Duplex stainless steel have lower nickel and molybdenum contents than austenitic stainless steels in corresponding corrosion-resistant environments. Due to the lower content of alloying elements, the cost of duplex stainless steel is lower, especially in the case of higher alloy surcharges. In addition, compared to austenitic stainless steel, it becomes possible to reduce the thickness of duplex stainless steel because of the increase in yield strength of duplex stainless steel. This combination not only reduces cost but also reduces weight. Any feasible way to reduce material cost without compromising performance is a matter of concern to the industry. Duplex stainless steels are more cost-effective than single-phase stainless steels, and are less expensive than other materials used in corrosive conditions. Compared with 300 series stainless steel, duplex stainless steel is also more cost-effective, and the method will be different. Its yield strength is twice that of 300 series stainless steel, that is, the thickness of stainless steel can be reduced under the same load. Because duplex stainless steel is easier to process and weld, its manufacturing cost is also lower than other materials.
When welding high-nickel alloys, small primary back welds and lower heat input can be used. Duplex stainless steels are generally welded using higher heat input and slight weaving. The ferrite content in duplex stainless steel makes fusion easier during welding, which also saves a lot of welding time.
The cutting speed of duplex stainless steel is comparable to that of high-speed tool 316 stainless steel, and the cutting time is shorter than that of high-nickel stainless steel. Except in extremely harsh corrosive environments, duplex stainless steels also consume less core and welding gas.
The variants of duplex stainless steel are not complicated. Traditional rolling mills and molds can be processed into parts of various shapes, which reduces the additional cost of purchasing special rolling mills and molds. In order to avoid the entry of carbon elements, the only requirement for the rolling mill and die is that the hardness is at least 34RHC.
In addition to the above material costs, there is also a life cycle cost to consider. Life cycle cost analysis is one of the quantitative analysis methods for selecting materials as final products or using components from the perspective of cost-effectiveness. Traditionally, the choice of material has always tended to choose a lower price, but at present this may not be a very economical way, because the life of the material may be longer than the product, considering the actual cost due to installation, regular maintenance and cycle replacement. or as short as the part requires. Considering the time-consuming installation of equipment in factories and processing plants, the cost control of each material selection needs to consider the time cost.
