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Influence of driving belt on driving efficiency

Drive belt plays a role in transmitting power in automobile driving. Because of the elastic sliding (i. E. skidding) in the belt drive, the drive belt always has a certain power loss, but if the "skidding" is serious, it will greatly reduce the transmission efficiency of the engine accessory machinery and increase the fuel consumption of the engine. High quality belt and pulley between the elastic sliding small, but also stable, high transmission efficiency, can play a certain role in saving energy. On the other hand, due to the requirement of miniaturization and lightweight of automobiles, the engine space is narrow, so it is very troublesome to replace the transmission belt. If the transmission belt is damaged in the course of driving, it will cause a great impact in all aspects, which wastes time and increases labor intensity. High quality belts generally predict their service life, in the normal service life will not be damaged. In this way, the car with damage before the overhaul will be replaced in time to avoid passive, waste of time. Chongqing Feilong-water pumps,oil dipsticks,rubber parts and so on.

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Automobile turbocharger

The automobile turbocharger uses the inertial impulse of the exhaust gas discharged from the engine to drive a single-stage axial-flow turbine to rotate at high speed. The turbine drives a centrifugal compressor mounted on the same shaft. The compressor filters the fresh air from the air pipe and pressurizes it into the cylinder. With the acceleration of the engine exhaust gas speed and turbine speed synchronization, compressor will compress more air into the cylinder, air pressure, density increases can burn more fuel, thus increasing engine output power and improving the use of automobile economy purposes. Because the turbocharger is installed on the intake and exhaust manifold of the engine and operates at high temperature, high pressure and high speed, the working environment is very bad, the working speed can reach more than 100,000 revolutions per minute, and the ambient temperature can reach more than 6,700 Baidu, the turbocharger can not work at such a high speed and temperature, its rotor can not work. Conventional steel needle or ball bearings are used to support the turbocharger, so the turbocharger uses fully floating bearings and uses the engine oil and coolant of the engine system to lubricate and cool it at the same time so that it can work properly. Feilong engine cooling water pump, the heart of the engine.

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Corrosion of automobile parts

The damage caused by the action of the surrounding medium is called the corrosion of parts. Corrosion mechanism can be divided into chemical corrosion and electrochemical corrosion. About 20% of automobile parts fail due to corrosion. The damage caused by the direct chemical action of metal parts and mediums is called chemical corrosion. Oxidation of metals in dry air and corrosion of metals in non-conductive media all belong to chemical corrosion. No corrosion occurs during chemical etching. Usually, a corrosion product film is formed on the surface of the metal. Electrochemical corrosion is the action of two different metals forming a pair of electrodes in a conductive solution, resulting in electrochemical reaction and corrosion, so that the metal used as an anode is corroded. The basic characteristic of electrochemical corrosion is the continuous corrosion of metals and the generation of electric current. Such corrosion is caused by corrosion of metals in acids, bases, salt solutions and moist air. The reason of electrochemical corrosion is that the metal contacts with the electrolyte, and the galvanic cell is formed by ion exchange. Chongqing feilong —water pumps,oil dipsticks,rubber parts and electronic water pumps.

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Fatigue wear of automotive parts

The phenomenon of loss of metal in the relative movement of parts is known as the wear of parts. The occurrence of wear will cause changes in the shape, size and surface properties of the parts, which will gradually reduce the working performance of the parts. Wear is sometimes beneficial, such as running-in. According to different friction principles, wear can be divided into abrasive wear, adhesive wear, fatigue wear and corrosion wear. Fatigue wear: Under the action of alternating load, the phenomenon of fatigue spalling on the surface of parts is called fatigue wear. It occurs mainly in the frictional state of pure rolling and rolling and sliding, such as the gear tooth surface. Fatigue wear is divided into non expansive and extended fatigue wear. Non extended fatigue wear: Due to periodic contact compressive stress, there are small pits on the friction surface, but with the increase of contact area, the unit contact area decreases and the small pits stop expanding. Extended fatigue wear: When the material plasticity is poor, there is a greater compressive stress on the contact surface, resulting in small cracks on the surface, and the growth of metal shedding to form pits and pits, so that the parts can not continue to work. Chongqing Feilong —water pumps,oil dipsticks, rubber parts ,electronic water pumps etc.

