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Specifications
347H is controlled, high carbon Nb stabilised stainless steel for elevated temperature service.
TP347H Austenitic Stainless Steel Seamless Pipe/Tube , Heat Exchanger Tube UNS S34709 1.4961
General Introduction
S347H is a austenitic chromium steel containing colubium. It is recommended for parts fabricated by welding which cannot be subsequently annealed. This type is also used for parts which are intermittently heated and cooled to temperatures between 800°F and 1600°F. The addition of columbium produces a stabilied type of stainless that eliminates carbide precipitation and, consequently, intergranular corrosion.
Chemical Composition
| C | Co | Cr | Mn | Ni | P | S | Si | Ta |
| Max |
|
| Max |
| Max | Max | Max |
|
| 0.08 | Trace* | 17.0-20.0 | 2.0 | 9.0-13.0 | 0.04 | 0.30 | 0.75 | Trace* |
Designed Features
• Superior general corrosion resistance over Type 321 due to stabilization with columbium.
• Reduced tendencies to form continuous networks of chromium carbides at the grain boundaries.
• Better high temperature properties than 304 or 304L. Generally used for parts which are intermittently heated up to 1500 deg. F. For continuous service the maximum temperature is 1650 deg. F.
• Type 347H has high carbon (.04 - . 10) for better high temperature creep properties. • Improved intergranular corrosion resistance.
Typial Application
