What are the methods for on site repair of large shaft wear

The problem of journal wear occurs from time to time in the management and maintenance of equipment in industrial enterprises. However, with the continuous improvement of the degree of automation and continuity of enterprise equipment, how to quickly and effectively solve problems and reduce maintenance costs, and ensure the safe and continuous production of enterprises is an important embodiment of the management ability of equipment managers in the new era. 1. Traditional methods of shaft wear repair 1. Playing "pitting" Advantages:

Low cost;Fast maintenance Disadvantages: low contact surface;Limitations;Short service life;Hidden danger 2, machining after repair welding Advantages: low maintenance costs Disadvantages:

Cannot be repaired repeatedly;Prone to broken shafts cause major accidents;The hidden danger is large, the comprehensive cost is high 3, the inlay Advantage: low cost Disadvantage: low contact surface;Short service life;Equipment beating big 4, brush plating, spraying advantages:

Low thermal stress, relatively little damage to the material Disadvantages: There is a limit on the wear size;Cannot be repaired on-site;Easy delamination;The cost is high 5, plug copper skin advantage: low cost;Fast maintenance Disadvantages:

Low contact surface;Short service life;The hidden danger is big.

2. The most cutting-edge shaft wear repair technology imported from the United States is the application field of high-thixotropic nano-metal polymer materials: the protection of pumps, water turbines, tanks, condensers, etc.;Wear repair of various bearing positions, bearing chambers (seats), keyways, threads, etc.;Casting defects, cracks, transformer oil leakage. The high-thixotropic nano-metal-based polymer composite material imported from the United States is a high-performance epoxy two-component composite material reinforced by carbon nanotubes and nano-inorganic materials.

The biggest advantage of this material is that special nano-inorganic materials are bonded with the oxygen of epoxy ring molecules to improve the bond between molecules, thereby greatly improving the comprehensive properties of the material, and can be well adhered to various metals, concrete, glass, plastics, rubber and other materials. It has good resistance to high temperature and chemical corrosion. At the same time, good machinability and wear resistance can serve the wear regeneration of metal parts.

Due to the wear and tear of the size of the sintering trolley, the sintering machine of the iron and steel enterprise stops due to the difference in running position, and the enterprise adopts the reversing behavior to resume the operation of the equipment, which eventually causes the shaft and the expansion sleeve to wear out and stop. The wear data related to the journal are as follows: 132 Sintering machine, gear drive shaft wear, journal:

380mm, matching method: use 3 sets of Z2 expansion sleeve, shaft diameter wear width: 400mm, due to the relative movement of the expansion sleeve and the shaft caused by wear, wear depth:

1-6mm.

2211F metal repair material is recommended for shaft wear on-site repair.

There are many ways to repair the wear of the bearing chamber, and it is recommended to use polymer composite materials.

keywords: Pump casing crack repair, stainless steel crack repair, weld crack repair, engine housing crack repair, shaft wear repair, keyway repair, cold welding without cracking, mold repair, crack porosity welding, welding without deformation.

Pump casing crack repair: pump casing, compressor casing, tank container, hydraulic cylinder, etc. due to casting defects, the running pump casing is more prone to leakage and cracking in vibration and temperature difference changes, and the traditional welding technology due to the unavoidable thermal stress and the selection of process, welding often causes secondary cracking damage, resulting in the strange phenomenon of the leakage point being bigger and bigger. For the cracked parts, it can be repaired by cold welding at room temperature, and after the repair is completed, it can be put into use directly, which will not cause stress changes to the surrounding area, and the repair strength is high, and the cracks can be repaired.

Shaft wear repair: The fatigue damage in the high-speed operation of the transmission shaft can be repaired by cold welding and wear-resistant, mainly including the repair of the bearing position of the roller press, the wear repair of the reducer shaft, the repair of the keyway rolling key, and the repair of the bearing position of the motor.

Traditional technologies such as repair welding machine processing, brush plating, thermal spraying, laser cladding, polymer composite material repair, etc., in order to have good maintenance effect, short time, and simple operation, it is recommended to use polymer composite materials for on-site repair.

At present, the common methods for repairing shaft wear in China are:

Bushing, surfacing welding, brush plating, thermal spraying, laser cladding, etc., these are several traditional repair methods.

Brush plating repair is the most convenient and high-wear repair method for low wear.

If you are particularly concerned about efficiency, you can use thermal spraying and laser cladding, and if you are concerned about the effect, you can try cold welding.

Compared with other repair welding methods, the repair speed of cold welding will be a little slower, but in the welding repair process of cold welding automatic repair, the repair temperature can be controlled below 70, and the overall metallographic structure is basically unchanged.

Example: Shaft repair case of lathe retrofit automation system.

There are traces of electricity everywhere in our lives now. Then you probably also know that electricity converts other forms of energy into kinetic energy through generators, and the common types of generators are wind turbines, hydroelectric generators, diesel generators, and so on. Although the types of generators are different, the basic composition and working principle are the same, all of which are based on the laws of electromagnetic induction and electromagnetic force, so that the rotor can rotate in the stator and do the movement of cutting magnetic field lines, so as to generate an induced electric potential, which is drawn out through the terminal and connected to the circuit, which generates a current.

Because the shaft is in the process of long-term operation, the speed is high, and the torque is large, and the transmission shaft wear problem will inevitably occur.

The common repair methods for the wear of the generator shaft are as follows:

1. Surfacing welding: a layer of wear-resistant, corrosion-resistant, heat-resistant and other metal layer welding processes is carried out on the surface or edge of the workpiece. The most common problems encountered in surfacing welding are cracking, thermal stress concentration, easy to cause deformation of the shaft, and generally need machining to achieve the required size.

