Application of Thermal Spray Technology to Repair Flew Pump Axle

â–¡ â–¡ Xu Jiafu Fujian Lianshi Cement Co., Ltd., Fujian Shunchang Ionization Arc Blast Wave and other heat sources will be to spray a variety of metal or non-metallic materials to the molten or semi-molten state, spray to the prepared part surface, forming a layer Solid wear-resistant spray welding overlay, which doubles the life of the equipment. This article describes the spraying process of the flour screw shaft of the Fule pump.

1 Introduction General mechanical components are affected by the outside world. They are often the initial fit of the components. On the other hand, they change the original geometry and shape of the components. The result is that the machine performance is stable and the service life is very stable. Great influence. If you completely replace the equipment or replace worn parts, you will waste a lot of metal materials and increase maintenance costs. In many cases, it is only necessary to restore the surface performance of the components and the requirements for the use of the equipment can be met again, thereby greatly reducing the cost.

Thermal spraying technology is a new technology for modernizing and protecting metal surfaces. It uses oxygen acetylene flame arc plasma arc, blast wave and other heat sources to heat all kinds of metal or non-metal materials to be sprayed to the molten or semi-molten state, and spray it onto the prepared part surface to form a layer of solid wear-resistant coating. Weld overlays to meet the requirements of various parts of the work environment, thereby multiplying the life of the equipment.

2 Damage to the screw shaft of the Fule pump Due to its advantages of compact structure, high transmission efficiency and low maintenance workload, the Fule pump, that is, the spiral pump, is widely used in the cement industry. Our company is a new dry process cement plant that introduced foreign advanced technology and equipment in the early 1980s. A total of 5 M-Fool pumps manufactured by American Fule Company were installed in the entire production process line. ,Respectively used for raw material pulverized coal cement and other system material transport, after many years of production and operation, in January 1999, the Taiwan elbow type 200 Fule pump used for kiln pulverized coal transportation abnormally approached the bearing of the drive end pulley There is a large continuous vibration. This abnormal vibration continued for more than half a month. It happened to be the maintenance of the kiln. After dismantling and inspection, it was found that the original position of the Fule Pump's screw shaft and the bearing bush matched. The original fitting size requirement of the first stage and the bearing sleeve is thorn, and the actually measured size abc at the rear part of the wear is respectively, but the wear causes the change of the original fitting property to increase the gap, which is the root cause of long-term continuous vibration.

1 Screw shaft 2 Adapter sleeve 3 End cover 4 Bearing seat 5 Bearing sleeve 6 Skeleton oil seal 7 Bearing 8 Oil nipple 9 Round nut and lock washer Sliding key Flat key Slewing screw shaft Stage 1 Pulley position Bearing position Melon seal 1 Flew pump screw shaft drive end Assembly intention Worm shaft wear after the measured size 3 Repair process Because the drive end of the Fule pump screw shaft is used as a thermal expansion end during assembly, that is, with the increase in temperature during the actual operation of the equipment , Allowing the segment and its matching bearing sleeve can have a slight relative free sliding, so the original design of the structure of 15 is more special, the shaft body of the base body layer material is carbon steel, in order to reduce the thermal expansion of the screw shaft Relative to the frictional resistance between the bearing sleeve, a friction-reducing material with a thickness of about 51 is embedded in the outer layer of the 15th-axis body. The structure and function of the brass is similar to that of a babbitt alloy lining. This special structure makes it Wear complex, this is mainly due to the thin outer layer of brass and the entire cylindrical surface wear, the use of surfacing can easily lead to local heat and produce thermal stress, resulting in brass deformation and cracking, and even melt through the entire Broken brass layer Its strength with the original surface of the carbon steel shaft, resulting in scrapping the screw shaft, it is not appropriate to use surfacing to repair the thermal spray this repair technology, the specific operating process is as follows, in order to eliminate the spiral shaft lamp section caused by uneven wear Large shape error to ensure the quality of spraying, the screw shaft is installed on the lathe to find the positive, and the car goes to the wear surface of the screw shaft 15 until a new metallic luster is exposed. After the process is completed, the outer diameter dimension of the crucible section is pan for reinforcing the brass. The bonding strength between the sprayed layer and the brass layer of the screw shaft segment base, and the fine thread is machined on 086.5, the thread parameter is pitch 1 = 0, and the thread height is cleaned with gasoline or acetone to remove residual oil impurities, etc. , And then evenly preheated with oxyacetylene flame, screw shaft enthalpy section, from time to time using a thermometer to measure the temperature of the shaft body, the general temperature control at 140160 弋, the workpiece rotation speed of 40 5,1! Pay attention to lightly loosening the lathe tip bearing during warm-up.