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Fuel cell engine

The automotive engine is a complex component, and an independent fuel cell stack can not be used as an automotive engine. It must be combined with fuel supply system, oxidizer supply system, water/heat management system and control system which can control various valve sensors and water, heat and air conditioning devices to export to the outside world. Power. The purity of fuel is related to the performance and reliability of batteries. The power density of fuel cell increases with the increase of oxygen pressure, but the increase of air supply pressure by air compressor will reduce the output power because of the parasitic power of compressor. The water / heat management inside the battery is the difficulty and key point of the fuel cell, and is the key to determine the performance of the battery. It is difficult to discharge heat at low temperature in a fuel cell stack. In view of this, Feilong Jiangli developed a thermal management system, so that the engine in the working cycle, to maintain the best temperature (90 degrees C), both fuel-efficient and to protect the engine.

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Auto parts process series-Welding technology

Welding is the use of heating or pressing, or both, and with or without filling materials, so that the workpiece to achieve a combination of a method. Welding has the following characteristics: Blanking stage: large and small, complex is simple: welding stage: small to large, simple to complex. Welding methods can be divided into: (1) fusion welding: melt the parent material of the metal to be welded to form a weld method. (2) press welding: during welding, pressure must be applied to the welding parts to complete the welding method. (3) Brazing: The method of using metal material with lower melting point than the parent material as the solder, melting the solder to fill the gap between the joints, and connecting the solder with the parent material. Feilong Jiangli has 5 welding robots.They are improving the production efficiency of stamping parts and make the value of products more advantageous.

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Auto parts process series-Sand casting for parts blank

The materials used in making molds are called molding materials. The sand molds are mainly molded sand and core sand, which are composed of sand, binder and additives. 1.Molding materials should have the following properties: (1)Plasticity: molding sand and core sand are easy to form under the action of external forces. (2)Sufficient strength: molding sand and core sand are not easy to destroy under external force. (3)Fire resistance: molding sand and core sand are difficult to soften, sinter and adhere at high temperature. (4)Permeability: molding sand and core sand must be easy to ventilate after compacting. (5)Concession: molding sand and core sand can be compressed when cooled. 2.Pattern and core box The pattern and core box are tools for making moulds and cores. The shape of a casting to form a shape equivalent to the external shape of the casting. The core forms the inner cavity shape of the casting, and the core box is the tool for making the core. Sand moulds and core boxes are used for multi-purpose wood casting. Metal mold, plastic mold and other patterns for special casting. 3.Modeling method According to the different methods of modeling operation, it can be divided into: (1)Manual molding: sand filling, compacting, mold lifting and so on mainly have the manual completion, the operation is flexible, the productivity is low, mainly uses in the single piece small batch production. There are many specific methods of manual modeling: whole mold modeling, three-box modeling, scraper modeling, false box modeling and so on. (2)Machine Modeling: Mechanization of sand filling, compacting and moulding, high productivity and large investment, mainly used for mass production 4.Technical problems to be solved in sand casting (1)The choice of pouring position: the main processing surface and large plane of the casting should be facing down, and the part of the Dian wall of the casting should be placed at the bottom. (2)Selection of parting surface: plane parting surface should be adopted as far as possible, the number of parting surface should be as small as possible, so that all or most of the castings are placed in the same sand mold. (3)Drawing inclination and casting fillet: In order to start the mold conveniently, the mold should have a certain drawing inclination, the higher the mold, the smaller the slope value: the inner wall inclination is larger than the outer wall inclination. In order to prevent the casting from producing stress and cracks at the wall joints and corners, the casting wall joints and corners should be designed into rounded corners.