2. Brush plating: Brush plating requires high surface pretreatment of the workpiece, the bonding strength is slightly lower than that of metallurgical bonding, and the coating layer is shallow, with large residual stress and easy to fall off.

3. Spraying process: It refers to heating and melting the coating material and spraying it onto the surface of the workpiece at a high speed to form a coating. However, the strength of the coating itself is low, and it cannot reach the strength of the metal itself, and the spray coating will produce certain pores, which will cause problems such as sagging, bubbles, and unevenness.

4. Laser cladding: Laser surfacing is to achieve heat input control by high-energy beam surfacing welding. The construction period is long and high, and because of the combination of electric fusion pools, there is a large internal stress, which is easy to produce deformation and cracks.

5. Soray carbon nanopolymer material: This is a new type of high-performance two-component polymer material, which is a "cold welding" process, which will not produce thermal stress during the repair process, and has good temperature resistance, chemical corrosion resistance, wear resistance and compression resistance. And the strength and hardness of the material are not only comparable to metal, but also have the concession and ductility that metal does not have, which can make the matching area of the contact surface reach 100%, and cooperate with the special repair process to ensure the size of the repair part and the matching part to the greatest extent to achieve the purpose of repair.

In the case of timely inspection and maintenance, the service life can be comparable to that of new parts.

Soray on-site repair ** motor shaft case show:

Hydro generator set: model SF160-14-950, rated power 160KW, rated speed 428R min, Feiyi speed 1087R min, shaft diameter 120mm, width 58mm, wear diameter, motor manufacturer provides temperature 70-80.

It is recommended to use Fushi Blue 2211F metal repair material to repair, this technology has solved many transmission parts wear problems, such as motors, fans, crushers, pumps, reducers and other equipment bearing positions, bearing chambers and other transmission parts of the wear.

To repair, shaft damage is a more common fault in the production activities of the enterprise, such as not timely repair not only leads to the damage or scrapping of related components, serious cases will lead to unplanned shutdown, the economic income and continuous production of the enterprise has an adverse impact.

If you think you're worn, I think you can go and replace it, or fix it, and see how to do it?

What to do with the wear and tear of the shaft, it turns out that the master repairs it like this, and it is too good to make it in China.

In view of the uneven wear of the shaft diameter, combined with the fact that there is no wear at both ends of the keyway, the keyway is adjusted to the uppermost end, and the aperture of the hydraulic coupler is directly repaired by using the non-worn part as the positioning surface.

Brief description of the repair steps:

1. Carry out all preparations before assembly, including the determination of the fit between the key and the keyway, the determination of the matching size of the journal and the preparation of installation tools (hydraulic equipment and impact tools, etc.);

2. The grease of the wear part of the shaft end is removed by the oxy-acetylene flame for grilling, the original color of the metal is polished with an angle grinder and an abrasive cloth, and cleaned with anhydrous ethanol;

3. Mix an appropriate amount of Fushilan 2211F metal repair material, evenly apply it to the surface of the journal, ensure that the worn parts are filled and repaired, and install the fluid coupling with Fushilan 803 release agent on the shaft hole in place.

Cold welding technology is the best, both surface bonding technology, the use of bonding means to repair the equipment, not only to avoid the deformation and cracks of the equipment caused by surfacing welding and thermal spraying, and there is no size and thickness limit of electroplating and brush plating, is a fast, effective and inexpensive modern maintenance means.

The inner ring of the bearing or the inner bore of the gear and the shaft surface are due to radial runout and stress concentration in the coordinated operation; At the same time, due to the high strength and hardness of the metal material, the metal parts are subjected to vibration impact and other composite forces during the operation of the parts, resulting in the "hard-to-hard" relationship of the metal parts, because the metal has no "concession", with the extension of time, part of the impact deformation becomes permanent deformation, the recovery stress decreases, and the gap between the parts is generated, resulting in the wear of the parts with relatively low hardness.

I think the main factor for bearing position wear:

1: Because the bearing installation does not meet the requirements of preload, the inner ring rotates relative to the shaft head, causing serious wear of the shaft journal; Sometimes the mounting tightness is too large, and the inner ring of the bearing bursts due to insufficient space for thermal expansion during the operation of the bearing.

2: the bearing seat and the bearing outer ring are not properly matched, when the tightness is too large, due to the different materials of the two, the expansion coefficient is different, the bearing seat is mostly cast iron or cast steel, the inner and outer rings of the bearing are high-carbon chromium steel, at a certain temperature, from the transition fit to interference fit, when the interference exceeds a certain range, it will cause the outer ring to burst; When the clearance is too large, the outer ring of the bearing rotates relative to the bearing housing, causing the bearing chamber to wear.

3: After analysis, for the equipment with large load and high speed, if the interference between the bearing and the shaft is insufficient (the preload does not meet the requirements), the creep sliding phenomenon in the circumferential direction will occur between the inner ring and the bearing due to the rotation of the inner ring under load, so that the wear degree of the mating surface will gradually increase, and the shaft and shell will be damaged.

Cold welding technology is mainly designed to make up for the deficiencies and defects of metallic and non-metallic materials. Because the material is a "variable" relationship, when the external force impacts the material, the material will relatively retreat to absorb the external force; At the same time, due to the interference fit of the hot-mounted bearing, the shrinkage force of the inner ring of the bearing and the tension of the high elasticity of the material work together with the mating surface, so that the parts always maintain a tight fit.

Please log in. In the equipment forum, there is a post detailing the "principles and applications of cold welding technology", and there are many industrial application cases in other sections.