I do not have any expertise in the area of molten sulfur. I have read if the sulfur is dry, 304 or 316 stainless steel will work equally well for molten sulfur. The presence of moisture or oxygen due to aeration will make the stream more corrosive, in which case 316 stainless steel might be preferred. I have also read that seamless carbon steel pipe is commonly used for this application. I am sorry I cannot give a more helpful answer.