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Crack and Rupture Analysis of drawing parts

The crack and fracture are mainly caused by the tensile stress exceeding the strength limit of the local blank. The reasons for this are: (1)The stamping performance of the material does not meet the requirements of the process. (2)When the sheet thickness exceeds the lower deviation, the material becomes thinner, the compressive stress on the unit area of the cross section increases, or because the material becomes thinner, the resistance decreases, and the sheet metal flowing into the die becomes too much and wrinkles first, then the material is not easy to flow and is cracked. (3)The surface quality of materials is poor. Scratches cause stress concentration and corrosion resistance. (4)The blank shape is big when the feed resistance is too large, the gap between the blank ribs is small, the radius of the die is too small, the outer slider is too deep, the drawing rib is too high, the surface of the blank and the radius of the die is not smooth. (5)The local drawing amount is too large, and the drawing deformation exceeds the material deformation limit. (6) In operation, the blank is biased, resulting in too much pressure on one side, and too little pressure on the side. Too large side is difficult to feed, causing cracking; too small side, too much feed, easy to wrinkle, difficult to feed after wrinkle, causing cracking. (7)Does not apply lubricants according to the process requirements, and the resistance increases, resulting in difficulty in feeding and cracking. (8)Improper installation of punching die or poor precision of the press cause gap deviation, resulting in uneven feed resistance.

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Cause and analysis of burrs of stamping parts

Last time, two reasons for burrs in stamping parts were analyzed: excessive blanking clearance, too small or uneven blanking clearance and blunt knife edge. Now we will analyze other reasons. (1)Improper blanking condition If the blank (including intermediate parts) is not in good contact with the punch or die, burrs will occur in the blanking process because the height of the workpiece is lower than the relative height of the positioning when trimming and punching with inappropriate relative height. (2)Improper mold structure (3)Material does not comply with process requirements. The relative clearance is unreasonable due to the material thickness excess or the use of wrong material (such as steel number is not correct) causing burrs in the workpiece. (4)The processing technology of the parts is poor, and the sharp corners or sharp corners can easily produce burrs due to excessive wear. Burrs not only make the deformation process easy to crack due to stress concentration after blanking, but also bring difficulties to the subsequent process of blank layering. Large burrs are easy to scratch the handle; when welding, the two plates are not well joined, easy to weld through, welding is not firm; riveting is easy to produce riveting clearance or riveting crack. Therefore, burrs outside the allowable range are extremely harmful. Burrs that have been produced can be eliminated by filing, rolling, electrolysis and chemical treatment. Feilong Jiangli ,a 40 years enterprise, is looking forward your welcome.

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Engine cooling mode

According to the cooling medium used, engine cooling methods can be divided into water-cooled and air-cooled. 1. Water-cooled one by one with water as the cooling medium, heat first from the machine to water, by the flow of water to heat away and then into the atmosphere. After heat dissipation, the water flows back to the hot part again. The normal working temperature of the engine can be maintained by properly adjusting the water and cooling intensity. At the same time, hot water can also be used to preheat the engine, which is convenient for starting in winter. The structure of water-cooled cooling system: water pump, radiator, fan, thermostat, expansion tank, warm air, engine water jacket, cooling pipe. 2. the heat of air-cooled parts is directly scattered into the atmosphere. At present, most of the cars are water-cooled.

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Perfect match of pump and thermostat

The engine is realized by the circulation of coolant. The component of the forced circulation of coolant is a water pump, which is driven by a crankshaft belt to promote the circulation of coolant throughout the system. Specializing in the production of water pumps for 40 years Feilongjiang Li's latest product - electric water pumps, it can accurately control the pump speed, and effectively reduce the loss of output power. The cooling of these coolants on the engine should be adjusted at any time according to the working conditions of the engine. When the engine temperature is low, the coolant circulates inside the engine itself. When the engine temperature is high, the coolant circulates between the engine and the radiator. The thermostat is used to control the coolant in different cycles. The thermostat can be regarded as a valve, its principle is to use materials that can be flexible with the temperature (paraffin or ether and so on) as a switch valve, when the water temperature is high material expansion top open valve, coolant for a large cycle, when the water temperature is low material shrinkage closed valve, coolant small cycle.