(4) Hot sandblasting The surface of the screw shaft to be coated is subjected to sandblasting to remove the oxide film and burrs on the thread surface. The blasting force is 0.5 or so.

Apply guns to the 15 thread surface. Firstly, select the medium-sized 3,1 aluminum-clad nickel wire to make a base coat with a thickness of 0.2 and then spray it with 02.3 brass wire. The oxygen pressure is 0.350.4 for spraying, the acetylene pressure is 0.070.08, compressed air. The pressure is 0.4 0.5MPa, the distance between the nozzle and the spiral axis is 180200mm, and the spiral axis speed is 10201.

In order to protect the adjacent 1 melon two-section axial surface from being damaged during spraying, a thick galvanized sheet of heat-insulating material 1 is preliminarily used to wrap it; at the same time, in order to prevent overheating oxidation and to avoid changes in the shaft body material, during spraying To ensure that the screw shaft body temperature can not be too high under the control of 200 or less, taking into account the amount of cutting allowance after the end of the outer diameter size should be. After spraying, the screw shaft should be kept stuck on the lathe and air-cooled to room temperature, and then it should be cut and processed several times. The tool must be sharp, and the cutting amount per cutting is controlled between 0.150.20 and not too much. The spiral axis speed is controlled at 203. At the end of the finishing line, due to the small feed rate, the line speed can be increased to improve the machining finish. The spiral shaft section can reach the original design requirements. 087h6.4 Advantages of thermal spraying 1 Brass spray coating With the characteristics of high hardness and high wear resistance, the sprayed layer has a porosity of 510, and there are tiny pits on the axial surface after processing. However, this does not affect the performance of the sprayed layer. On the contrary, it also has oil storage properties and reduces the relative sliding friction.

Save money and increase economic efficiency. If the import of the same root screw shaft takes about 60,000 yuan, and the cycle at least a few months; and the total cost of thermal spray repair is only 2,000 yuan, and the entire maintenance process does not exceed 1 day, which avoids the lack of imported parts and The resulting loss of production.

Therefore, the metal structure of the base body will not be changed, and the strength of the component will not be reduced or deformed.

And the electric 5!1 key is only 0.010.5 dozens, so the thermal spray technology can repair the wear of the parts much larger. Thermal spraying can be applied to a wide range of materials and is not limited by the weldability. It can be various metals such as high and low carbon steel, non-aluminum-free aluminum, copper and zinc, various alloy powders, and non-metallic materials, such as plastics and ceramics.

The editor Shen Ying received the original motor 2.2 of the vertical double-layer grid wheel feeder. Due to the high cement temperature of the warehouse and the frequent start-up of the motor, the motor has serious heat and will be burned in less than a year. After switching to a domestic 3kW motor and installing an axial fan on the side of the feeder, the temperature of the motor was significantly reduced and the operation was normal. The contactor controlling the charging motor is frequently worn and worn, and the contacts will be seriously worn after the year. The domestically produced parts may not be replaced due to the difference in the operating power supply or the installation method and the imported parts. We will install the domestic contactor contacts in the original imports. Contactors, the use of good results.

Compared with imported accessories, domestic accessories have great price advantages, and their performances vary, and the use of some accessories is listed in recent years. Through the localization of imported equipment accessories on the 6RS cement Packaging production line, not only the normal operation of the equipment is ensured, but also Reduced maintenance costs and accumulated savings.

Edit Li Yu

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