Introduction to the fixing method of the inner ring of imported bearings

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Imported bearings are divided into inner and outer rings. I think everyone knows this. So what is the fixing method of the inner and outer rings of the imported bearing? First, let’s introduce the fixing method of the inner ring of the imported bearing.

1. Fixed shoulder

The inner ring of the bearing is axially fixed by the shoulder and interference.

Suitable for supporting structures fixed at both ends.

The structure is simple and the outline size is small.

2. The circlip is fixed

The inner ring of the bearing is axially fixed by the shaft shoulder and the lock nut.

It can bear small bidirectional axial load.

The axial structure size is small.

3. Lock nut to fix

The inner ring of the bearing is axially fixed by the shaft shoulder and the lock nut. And there is a stop washer to prevent loosening, reliable, suitable for high-speed, heavy-duty occasions.

4. End face thrust washer fixed

The inner ring of the bearing is axially fixed by the shaft shoulder and the shaft end retaining ring. The shaft end retaining ring is fixed on the shaft end with screws. The fixing screws should have anti-loosening devices.

It is suitable for occasions where the shaft end is not suitable for thread cutting or the space is restricted.

5. Adapter sleeve fixed

Relying on the radial size of the inner hole of the adapter sleeve being compressed and clamped on the shaft, the axial fixation of the bearing inner ring is realized.

6. Withdrawal sleeve fixed

The clamping method of the withdrawal sleeve is the same as that of the adapter sleeve. However, because the withdrawal sleeve has a special nut, the bearing is easy to load and unload, and it is suitable for fixing the double row spherical bearing with large radial load and small axial load on the optical axis.

Decho is a professional supplier of imported bearings. If you need these bearings, pls contact us by email [email protected]

What causes the poor operation of stainless steel needle roller bearings?

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Stainless steel needle roller bearings can be used in medical equipment, food processing, optical instruments, precision instruments, machine tool motors, machining and other industries. However , Some problems will inevitably occur during use.

The problem listed below :

1. shaft heating

Solution: If it is because the sealing ring on the shaft is too tight, you can adjust the position of the packing back cover appropriately. If it is caused by the friction between the stainless steel needle bearing cover and the shaft in the radial direction, you need to adjust the difference between the two Clearance.

2. bearing heating

Solution: If the lubricating oil of the bearing is not enough, you need to check whether the oil circuit is normal and add lubricating oil regularly. If the assembly is not aligned correctly, you can add a gasket at the base of the bearing.

3. axial runout

Solution: If it is because the bearing is not stable, you can use a roller ring to fix it. If it is because the stainless steel bearing clearance is too large to cause axial runout, you need to adjust the gap.

4. oil leakage

Solution: If it is because of the failure of the sealing decoration, you need to replace the sealing material. If it is because the lubricating oil has increased too much, the oil volume needs to be reduced. Generally, the oil volume can be increased at the standard height.

5. the amount of oil on the main friction surface is small

Solution: If it is because the oil ring rotates slowly, you need to check whether the oil ring has fallen off, if it needs to be fixed in time, if it is because the oil groove is shallow and the oil pipe is blocked, you need to deepen the oil groove and clean the oil pipe. .
Among the many parts of mechanical equipment, stainless steel bearings are used frequently, and occasionally, they may malfunction during use. What is the cause? Once it malfunctions, it will seriously delay production.

After years of accumulated experience, stainless steel needle roller bearing technicians have summarized the following four reasons for the poor operation of stainless steel bearings:

Four reasons for the poor operation of stainless steel bearings.

1. Poorly smooth

In many cases, the poor operation of stainless steel bearings is due to poor smoothness. If the bearing surface is relatively smooth, hotness can reduce wear and friction and reduce the chance of rust.

2. Bearing over temperature

In many cases, if the temperature of the stainless steel bearing is too high during use, it is easy to cause poor operation. The bearing accuracy is relatively low, the type selection is not good, and the cooling effect is not safe. It is easy to cause the bearing over-temperature phenomenon.

3. Dust and environmental pollution

Dust and particles floating in the environment will enter the single weight of the stainless steel bearing. If the bearing is not cleaned regularly, the dust and impurities will wear the bearing and cause poor operation.

