I came across a strange behaviour of this material after typical step cooled heat treatment in all weld metal where there was a significant loss of impact toughness at -20°C which was retrieved at lower temperatures i.e. it was significantly tougher at -30°C than -20°. X and J factors were low and given the low oxygen regime of the GTAW process it was fully expected to achieve good results. I have seen a similar effect with E9018-B3 SMAW electrodes although here the “dip” is not as significant and noticeable. Could this mean that the cleanliness of the weld metal is having an effect?

I would appreciate any ones thoughts on this matter
Mark Golding