A possible cost reduction almost always spikes interest in any material. If it is possible to retain quality and reduce material cost, even more interest is spiked. Duplex is cost-effective in more than one way. The material costs less than many other materials used in a corrosive atmosphere. When compared to 300 series stainless steel, the cost reduction is realized in a different manner. Duplex's yield strength is double that of the 300 series stainless steel. This factor allows the use of a thinner material to support a like load. The cost of fabricating duplex usually is lower than for other materials because of its comparative ease of machining and welding. When high-nickel alloys are welded, small stringer beads and low heat input are recommended. This is not the case with duplex. Higher heat input and a slight weave bead are recommended for this material. The ferrite content causes the welding to be less intimidating than when welding hig- nickel alloys. This factor alone saves significant weld time. Duplex's machining rate of travel is similar to that of 316 stainless steel with high-speed steel tooling, and duplex requires fewer machining labor hours than high-nickel alloys. Welding wire and gas costs are less with duplex, except when the corrosive atmosphere is extreme. In the case of severe corrosion and the possibility of stress corrosion cracking, it is necessary to use ERNiCrMo-3 wire, which is much more expensive (around $30 per pound) than ER2209 (around $11 per pound), which is the matching filler wire. Forming duplex is not complicated. The material can be bent and rolled by almost the same methods as 50,000-PSI-yield-strength material. Conventional rolls and dies are sufficient for forming most shapes, which eliminates the added cost of purchasing special rolls and dies. The only significant requirement is that the dies and rolls must have a hardness of at least 34 Rockwell C to prevent carbon impregnation. | 