FCAW에서 용접변수에 따른 용접금속 확산성수소량과 저온균열감수성 변화

Abstract

The effects of welding parameters such as contact tip-to-work distance (CTWD), voltage, and current on the weld metal diffusible hydrogen contents (HD) were investigated and rationalized by the calculation of heating time and amount of heat generated in the extension length of flux cored wire. As CTWD increased from 15 to 25mm, HD decreased from 8.46 to 5.45mL/100g deposited metal. Calculations showed that, with an increase of CTWD, the amount of heat generated increased from 46 to 92J in addition to an increase of heating time. Increase of current from 250 to 350A, however, gave little variation of HD. It showed that the amount of heat generated changed little and heating time was decreased with an increase of current. It also showed that CTWD is more influential than voltage in relatively lower heat input ranges, while voltage is more in higher input ranges.