Grade quotation brief
316L vs 317L Stainless Steel
Quote 316L where documented process and cleaning conditions provide an accepted corrosion and fabrication basis. Quote 317L when chloride-bearing, acidic or oxidizing chemistry makes the 316L margin too narrow and the project can qualify S31703 in the required form. The higher molybdenum range supports a corrosion comparison but does not establish service life, universal resistance or a drop-in substitution.
Quote 316L where service evidence and the full process cycle support it. Quote 317L as a targeted higher-molybdenum austenitic option when the corrosion review shows a narrow 316L margin, but do not assume that one chemistry increment solves every acid, chloride or crevice mechanism. Where 317L remains marginal, compare duplex, 6Mo or other approved materials using the same design and procurement basis.
Unsure whether 316L or 317L matches the operating temperature and chemistry? Send the service conditions with the RFQ. We quote the approved designation, product form and test plan.
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Illustrations identify the compared grade references; they are not photographs of the quoted material or proof of a mill heat.
Decision matrix
Key Differences
Full grade sheets:316L Stainless Steel/317L Stainless Steel
| Factor | 316L | 317L | Procurement decision |
|---|---|---|---|
| Chemistry | 316L has the displayed ASTM A240 molybdenum range of 2.00-3.00 percent with lower chromium and nickel ranges. | 317L has the displayed molybdenum range of 3.0-4.0 percent with higher chromium and nickel ranges. | Treat added alloy as a candidate margin for a defined environment, not as proof of a service result. |
| Mechanical summary | The displayed annealed 316L flat-product minimum tensile and yield values are lower than the displayed 317L values. | The summarized 317L flat-product minimums are higher while its listed elongation remains in the austenitic range. | Use only current product-form and code values; the comparison does not authorize a section or allowable-stress change. |
| Corrosion screening | 316L is evaluated where service data supports its margin against process, cleaning, chloride and crevice conditions. | 317L is evaluated when additional molybdenum may address a specifically identified localized-corrosion limitation of 316L. | Identify the failure mechanism and compare concentration, temperature, deposits, oxidants and weld condition. |
| Supply and welding | 316L is commonly available in a wider range of forms, fittings, finishes and established consumable routes. | 317L availability and matching consumables can be more product- and schedule-dependent and need early confirmation. | Quote the complete form, welding and inspection package before approving a material change. |
Service and production route
Corrosion and Fabrication Boundaries
316L corrosion screening
- For this 316L vs 317L review, Molybdenum-bearing 316L improves localized-corrosion resistance versus the 304/304L chromium-nickel family in many chloride, chemical-cleaning and coastal exposures; lower carbon reduces sensitization risk in suitable as-welded construction but does not raise pitting resistance beyond the 316 alloy family.
- For this 316L vs 317L review, Permanent seawater immersion, hot concentrated brine, tight crevices, deposits and poorly drained wet-dry cycling can still pit 316L — screen duplex 2205 or higher alloys after engineering review rather than relying on a marine-grade label.
- For this 316L vs 317L review, Review chlorides, temperature, pH, deposits, crevices, drainage, cleaning chemistry, weld heat tint and surface finish for the actual as-welded component. A grade designation alone is not a service-life guarantee.
317L corrosion screening
- For this 316L vs 317L review, General corrosion resistance comes from the chromium-rich passive film; nickel, molybdenum, nitrogen and copper change performance by grade.
- For this 316L vs 317L review, Check chlorides, temperature, crevices, deposits, process chemistry and cleaning conditions. A grade designation alone is not a service-life guarantee.
