| Customization: | Available |
|---|---|
| Type: | Coil |
| Standard: | AISI, ASTM, DIN, JIS, GB |
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Alloy 347 is a stabilized, austenitic, chromium steel containing columbium which allows for the elimination of carbide precipitation, and, consequently, intergranualr corrosion. Alloy 347 is stabilized by the additions of chromium and tantalum and offers higher creep and stress rupture properties than alloy 304 and 304L which may also be used for exposures where sensitization and intergranualr corrosion are of concern. The addition of columbium also allows Alloy 347 to have excellent corrosion resistance, even superior to that of alloy 321. 347H is the higher carbon composition form of Alloy 347 and demonstrates improved high temperature and creep properties.
Composition
The following table shows the chemical composition of grade 347H stainless steel.
| Element | Content (%) |
| Iron, Fe | 62.83 - 73.64 |
| Chromium, Cr | 17 - 20 |
| Nickel, Ni | 9 - 13 |
| Manganese, Mn | 2 |
| Silicon, Si | 1 |
| Niobium, Nb (Columbium, Cb) | 0.320 - 1 |
| Carbon, C | 0.04 - 0.10 |
| Phosphorous, P | 0.040 |
| Sulfur, S | 0.030 |
The physical properties of grade 347H stainless steel are given in the following table.
| Properties | Metric | Imperial |
| Density | 7.7 - 8.03 g/cm3 | 0.278 - 0.290 lb/in³ |
The mechanical properties of grade 347H stainless steel are displayed in the following table.
| Properties | Metric | Imperial |
| Tensile strength, ultimate | 480 MPa | 69600 psi |
| Tensile strength, yield | 205 MPa | 29700 psi |
| Rupture strength (@750°C/1380°F, time 100,000 hours) | 38 - 39 MPa, | 5510 - 5660 psi |
| Elastic modulus | 190 - 210 GPa | 27557 - 30458 ksi |
| Poisson's ratio | 0.27 - 0.30 | 0.27 - 0.30 |
| Elongation at break | 29% | 29% |
| Hardness, Brinell | 187 | 187 |
Machining grade 347H stainless steel is slightly tougher than that of grade 304 steel. However, the hardenability of this steel can be minimized by the use of constant positive feeds and slow speeds.
Grade 347H stainless steel can be welded using most of the resistance and fusion methods. Oxyacetylene welding is not preferred for this steel.
Forging, upsetting and other hot work processes can be performed at 1149 to 1232°C (2100 to 2250°F). The grade 347H steel has to be water quenched and annealed to obtain maximum hardness.
Grade 347H stainless steel can be readily stamped, blanked, spun and drawn as it is quite tough and ductile.
Grade 347H stainless steel can be annealed at temperature ranging from 1010 to 1193°C (1850 to 2000°F) and then quenched with water.
Grade 347H stainless steel is unresponsive to heat treatment. The hardness and strength of the steel can be increased through cold working.
| Grade | UNS | DIN | EN | AMS | ASTM |
| 347H | uns S34709 |
ASTM A182
ASTM A213
ASTM A240
ASTM A249
ASTM A271
|
347H steel is widely used, especially in high temperature and high pressure environments. The following are the main application areas of 347H steel:
Superheater and reheater of large boilers: 347H steel is widely used in superheaters and reheaters of large boilers due to its excellent high temperature resistance, and can withstand high temperature and high pressure working environments.
Steam pipes: In steam pipe systems, 347H steel has become one of the preferred materials due to its good corrosion resistance and high temperature resistance, ensuring safe and efficient transmission of steam.
Petrochemical heat exchanger pipe fittings: In the petrochemical industry, heat exchangers are one of the key equipment. 347H steel is used to manufacture heat exchanger pipe fittings due to its excellent corrosion resistance and high temperature resistance, ensuring the long-term stable operation of the equipment.
Nuclear power equipment: Nuclear power equipment has extremely high performance requirements for materials. 347H steel plays an important role in nuclear power equipment due to its excellent high temperature resistance, corrosion resistance and strength retention ability.
Aerospace field: In the aerospace field, materials need to withstand extreme temperature and pressure conditions. 347H steel is used to manufacture key components in aerospace equipment due to its excellent performance.
Other industrial applications: In addition, 347H steel is also widely used in chemical processing equipment, food processing equipment and storage containers, catalytic cracking units in refineries, and many other industrial fields
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