317 stainless steel tube is chosen when 316 starts to pit or corrode. The extra molybdenum, 3–4% against 2–3% in 316, lets it handle stronger acids, higher chlorides and the wet flue gas condensate found in scrubbers. Pick 317 (UNS S31700) for unwelded lines, and 317L (UNS S31703, DIN 1.4438) where the tube will be welded, since its lower carbon keeps the weld zone from losing corrosion resistance.
At Metinox Overseas in Mumbai, we supply TP317 and TP317L tubes as cold drawn seamless or welded tubing to ASTM A213, A249 and A269, with bright annealed or polished finishes on request. Tell us your size, wall and quantity, and we’ll quote the right grade and form.
Ready with your size and quantity?Request a quote for 317 and 317L stainless steel tubing.
Table of Contents
317L vs 316L: Is the Extra Molybdenum Worth It?
| Grade | UNS | Molybdenum (%) | PREN | Recommended Service |
|---|---|---|---|---|
|
316L |
S31603 |
2.0 to 3.0 |
About 24 |
Chlorides and mild acids, with welding |
|
317 |
S31700 |
3.0 to 4.0 |
About 28 to 30 |
Harsher acids and chlorides, no heavy welding |
|
317L |
S31703 |
3.0 to 4.0 |
About 28 to 30 |
Harsher acids, chlorides and flue gas, with welding |
Where 317L Stainless Steel Tubing Is Used
Each use below comes down to molybdenum and chloride resistance.
- Flue gas desulphurisation. The wet, acidic, chloride bearing condensate attacks 316L, and 317L holds up better.
- Pulp and paper. Bleaching and process liquors are acidic and chloride bearing.
- Chemical and fertiliser plants. Stronger acids call for the extra molybdenum.
- Power plant condensers and heat exchangers. Chloride bearing cooling water pits lower grades, as covered in ourheat exchanger tubes andcondenser tubes pages.
- Marine and offshore. Sea water and salt laden air are chloride heavy.
If your service is harsher still, look at ourduplex tube orsuper duplex tube pages. For milder service, ourstainless steel 304 tube page may be enough.
Request a Quote for 317 and 317L Stainless Steel Tubing
Tell us the grade, form, OD, wall, length, finish and quantity, and we will respond with the right 317 stainless steel tube or 317L tubing for your line. You can also browse all of ourstainless steel tubes.
Questions about a grade, size or standard?Contact our team.
Frequently Asked Questions
Both carry 18 to 20 percent chromium, 11 to 15 percent nickel and 3 to 4 percent molybdenum. The difference is carbon, which is 0.08 max in 317 and 0.035 max in 317L. The lower carbon keeps 317L corrosion resistant after welding.
317L has 3 to 4 percent molybdenum against 2 to 3 percent in 316L, so it resists pitting and acids better. Typical PREN is about 28 to 30 for 317L and about 24 for 316L. Choose 317L for harsher chlorides, acids and flue gas service.
S31700 is the UNS number for 317 and S31703 is the number for 317L. They are close grades that differ mainly in carbon. Some pages use the two numbers loosely, so check which one your specification names.
DIN 1.4438 is the Werkstoff number for 317L, and 1.4449 is the number for 317. Both numbers also appear in EN specifications. Use the number your drawing names when you order DIN 1.4438 tubes.
It is made both ways, and also as ERW tube. A 317L stainless steel seamless tubing suits high pressure, boilers and heat exchangers, while SS 317L welded tubing and 317L ERW tubes suit process lines and larger sizes. Tell us your duty and we will suggest the right form.
SA 213 TP 317L is the ASME version of ASTM A213 grade TP317L, which covers seamless austenitic tube for boilers, superheaters and heat exchangers. It uses the same chemistry as 317L.
No. ASTM A312 TP 317L is a pipe standard, sized by NPS and schedule. Tubes are made to ASTM A213, A269 or A249 and sized by outside diameter and wall. For pipe, see ourstainless steel 317L pipe page.
317 and 317L tube have a minimum tensile strength of 515 MPa and a minimum yield of 205 MPa. Minimum elongation is 35 percent and maximum hardness is 90 HRB or 192 HBW. These are minimums from the standard, not typical values.
Yes, 317L stainless steel polish tubing is available on request, including bright annealed, mechanically polished and electropolished finishes. Tell us the roughness you need and we will confirm what can be supplied.
Annealed 317L is non magnetic. Cold work such as bending can make it slightly magnetic, which is normal and does not mean the grade is wrong.
Seamless tube follows the A213 range of about 3.2 mm to 127 mm OD, and welded and ERW tube starts at about 6.35 mm OD. Wall runs from about 0.4 mm to 12.7 mm. Send us your OD, wall and length and we will confirm.
We supply EN 10204 3.1 mill test certificates, with 3.2 on request. Third party inspection can be arranged if your order calls for it.
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