1 Outline the rapid development of the global economy in the 20th century. At the same time, the arbitrary development of natural resources and the unrequited use of the environment have caused major problems such as global ecological destruction, waste of resources and shortages, and environmental pollution. In the face of the serious problem of dealing with a large number of failures and scrapped products, remanufacturing engineering came into being. Remanufacturing engineering is the best way to solve resource waste, environmental pollution and refurbishment of used equipment. It is a green system project in line with the national sustainable development strategy.

Since the laser has entered the field of processing as a strong, non-contact, clean heat source, it has solved many problems that cannot be processed and difficult to process by conventional methods, greatly improving production efficiency and processing quality, and providing an advanced method for remanufacturing. Effective technical means.

Laser processing technology has been hailed as "a common means of processing in the future manufacturing industry." For centuries, the field of material processing has shifted from the era of manual processing to the era of flame processing, and from the era of flame processing to the era of electrical processing. The emergence of laser processing is driving the current era of electrical processing to the era of light processing. Laser processing technology combined with remanufactured products, the laser remanufacturing engineering technology and laser remanufacturing industry are important components of the remanufacturing engineering and remanufacturing industries. Among various remanufacturing technologies, laser remanufacturing has unique technological advantages and broad development prospects.

2 Laser remanufacturing technology features 2.1 Laser remanufacturing technology characteristics Remanufacturing is a kind of recycling treatment in the stage of product maintenance and scrapping. It is the industrialization of repairing and transforming used equipment with high technology.

The remanufactured object can be either a device, a system, a facility, or a component. Laser remanufacturing is based on the loss of use value of damage, waste parts as remanufactured blanks, using laser cladding technology as the main technology to carry out batch repair and performance upgrade, the laser remanufactured products obtained in the technical performance Both the quality and the quality can reach or exceed the level of new products. Laser remanufacturing is a scale production mode that facilitates online quality control of production automation and products, helps reduce costs, reduces resource and energy consumption, reduces environmental pollution, and achieves maximum economic benefits with minimal investment.

It has the basic characteristics of high quality, high efficiency, energy saving, material saving and environmental protection.

The biggest advantage of the green laser remanufacturing project is the ability to prepare coatings superior to the properties of the base material by advanced forming techniques, such as surface strengthening treatment with metal materials, laser micro-profile cladding and other techniques to repair and strengthen the surface of the parts. To impart high temperature, corrosion resistance, wear resistance, fatigue resistance, radiation resistance, etc., the surface material thickness of this layer is from tens of micrometers to several millimeters, compared with the overall material of the fabricated parts, the thickness is small and the area is small, but However, it bears the main function of the working parts, so that the workpiece has higher wear resistance, corrosion resistance and high temperature resistance than the bulk material.

One of the important differences between laser remanufacturing technology and traditional manufacturing technology is the use of original parts as remanufactured blanks, laser remanufacturing forming technology, to restore the size, shape and performance of parts to form laser remanufactured products. It mainly includes the reuse of remanufactured old parts on new products, and the restoration, improvement and re-manufacturing of the performance, reliability and longevity of long-term used parts, so that the products or equipment are less polluted by the environment. Regain the best performance requirements with the highest resource utilization and lowest input costs.

2.2 Characteristics of laser cladding technology Laser cladding technology is one of the basic technologies of laser remanufacturing. It uses the characteristics of high power and high energy laser beam focusing energy to instantly melt the surface of the workpiece. The surface-preset or synchronously-supplied alloy powder is completely melted. After the laser beam is scanned, the alloy solidifies rapidly, and a dense cladding layer that is completely metallurgically bonded to the part substrate is obtained. Laser cladding can coat high-melting materials on the surface of low-melting materials, and the material composition is not limited by common metallurgical thermodynamic conditions. Therefore, the coating materials are widely used, usually using heat resistance, wear resistance, corrosion resistance and fatigue resistance. Good performance materials.

Compared with other traditional processing technologies, laser cladding has the following remarkable features: 2.2.1 The photo-cladding layer and the substrate are metallurgically bonded, and the bonding strength is not less than 90% of the original matrix material, so it can be used for some heavy loads. Surface strengthening and repair of parts under conditions, such as surface strengthening and repair of large rolls, large gears, large crankshafts and other parts.

2.2.2 The surface of the matrix material is micro-melted during laser processing. The micro-melting layer is only 0.050.1 mm. The heat affected zone of the substrate is extremely small, generally 0.10.2 mm.