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Hydraulic shock absorber

The greater the damping force of the shock absorber, the faster the vibration is reduced, but the effect of the parallel elastic elements can not be fully exerted. At the same time, the excessive damping force may also lead to damage to the connecting parts and frame of the shock absorber. In order to solve this contradiction between elastic elements and shock absorbers, the following requirements are put forward for shock absorbers. (1) In the compression stroke of the suspension, the damping force of the shock absorber should be small so as to make full use of the elasticity of the elastic elements to mitigate the impact. (2) In the suspension stretching stroke (the distance between the bridge and the frame) the damping force of the shock absorber should be large in order to reduce the vibration rapidly. (3) When the relative speed between the axle (or wheel) and the frame is too high, the shock absorber should be able to automatically increase the area of the liquid flow passage, so that the damping force is always within a certain limit to avoid excessive impact load. Cylinder shock absorber is widely used in automobile suspension system, and it can reduce vibration in compression and stretching stroke. It is called bidirectional action shock absorber, and a new type of shock absorber is adopted, which includes air-filled shock absorber and resistance adjustable shock absorber.

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Water seal

Engine cooling water pump is the main part of the cooling system of automobile engine. Its function is to force the cooling fluid in the engine to circulate in the cooling system and reduce the influence of high temperature on the engine during the working process of the engine. Water seal is the core of the work of the pump. The movement of the water seal itself is very simple, just rotates with the shaft. . Water seal, pump body and bearing are super-hard matching mechanical seals. This kind of seals is composed of static rings and dynamic rings, which are perpendicular to the shaft, and the smooth and straight surface of each other, and do relative rotation. Coolant movement in the pump is very complex, different types of water seals, using different types of coolant, if the water package is equipped with problems, the engine coolant will appear seepage, then the pump bearing lubrication will be washed away, the entire pump function will be invalid. There are two main types of water seals: one is separated (rotating ring parts and static ring parts are respectively installed on the pump), the other is integrated (rotating ring parts and static ring parts are first installed together, and then installed on the pump), separated water seals are mainly used in larger pumps, now commonly used is integrated water seals.

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The role of automotive rubber products in Automobiles Today

Automobile rubber products can be divided into six categories: tires, sealants, shock absorbers, tape products, rubber tube products and other products (such as wipers, fenders, adhesives, sealants and interior decoration products). Today's first category: auto tires: The tire is one of the important parts of the automobile, it contacts with the road directly, and works with the automobile suspension to alleviate the impact when the automobile is running, to ensure that the automobile has good ride comfort and ride comfort; to ensure that the wheel and road surface have good adhesion, improve the traction, braking and passing of the automobile; to withstand the weight of the automobile; The importance of tire in automobile has attracted more and more attention. Nowadays, the main components of most automobile tire materials are natural rubber or synthetic rubber. The comprehensive performance of natural rubber is superior to that of synthetic rubber, so the advanced tire uses natural rubber. In order to make rubber have the properties required to make tires, it is necessary to infiltrate different chemical materials into the rubber, namely chemical additives. One of the most important additives is carbon black, because carbon has a special adsorption, carbon particles and rubber molecules bond very well, making the rubber hardness, strength and grindability. Because carbon black and rubber are basically equal, the main material from the car tire is actually a rubber and carbon black composite material.

