Welding of High Manganese Austenitic Cast Steels Using Stainless Steel Covered Electrode

In this study, the characterization of production welds for high manganese steel castings exposed to little or no wear and moderate stresses, using the ER 307 stainless steel covered electrode, was investigated. The macro- and microstructural examinations were performed by means of stereo microscopy, optical microscopy, scanning electron microscopy and energy-dispersive spectrometry (EDS) to differentiate weld metal, partially melted zone (PMZ), heat-affected zone (HAZ), and base material (BM). Transverse micro-hardness test, Charpy impact tests and ultimate tensile tests were performed to evaluate the mechanical properties of the joints. The chemical analysis and elemental mapping were utilized to analyze the joint cross section in percentage weight with both optical emission spectrometer and X-ray spectrometer. The results indicated that the reduction in dilution from root to face regions led to an increase in the amount of delta ferrite contents through the weld passes from the root to the face. Moreover, the liquation cracks occurred due to the combination of eutectic phase formation, low thermal conductivity, and the large freezing range of the base metal. These cracks originated at the PMZ and propagated from the PMZ through HAZ to BM and lowered the tensile strength, % elongation and toughness of the weld joint by about 6 %, 27 % and 33.5 %, respectively.