Method and system for utilizing materials of differing thermal properties to increase furnace run length

A furnace comprising:

• a heated portion;
• a plurality of straight tubes formed of a first material and at least partially disposed in the heated portion;
• a plurality of return bends coupled to the plurality of straight tubes, the plurality of return bends formed of a second material and at least partially disposed outside of the heated portion, wherein properties of the second material facilitate wear resistance of the plurality of return bends;
• a plurality of plug headers coupled to the plurality of straight tubes at an end opposite the plurality of return bends, the plurality of plug headers formed of the second material;
• wherein the first material exhibits a design-maximum tube-metal temperature greater than the second material thereby facilitating increased run time of the furnace;
• and
• wherein the second material exhibits wear-resistance properties greater than the first material facilitating wear resistance of the furnace.