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Automobile rubber pipes

Today, we learn the fifth categories of automotive rubber products: Rubber pipe products are used in the chassis, engine and body of the three parts, for oil transportation, gas transmission, drive, control, brake, cooling and heating seven systems of rubber pipe, play a role in fuel supply, gas supply, water supply and power transfer. The types of hoses include fuel pipe, water conveying hose, brake hose, vacuum hose, air conditioning hose, radiator hose, power steering hose and special branch hose. In addition, the last major category of automotive rubber products is other products, the main varieties of brake film, leather bowl and dust shield.

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Characteristics of rubber bushing

[Feilong Jiangli rubber products series] In the guiding device of suspension system (such as swing arm, rear axle, etc.), more and more hinge points connected with the body are connected by rubber sleeve. Rubber axle sleeve has become an indispensable component in automobiles because of its good vibration isolation performance, elastic characteristics and attenuation characteristics. Characteristics of rubber bushing 1.  Since the shape of rubber parts has more freedom of choice, the stiffness of three directions (axial, radial, torsional) can be properly selected. 2.  It can be vulcanized firmly with metal, simplifying the structure of fixing and supporting. Therefore, any of the three directions can be used to support the load. 3.  The elastic modulus of rubber is smaller than that of metal, which can produce greater elastic deformation. 4.  The internal friction of rubber is larger than that of metal and tends to increase with the increase of frequency. Therefore, the resonance amplitude can be reduced by using rubber sleeve. when rubber is at low temperature, the dynamic elastic coefficient will rise sharply. Therefore, when choosing the rubber bushing material, we should strive to improve the material's high temperature resistance, low temperature resistance, oil resistance and so on.

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Effect of ignition time on particle size and particle size distribution

Ignition time has little influence on the mixture formation of PI engine, but it has great influence on GDI engine. The C engine is mainly used for analysis. The bigger the ignition advance angle is, the shorter the mixing time and the more inhomogeneous the mixing will be. Therefore, the nucleate particles will increase the ignition advance angle and the quantity concentration will gradually increase. Because the oxidation rate and formation rate of particulate matter have little change with ignition advance angle, the change of aggregated particulate matter with ignition advance angle is not obvious. With the increase of ignition advance angle, nitrogen oxides emissions gradually increased, and CO and HC. gradually increased. Feilong Jiangli automobile water pump, professional design and production for 30 years.

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Wheel retardation force

Wheel blocking power mainly comes from 3 aspects: (1) the structure of the tire itself; between the wheel friction pairs and the braking system. (2) external factors: vehicle detection, tire and ground friction. The braking force of automobile wheels is reflected by the friction between the tire surface and the brake drum surface when it is running freely. Therefore, the influence of the tire on the braking force is also greater. (1) If the tread pattern is too deep or obviously damaged, the friction coefficient increases abnormally when the tread roller is running freely, which results in the increase of the friction force which blocks the wheel running. (2) The rim or hub deforms and loses roundness, making it run irregularly in motion, causing the wheel to rotate unbalanced, causing the wheel to jump and yaw when it rotates, resulting in excessive blocking force. (3) When the tire pressure is too small, the tire deformation on the hard roller is large, so that the contact area between the tire and the brake roller increases, resulting in the increase of hysteresis loss during rolling, thereby increasing the wheel resistance. If the diameter of the tire is too small, the depth of the wheel falling into the middle of the two brake drums will increase, and the axle load will tilt forward, which will result in a larger drag force. (3) assembly factors: wheel friction pairs and brake systems are poorly assembled, increasing friction factor or friction area. (1) during the shunting and shunting of shunting personnel, the speed of the vehicle is fast, which results in the small axle load data and increases the retardation force. (2) The misalignment of the vehicle position on the shunting line leads to the uneven distribution of the axle load between the left and the right, which is the increase of the side block force on the side with more axle load distribution.