4. Power supply system problems

If the power supply is frequently switched on and off, it will cause the working voltage and current to fall out of frame, which will lead to over-temperature or poor operation due to load, which will shorten the life of the stainless steel bearing. The higher the power, the greater the exchange voltage, and the easier it will be. risk.

Decho is a professional supplier on stainless needle roller bearings, pls do not hesitate to contact us by email if you need any . [email protected]

do you know how many kinds of cages for needle bearings ?

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The structure of needle roller bearings can be roughly divided into the following types:

1 Needle roller bearings with inner ring and outer ring.

2. Needle roller bearings without inner ring.

3. Needle roller bearings without cages on inner and outer rings.

In the first two structures mentioned above, it can be with or without a cage, because the full needle roller (without cage) bearing has a low speed, but its load-bearing capacity is extremely large, so the application is still Need to retain this structural form. Needle roller bearings without an inner ring can be divided into two structures: a solid outer ring and a stamped outer ring. Due to the different structure of needle roller bearings, the shape of the cage is also different. Each cage structure has its own characteristics. Several commonly used bearing cages are described as follows:

1. “K” shaped bearing cage

“K” shaped bearing cage

Its main advantage is that the rigidity and strength are high, and the outer diameter guide or inner diameter guide can be adopted in the design according to requirements. Tube material processing is used in production, except for the window punching process, no complicated molds are required, so it is not only suitable for mass production, but also for small batch production, especially for small-sized bearings, using “K”-shaped cages. It has better manufacturability than the “M”-shaped cage. For double-row and multi-row needle roller bearings, from the analysis of the processability of the double-row or multi-row window holes of the cage, the “K” shape has better conditions than the “M” shape, so the “K” shape cage becomes the current needle roller retainer. The common structural form of the frame is due to the development of bearings. There is a trend to increase the number of rolling elements. Due to the excessive thickness of the wall of the “K”-shaped cage, such as increasing the number of window holes, it is easy to cause the distortion of the cage lintel during processing. The number of needles of the “K”-shaped cage is generally less than that of the “M”-shaped cage of the same series.

2. “M” shaped bearing cage

Its main advantage is that it can maintain a larger number of needle rollers and the lubrication conditions are also better. The cage can only be guided by the outside, which is a better cage structure for single row needle roller bearings. “M”-shaped cages can be produced with tube materials. Only in the window punching process, it is more difficult to master than “K”-shaped cages. It is suitable for mass and small batch production, and it is also one of the commonly used structures.

3. Thin-wall stamping “M”-shaped bearing cage

Not only can it keep more needle rollers, but the needle rollers have the largest length, so that the bearing can achieve the most ideal load capacity. In addition, the cage requires surface treatment to obtain better rigidity and improve wear resistance. Due to the limitation of thin wall, this kind of cage can only be applied to medium-sized bearings.

4. “I” shaped bearing cage

Needle roller bearings without inner and outer rings are one of the structures designed by our country. This kind of cage has the advantages of simple geometry, better craftsmanship, and fewer procedures. It is recommended to use 20 steel pipes to process, which can meet the requirements of not falling or clamping the roller needle after punching the window hole, and does not need to carry out the rolling printing process.

5. New “K” shaped bearing cage

It is one of the structures designed by our country. This product also has the advantage that the needle cannot be dropped or clamped after the window hole is punched. In foreign countries, this structure is only used for bearings with a solid outer ring, and the outer diameter does not require locking needle rollers. The improved domestic “K”-shaped structure has ideal manufacturability. It has been gradually developed through the summary of domestic production practices and needs further testing and improvement.

6. “O” shaped bearing cage

It is mostly used for bearings with a stamped outer ring, and the cage requires surface heat treatment to enhance rigidity.

7. “M” shaped bearing cage without ribs

This structure is stronger than the above-mentioned “O”-shaped cage and has better lubrication conditions. The cage requires surface heat treatment. This structure is also mostly used for bearings with stamped outer rings.

