Type 347 / 347H stainless steel is an austenitic grade of chromium steel, which contains columbium as a stabilizing element. Tantalum can also be added for achieving stabilization. This eliminates the carbide precipitation, as well as intergranular corrosion in steel pipes. Type 347 / 347H stainless steel pipesoffer higher creep and stress rupture properties than grade 304 and 304L. This makes them suitable for exposures to sensitization and intergranular corrosion. Moreover, the inclusion of columbium allows 347 pipes to have excellent corrosion resistance, even superior to that of 321 stainless steel pipes. However, 347H steel is the higher carbon composition substitute of stainless steel pipe grade 347. Therefore, 347H steel pipes offer improved high temperature and creep properties.
With wide experience and expertise, FUJINAWA Group is one of the leading 347/347h stainless steel pipe/tube manufacturers and suppliers. We have hundreds of high-qualified workers at your service. Please rest assured to get the competitive price 347/347h stainless steel pipe/tube for sale with us.
Our range of SS 347 Tubing is extremely economical, and thus making our products highly valuable among our clients. Most sizes of SS 347 Tubes tube can be cut to exact sizes. Non standard sizes of SS 347 Seamless Tubing can be made to order. SS 347H Tubes are available in diverse sizes, grades and shapes, and are quality passed and tested as per international standards. FUJINAWA Tubes as well fabricate and design these SS 347H Tubing in different specifications and designs as per requirements of our customers.
Standard:
| STANDARD | UNS | WERKSTOFF NR. |
| SS 347 | S34700 | 1.4550 |
| SS 347H | S34709 | 1.4961/1.4912 |
Chemical Properties:
| C | Cr | Mn | Ni | P | S | Si | Cb/Ta | |
| 347 | 0.08 max | min: 17.0 max: 20.0 | 2.0 max | min: 9.0 max: 13.0 | 0.04 max | 0.30 max | 0.75 max | min:10x C max: 1.0 |
| 347H | min: 0.04 max: 0.10 | min: 17.0 max: 20.0 | 2.0 max | min: 9.0 max: 13.0 | 0.03 max | 0.30 max | 0.75 max | min:10x C max: 1.0 |
Mechanical Properties:
| Grade | Tensile Strength ksi (MPa) min | Yield Strength 0.2% ksi offset ksi (MPa) min | Elongation (% in 50mm) min | Hardness (Brinell) MAX | Hardness (Rockwell B) MAX |
| 347/347H | 75 (515) | 30 (205) | 40 | 201 | 95 |
Physical Properties:
| Density lbm/in3 | Coefficient of Thermal Expansion (min/in)-°F | Thermal Conductivity BTU/hr-ft-°F | Specific Heat BTU/lbm -°F | Modules of Elasticity (annealed)2-psi | |
| at 68 °F | at 68 – 212°F | at 68 – 1832°F | 68-932°F | at 32 – 212°F | in tension (E) |
| 0.288 | 9.2 | 11.4 | 14.7 | 0.12 | 28 x 106 |
Corrosion Resistance:
1、Offers similar resistance to general, overall corrosion as Alloy 304
2、Used for applications where alloys such as Alloy 304 are vulnerable to intergranualr corrosion
3、Generally used for heavy welded equipment which cannot be annealed and for equipment which is operated between 800 to 150°F (427 TO 816°C)
4、Alloy 347 is preferred over Alloy 321 for aqueous and other low temperature environments
5、Primarily used in high temperature environments where resistance to sensitization is necessary, in turn preventing intergranualr corrosion at lower levels
6、Susceptible to stress corrosion cracking
7、Exhibits oxidation resistance similar to all other 18-8 austenitic stainless steels
Weldability
1、Austenitic stainless steels are considered to be the most weldable out of all high alloy steels
2、Can be welded by all fusion and resistance welding processes
Heat Treatment
1、Annealing temperature range is 1800 to 2000°F
2、May be stress relief annealed within the carbide precipitation range of 800 to 1500°F without any danger of subsequent intergranualr corrosion