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The cause of engine carbon deposition and its influence on engine

The formation of carbon deposition is often caused by carelessness of drivers. 1. adopt the "high speed low speed" bad driving habits. 2. long idle speed and low speed running. 3. the use of purity and quality can not meet the requirements of gasoline. These bad factors will have different effects on the engine, such as 1. Cold start is difficult, the idle speed of the cold car can not reach the prescribed speed, when serious, the idle speed of the cold car will stall, and the idle speed of the hot car is low. 2. engine power decreases, acceleration is not smooth, fuel consumption increases. 3. The engine exhaust emission becomes worse, and the service life of spark plug, oxygen sensor and ternary catalytic converter will be shortened at the same time. 4. Carbon deposition will also cause engine piston ring stuck, affecting the sealing performance of the piston ring, resulting in increased oil consumption, resulting in engine oil burning, shortening the service life of the engine. Feilong Jiangli Ltd suggests that you develop good driving habits, do a good job of car maintenance, so that their love life is longer.

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Plastics for automobile parts

Plastic is a kind of macromolecule material which is produced by complex chemical reactions such as polymerization, resin bonding, resin addition, condensation and so on. Properties: It is a light material (1/8 of steel), high specific strength, good chemical stability, corrosion resistance, good insulation, wear resistance, sound absorption, easy processing and molding. The main applications are: Installations: dashboard and gasket, sundries box, steering wheel, joystick, interior trim panel, seat armrest, door lining, various filling materials, etc. External fittings: sealing strip, bumper panel, fender, skirt edge, trim strip, hose, shock absorber gasket, handle, etc. Others: air filter housing, fan blades, various sensors, electrical appliances, and some gear. With the continuous improvement of advanced engineering plastics in performance, it is being developed and applied in automobile engine cover, roof, luggage rack and other parts. Plastics are divided into thermoplastics and thermosets. Thermoplastic softens after heating, has plasticity, machinability, and hardens after cooling; if it softens after reheating, hardens after cooling. This process can be repeated and has no effect on its structural properties. For example, polyfluoroethylene, polystyrene, polyamide (also known as nylon) and so on, they have simple molding process, high production efficiency, certain mechanical properties, but low heat resistance and rigidity. Thermoplastics are most widely used in automobiles. Commonly used are: ABS (acrylonitrile butadiene styrene), PP (polypropylene), PE (polyethylene) and so on. Thermosetting plastics react chemically when heated and harden after solidification; they cannot be softened by reheating. Such as phenolic resin, epoxy resin and so on. They are highly heat-resistant, pressure resistant and difficult to deform, and are relatively inexpensive, but the molding process is complex and the production efficiency is low.

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Brief analysis of automobile common materials

There are many kinds of materials used to produce automobiles: iron and steel, non-ferrous metals, plastics, rubber, glass, ceramics and so on. According to statistics, in recent years, the weight composition ratio of the main materials of an ordinary car is approximately 65%-70%, 10%-15% of non-ferrous metals, and 20% of non-metallic materials. Various new materials, such as light metal materials, composite materials, high-tech synthetic materials, are increasingly used in modern automobiles. Metal materials have various properties. It has physical and chemical properties, mechanical properties and process properties. Physical and chemical properties refer to the properties of metal materials under various physical conditions and the ability to resist the erosion of various chemical media. Density: mass per unit volume; thermal conductivity: the ability to conduct heat; electrical conductivity: the ability to conduct electric current; thermal expansion: the ability to increase volume when heated; melting point: the temperature when the solid state becomes liquid; magnetism: the magnetic conductivity of metallic materials is called magnetism; corrosion resistance: metal resists the occurrence of the surrounding medium at room temperature The ability of chemical reactions to be destroyed; oxidation resistance: the ability of metals to resist oxidation at high temperatures. Mechanical performance refers to the resistance of metallic materials under various loads (external forces). It has the following indicators: Impact toughness: the ability of metal materials to resist failure under impact loading is called impact toughness. Fatigue strength: Fatigue cracks occur in metal materials under cyclic loading and lead to fracture called fatigue fracture; the maximum stress that does not produce fracture under repeated cyclic loading is called fatigue strength; the fatigue strength is measured by fatigue test; when the number of stress cycles of metal materials reaches 107, the parts are still Without breaking, the maximum stress at this time can be used as fatigue strength. For some high strength steels, the maximum stress at 108 cycles of stress is their fatigue strength. Cutting performance: cutting performance refers to the difficulty of machining metal materials. Heat treatment performance: heat treatment performance refers to the ability of metal materials to adapt to various heat treatment processes.

