... :ASME,ANSI,ASTM,DIN,GB 2.Material:25Cr35Ni+MA 3.ISO9001:2008 Heater Radiant Coil1.Standard:ASME,ANSI,ASTM,DIN,GB2.Material ... , and the height of the heater may vary from 30 to 50m.Before the 1960s,cracking tubes were rranged in horizontal rows ... (20,000 mta,metric tonnes per annum).Modern designs use tubes arranged in vertical rows,providing superior mechanical performance and higher ...