerate the wear of the cylinder liner.
3) Long-time low temperature operation. For a long period of low temperature operation, the first cause poor combustion, carbon deposits spread from the upper part of the cylinder liner, which causes severe abrasive wear on the upper part of the cylinder liner; and second, it causes electrochemical corrosion.
4) Frequent use of inferior lubricating oils. Some owners save time by saving money. They often use low-quality lubricating oils in roadside shops or illegal oil dealers. As a result, the upper part of the cylinder liner is strongly corroded, and the amount of wear is 1-2 times greater than normal.
3, wear caused by improper maintenance
1) The cylinder sleeve is improperly installed. When installing the cylinder liner, if there is an installation error, the cylinder centerline and the crankshaft axis are not perpendicular, which will cause abnormal wear of the cylinder liner.
2) The connecting rod copper sleeve hole is skewed. In the repair, when reaming the small copper sleeve of the connecting rod, the reamer tilts and causes the copper sleeve hole of the connecting rod to deflect. The center line of the piston pin is not parallel to the center line of the small head of the connecting rod, forcing the piston to tilt to one side of the cylinder sleeve. , Can also cause abnormal wear of the cylinder liner. 3) The connecting rod is bent and deformed. Due to accidents or other reasons, the impacted connecting rods will be bent and deformed. If they are used without timely correction, they will also accelerate the wear of the cylinder liner.
3) The crankshaft connecting rod journal and main journal are not parallel. Due to the burning of tiles, etc., the engine will deform the crankshaft due to severe impact. If it is not corrected and continues to be used, it will also accelerate the wear of the cylinder liner. Second, to reduce the cylinder sleeve wear measures 1. Correct start and start When the engine cold start, due to low temperature, oil viscosity, poor fluidity, so that the oil pump is not enough oil. At the same time, the oil on the original cylinder wall flows down along the wall of the cylinder after being stopped, so it is not lubricated properly at the moment of start-up, so that the wear of the cylinder bore is greatly increased at the time of starting.
Therefore, when the engine is started for the first time, the engine should be idled for several revolutions before it starts to be lubricated. After starting, it shall be heated up at idle speed, and it is forbidden to slam the oil port. When the standby oil temperature reaches 40Â°C, it shall be started again. At the beginning, the low gear shall be adhered to, and the mileage shall be traveled in each gear step by step until the oil temperature is normal before it can be changed to normal. Driving.
4) The correct selection of lubricating oil must be selected in strict accordance with the season and engine performance requirements of the best viscosity value of the lubricating oil, are not free to use poor quality lubricating oil, and often check and maintain the quantity and quality of lubricating oil.
5) Strengthen the maintenance of the filter The air filter, the oil filter and the fuel filter maintain a good working condition, which is essential to reduce the wear of the cylinder sleeve. Strengthening the maintenance of â€œthree filtersâ€ is an important measure to prevent mechanical impurities from entering the cylinders, reducing cylinder wear, and prolonging the service life of the engine. This is particularly important in rural areas and in many windy areas. Some drivers are absolutely wrong in order to save fuel without installing air filters.
6) Keep the normal operating temperature of the engine The normal working temperature of the engine should be 80-90Â°C. If the temperature is too low, good lubrication cannot be maintained, the wear of the cylinder wall will increase, the water vapor in the cylinder will condense into water droplets, dissolve the acidic gas molecules in the exhaust gas, generate acidic substances, and cause corrosion and wear of the cylinder bore. Tests have shown that when the cylinder bore temperature drops from 90Â°C to 50Â°C, the cylinder wear is 4 times that at 90Â°C. If the temperature is too high, the strength of the cylinder will be reduced and the wear will be aggravated. It may even cause the piston to expand too much and cause an "expansion cylinder" accident.
7), improve the quality of the warranty In the use of the process, promptly identify problems and eliminate them at any time, replace or repair damaged and deformed accessories at any time. When installing cylinder liners, strictly inspect and assemble according to technical requirements. In the warranty-for-ring operation, the piston ring with proper elasticity should be used to reduce the elastic force so that gas can enter the crankcase to blow off the oil on the cylinder wall and increase the wear of the cylinder wall. Excessive elasticity directly aggravates the wear of the cylinder wall. Or the wear of the oil film on the cylinder wall is exacerbated.