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Repair automobile parts by electroplating

The damage of automobile parts mainly includes four types: deformation, fracture, corrosion and wear. The first three types of damage are usually repaired by cold working, hot working or gluing. If the general parts deformation can be cold-pressed or hot-pressed after correction for mechanical repair; shaft parts can be broken by inlaying, welding, forging and other methods to repair; cylinder block water jacket cracks can be repaired by welding, riveting or adhesive methods. Parts wear is the most common damage. Parts that have not worn out beyond the specified repair size are processed according to repair size. Parts that have worn out beyond the repair size are repaired by surfacing, spraying, electroplating and other metal covering processes and adhesive methods. Electroplating Repair Method This method is to use the part to be repaired as the cathode, so that the metal cations in the electrolyte move toward the part (cathode) under the action of electric field force, and deposit on the surface of the part. The advantage of the electroplating method is that it can obtain a good wear resistant layer and no distortion of the parts. Chromium plating is often used to repair automobile parts, followed by iron plating chromium plating and iron plating are both electrode crystals, with similar ultra-fine grains and high dislocation structure and large internal stress, and is stratified, with a large number of microcracks. But the chromium plating layer and the iron plating layer have their own characteristics, such as high hardness, good wear resistance, and prolonging the service life of the parts. The disadvantages are low current efficiency, slow deposition, thin coating, high cost, and highly toxic chromium anhydride, serious environmental pollution. The electrolyte temperature of iron plating used to be above 90 C, which can reduce the internal stress of the coating and prevent peeling, but the hardness of the coating is on the low side. In 70s, the wear resistance and the bonding strength of the coating were increased by using low temperature iron plating at 45 C. Iron plating also has the advantages of fast accumulation, low cost and no pollution to the environment.

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Carbon dioxide welding to repair auto parts

The significance of automotive parts repair is to repair old and waste, reduce the consumption of new parts, thereby saving raw materials, energy and manpower for manufacturing parts.  The damage of automobile parts mainly includes four types: deformation, fracture, corrosion and wear. The first three types of damage are usually repaired by cold working, hot working or gluing. If the general parts deformation can be cold-pressed or hot-pressed after correction for mechanical repair; shaft parts can be broken by inlaying, welding, forging and other methods to repair; cylinder block water jacket cracks can be repaired by welding, riveting or adhesive methods. Parts wear is the most common damage. Parts that have not worn out beyond the specified repair size are processed according to repair size. Parts that have worn out beyond the repair size are repaired by surfacing, spraying, electroplating and other metal covering processes and adhesive methods. Automatic surfacing is to install parts on the surfacing machine and turn them on side. Commonly used automatic surfacing has three technologies: vibration surfacing, carbon dioxide protection welding and submerged arc welding.  Carbon dioxide protection welding is carried out under the covering of carbon dioxide gas. Because carbon dioxide can react with carbon in molten iron to form carbon monoxide at high arc temperature, some carbon monoxide gases escaped from molten iron pool and become pores in the welding layer, thus affecting the surfacing quality.  Therefore, in order to reduce the porosity, carbon dioxide shielded welding mostly uses special low-carbon manganese-silicon alloy steel wire with low carbon content and sufficient deoxidizer. The wire diameter is 0.4-0.6 mm. The surfacing layer has high strength, few pores and no cracks, but the hardness is low. This method is suitable for repairing cab, leaf plate and other thin plate parts.

