JIS G3459 SUS 347 HTP Stainless Steel Pipe
JIS G3459 SUS 347 HTP Stainless Steel Pipe - Composition, Properties & Equivalents
Detailed material data for JIS G3459 SUS 347 HTP austenitic stainless steel pipe: chemical composition, mechanical properties, thermal and electrical physical properties, full international equivalents, and application guide.
Hot rolling, hot extrusion, cold drawing, cold rolling, welding, solution annealing
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JIS G3459 SUS 347 HTP Stainless Steel Pipe Introduction
SUS 347 HTP is a niobium-stabilized austenitic stainless steel pipe grade specified in JIS G3459 for high-temperature service. It contains columbium (niobium) plus tantalum to prevent intergranular corrosion after exposure to temperatures in the chromium carbide precipitation range.
- Excellent resistance to sensitization and intergranular attack
- Higher creep and stress-rupture properties than unstabilized grades at elevated temperatures
- Good oxidation resistance up to approximately 815°C (1500°F)
- Typically supplied in solution-annealed condition, sometimes with a stabilizing heat treatment
This grade is widely used in refinery piping, chemical process equipment, and superheater/reheater tubing.
JIS G3459 SUS 347 HTP Stainless Steel Pipe Chemical Composition
The chemical composition of SUS 347 HTP according to JIS G3459. The niobium (plus tantalum) content is controlled to at least 10 times the carbon content to ensure complete stabilization. Phosphorus and sulfur are restricted to typical austenitic stainless steel levels. All values are ladle analysis.
| Element | Standard Value | Remarks |
|---|---|---|
| C (Carbon) | ≤0.08 | Max |
| Si (Silicon) | ≤1.00 | Max |
| Mn (Manganese) | ≤2.00 | Max |
| P (Phosphorus) | ≤0.045 | Max |
| S (Sulfur) | ≤0.030 | Max |
| Ni (Nickel) | 9.00 – 13.00 | Range |
| Cr (Chromium) | 17.00 – 19.00 | Range |
| Nb+Ta (Niobium + Tantalum) | ≥10 × C% | Minimum, ensures stabilization |
JIS G3459 SUS 347 HTP Stainless Steel Pipe Thermal and Electrical Physical Properties
Typical physical properties for SUS 347 type stainless steel at ambient and elevated temperatures. These data are representative for fully austenitic stabilized stainless steels after solution annealing. Actual values may vary slightly with product form and processing history. These properties are not specified in JIS G3459 but are essential for engineering design.
| Property | Typical Value | Unit | Condition / Temperature |
|---|---|---|---|
| Density (ρ) | 8.0 | g/cm³ | 20°C |
| Elastic Modulus (E) | 193 | GPa | 20°C |
| Shear Modulus (G) | 77 | GPa | 20°C (estimated) |
| Poisson Ratio (ν) | 0.28 | – | 20°C |
| Thermal Expansion Coefficient (α) | 16.6 | 10⁻⁶/K | 20–100°C |
| Thermal Expansion Coefficient (α) | 17.2 | 10⁻⁶/K | 20–200°C |
| Thermal Expansion Coefficient (α) | 17.7 | 10⁻⁶/K | 20–300°C |
| Thermal Expansion Coefficient (α) | 18.1 | 10⁻⁶/K | 20–400°C |
| Thermal Expansion Coefficient (α) | 18.5 | 10⁻⁶/K | 20–500°C |
| Thermal Conductivity (λ) | 16.2 | W/(m·K) | at 100°C |
| Thermal Conductivity (λ) | 17.5 | W/(m·K) | at 200°C |
| Thermal Conductivity (λ) | 18.8 | W/(m·K) | at 300°C |
| Thermal Conductivity (λ) | 20.2 | W/(m·K) | at 400°C |
| Thermal Conductivity (λ) | 21.5 | W/(m·K) | at 500°C |
| Specific Heat Capacity | 500 | J/(kg·K) | 20°C |
| Electrical Resistivity (ρ_e) | 0.73 | µΩ·m | 20°C |
JIS G3459 SUS 347 HTP Stainless Steel Pipe Mechanical Properties
Tensile properties at room temperature for SUS 347 HTP pipe in the solution-annealed condition as required by JIS G3459. The values apply to longitudinal test specimens taken from the pipe wall. Elongation requirements differ slightly with pipe dimensions; the listed value corresponds to wall thickness ≤8 mm. Actual strength may be higher depending on processing and heat treatment.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (0.2% offset, ReH) | ≥205 | MPa | Room temperature, longitudinal specimen |
| Tensile Strength (Rm) | ≥520 | MPa | Room temperature, longitudinal specimen |
| Elongation (A) | ≥35 | % | Gauge length 50 mm (JIS No.11/12 test piece), wall thickness ≤8 mm |
JIS G3459 SUS 347 HTP Stainless Steel Pipe Fully Equivalent Material Standards & Substitutable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| United States | ASTM A312/A312M | TP347H | Seamless and welded austenitic stainless steel pipe for high-temperature service |
| United States | ASME SA312/SA312M | TP347H | Identical to ASTM A312, for ASME pressure vessel applications |
| Europe | EN 10216-5 | 1.4550 (X6CrNiNb18-10) | Seamless stainless steel tubes for pressure purposes, stabilized grade |
| China | GB/T 14976-2012 | 06Cr18Ni11Nb (S34779) | Seamless stainless steel pipes for fluid transport, equivalent to TP347 |
JIS G3459 SUS 347 HTP Stainless Steel Pipe Application Introduction
SUS 347 HTP is specifically designed for high-temperature corrosive environments where intergranular corrosion and creep resistance are critical. Its stabilized chemistry makes it superior to standard 304H or 316H in many refinery and chemical plant services.
- Ideal for continuous service temperatures up to around 800°C.
- Resistant to polythionic acid stress corrosion cracking in refinery environments.
- Commonly specified for hydrogen reforming, ethylene cracking, and fluid catalytic cracking units.
Product Applications: Superheater and reheater tubing, Process piping in refineries, Heat exchanger tubes and pipes, Boiler tubes, Pressure vessel shells and components, Furnace rolls and radiant tubes
Processed into products: Pipe spools and fittings, Tube-to-tubesheet expansion joints, High-temperature headers and manifolds, Thermal reactor components, Steam piping systems, Welded and seamless pipe sections for high-temperature loops
Application industries: Oil & gas refining, Petrochemical processing, Power generation (fossil fuel and nuclear), Chemical and pharmaceutical processing, Heat treatment and furnace construction, Food processing (high-temperature pasteurization)
JIS G3459 SUS 347 HTP Stainless Steel Pipe Similar/Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3459 | SUS 321 HTP | Titanium-stabilized austenitic pipe; similar high-temperature resistance, slightly lower creep strength than 347H |
| United States | ASTM A312 | TP321H | Titanium-stabilized; used in similar applications but with different welding characteristics |
| Japan | JIS G3459 | SUS 347 TP | Standard 347 pipe without high-temperature designation; may have less strict control over grain size or heat treatment |
| Europe | EN 10216-5 | 1.4878 (X9CrNiNb18-9) | Niobium-stabilized, close in composition but with slightly different controlled elements |
Notes:
HTP denotes High Temperature Pipe in JIS G3459. The grade is typically supplied in the solution-annealed condition, but a stabilization heat treatment (850–930°C) may be applied to improve resistance to intergranular corrosion. Users should consider the need for post-weld heat treatment depending on service conditions. For sour service, compliance with NACE MR0175/ISO 15156 should be verified as solution-annealed 347 may be accepted within hardness limits.
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