8. Two-half combined bearing cage

As shown in the figure above, the two-half combined cage has different structures. Firstly, the integral cage with the equally divided window holes is processed, and then the annular ribs at both ends of the window holes of the cage are cut off. When the bearing is installed, two more long needles with the same height as the cage are added. As shown in Figure b, a small opening is cut off at both ends of the cage window hole, and two roller needles of equal length are installed during installation. Figure c is a cut on a wider lintel on the cage to form a gap between the two halves of the cage without adding additional needles. Bearings with this structure cause uneven load distribution of the bearing due to the unequal division of the needle roller positions, and the lintels on both sides of the cage bear greater stress, which will cause damage to the bearing when the speed is high. The working performance of the bearing is not as good as the bearing of the above two structures.

In addition, there are structures such as “W”-shaped bearing cages and “I”-shaped bearing cages, but they are not as widely used as the above-mentioned cages.

Tianjin Decho is a professional supplier on all kinds of needle bearings. If you need to buy any needle bearings, pls send your request to [email protected]

The key points of actual operation of the disassembly method of automobile needle roller bearing

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There are generally 3 points for actual operation of the disassembly method of automobile needle roller bearing

1) The knocking method, under normal circumstances, when the bearing needle roller is removed by the knocking method, the key function of the knocking force lies in the inner ring of the bearing, and it cannot be added to the turning body of the bearing and the maintenance wall; in other words, this type of disassembly method The key lies in the selection of the top priority, and the placement of the protective layer pad should be appropriate.

2) The thermal disassembly method, the engine oil should be heated to 100 degrees Celsius in actual operation, and then the engine oil should be irrigated onto the bearing needles that are willing to be disassembled. After your bearing ring is heated and deformed, the bearing needles can come out, which is very easy to operate. .

Compared with the two disassembly methods, it is more stable and reliable to disassemble the bearing needle by pressing method. It uses a punch to push the bearing, so that it is not easy to cause damage to the equipment, and the bearing needle can maintain a stable consistency. Sex.

3) There is also a drag-out method. In this way, a professional puller must be used for disassembly. If the rocker of the puller is selected, it can be gradually pulled out.

Fully grasp the load force of all bearing needles, so that higher quality bearing products can be purchased, and then consider the requirements of the application of mechanical equipment, so the load force has become one of the key information for selecting needle roller bearings.

Generally speaking, needle roller bearings can be used to bear heavy loads; while ball bearings are used to bear light or medium level loads; bearings manufactured by nitriding steel or bainite heat treatment can bear impact and vibration loads . It is not difficult to see that for safety considerations, it is necessary to master the characteristics of bearings in industrial production.
If the load is unqualified, it will cause greater damage to the middle and late application of bearing needle rollers. It is not difficult to see that the quality of bearing needle rollers is related to the operating conditions of industrial equipment. A good bearing needle roller can make full use of its effect, make the transmission system of machinery and equipment smooth, improve efficiency, and can reasonably alleviate the friction between each component and improve the service life of machinery and equipment.

Improper assembly will cause various failure forms of the bearing, and often the matching between the inner hole of the bearing and the shaft and the improper fit between the shaft diameter and the bearing seat hole often occur.

The matching between the inner hole of the bearing and the shaft adopts the basic hole system, and the matching between the outer circle of the bearing and the bearing seat hole adopts the basic shaft system. Generally, the shaft and bearing inner race of centrifugal pumps, centrifuges, reducers, motors and centrifugal compressors that work under normal load conditions adopt j5, js5, js6, k5, k6, m6 coordination, and the bearing housing holes and bearings The outer seat ring adopts j6 and j7 coordination. Rotating races (inner races of most bearings are rotating races, outer races are not rotating races, a few bearings are the opposite), usually with interference fit, bearing needles can avoid races under load Rolling and sliding occur on the mating surface of the shaft diameter and the bearing seat hole.

But sometimes because the shaft diameter and the size of the bearing seat hole are not measured or the mating surface roughness does not meet the standard requirements, excessive interference fit is caused, and the bearing seat ring is greatly squeezed, resulting in the radial clearance of the bearing itself. Reduced, making the bearing difficult to rotate, heating, abrasion intensified or stuck, and in severe cases, it will cause the inner and outer races of the bearing to crack during installation. The non-rotating seat ring often adopts a fit with little clearance or interference. In this way, the non-rotating seat ring may produce a small creep, and the contact surface of the seat ring and the rolling element is constantly replaced, and the raceway of the seat ring wears evenly. At the same time, it can also eliminate the axial jam of the rolling elements in the bearing due to thermal elongation of the shaft. However, excessive clearance fit will cause the non-rotating race to rotate with the rolling elements, causing serious wear on the shaft (or bearing seat hole) and the inner race (or outer race), and friction will cause the bearing to heat and vibrate.

