Provide carbon steel plate material thicker than 16 mm in accordance with ASME SA 516 Grade 70; carbon steel flanges and forgings in accordance with SA 105; carbon steel pipes in accordance with SA 106 Grade B or C. Provide tubesheet material of SA 515 Grade 70, SA 516 Grade 70, or SA 105. Provide seamless tube material of SA 210, SA 214, SA 178 or SA 179. Weld and roll tube to tubesheet joints at each end. Post weld heat treat the shell after completion of welding with temperature and hold times in accordance with ASME Code, Section 1, Power Boilers. Do not weld, burn or work on the boiler shell after completion of post weld heat treatment.