Laser manufacturing technology opens up new ways to repair and rebuild equipment and parts

First, power equipment repair and transformation

1. In metallurgy, petroleum, chemical industry, electric power, railroad, ships, mining, aviation and other pillar industries of the national economy using a large number of turbine rotating equipment, such as: turbine, centrifugal compressor, axial fan, screw compressor, blast furnace turbine power generation TRT, flue gas turbine, generator, reciprocating compressor, aircraft engine, ground combustion engine, hydraulic turbine, oxygen generator, water pump, diesel engine, industrial turbine, speed increaser, etc. Especially since the late 70s, the introduction of a large number of imported turbine rotating equipment, after a long period of service under various conditions, due to corrosion, wear and fatigue and other factors, all equipment are in use damage failure, some are in the scrap or will be scrapped state. And conventional technology and process methods can not, and dare not move and these key, valuable equipment, a slight error will cause equipment failure and damage, which is potentially huge output and economic losses.

2. In the iron and steel metallurgy industry, the rotating equipment is the carrier to provide energy and power. Ultra-high-speed laser cladding technology meets the requirements for specific properties of material surfaces while saving a large amount of precious elements. Steel enterprises have various specifications of imported and domestic axial compressors, single-stage and multi-stage centrifugal blowers, induced draft fans, dust fans, H-type oxygen presses, nitrogen presses, screw compressors, various types of turbines in captive power plants, single-stage and double-stage turbine power generation TRT units used for blast furnace energy recovery, various power generation and electric motors, large pumps and other turbine power equipment. Remanufacturing engineering technology provides comprehensive technology for these major key equipment with safety, reliability, quality assurance and stable performance enhancement. Laser cladding profiling technology and laser rapid forming technology in these key equipment and parts repair and reuse applications, and remanufacturing engineering technology has been developed, but also for the steel industry enterprises to save a lot of maintenance costs, creating a considerable economic benefits.

Second, the high load, high speed, high precision, high alloy parts repair and strengthening

Steel enterprises, a variety of hot rolling, cold rolling lines, galvanizing lines and other production processes use a large number of high load, high speed, high precision, high alloy load-bearing equipment, its parts in service under the production conditions, corrosion, wear and fatigue damage or failure and scrap. And a large number of these equipment parts in the steel production formed a large production consumption, occupying a very large production costs and waste of resources. According to preliminary estimates, the national steel industry each year only a variety of rolling steel production line on the consumption of important parts amounted to 10 billion yuan. The traditional approach is mainly to replace these equipment parts, even because the parts can not use scrapped or replace the whole machine, must reserve a large number of spare parts, taking up a huge amount of money and resources. At the same time, the damage failure and scrap parts or the whole machine basically as scrap processing, so the chain of superposition caused by the waste of resources and funds is very alarming.

Laser cladding technology, laser rapid forming manufacturing technology, laser nano-alloying and surface strengthening technology and other high-tech technology, the effective application of such equipment and parts to open up a new way to repair and recycle. Not only can make the failure or scrap equipment and parts "back to life", but also can make the new product to extend the service life, and can even achieve the effect of multiple life cycles. For example: in cold, hot rolling steel production lines used in a variety of drive shaft, fork head, intermediate shaft, drive gear, universal joint, flat head set, roll shaft, flying shear, roll end sleeve, winder spring seat box, reducer gear shaft and shell, and so on a large number of easy to wear and fatigue parts, after laser profiling technology and rapid forming technology repair, the use of performance to restore the original technical indicators of the new parts. Moreover, most of them can improve their service life cycle again. There are, can be repaired several times, to achieve the effect of multiple life cycles.

Various rolls, conveyor rolls, support rolls, vertical rolls, guide rolls, sinker rolls and other roll-type parts on the rolling line are made of different materials such as various forged alloy steel, cast alloy steel, alloy cast iron, ductile iron, etc. All kinds of rolls are used in high temperature, high variable load, hot and cold alternation, corrosion, wear and fatigue working conditions. According to preliminary statistics, the annual consumption of various rolls in national steel enterprises is about 8-10 billion yuan. The use of laser nano-ceramic alloying and laser composite strengthening technology for surface strengthening treatment improves the surface strength, hardness, wear resistance, thermal stability and red hardness and corrosion resistance, fatigue resistance and other performance indicators, effectively improving the rolls of steel throughput. By the application of many steel enterprises, generally make rolls and other kinds of roll use cycle can be increased by 50% to several times. Laser rapid forming technology and remanufacturing engineering technology can create very considerable economic benefits and far-reaching social benefits.

Laser cladding equipment refers to a different way to add material on the surface of the substrate to be placed on the selected coating material by laser irradiation to make it and the substrate surface a thin layer of simultaneous melting, and rapid solidification to form a very low dilution, and the substrate into a metallurgical combination of surface coatings, significantly improve the wear resistance, corrosion resistance, heat resistance, oxidation and electrical properties of the grass-roots surface process, so as to achieve the purpose of surface modification or repair. It not only meets the requirements for specific properties of the material surface, but also saves a large amount of precious elements.

In conventional laser cladding process, the laser energy is mainly used to melt the base material to form a molten pool, and the powder is injected into the molten pool and then melted and solidified to form a protective coating.

Ultra-high speed laser coating technology essentially changes the melting position of the powder, so that the powder intersects with the laser above the workpiece and melts, and is then uniformly coated on the workpiece surface. The coating rate can be as high as 20-200 m/min. Due to the low heat input, heat sensitive materials, thin wall and small size components can be coated by this technology, and it can be used for new material combinations, such as aluminum-based materials, titanium-based materials or cast iron materials. Because the surface quality of the coating is significantly higher than that of ordinary laser cladding, it requires only simple grinding or polishing for application, thus reducing material waste and subsequent processing.