With the development of the rural economy, the number of individual agricultural machinery parts processing and distribution companies has increased substantially, and counterfeit and shoddy accessories have flooded the agricultural machinery maintenance market, which has led to a significant increase in the repair rate of agricultural machinery, which has seriously affected the efficiency of agricultural machinery operations and the revenue of operators, and even caused traffic accidents. And personal injury. We start from the interests of the majority of organic households, collect and sort out a simple method to identify genuine and fake agricultural machinery parts, for reference when farmers choose accessories.
First, common features of fake and shoddy accessories. False: The identification of fake products is incomplete, and "three nothing" products are mostly. There is a serious overshoot and damage: the size, shape or position of the fittings is poor, or there are scratches, cracks, incomplete and severe corrosion.
Take: Take the registered trademarks, certificates of conformity, and packaging of regular manufacturers. This type of product is generally well-made, but there are cutting corners in material selection and processing. If not according to the technical requirements of cutting, heat treatment and not connected by the correct method.
Counterfeit: Forged trademarks, certificates of conformity and packaging, using cheap, easy-to-process materials to replace the materials required for the original design, shoddy, to replace the high-quality cast iron, cast steel, and high-quality steel And powder metallurgy materials. Such as castings have serious pores, shrinkage holes and cracks.
Second, how to buy qualified agricultural machinery parts
1. Select provincial, municipal, and county agricultural machinery departments designated, hold a business license and "Hebei Province agricultural machinery maintenance (parts supply) technology certification." With good reputation, the workers have their certificates and have certain operating scale agricultural machinery parts supply units.
2, purchase regular product manufacturer product identification complete product.
3, purchase authentic original parts and spare parts produced by the complete plant.
4, according to product specifications and parts atlas and other technical documents, notes accessories name, model, trademark, single number, technical requirements (such as materials, dimensions, tolerances, mechanical strength and connection methods, etc.) for reference when buying, It is best to prepare some simple inspection tools (such as vernier calipers, small files, etc.).
Third, identify the basic knowledge of genuine and fake accessories
1, the authenticity of the identification of accessories materials In inferior accessories, about 35 percent of the material species shoddy. The most common alternative materials are plain grey cast iron (hereinafter referred to as gray iron) and ordinary low-carbon steel (hereinafter referred to as low-carbon steel). Materials that are often replaced include high-quality cast iron (such as ductile iron, hereinafter referred to as ductile iron), cast steel, high-quality steel, alloy steel, and powder metallurgy materials. There have also been cases where copper and aluminum were replaced. The authenticity of accessory materials can be identified by referring to the following methods.
1) see the cutting surface: gray iron: gray, very dark luster, the surface looks rough; ductile iron: gray, shiny gray iron than gray, rough surface like gray iron; steel: a brighter luster (but The cast steel is slightly darker. The structure is fine, and the surface of grinding or reaming is bright as a mirror surface. The hand touch feels smooth and delicate. The chrome steel grinding surface often has small and bright spots. Iron-based powder metallurgy; silver gray, fine organization, its luster between steel and iron. In addition, rubbing the smooth cutting surface by hand, the gray iron can dye the hand dark gray, and it is not easy to wipe. Ductile iron can also make hands black, but lighter than gray iron, while steel does not stain hands (except dust).
