[ Chemical Industry ]
[ Chemical Industry ]
• Stainless steel : generally good corrosion resistance to water , alkalis , minerals , and dry solvents .
• Type austenitic 304 : unsuitable for use in seawater , unlike 316 . 316 will likely be subjected to crevice corrosion without galvanic coating or use of 316L / 316 ELC .
• Duplex : more corrosion resistant , especially regarding stress corrosion cracking .
• Super austenitic : excellent corrosion resistance to a wide range of fluids , seawater , brine solution , caustic , and any mineral acid .
• Super duplex : for caustic and mineral acids .
Valve manufacturing process Based on the relevant requirements , industrial valve manufacturers consider the advantages and disadvantages of casting and forging methods . Choosing which method to employ depends on factors such as desired strength , design complexity , production volume , and budget constraints . By understanding the pros and cons of each method , manufacturers can optimise their valve manufacturing process for various applications . At first glance , valves may seem to consist of a few parts , but sealing is complex , particularly when demanding zero leakage during fluid / gastight testing . This complicates the manufacturing process . Due to the wide variety of valve specifications and the presence of the valves in all types of environments , the material requirements for stainless steel are very strict . However , valve manufacturers perform a bubble seal test before the valve leaves the factory . Here , the seat is tested for significant leakage . Other key parameters include flow speed , valve function ( on / off or modulating ), whether fire safety is required , and other additional functional requirements .
Casting process The correct and effective control of casting solidification is the first important condition for obtaining quality products . This process programme includes the pouring system , riser , and complementary process amount . Due to their uneven wall thickness , valve parts cast in steel should undergo sequential cooling and sequential solidification to reduce the internal stress of the casting , shrinkage , and other defects . Attention should be paid to design , the pouring system , correct pouring positioning , riser design , volume shrinkage calculations , and shrinkage control . In the machinery industry , thin shell casting is more complex and difficult . However , valve casting is an important part of the manufacturing process , as good casting determines the success of a valve .
Stainless steel valves have various applications due to their excellent performance in terms of temperature limits , corrosion resistance , and high-pressure tolerance .
Forging process Forging a valve involves correctly shaping stainless steel , heating , and pressing the block with industrial tools at forging temperature . Industrial forged valves are generally used on small , high-grade pipelines with high processing costs . Forged valves have increased performance in severe service and high-temperature applications . The forging process eliminates surface porosity , removes internal voids , decreases wall thickness , and allows for a smaller temperature gradient and less thermal fatigue . Forged valves can withstand the stresses of high-temperature applications and high pressures without compromising their integrity while boasting better corrosion / heat resistance , tensile strength , higher strength , ductility , durability , and
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