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Inspection of rolling bearings for automobiles

Rolling bearings on automobiles include ball bearings, roller bearings, tapered bearings and needle roller bearings. They often work under high speed and heavy load conditions and bear considerable alternating loads. Therefore, rollers and raceways often produce serious wear, fatigue spalling, fracture, ablation (that is, high temperature annealing, serious, the color is purple black, similar to blue) and other phenomena. When rolling bearing, a component usually does not need to decompose and check the damage condition of each part. When inspecting, the bearings are cleaned and rubbed. The quality of the bearings can be appraised by means of external inspection, idling test and internal clearance inspection if necessary. (1) appearance check. In the inspection, if the following damage phenomena are found, they should be replaced in time. Rollers (ball, cylindrical roller, tapered roller, needle) and internal and external raceways are discolored by ablation; in the internal and external raceways of bearings, there are impact marks, marks and scratches; in the internal and external raceways of bearings, rolling bodies (ball, cylindrical roller, tapered roller, needle) on the occurrence of cracks, metal delamination, scaly peeling and a large number of (ball, cylindrical roller, tapered roller, needle) Usually more than one third of the area) black spots; excessive wear in the groove of the retaining roller, the roller can fall out by itself; due to tapered roller wear, its small end of the working face protruding out of the bearing outer seat ring end; tapered roller bearing inner ring large end of the internal end of the notch and metal spalling. In the inspection of rolling bearings, if only minor corrosive black spots are found in the bearings and minor defects in the cage are found, without affecting the rotation of the bearings, they can generally continue to be used. (2) idling inspection. The experiment mainly depends on whether the bearing rotates flexibly, whether there is noise or whether it is stuck or not. The inhomogeneity of the bearing rotation can be judged from the feeling on the hand (the old bearing is allowed to have a slight noise). (3) internal clearance check. The measurement of internal clearance and wear of ball bearings can be judged by measuring their radial and axial clearance. Axial clearance inspection: the bearing outer seat ring is placed on two cushion blocks, and the inner seat ring is suspended, and then a small plate is placed on the inner seat diagram, the dial stylus against the center of the plate, the maximum allowable value of axial clearance is 0.20 ~ 0.25 mm. Radial clearance inspection: Place the bearing on a flat plate so that the dial gauge stylus against the bearing outer seat, and then hand press the bearing inner ring, the other hand reciprocating push the bearing outer ring, the number of meter needle swing is the radial clearance of the bearing. The maximum allowable value of radial clearance is 0.10~0.15mm.

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Grinding of automobile parts

Grinding is the process of grinding metal with a grinding wheel on a grinder. Grinding is one of the main methods of finishing. In the automobile industry, the grinding machine accounts for about 25%. Therefore, finishing and grinding of hardened materials is a common method. In addition, grinding is easy to automate, and is conducive to efficient production. Grinding has the following characteristics: 1. The grinding wheel has high abrasive hardness and good heat resistance, so it can grind hard materials that metal tools can not process. 2. Grinding can remove very thin and very fine chips, the chip thickness is generally only a few microns, therefore, has a strong correction ability, processing accuracy can reach T6~IT5, surface roughness of Ra0.1 micron. 3. high grinding speed. 4. The cutting temperature is high, and the instantaneous maximum can reach 1000 degrees Celsius. Therefore, the grinding surface is easy to produce residual stress, burn and crack. According to the geometry of the object, grinding can be divided into outer circle, inner circle, plane and formed surface. By clamping and driving the workpiece, it can be divided into centering grinding and centerless grinding. According to the feed direction, it can be divided into longitudinal feed and transverse feed. According to the working surface types of grinding wheels, they can be divided into peripheral grinding, end grinding and peripheral grinding. The types of grinding machines commonly used in automobile manufacturing are ordinary grinder and special grinder. Ordinary grinder includes: cylindrical grinder, internal grinder, surface grinder, centerless grinder, etc. Special grinding machines include camshaft grinder, crankshaft grinder, cross shaft grinder and so on.

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