Bohler ASN 5-UP description: Sub-arc wire/flux combination for CrNiMo steels containing 3-4 % Mo e.g. 1.4438 / 317L. The weld metal shows a stable austenitic microstructure with good pitting resistance (PREN > 33) and crevice corrosion resistance as well as an excellent toughness behaviour down to -196°C. BOHLER BB 203 is a fluoride-basic agglomerated flux providing good operating characteristics, smooth beads and a low-hydrogen weld metal.