2) The boring experiment was conducted after the purchase was confirmed and the supplier agreed to assume the quality responsibility. Select the non-matching surface using a normal boring tool to cut the fittings. Because of the different materials, various metal materials react differently when being boring. Gray iron: boring cutting resistance is small, when the boring when the "squeak" sound, the sickle surface is basically non-stick crumbs, swarf is grayish black, there are a small amount of silver white highlights, look at the particle size is different, with small particles fine Mainly, grinding with fingers, it is easy to make the fingers black; ductile iron: resistance when boring is slightly larger than gray iron, there are also more obvious "click" sound, very little sticky, swarf is grayish black, there are Fine highlights, crumb end particle sizes, but mainly large granules, finger rubbing at the end of the crumbs can stain the fingers black, but it is lighter than the grey iron dyed black; white iron: radiating loudly when boring Gurgling sound, no crumbs, only light at the time of the licking, no scars, scratches on the guillotine surface; steel: Most of the steel parts are cold or heat-treated, the surface is hard, and the whistle "Sound, but it sounded much lighter when boring white iron. It was bright, and after boring, there was a small amount of crumbs after the guillotine. It was bright gray, and the granules were relatively uniform. When low-carbon steel is being boring, the sound is very small, and it has a soft feeling. The crumbs are easy, and the scars on the surface are more obvious. Copper: When boring, the most obvious feature is that the boring tool is easy to slip, and the swarf is easy to stick.锉 锉 锉 锉 锉 锉 锉 锉 锉 锉 锉 锉 锉 锉. Aluminum: boring is very easy, more crumbs and faster, the surface is gray or silver white, sticky and heavy and difficult to brush off; iron-based powder metallurgy: less boring resistance, feel with low carbon steel, sounds like gray Iron, non-stick crumbs, crumb-like particles similar to ductile iron, darker in color, and stained, are slightly lighter than ductile iron.
3) Test Density: The weight of the sample and the test piece shall be weighed separately with an instrument. If they are the same, they may be regarded as meeting the requirements of the material type.
4) Listening to the percussion sound: Suspend the accessories and hit with a hammer or other metal object. The percussion force should not be too large. The ears should be close to or be heard by the test piece. The sound they make is different. Gray iron: The sound is low and the duration is very short. Ductile Iron: The sound is crisp, there is reverberation and the duration is short. Steel; sound clear, sound like thin ring tone, longer duration.
2, observe the surface defects to determine the quality of accessories. In casting production, due to the influence of raw material characteristics, operation technology and production conditions, some casting defects will inevitably occur. We should judge the quality of the parts according to the nature, location and severity of defects.
1) Hole defects: This is the most common defect found on cast iron parts. Such as: pores, pinholes, shrinkage and shrinkage and so on. The following criteria can be used to determine if an accessory is available.
1 The surface that matches the rotating journal, such as the inner wall of the bushing, sliding bearing, etc., does not allow hole-like defects.
2 interference fit surface, such as the seat hole wall of the installation rolling bearing and the axial hole wall of the pulley, gear, etc., allow the existence of the diameter of not less than 1/20 of the minimum width of the surface being investigated, the depth is not greater than the diameter (path) 1/ 4. The number is not more than 3 holes, but the distance between the hole and the edge of the inspected surface shall not be less than 5 times the hole diameter (the maximum value). Shrinkage is calculated as the diameter of the cavity in the distribution range.
3 Sealing surfaces, such as the mating surfaces of the housings, end caps and their mating parts, are allowed to have a diameter not less than 1/20 of the minimum width of the bonding surface, a depth no greater than 1/3 of the diameter, and a margin not less than the diameter Five times, the spacing is not less than 5 times the diameter of the non-penetrating holes.
4 supporting surface, the lower surface of the bearing housing, the shell as a basic part to connect the contact surface of the working device without sealing requirements, allowing the existence of 1/10 of the diameter is not greater than the minimum width, the depth does not exceed 1/10 of the wall thickness , Holes and margins are not less than 1/3 of the minimum width and no more than 5 holes.
Other surfaces can be selected based only on strength, stiffness requirements, and appearance requirements.
2) Defects in size, shape, and position, such defects are commonly seen in size, casting errors, casting errors, etc.
1 Out of tolerance, such as length, thickness or hole clearance, when the size and requirements are different, you should give up the purchase.
2 casting wrong type (also called wrong box). At this point it can be seen that part of the casting is offset from the other part at the parting plane. Mistakes tend to reduce the wall thickness after processing, affect the strength, and may also affect the relationship with other parts or affect the appearance. If the staggered size is not greater than 1/30th of the thinnest part of the wrong part, consider using it.
3 casting wrong core (bias core). The larger the wrong core, you can see the side of the casting hole wall thicker, the other side is thinner, not only affect the strength of the parts, but also tend to cause installation trouble. Therefore, it is best not to buy the wrong core casting.