2.2.3 During the laser processing, the temperature rise of the substrate does not exceed 80 °C, and the thermal deformation after laser processing is small. Therefore, it is suitable for strengthening or repairing some high-precision parts or parts with strict requirements for deformation, such as surface strengthening treatment of finishing rolls.

2.2.4 Laser cladding technology has good controllability and easy automatic control. It can repair complex parts of geometric shapes, such as turbine power blades.

2.2.5 There is no coarse casting structure between the cladding layer and the substrate. The cladding layer and its interface structure are dense, the crystal is fine, and there are no defects such as holes, inclusions and cracks. The metallographic structure is as shown.

2.2.6 The laser cladding composite layer consists of the gradient functional materials with the characteristics of the bottom layer, the middle layer and the surface layer. The bottom layer has the characteristics of good wettability with the matrix and high bonding strength. The middle layer has certain strength, hardness and crack resistance. Advantages; the surface layer is resistant to erosion, abrasion and corrosion, which makes the repaired equipment more secure in terms of safety and performance.

2.2.7 Laser cladding technology can repair and manufacture parts with any shape, and the thickness of the cladding layer can reach the predetermined geometric size requirements as needed.

The application and development of laser cladding technology solves the limitations of traditional surface processing such as electric welding, argon arc welding, spraying, coating, etc., which can not be overcome, the thermal deformation of the process, the coarseness of the structure, the thermal fatigue damage and the poor bonding strength. Series of technical problems. At present, this technology has been successfully applied to the remanufacturing of major mechanical equipment represented by turbo-powered mechanical equipment, and has been widely recognized by users.

3 laser remanufacturing technology engineering application status Laser remanufacturing is the emerging cutting-edge technology of remanufacturing, which develops rapidly. Since the birth of laser cladding technology, it has been used as a repair technology for many important applications. Internationally, it is used by the British PR Aero Engine Company for the repair of turbine engine blades, and the US Naval Laboratory is used to repair the ship's propeller blades. In China, laser remanufacturing technology has also made great progress in recent years. With the introduction of circular economy theory and the requirement of building a conservation-oriented society, the scope of engineering application of laser remanufacturing technology has gradually expanded. At present, there are more than 10 laser remanufacturing companies, of which Shenyang Continental Laser Technology Co., Ltd. is the largest laser remanufacturing high-tech enterprise in China. Since its establishment in 1998, Shenyang Continental Laser Technology Co., Ltd. has been committed to the development of laser cladding technology and laser remanufacturing products and its industrial application, and gradually formed an independent intellectual property system and quality technical standards system.

At present, it has successively applied to more than ten industries such as petrochemical, electric power and metallurgy, flue gas turbines, centrifugal compressors, screw compressors, ground gas turbines, TRTs, generator rotors, industrial steam turbines, reciprocating compressors, steam turbines, Ten major units such as axial flow fans and various shaft parts, key equipment such as continuous casting and rolling line, hot rolling line and high line, and hot end parts of aero-engines and large internal combustion engines, etc. Laser remanufacturing of various products has been recognized and trusted by more than 200 companies, saving users hundreds of millions of product maintenance costs and achieving significant economic and social benefits. Up to now, Shenyang Continental Laser Technology Co., Ltd. has applied for 22 patents in laser remanufacturing, including 19 invention patents, 2 authorizations, 3 utility model patents, and 3 authorizations. In this year, he applied to the National Standardization Committee to form a "Laser Remanufacturing Professional Technical Committee". At the same time, he constantly improved the existing laser remanufacturing technology standards and strived to declare national industry standards to constrain and standardize the technical behavior of the laser remanufacturing industry. Guarantee the quality of laser remanufactured products. With the development and implementation of laser remanufacturing product quality standards, laser remanufacturing technology will certainly develop at a faster rate.

4 Engineering application examples of laser remanufacturing 4.1 Typical cases of laser remanufacturing machinery and equipment 4.1.1 Flue gas turbines Gas turbines are important energy recovery equipment in the petrochemical industry catalytic cracking unit, working in high temperature, dust and corrosive environments. The frequent failure of the flue gas turbine has seriously affected the production and economic benefits of the enterprise. The damage of YLII-4000 H(Q) flue gas turbine of Sinopec Yumen Oilfield Company's refining and chemical plant is as shown in Figure 6. The top of I and II moving blades is eroded to form a corner; the root of the inlet end is rushed. The eclipse forms an erosion pit; the root of the exhaust rim is erosion-thinned, and the lock is partially eroded by about 2/3. I and II discs are exhausted on the side of the exhaust side of the rim; the end face of the intake side is eroded from the lock socket to the root (R joint); the annular erosion groove is formed; the middle of the rim is eroded to form Annular erosion groove. The main shaft diameter of the coupling end is worn and scratched; the main shaft diameter of the non-coupling end is seriously worn; the entire shaft surface has wear grooves, and there is a deep groove with a width of 7 mm and a depth of 6 mm; the flange is connected with the wheel The air seal shaft wears. After the laser remanufacturing of Shenyang Continental Laser Technology Co., Ltd.

