This is highlighted to welder qualification according to ISO 9606-1 BW only qualify for BW, FW only qualify for FW, If welder make the test coupon accordance to Annex C, the welder will make the combined FW / BW in the same test coupon. The important issues when make the test coupon. Lack of side wall fusion at the vertical wall (unbevelling side). Photos | docs.duybien.com Slag inclusion occurs at the stop and restart location. Incorrect toe at PC position or overlap. Undercut occurs at the top of plate (PC), PF and PE positions. Incomplete fusion to the root of vertical side. In the fillet weld found the most lack of side wall fusion or the root bead found unmelt to the base metal due to incorrect technical when made the root run.