Decho is a professional supplier on needle bearings, if you have any request , pls donot hesitate to contact us by email [email protected]

The influence of molten iron superheat on the quality of malleable steel pipe fittings

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The hot metal overheats, which is the primary condition for improving the quality of malleable steel pipe casting. Research on the metallurgical properties of molten iron found that cast iron still maintains an inhomogeneous state for a long time after melting. The specific reason is not fully understood for the time being. It is generally believed that molten iron contains a variety of impurities, some of which hinder the dissolution of graphite, so that solid graphite crystals dissolve too slowly in molten iron, resulting in non-uniformity of performance and organization. High temperature and overheating can speed up the dissolution of carbon and the homogenization of molten iron. The molten iron can get a series of benefits after entering high temperature and overheating.

The primary indicator of molten iron quality is the temperature of molten iron. Regarding the influence of molten iron overheating temperature on the quality of malleable steel pipe fittings, there have been different opinions in recent decades. One view is that the higher the molten iron superheat temperature, the better, which can refine the graphite and improve the mechanical properties of the casting; the other view is that the molten iron superheat temperature has a critical temperature. When the value exceeds this value, the quality of the casting decreases with the increase of the overheating temperature.

Although the casting process temperature of malleable steel pipe parts is not high, most of them are between 1260 and 1400 degrees Celsius. But from the point of view of obtaining high-quality molten iron, it should have a higher melting temperature. High temperature smelting ensures high iron tapping temperature, Fe, Si, Mn burns less, furnace conditions are stable, chemical composition fluctuations are small, high temperature smelting, S, Q, H, N and inclusions in the molten iron will be reduced, and the charge Bad heredity will be reduced.

1) At high temperature, the activity of carbon increases, and the activity of silicon decreases. The deoxidation effect of carbon on FO, MnO, SO2 and other oxides is dominant, which promotes the reduction of oxides, thereby effectively clearing the non-metallic inclusions in the molten iron. .

2) The hydrogen and nitrogen molecules in the molten iron are easily concentrated in the CO bubbles formed by deoxidation at high temperatures, and escape from the molten iron with the bubbles, thereby effectively clearing the gas in the molten iron.

3) At high temperature, the kinematic viscosity of molten iron decreases, the mass transfer is accelerated, and it is easy to achieve homogenization in convection and electromagnetic stirring.

Only the molten iron that has undergone high-temperature heat treatment can cast excellent malleable steel pipe fittings. The molten iron is released at high temperature and low temperature casting is the prerequisite to ensure the quality of malleable steel pipe castings.

Decho is a professional supplier on malleable iron pipe fittings. Pls feel free to contact us by email whenever you have any request .  [email protected]

What are the surface inspections of casting products?

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1. Liquid penetration testing

Liquid penetration testing is used to inspect various opening defects on the surface of castings, such as surface cracks, surface pinholes and other defects that are difficult to find with the naked eye. Commonly used penetrant detection is color detection, which is to wet or spray a colored (usually red) liquid (penetrant) with high penetrating ability on the surface of the casting. The penetrant penetrates into the opening defect and quickly wipes off the surface penetrant. Then spray the easy-drying display agent (also called developer) on the surface of the casting. After the penetrant remaining in the opening defect is sucked out, the display agent is dyed, which can reflect the shape and shape of the defect. Size and distribution. It should be pointed out that the accuracy of penetrant detection decreases with the increase of the surface roughness of the tested material, that is, the lighter the surface, the better the detection effect, and the surface detection accuracy of the grinding machine is the best, and even intercrystalline cracks can be detected. In addition to color detection, fluorescent penetrant detection is also a commonly used liquid penetrant detection method. It needs to be equipped with ultraviolet light for irradiation observation, and the detection sensitivity is higher than that of color detection.

