... , water wall panel, economizer, super heater, boiler and heat exchanger with seamless steel tubes, and to transport liquid, gas, oil etc. Standard:API ... : Bright annealed,Spheroidize annealed, Normalized, Stress relieved, Cold finished, Quenched and Tempered Delivery Condition:BKS, NBK, BK, BKW, GBK(+A), NBK ...