Stainless Steel 347 Seamless Pipes & Tubes
SS 347 (UNS S34700) is a niobium (columbium)-stabilized austenitic stainless steel providing superior resistance to intergranular corrosion at elevated temperatures. Preferred over 321 where intermittent heating is involved, as niobium provides more reliable stabilization than titanium.
Size Range
1/4" NPS to 10" NPS (6.35mm to 273.1mm OD)
Wall Thickness
SCH 5S to SCH 160
Standards
4 specs
Chemical Composition (% by weight)
| C | Mn | Si | Cr | Ni | Nb+Ta | P | S |
|---|---|---|---|---|---|---|---|
| 0.08 max | 2.00 max | 0.75 max | 17.0-19.0 | 9.0-13.0 | 10xC min | 0.045 max | 0.030 max |
Mechanical Properties (Minimum at Room Temperature)
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| 515 MPa min | 205 MPa min | 35% min | 92 HRB max |
Physical Properties - SS 347
| Density | Melting Range | Thermal Conductivity | Electrical Resistivity | Specific Heat | Coeff. of Thermal Expansion |
|---|---|---|---|---|---|
| 7.96 g/cm3 | 1400-1425 C | 16.1 W/m-K | 730 nOhm-m | 500 J/kg-K | 17.2 um/m-C |
Corrosion Resistance - SS 347
| Property | Value |
|---|---|
| Pitting Resistance (PREN) | ~17.5 |
| Max Service Temp (Oxidizing) | 900 C |
| Intergranular Corrosion | Resistant (Nb stabilized) |
| Stress Corrosion Cracking | Susceptible in chlorides >60C |
| General Corrosion Rate | <0.1 mm/yr in mild acids |
| Seawater Resistance | Limited |
Equivalent International Grades
| ASTM | JIS | BS | GOST |
|---|---|---|---|
| TP347 | SUS 347 | 347S31 | 08Kh18N12B |
SS 347 vs Comparable Grades
| Grade | UNS | Tensile | Yield | PREN | Max Temp |
|---|---|---|---|---|---|
| SS 321Austenitic Stainless Steel | S32100 | 515 MPa min | 205 MPa min | ~17.5 | 900 C (continuous) |
| SS 304 / 304LAustenitic Stainless Steel | S30400 | 515 / 485 MPa min | 205 / 170 MPa min | ~18 | 870 C |
| SS 310SAustenitic Stainless Steel | S31008 | 515 MPa min | 205 MPa min | ~25 | 1150 C (intermittent 1035 C continuous) |
Applicable Standards
Applications
Key Advantages of SS 347
SS 347 Applications by Region
Middle East (UAE, Saudi Arabia, Qatar, Oman, Kuwait)
Specified for refinery catalytic cracker tubes, reformer piping, and high-temperature equipment in UAE, Saudi Arabia, and Kuwait.
Europe (Germany, UK, Norway, Netherlands, Italy)
Used in petrochemical and power plant applications in Germany, Netherlands, UK, and Scandinavia.
United States
Standard specification for refinery and petrochemical high-temperature applications.
Frequently Asked Questions about SS 347 Seamless Pipes
Quick Specifications
1/4" NPS to 10" NPS (6.35mm to 273.1mm OD)
SCH 5S to SCH 160
Industries Served
Related Grades
Ready to Order SS 347 Seamless Pipes?
Stancor is India's leading manufacturer of SS 347 seamless pipes, exporting to UAE, Saudi Arabia, Qatar, Germany, UK, and USA. Contact our sales team for competitive pricing, fast delivery, and full material certification.