2. Eddy current testing

It is suitable for checking the defects below the surface which are generally not more than 6-7mm deep. There are two types of eddy current testing: the placement coil method and the through coil method. When the test piece is placed near a coil with alternating current, the alternating magnetic field entering the test piece can induce a current (eddy current) flowing in an eddy current direction perpendicular to the excitation magnetic field in the test piece. The eddy current will Generate a magnetic field opposite to the direction of the exciting magnetic field, so that the original magnetic field in the coil is partially reduced, which causes the change of the coil impedance. If there are defects on the surface of the casting, the electrical characteristics of the eddy current will be distorted, thereby detecting the existence of the defect. The main disadvantage of eddy current testing is that the size and shape of the detected defect cannot be displayed visually. Generally, only the surface position and depth of the defect can be determined. In addition, it is not as sensitive as penetrant detection for detecting small opening defects on the surface of the workpiece.

3. Magnetic particle testing

It is suitable for detecting surface defects and defects several millimeters deep below the surface. It requires DC (or AC) magnetization equipment and magnetic powder (or magnetic suspension) to perform detection operations. Magnetizing equipment is used to generate a magnetic field on the inner and outer surfaces of the casting, and magnetic powder or magnetic suspension is used to display defects. When a magnetic field is generated within a certain range of the casting, the defects in the magnetized area will produce a leakage magnetic field. When the magnetic powder or suspension is sprinkled, the magnetic powder is attracted, so that defects can be displayed. The defects displayed in this way are basically defects that cross the lines of magnetic force, but they cannot be displayed for long-length defects parallel to the lines of magnetic force. For this reason, the magnetization direction needs to be constantly changed during operation to ensure that various defects in unknown directions can be detected. .

4. Radiographic testing

Generally, X-rays or γ-rays are used as the radiation source, so equipment and other ancillary facilities are needed to generate radiation. When the workpiece is exposed to the radiation field, the radiation intensity of the radiation will be affected by the internal defects of the casting. The intensity of the radiation emitted through the casting varies locally with the size and nature of the defect, forming a radiographic image of the defect, which is developed and recorded by radiographic film, or real-time detection and observation through a fluorescent screen, or detection by a radiation counter.

5. Ultrasonic testing

It is used to check internal defects. It uses sound beams with high-frequency sound energy to propagate inside the casting. When it encounters internal surfaces or defects, it reflects and finds defects. The magnitude of the reflected sound energy is a function of the directivity and properties of the inner surface or defect and the acoustic impedance of this reflector. Therefore, various defects or the sound energy reflected by the inner surface can be used to detect the location, wall thickness or surface of the defect The depth of the next defect. Ultrasonic testing, as a widely used non-destructive testing method, has its main advantages in: high detection sensitivity, which can detect small cracks; and large penetration capability, which can detect thick section castings. Its main limitation lies in: it is difficult to explain the reflection waveform of the disconnected defect with complex outline size and poor directivity; for undesirable internal structure, such as grain size, structure, porosity, inclusion content or fine dispersion Precipitates, etc., also hinder the interpretation of the waveform; in addition, the standard test block should be referenced when testing.

Decho is a professional supplier on casting products , if you have any request , pls feel free to contact us by email [email protected]

What are the valve installation requirements?

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1. Before installing the valve, carefully check whether the model and specifications of the valve used are consistent with the design;

2. According to the valve model and factory manual, check whether the valve can be used under the required conditions;

3. When lifting the valve, the rope should be tied to the flange connection between the valve body and the bonnet, and not tied to the handwheel or valve stem, so as not to damage the valve stem and handwheel;

4. When installing the valve on a horizontal pipeline, the valve stem should be vertically upward, and the valve stem should not be installed downward;

5. When installing the valve, it is not allowed to use the forced pairing connection method to avoid damage due to uneven force;

6. Rising stem gate valves should not be installed in damp underground places to avoid corrosion of valve stems.

Assembly requirements

The cleaned parts must be sealed and stored for installation. The requirements for the installation process are as follows:

1. The installation workshop must be clean, or set up a temporary clean area, such as newly purchased color striped cloth or plastic film, to prevent dust from entering during the installation process.

