Innovative surface welding with micro-jet cooling

Purpose: of that paper was analysing main surfacing welding process with parameters of micro-jet cooling. The main reason of it was investigate possibilities of getting varied amount of martensite and bainite in surface weld of machine shafts. For getting various amount of martensite and bainite in this method it is necessary to determine the main parameters of the process such as. number of jets, diameter of stream of the micro-jet injector, type of micro-jet gases, micro-jet gas pesure. Design/methodology/approach: During research with varied micro-jet parameters the chemical analysis, micrograph tests and hardness test of the metal weld were carried out. Findings: There were gettable varied amount of martensite and bainite in weld surface metal in terms of micro-jet cooling parameters (numbers of jet, gas pressure). Possibilities of steering the structure (varied amount of martensite and bainite in this case) using micro-jet technology must be treated as an innovate way for MIG/MAG welding. Research limitations/implications: That research was made for MIG/MAG method (according to PN-EN ISO 4063:2009) only. Another method of welding in this article was not tested. Other methods (for eg. TIG) have not been tested, but it is suspected that similar phenomena are taking place. Practical implications: Micro-jet cooling it is way to get various amount of martensite and bainite in surface weld than the usual methods of welding. It is very important because it could be used to steering of weld joint structure and mechanical properties (for example hardfacing or wearfacing). Originality/value: In this research new method of cooling weld joint during welding was used. At the present time use of micro-jet cooling while MIG is in the testing phase and requires an accurate diagnosis.This method is very promising and capable of industrial application, mainly due to the significant improvement of weld quality and reduces costs in welding regeneration.