Repair of failed plunger by supersonic arc spraying of wear-resistant and high-temperature alloy coating

       The aluminum-zinc coating has better corrosion resistance and better protection to the substrate. The self-corrosion potential of aluminum-zinc coating is lower than that of carbon steel, so it can play a cathodic protection role of sacrificial anode. Even if the coating is partially damaged, it can also play a better protective role. In addition, arc spraying nickel-chromium and iron Chromium-aluminum coatings are also effective against high-temperature corrosion. The quality of supersonic arc spraying is better than that of ordinary arc spraying, the coating is dense and uniform, and the porosity is low.

    Corrosion of boiler water walls is a major economic and technical problem, and the losses caused by the replacement of water walls as well as the cost of production downtime are high. During the operation of the furnace water cooling tube wall, due to the high working temperature and high sulfur content, Fe element reacts with S element in high temperature air to form FeS. Slag and coal ash have an erosive effect on the pipe wall, which aggravates the corrosion of the pipe wall. The coating prepared by the supersonic arc spraying process is uniform and dense, with low surface roughness and strong bonding force. The quality of the coating is greatly improved. With the development of petrochemical industry, due to various corrosion reasons, the possibility of accidents in chemical storage tanks and pipelines has greatly increased, which not only caused huge economic losses and environmental pollution, but also caused a large number of casualties. Corrosion protection and maintenance of chemical products has always been a major problem that plagues the development of the petrochemical industry. The lightly polluted oil tank of the supersonic arc fuel injection plant has greatly improved the service life of the recovered oil tank, from the original 3 years to 8 years.



Anti-wear coating

    Using thermal spraying method to prepare wear-resistant or wear-resistant coating on the surface of mechanical parts to repair or strengthen parts is an important aspect of the application of thermal spraying technology. The coating prepared by the supersonic spraying method has high bonding strength and low porosity. After turning and grinding, it can well meet the requirements of precision and surface finish. The application in the field has created good technical and economic benefits. Due to the increasingly harsh working environment of construction machinery, the plunger in the hydraulic system often suffers from adhesive wear and abrasive wear, resulting in overload of the hydraulic system and pollution of hydraulic oil, making the hydraulic system unable to work normally. The failed plunger is repaired with supersonic arc spraying wear-resistant and high-temperature alloy coating. The repaired plunger can not only be restored to use, but also its service life has been extended from the original 15 to 20 days to an average of 45 days, so that the service life of the plunger can be increased. It has more than doubled, and has better economic benefits.

Universal ultrasonic flame spray technology.

    Using kerosene as fuel, oxygen and compressed air as combustion accelerant, the control system sends kerosene and oxygen (compressed air, or a mixture of oxygen and compressed air) to the spray gun at a certain flow rate, and then atomized and mixed by high-performance atomizing nozzles. It is injected into the combustion chamber of the spray gun, and the mixture is ignited and burned by the spark plug to form high temperature and high pressure gas, which is made to reach supersonic speed through the Laval nozzle. The sprayed powder is fed into the supersonic jet from the low-pressure area of the nozzle. Under the heating and acceleration of the spray gun, the powder is sprayed by the sprayer, and the powder is sprayed on the surface of the workpiece at a high speed to form a coating. The key of the smoke spray system is to adjust the speed and temperature of the smoke flame. By adjusting the flow ratio of kerosene and oxidant (mixed gas of oxygen and compressed air) entering the spray gun, the heating and acceleration of the spray powder are controlled to meet the requirements of spray materials. , the preparation of high-performance metal coatings, alloy coatings and oxide ceramic coatings.



Application of Universal Ultrasonic Flame Spraying Technology

    Using oxygen kerosene supersonic flame spraying technology, using oxygen kerosene supersonic flame spraying technology, using gas kerosene supersonic flame spraying technology, using gas kerosene supersonic flame spraying technology, the flue gas flow rate and temperature are continuously adjustable within a large range, It can meet the spraying requirements of various spraying materials, and the coating has high bonding strength and low porosity. It has a wide range of application prospects in electric power, mining metallurgy, petrochemical, tanning and other industries.

In the iron and steel industry, there are many rolls and conveying rolls that need wear-resistant strengthening or repair, among which, the bottom roll of the continuous annealing furnace for cold-rolled strip steel is particularly important. Nodules on the surface of the rollers are actually adhesive wear. In order to reduce the loss of steel strip nodules to production, thermal spraying technology is widely used. It is often used for spraying NiCr-Cr3C2 coating on the surface of the roll, which has high temperature oxidation resistance, thermal shock resistance and wear resistance, which can make the furnace bottom bar work continuously for a long time at high temperature, and is resistant to periodic thermal shock. When the low-roll rolling temperature of the furnace is above 900°C, carbon black alloy is generally sprayed. Ultrasonic flame spraying technology has unique advantages in spraying carbide ceramics, and the metallurgical industry has a huge demand for carbide cermet coatings, making it widely used.