2. Assemblers must wear clean cotton overalls, cotton caps, no leakage of hair, clean shoes on feet, plastic gloves on hands, and degreasing.

3. The assembly tools must be degreased and cleaned before assembly to ensure cleanliness.

Decho is a professional supplier on valves , If you need any , pls contact us by email [email protected]

Problems that should be paid attention to when installing grooved pipe fittings

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At present, the grooved pipe joint connection method is gradually promoted in various types of building installations. Its fast and reliable characteristics are being recognized by colleagues in the installation industry, and it is also widely used in fire protection engineering construction. However, what problems should be paid attention to when connecting rigid clamps and flexible clamps with different connection methods?

1. Install the rigid clamp on the DN≤250 pipeline according to the product manual provided by the manufacturer. Generally, satisfactory results can be obtained.

2. When connecting flexible clamps on DN≥300 pipelines, pay attention to the following installation details:

1) Quality of incoming steel pipe:

The tolerances of the outer diameter, wall thickness uniformity, and out-of-roundness of the pipe ends of the incoming steel pipe cannot exceed the standard requirements. When loading and unloading the steel pipe, it is necessary to prevent the deformation of the nozzle.

2) Measurement and visual inspection of pipe end before pressing groove:

Before the pipe end is grooved, check whether the end face of the nozzle is perpendicular to the center line of the pipe, whether the tolerance of the out-of-roundness of the nozzle exceeds the standard, and whether the burrs around the nozzle are removed and polished, such as the out-of-roundness or deformation of the nozzle , It must be removed.

3) Press groove processing:

For long steel pipe pressing grooves, support brackets must be installed, and ball bearing support points are installed on the brackets to reduce the fluctuation of pipe rotation during groove pressing. Strictly press the groove depth, which must meet the requirements of the product manufacturer’s instructions. During operation, attention should be paid to the rate at which the groove depth is gradually reached, and the mold that exceeds the service life should be replaced in time. When carrying, hoisting, loading and unloading the finished pipes, the pressure groove of the pipe mouth should be protected to avoid deformation.

4) Appearance quality of approach clamp:

Since large-diameter clamps are manufactured by ball milled cast iron sand molds, the manufacturing accuracy is affected by various factors. Therefore, the appearance should be sampled

5) Matters needing attention when installing the clamp:

The installation quality of the clamp, especially the installation quality of the flexible clamp, depends on the above-mentioned requirements: that is, the material of the pipe, the shape size, the deformation of the nozzle, the quality of the pressure groove, the quality of the clamp itself, and the size Ensure that all clamps are inserted into the groove.

6) Attention should be paid to the installation of large-caliber flexible clamps with DN≥300 and above:

Inspection of the material and appearance of the rubber sealing ring: The rubber sealing ring of each manufacturer varies according to the medium used, and its manufacturing material and formula are different, but the installation unit must ask the manufacturer for the same product quality commitment and rubber seal as its unit engineering service life The physical and mechanical performance test report of the ring should be free from damage and deformation in appearance inspection. Bubbles, impurities, cracks, and uneven defects on the rubber sealing surface are not allowed.

3 Installation of grooved pipe fittings:

a. Touch the grooves and holes by hand and observe with eyes for a week. There should be no remaining burrs, breakages, or cracks.
b. Lubricant is spread around the rubber sealing ring and then clamped on both ends of the steel pipe by hand. At this time, ensure that the tension around the rubber sealing ring is basically the same.
c. Two pieces of grooved pipe fittings, tighten the bolts symmetrically on both sides, so that the gap between each groove is basically equal. When it is close to tighten and not in close contact with the rubber seal ring, use both hands to rotate the grooved pipe fittings to make the entire pipe and the sealing ring evenly contacted. Observe that each piece of the grooved pipe fitting has entered the groove, and then tighten the bolts symmetrically and successively. . When tightening, the sealing ring is found to be wrinkled and raised, and the sealing ring should be replaced.

4. It is necessary to ensure that the convex edge of the grooved pipe fits into the groove and then tighten the bolts symmetrically on both sides.

