Earlier, before 50-70 years, any running part in an industry failed it was replaced immediately by new spare one and then failed part was scraped. This was against law of conservation of enregy-resources. Gradually a need aroused, to encounter this problem, which gave birth to the new branch in Welding which is Maintenance and Repair Welding. Concept developed to promote this branch was stated as “Why to Replace when you can Repair!!!
As we all know, in industry each and every part under goes wear because of surrounding conditions. To encounter such wear of parent material of component, wear mechanism was studied and with respect to its severity proper surface treatment to the parent material was given. It is carried out either before or after the component is subjected to its service. Many new technologies and alloys were developed pertaining to exposed environment of the component. Wear particularly Abrasion, Erosion, Gouging (Impact abrasion) are experienced majorly in cement industry, mining and construction, power industry, sugar industry, Railways, Steel industry etc.
Technologies include to enhance life of the component are Hardface Welding, Brazing, Thermal Spraying, Wear lining, Hardbanding, Arc spraying (Aluminum/S.S.) etc. Alloys developed for abrasion and erosion resistance were having high volume fraction of metal carbides in their microstructure and for high temperature applications complex carbides of refractory elements were formed in microstructure. Also, Work Hardening type of alloys were developed which were extensively used as Impact- Abrasion Resistance materials.
Few examples of components which are repaired extensively time to time are Grizzly Bar, Sinter star, Crusher Blades, Impellers, Fan Blades, Gears, Pinion, Pump body, Guide Vanes, Coal burners guide vanes, etc
Keep reading, Happy welding…