Spiral Pipe Also known as spiral Steel Pipe and spiral welded pipe spiral pipe is low carbon structural steel or low alloy structural steel strips by a helix angle (called forming angle) rolled into a tube, then the tube seam welded together made, it can be with a narrow strip steel production of large diameter steel pipes.Also known as helical or spiral tube body. Spiral tube outer diameter of about 30 nm and an inner diameter of about 10 nanometers, adjacent helical pitch of about 11 nm. 1 week of each spiral from 6 surrounded nucleosome, H1 histone in the spiral cavity of the inner surface of maintenance of spiral structure plays an important role. The nucleosome composed of 10 nm, 30 nm fiber to form spiral of crude fiber, so that further compression 6 times the length of DNA.
(1) raw materials that strip, wire, flux. We must go through rigorous physical and chemical testing before it is put.
(2) strip head and tail docking, single or double wire submerged arc welding, in rolled steel by automatic submerged arc welding.
(3) before forming the strip after flattening, cutting, trimming, planing, surface cleaning conveyor and I crimping process.
(4) the use of electric contact pressure gauge to control both sides of the conveyor pressure cylinder pressure to ensure the smooth delivery of the strip.
(5) the use of internal or external control roll forming.
(6) adopted the weld gap control device to ensure the weld gap to meet the welding requirements, diameter, the wrong side and the weld gap have been strictly controlled.
(7) within the welding and soldering are used outside the United States Lincoln welding machine for single or double wire submerged arc welding, thereby obtaining a stable welding specifications.
(8) finished welding the weld line continuous ultrasonic injury checks to ensure 100% coverage of non-destructive testing of spiral weld. If defective, automatic alarm and spraying tags, production workers so adjusting the process parameters, and remove defects.
(9) by air plasma cutting machine will cut a single tube.
(10) cut into a single steel pipe, steel pipe each batch must be strict inspection system, the mechanical properties of the weld inspection, chemical composition, fusion status, steel pipe surface quality and after NDT inspection to ensure that qualified Pipe Process before we can formally put into production.
(11) with a continuous sonic flaw marks the site of the weld, manual ultrasonic and X-ray review, if there are defects after repair again after destructive testing, until the confirmation defect has been eliminated.
(12) strip butt weld and intersect with spiral weld small joint where the pipe all through the X-ray television or film examination.
(13) of each pipe after hydrostatic test pressure radial seal. Test pressure and time by the steel pipe pressure microcomputer detection device strictly controlled. Test parameters are automatically printed record.
(14) pipe end machining, so that the end vertical, bevel and blunt edge be accurately controlled.
Photos of our Spiral Pipes:
Application solutions, emulsions cleaning steel look to reach the removal of oil, grease, dust, smoothing agents, and similar organic matter, but it does not remove the steel appearance of rust, scale, welding flux, and thus the corrosion produced only as adjuvant trick.
2, tool rust
The primary use of tools such as steel wire brush polished look, you can remove loose or tilt of the oxide scale, rust, welding slag. Hand tools rust can reach Sa2 level, power tools rust can be reached Sa3 level, if the outer steel skin attached to solid iron oxide, the results are not ideal tools rust, corrosion of the anchor pattern depth of less than construction requirements.
Common chemical and electrolytic pickling two ways to do disposal pipeline corrosion using only chemical pickling can descaling, rust, old coatings, and sometimes used as a sand-blasting and then disposed of after. Chemical cleaning is important in allowing the appearance of the inevitable arrival of cleanliness and roughness, but the anchor pattern shallow, and easy on the case of forming pollution.
4, spray (throwing) radio rust
Spray (throwing) radio rust is the result of high-power motor driven spray (throwing) radio blade speed reverse, so that grit, steel shot, wire segments, minerals and other abrasive under the centrifugal effect of the outer pipe were shot dispose spray (throwing) not only can completely eliminate rust, oxides and dirt, and steel in the fierce impact and abrasive friction effects, but also to reach an average roughness needs.
Spray (throwing) radio rust, it can be extended not only physical adsorption outer tube, and can enhance the effect of the mechanical adhesion of the coating and the outer tube. Thus, the spray (throwing) radio rust rust is an ideal method for pipeline corrosion. Generally, blasting (sand) blasting is mainly used for disposal of the tube look, blasting (sand) blasting is mainly used for surface of the pipe surface disposal.
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