This “knocked-in” means that the protruding embedment located on the protruding edge of the grooved pipe fitting and having the same height as the depth of the pipe groove should be flush with the concave embedding that appears after the nozzle is pressed. The flange of the finished clamp sometimes appears too thick, deformed, or even twisted too much. If it can be repaired on site, it can be repaired. If it cannot be repaired, it can only be discarded and replaced with another. This requires on-site operators to observe and inspect one by one, and basically meet the requirements before installing to avoid rework.

 

Decho is a professional supplier on grooved pipe fittings . If you need any , pls contact us by email [email protected]

Advantages and disadvantages of Dacromet bolts

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Dacromet bolt is the transliteration and abbreviation of English DACROMET. Dacromet is a new kind of surface treatment technology. Compared with the painful electroplating technology, Dacromet can be said to be a kind of “green plating”. So, what are the advantages of Dacromet bolts compared with other bolts?

Advantages

1. Although the thickness of the Dacromet film is only 4-8μm, its anti-rust effect far exceeds the traditional electro-galvanizing, hot-dip galvanizing or paint coating method, so Dacromet bolts also have excellent anti-corrosion properties. Rust effect.

2. Dacromet’s processing technology determines that Dacromet bolts will not appear hydrogen embrittlement, so Dacromet bolts are very durable.

3. Dacromet bolts are very resistant to high-temperature corrosion, and the heat-resistant temperature can be as high as 300℃. The traditional galvanizing process is far inferior to it.

4. Good adhesion and recoating performance: The coating on Dacromet bolts can produce good adhesion with the metal substrate in contact, and it has strong adhesion with other coatings. The processed parts are easy to color. The bonding force with the organic coating even exceeds that of the phosphating film.

5. Dacromet bolts will not produce gas and sewage that are good for the natural environment during the entire process of production, processing and coating coverage, and no subsequent treatment is required, which greatly reduces the treatment cost.

Disadvantages

Although Dacromet bolts have many advantages, some of its disadvantages cannot be ignored.

1. Some Dacromet bolts contain chromium ions that are harmful to the environment and human body. Chromium ions can cause very serious consequences, especially the role of hexavalent chromium ions that can cause cancer, which should be paid attention to.

2. The coating surface color of Dacromet bolts is single, only silver white and silver gray, which is not in line with today’s personalized society. Although there are other ways to add color to it, there are some troubles after all.

Decho is a professional supplier on dacromet bolts , if you need any , pls contact us by email [email protected]

Precautions for Dacromet bolt application and causes of rust

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Dacromet bolts are bolts with Dacromet plated on the bolt surface. It is a new type of surface treatment technology. Compared with the traditional electroplating process, if you only compare the anti-corrosion and oxidation functions, hot-dip galvanizing and mechanical galvanizing are better choices. However, in addition to these two points, these two surface treatment methods make it more difficult to match the bolt and the nut due to the thickening of the surface of the bolt. Therefore, considering more aspects, Dacromet bolts are a better choice.

Dacromet bolts still use a kind of “green plating” bolts. It is more environmentally friendly than ordinary galvanizing, mechanical galvanizing and hot-dip galvanizing and will not cause pollution.

Pay attention to the following items in the process of using Dacromet bolts:

1. Dacromet bolts will age rapidly when exposed to light, so the coating process should be carried out indoors.

2. If the baking temperature of Dacromet bolts is too low or too high, it will lose its anti-corrosion ability. Therefore, Dacromet bolts should be baked in a suitable temperature range.

3. The life cycle of Dacromet bolts is very short and should be used up as soon as possible.

4. Dacromet bolts have poor wear resistance, so they should be sealed with other wear-resistant coatings after the bottom coating.

Reasons for the rust of Dacromet bolts

Also pay attention to the rust of Dacromet bolts. There are four reasons for the rust of Dacromet bolts:

1. Use treated Dacromet bolts with lock washers. Due to the different corrosion potentials of the two metal materials, Dacromet bolts with lower potentials are more likely to be corroded.

2. The coating on the surface of the Dacromet bolt is not evenly covered, and the rust will start in the uncovered area.

3. Because the pretreatment did not remove the rust on the rough embryo, red rust will appear from under the coating.

4. Dacromet bolts are not resistant to acid and alkali, so the acid and alkali environment is also the cause of rust.

Decho is a professional supplier of dacromet bolts , if you need any , pls contact us by email [email protected]