- Austenitic SS 317L Pipes and Tubes
Austenitic SS 317L Pipes and Tubes
317L pipe and tube are made with low carbon corrosion-resistant austenitic chromium-nickel-molybdenum stainless steel. The high content of these elements makes sure that the alloy has superior chloride pitting and general corrosion resistance to the traditional 304/304L and 316/316L grades.
317L stainless steel pipe and tube are manufactured with stainless steels containing molybdenum-bearing austenitic materials with increased resistance to chemical attack as compared to the traditional chromium-nickel austenitic stainless steels like SS 304.
GRADE | NI | CR | MO | C | MN | P | S | Fe | |
---|---|---|---|---|---|---|---|---|---|
SS 317L | MIN % | 11 | 18 | 3 | – | – | – | – | BALANCE |
MAX % | 15 | 20 | 4 | 0.03 | 2 | 0.045 | 0.03 | ||
SS 317 | MIN % | – | – | – | – | – | – | – | BALANCE |
MAX % | 13 | 19 | 3.5 | 0.08 | 2 | 0.045 | 0.03 |
Production Process
Grade SS 317L or UNS S31703 are manufactured with the processes like ERW ( Electric Resistance Welded), Seamless, and EFW ( Electric Fusion Welding). 317L Pipes and Tubes with different forms such as round, square, rectangle, etc. come in specific end as Plain End, Bevel End and Threaded End with normal thickness of different schedule ranging from SCH 5 to SCH XXS.
Processes like pilgering, extrusion, tube mill, and piercing are used to manufacture pipes and tubes. Such processes need to be followed by heat treating and mechanical testing.
Mechanical Testing
Grade | Tensile Strength | Yield Strength | Elongation |
---|---|---|---|
[MPA] | [MPA] | (% in 50mm) min | |
SS 317L | 515 | 205 | 35 |
Fabrication and Heat Treatment Process
The heat treatment process cannot be used to heat treat alloy 317L. Heat treatment is needed during or after fabrication to eliminate the effects of cold forming or to dissolve precipitated chromium carbides due to thermal exposures.
PHYSICAL PROPERTIES
Grade | Density(g/cm3) | Elastic Modulus(GPa) | Mean Co-eff of Thermal Expansion (μm/m/°C) 0-100°C | Thermal Conductivity (W/m.K) at 100°C |
---|---|---|---|---|
SS 317/ 317L | 8 | 193 | 16 | 16.3 |
317L stainless steel tubing and piping need to be annealed and it can be accomplished by heating in the temperature range of 1900°F to 2150°F (1040°C to 1175°C) followed by air cooling or a water quench, depending on the thickness of the section.
The recommended initial temperature range for forging of alloy 317L is 2100°F-2200°F (1150°C-1205°C) with a finishing range of 1700°F-1750°F (927°C-955°C).
Properties
317L pipe and tube have extra-ordinary carbon contents, which is the reason why they have better creep strengths. Stainless Steel 317L pipe and tube have good resistance to oxidation due to their higher chromium content. 317L pipes and tubes may suffer from embrittlement if they are exposed to temperatures above about 350°C.
317L tube and pipes are also known for their higher creep, stress-to-rupture, and tensile strength at higher temperatures than conventional stainless steels. 317L alloys represent better improvements over conventional SS 317 stainless.
The mix of molybdenum and nitrogen in 317L pipes and tubes is popularly effective in improving resistance to corrosion due to pitting and crevice, particularly in process streams containing acids, chlorides, and sulfur compounds at increased temperatures. Nitrogen also helps in increasing the strength of 317L alloy. All these alloys are meant to serve in severe conditions like flue gas desulfurization (FGD) systems.
Application
Due to the excellent corrosion resistance of alloy 317L pipe and tube, they have got many applications. It has better resistance in sulfuric acid, acidic chlorine, and phosphoric acid. 317L pipe and tubes are used in particular applications like food and pharmaceutical processing applications.
- Off-Shore Oil Drilling Companies
- Power Generation
- Petrochemicals
- Gas Processing
- Specialty Chemicals
- Pharmaceuticals
- Pharmaceutical Equipment
- Chemical Equipment
- Sea Water Equipment
- Heat Exchangers
- Condensers
- Pulp and Paper Industr
Specification
Stainless steel 317L Seamless Pipe: ASTM/ASME SA 312/ A 312
Stainless steel 317L Seamless tube: ASTM/ASME SA 213/A 213
Stainless steel 317L ERW Pipe : ASTM/ASME SA 312/ A 312
Stainless steel 317L ERW Tube : ASTM/ASME SA 249/ A 249