COMPARISON OF PROCESS STABILITY AND WELD QUALITY OF SIMILAR MMAW ELECTRODES PRODUCED BY VARIOUS MANUFACTURERS

Abstract

Some experimental investigations have been carried out to study the behaviour of rutile type coated electrodes of different sizes produced by different manufacturers for arc stability and weldment mechanical properties. For arc stability of rutile type electrodes, the time analysis does not indicate any definite trend so the results have been interpreted on the basis of voltage and current analysis. The experimental results reveal that relatively better arc stability has been found with electrodes produced by M/S Advani-Oerlikon (Manufacturer Ml) for 3.15 and 4.0 mm electrodes. The melting rate (gm/J) reduces with the increase in the electrode diameter. The mechanical testing of weldments indicate that all the electrodes which have been used conform to the DIN standard i.e. they qualify the requirement of the code. However, with rutile type electrodes either only higher tensile strength or higher toughness properties can be obtained. The other one shall be relatively lower. Further on the basis of tensile testing very little strain hardening has been found in the weldment. No critical increase in hardness in heat affected zone has been observed with the used electrodes.