The vast majority of austenitic grades – which represent between 65 % to 70 % of all stainless steels manufactured globally – were initially designed for wrought products and then adapted for castings . But the manufacturing processes involved in the two product forms are very different , as is the mechanical properties and performance of the materials produced . Cast alloys possess lower strength properties and sometimes different corrosion resistance levels compared to their wrought counterparts despite having the same or a very similar chemical composition . Furthermore , some of the higher alloyed wrought grades are notoriously difficult to cast and are susceptible to defects as cast materials . Two of the well-known ‘ superaustenitic ’ stainless steels – S31254 and N08367 – were developed as wrought materials in the 1980s and utilised for piping in seawater environments in the oil and π www . valve-world . net Valve World September 2024
MATERIALS
Innovative cast alloys expand
A new series of high strength austenitic stainless steels has been developed specifically for cast products , offering improved properties over traditional options like 6Mo grades .
Philip Roscoe , N ’ GENIUS Materials Technology
valve manufacturing options
Casting N ’ GENIUS 326L35M4N at Furniss & White ( Foundries ) Limited
Design flexibility , quick turnaround times and cost-efficiency are among the many reasons why stainless steel castings are an important component in high quality valve manufacturing . The casting process allows for materials to be moulded into detailed , complex shapes and sizes in a relatively short timeframe . And because of the reduced labour and lead times required compared to forging , the costeffectiveness of producing cast components for valves can be a big advantage during both the specification process and the manufacturing stage . With European-based stainless steel producers facing added pressures of high energy costs and low margins due to market prices set in other regions of the world , it is a highly competitive industry for the manufacturers . Fortunately , the future looks promising for the stainless steel casting industry with annual growth of more than 4 % expected until at least 2032 , particularly for large components . Applications in the aerospace , energy and automotive sectors are driving the demand for stainless steel cast products including cast valve bodies and with governments committing to increased spending in the defence industry , it is a market poised for expansion .
With these industries and others prioritising a shift towards advanced materials which are more durable and sustainable , investment in R & D and innovation is fast becoming an important strategy for manufacturers . However , alloy development in stainless steels is not traditionally associated with the castings industry .
A cast material is a different animal
The vast majority of austenitic grades – which represent between 65 % to 70 % of all stainless steels manufactured globally – were initially designed for wrought products and then adapted for castings . But the manufacturing processes involved in the two product forms are very different , as is the mechanical properties and performance of the materials produced . Cast alloys possess lower strength properties and sometimes different corrosion resistance levels compared to their wrought counterparts despite having the same or a very similar chemical composition . Furthermore , some of the higher alloyed wrought grades are notoriously difficult to cast and are susceptible to defects as cast materials . Two of the well-known ‘ superaustenitic ’ stainless steels – S31254 and N08367 – were developed as wrought materials in the 1980s and utilised for piping in seawater environments in the oil and π www . valve-world . net Valve World September 2024
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