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Views: 5 Author: Wang Publish Time: 2024-08-23 Origin: Site
Type 347 is a niobium stabilized chromium nickel austenitic stainless steel with corrosion resistance similar to 304/304L. This grade is typically used in the 800-1500˚F temperature range where it is stabilized against chromium carbide precipitation by the addition of niobium, which results in the precipitation of niobium carbides. Type 347 has excellent intergranular corrosion resistance after exposure to this temperature range, and this grade resists oxidation up to 1500˚F. It also possesses good low temperature toughness and is non-magnetic in the annealed condition.
Stainless Steel 347 has slightly improved corrosion resistance over type 321 stainless steel in strongly oxidizing environments. Alloy 347 is a columbium(niobium)/tantalum stabilized austenitic chromium-nickel stainless steel which was developed to provide an 18-8 type alloy with improved intergranular-corrosion resistance. Alloy 347 has a slightly improved corrosion resistance over other alloys of stainless steel in strongly oxidizing environments as a result of the addition of columbium (niobium) and tantalum. Columbium-tantalum carbides precipitate within the grains instead of forming at the grain boundaries. Type 347 should be considered for applications requiring intermittent heating between 800ºF (427ºC) and 1650ºF (899ºC), or for welding under conditions which prevent a post-weld anneal.
The alloy also offers good resistance to polythionic acid stress corrosion cracking and is a useful material for use around reactor plants. Type 347 is non-magnetic in the annealed condition and can only be hardened by cold working. The alloy finds use in the oil, gas and chemical sector as well as the nuclear industry. Type 347 is also used for heavy welded assemblies which cannot be annealed after welding or where the operating conditions cause exposure within the temperature range between 426.67° to 815.55°F.
347 is an austenitic stainless steel containing niobium. In terms of chemical composition, 347 can be seen as 304 stainless steel with the addition of niobium. Niobium is a kind of rare earth element, which performance is similar to titanium. When added to the alloy, niobium can refine grains, resist intergranular corrosion and increase strength without reducing plasticity. It can thus save cost by reducing the thickness of the material and be used for structural strength parts.
Type 347 exhibits good corrosion resistance in acid, alkali and salt liquid. It has good oxidation resistance and weldability in air below 800°C. In comparison with 304 stainless steel, 347 stainless steel features excellent high temperature stress rupture and high temperature creep resistance performance.
Fe | Rest |
Cr | 17,00 - 19,00 |
Ni | 9,00 - 13,00 |
Mn | max. 2,00 |
Nb | max. 1,00 |
Si | max. 1,00 |
C | max. 0,08 |
P | max. 0,045 |
S | max. 0,015 |
Mechanical property requirements for annealed product as specified in ASTM A240 and ASME SA240
Property | Stainless steel 347 |
Yield Strength, min. (ksi) | 30 |
Tensile Strength, min. (ksi) | 75 |
Elongation, min. (%) | 40 |
Hardness, max. (Rb) | 92 |
Property | Stainless steel 347 |
Density, lb/in3 | 0.288 |
Modulus of Elasticity, psi | 28.0 x 106 |
Coefficient of Thermal Expansion, 68-212˚F, /˚F | 9.3 x 10-6 |
Thermal Conductivity, Btu/ft hr ˚F | 9.2 |
Specific Heat, Btu/lb ˚F | 0.12 |
Electrical Resistivity, Microohm-in | 28.4 |
Stainless steel 347 can withstand high temperatures and perform well in harsh environments. Their ability to operate between -10°C and 816°C makes them suitable for applications in the petrochemical and refining industries. The addition of tantalum and columbium to their composition increases the pipes’ strength and makes them oxidation-resistant. This addition can also offer protection against polythionic acid stress corrosion cracking.
Stainless steel 347 are highly corrosion-resistant and ideal for extreme environments. They exhibit outstanding resistance to organic chemicals, inorganic chemicals, and acidic solutions, making them ideal for use in the chemical processing industry. These pipes also resist intergranular and crevice corrosion, reducing the risk of corrosion-related failure.
Durability is one of the properties that make stainless steel 347 popular in several industries. These strong pipes resist deformation better than other materials, making them efficient in harsh environments. This strength and durability are particularly useful in the offshore and marine industries, where the pipes can withstand harsh saltwater environments.
Stainless steel 347 are easy to weld thanks to their high ductility and low thermal conductivity. This makes them viable for fabricatingcomplex structures, piping, and tanks, leading to improved project efficiency and reduced downtime. Furthermore, these pipes have excellent dimensional stability, enabling precise fabrication and fitting for different applications.
Stainless steel 347 are cost-effective in the long term despite initially being more expensive than other materials. They offer a longer lifespan and require less maintenance than other materials, reducing repair and maintenance costs. Stainless steel 347 are also recyclable, making them an environmentally friendly option, unlike other alternatives.
347 stainless steel, with its excellent corrosion resistance, high-temperature stability, and mechanical properties, is very suitable for use in chemical, petroleum, medical, food, and other fields. Especially in harsh working environments like high temperature, high pressure, and corrosion, the stability and durability of 347 stainless steel are widely recognized and applied.
As technology advances and the pursuit of material properties continues, 347 stainless steel will continue to play its unique advantages in various fields in the future, contributing to the industrial development and quality of life of humanity. At JN Alloy, we specialize in the production of 347 stainless steel, offering a material that excels in high-temperature and corrosive environments. Our commitment to quality ensures that our steel meets the diverse needs of industries ranging from petrochemical to aerospace.