(3) Inclusion defects and damages. Inclusion defects refer to the inclusion of foreign materials such as other metals, iron particles, mineral slag, or molding sand in the casting body. If the processing surface has inclusions, a hole filled with foreign matter will form on the machining surface, which will directly affect the fitting of the surface of the part. Therefore, fittings with inclusions on the surface are not recommended. In addition, the mating surface of the fittings must not be deformed or incomplete, and cracks must not be present in any part.
3, carefully check the product's legal identity and manufacturer's security mark
1) The product's legal mark is mainly: 1 There is a product quality inspection certificate; 2 There is a Chinese product name, name and address of the factory; 3 There are product specifications and models, grades and registered trademarks.
2) Look at the mark: Each manufacturer has its own special mark when manufacturing and processing, and the materials used and the processing technology adopted are different. For example, the security mark of Wuxi Weifu Oil Pump Nozzle Factory is two oil pump test benches, and the anti-counterfeiting mark is one-time. The plungers produced by Luoyang Tractor Factory and Qinghai Oil Pump Nozzle Factory are black, and the plungers and oil valves produced by the Lanzhou Oil Pump Nozzle Factory all have an arcuate retracting knife.
4. Experience Judgment and Detection Use the caliper to measure the size of the accessories and compare it with your own data card to identify the authenticity. The following describes the identification methods of several common accessories.
1) Identification of common agricultural vehicle accessories Steel rings: No matter what type of steel ring, the side should be marked with certificates, trademarks, models, specifications, and the name of the factory, and it should be clear, smooth, shiny, and free of cracks. Top grade.
Rolling bearings: General genuine bearing looks bright, coated with rust-proof oil; ball bearings to keep the rivets between the frame evenly riveted, the rivet head is not biased; with your fingers to cover the bearing inner ring, in the outer ring to make a mark, repeatedly rotating the bearing, each Different marks stop position is genuine.
Gears and oil seals: The tooth surface of genuine gears is smooth, coated with anti-rust oil, and the side has a stamped number; the genuine oil seal has a smooth surface; the lips have no burrs and the springs that closely follow the lip do not fall off; O-rings have good roundness and smoothness. Flash, good elasticity.
2) The identification of the three large parts of the plunger: Observe whether the plunger is flexible in the movement of the plunger sleeve and whether there is any trace of wear on the surface. Then perform the sliding test: Hold the cleaned plunger sleeve with your fingers, tilt 45 Degree, gently pull out the plunger about 1/3, and then release, the plunger should be free to slide down on the plunger sleeve bearing surface under its own weight, and then pull out the plunger, turn any angle, use the same method to test, the result Should be the same. Sealing test: plug the plunger sleeve's oil inlet, oil return port and guide hole with one hand, pull the plunger out with another hand, and place it in the medium or maximum oil supply position, the plunger The lower position is pulled outwards, and the distance to pull out is limited to the extent that the plunger upper edge does not expose the plunger oil hole. At this time, a significant suction force is felt. When the plunger is released, the plunger can quickly return to the original position.
Outlet valve: First check the decompression belt and the sealing cone for wear, and then perform the sliding and sealing test. Slidability test: Take the oil valve seat cleaned in diesel oil, and draw 1/3 of the valve body in the vertical position. The release valve body should be able to fall freely on the valve seat support surface under its own weight. Rotate the valve body at any angle and repeat the above procedure. The result is the same as genuine. Sealing test: Seal the cone surface, hold the oil valve seat with thumb and middle finger, hold the index finger on the hole in the lower plane of the oil valve body, and put the valve body of the oil valve into the valve seat, when the decompression ring When the belt enters the valve seat, press the valve body gently. If you feel the air compression force, release the hand, the valve body should be able to pop up.
Injector: Look at the appearance If there is traces of carbon deposits or the needle valve is black, it means that it has been used. Check on the nozzle tester. Under the specified pressure, the nozzle injection should be started and ended obviously, no droplets are allowed. The oil phenomenon should be accompanied by a crisp sound when spraying oil. The sprayed oil should be uniformly misty. There should be no obvious flying droplets and uneven brightness.
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