According to statistics, about 120 sets of flue gas turbines are currently used online in China. Due to the poor operating conditions, different degrees of damage often occur. From 1999 to the end of 2005, Shenyang Continental Laser Technology Co., Ltd. laser remanufactured a variety of flue gas turbines and models as shown: Among them, laser remanufactured flue gas turbines accounted for about 80% of all operating flue gas turbines, part The flue gas turbine is remanufactured by multiple lasers.

4.1.2 Turbine steam turbine is the core equipment of thermal power plant, which is the foundation of China's power industry and reflects the level of machinery manufacturing in a country. Because it works under high temperature, high pressure and other harsh conditions, it is very easy to damage. 0 is the rivet airflow erosion damage state of the 800,000 kW steam turbine rotor blade imported from Russia by Suizhong Power Generation Co., Ltd. At that time, the Russian steam turbine manufacturer thought that it could not be repaired, and it needed to replace the new piece, the cycle was three months, and finally the Shenyang Continental laser. Technology Co., Ltd. completed the re-manufacturing of the laser with 12 days, which saved huge economic losses for the user.

Due to the special working conditions of the steam turbine, a large number of unit parts are damaged every year. The laser remanufacturing technology is used to restore and upgrade some key components of the steam turbine, such as turbine journals, final blades and partitions. It can save a lot of money and raw materials, and can also alleviate the contradiction between the supply and demand of steam turbines in China.

4.1.3 Screw Compressor The screw compressor is a volumetric gas compression machine with a working volume for rotary motion. Widely used in mining, chemical, power, metallurgy, construction, machinery, refrigeration and other industrial sectors. Statistics show that screw compressor sales account for more than 80% of all volumetric compressor sales, and 50% of all running positive displacement compressors are screw compressors. In the future, the market share of screw compressors will continue to expand.

The screw compressor rotor has high precision level, complicated production process, high production cost and long cycle. The process conditions of the rotor are harsh, the working pressure is from normal pressure to several atmospheres, the air is filtered, and it can be used continuously for more than 10 years. However, in operation, the working environment of the screw rotor is poor, and it is damaged by impurities, overload or accidental factors in the gas, which seriously affects the service life of the gas compressor. If it is remanufactured, it is unbearable for the user from the construction period to the cost. The birth and development of laser remanufacturing technology solves the problem that the traditional method can not restore and improve the performance of the damaged screw compressor, and brings new technical means for the remanufacturing of the screw compressor. The reason for the failure is the axial displacement of the rotor during operation, causing the rotor working surface to wear.

Laser remanufacturing engineering is a multidisciplinary interdisciplinary discipline of equipment engineering, materials engineering, mechanical engineering, maintenance engineering, surface engineering, and environmental protection. The quality control of laser remanufacturing products is the core of laser remanufacturing engineering. Laser profiling technology and surface technology are the key technologies of laser remanufacturing engineering, and the application of these technologies is inseparable from product failure analysis, detection and diagnosis. Life assessment, quality control and many other disciplines. Laser remanufacturing machinery involves a variety of technologies, the main process flow is shown.

5 Conclusions (1) Laser remanufacturing engineering is an effective method and way to solve resource waste and environmental pollution, and is a green system project in line with the national sustainable development strategy.

(2) Laser remanufacturing is a new frontier technology for remanufacturing. It has the basic characteristics of high quality, high efficiency, energy saving, material saving and environmental protection. Laser remanufacturing products can reach or exceed the level of new products in terms of technical performance and quality.

(3) Laser remanufacturing technology has developed rapidly in China and is widely used in petrochemical, electric power, metallurgy, railway and other industries, providing new technical means for the repair and transformation of many damaged or scrapped major equipment and imported equipment in China.

(4) Carrying out major equipment laser remanufacturing, developing fast, efficient and precise laser remanufacturing technology not only has broad market demand, but also has significant economic and social benefits.

Baking Sheet

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