Crack Test of Mild Steel Electrode with Slit Type Specimens
In welding of rimmed steel
1953 Volume 22 Issue 8 Pages 258-265
Details
1953 Volume 22 Issue 8 Pages 258-265
About 40 commercial mild steel electrodes of different types (all except three passing the mechanical test specified by AWS or JIS) were used for welding slit-type crack test specimens prepared of several grades of rimmed steels and the crack development in them has been observed with the folio wing results:
1) Apparently there is no relationship between the mechanical properties of all deposit metals and crack tendency.
2) In the room-tempreture welding of steel plates with ordinary composition, with some exceptions there is a very low incidence of crack development whatever electrode may be used.
3) Considerable variance in crack tendency is observed depending upon the grade of electrode, with high-S (for instance, 0.046%) steel plates to be welded at room temperature.
4) Crack tendency of steel plates with usual components when they are welded at low temperature, say 0°C, follows the same pattern as. that of high-S steel but is not so marked as the latter.
5) Deoxidation of. deposit metal seems to have something to do with crack tendency. Effect of deoxidation is great when high-S steels are welded or welding is done at low temperature. Every type of electrode with high Si/Mn deposit metal, excepting low hydrogen type, possesses high crack tendency.
Low hydrogen type is most stable to cracks, followed by the ilmenite type, containing a conside-rable amount of Mn and low Si/Mn, with fairly good stability.