| Operation | 316L | 317L |
|---|---|---|
| Welding | Generally weldable with a qualified austenitic procedure, matching or over-alloyed filler where required, controlled heat input, purge on tubular joints and heat-tint removal when corrosion service demands it. The ≤0.030% carbon limit reduces sensitization (IGC) risk in the HAZ for as-welded tanks, pipe and structural weldments, but it does not qualify the WPS, filler or surface restoration — and Mo alloying is still not a substitute for duplex or higher alloys in severe chloride envelopes. | Generally weldable with a qualified procedure and matching or over-alloyed filler where required; remove heat tint when corrosion service demands it. |
| Forming | Annealed 316L sheet and strip draw and bend well, but the alloy work-hardens during forming — tooling load, springback, bend direction, draw ratio and any intermediate anneal must be proven on the actual gauge and reduction route. | Good ductility is typical, but rapid work hardening increases forming load and springback; bend radius and intermediate annealing depend on grade and reduction. |
| Machining | Use rigid tooling, positive feeds and controlled cutting heat to avoid a work-hardened surface; qualify the route on the delivered condition. Free-machining sulfur grades require separate corrosion and welding review. | Use rigid tooling, positive feeds and controlled heat because the material work-hardens; free-machining grades require separate corrosion and welding review. |
| Heat treatment | Solution annealing with rapid cooling restores the intended annealed austenitic condition after suitable cold work or fabrication where applicable. Conventional quench-and-temper treatment does not through-harden austenitic 316L; do not rely on post-weld anneal unless the project actually schedules it. | Solution annealing and rapid cooling restore the intended condition where applicable. Austenitic grades are not hardened by conventional quench-and-temper treatment. |
Reference data
Composition and Mechanical Requirements
Values below come from each grade's displayed reference dataset. Product form, thickness, condition and contracted standard can change the applicable acceptance table.
Chemical composition (wt%)
| Element | 316L | 317L |
|---|---|---|
| C | ≤0.030 | ≤0.030 |
| Mn | ≤2.00 | ≤2.00 |
| Si | ≤0.75 | ≤0.75 |
| Cr | 16.0–18.0 | 18.0–20.0 |
| Ni | 10.0–14.0 | 11.0–15.0 |
| Mo | 2.00–3.00 | 3.0–4.0 |
| P | ≤0.045 | ≤0.045 |
| S | ≤0.030 | ≤0.030 |
| N | ≤0.10 | ≤0.10 |
Mechanical properties
| Property | 316L | 317L |
|---|---|---|
| Tensile strength | ≥485 MPa (70 ksi) | ≥515 MPa (75 ksi) |
| Yield strength (0.2%) | ≥170 MPa (25 ksi) | ≥205 MPa (30 ksi) |
| Elongation (50 mm) | ≥40% | ≥40% |
| Hardness | ≤217 HBW | ≤217 HBW |
Quotation workflow
Application Decisions
- For chemical equipment, provide the complete stream composition, concentration ranges, impurities, pH, temperature, pressure, velocity, aeration and shutdown conditions.
- For pulp and scrubber systems, document oxidants, chlorides, condensate, deposits, wash cycles, abrasion, weld condition and inspection history.
- For hygienic systems, separately specify product contact, cleaning chemistry, surface roughness or sample, weld finish, passivation and contamination controls.
- For a failed 316L component, confirm whether pitting, crevice attack, general corrosion, cracking, erosion, fabrication or cleaning caused the damage before selecting 317L.
Quote 316L when
- General marine, chemical and food-grade duty where 316L has a service record
- Pharmaceutical, food and hygienic projects approved around 316L form, finish and weld controls
- Orders requiring broad availability in common sheet, coil, pipe, tube, bar and fitting routes
- Process duties whose complete operating and cleaning cycle remains within the documented 316L basis
Quote 317L when
- Selected scrubber, pulp and chemical-process zones where corrosion data shows insufficient 316L margin
- Acidic or chloride-bearing equipment qualified for S31703 chemistry, welding and surface restoration
- Retrofit reviews where inspection has identified a 316L corrosion mechanism that added molybdenum may address
- Projects that can obtain the required 317L form, dimensions, matching consumables and certificate scope
Hold point
Do Not Substitute Without Review
- Do not supply 317L against a 316L order, or 316L against a 317L order, without an approved deviation and corrosion, design and welding review.
- Do not infer identical mechanical requirements or design allowables from their shared low-carbon austenitic family.
- Do not assume 317L solves every condition that damages 316L; the mechanism may require duplex, 6Mo, nickel alloy, lining or process change.
- Do not reuse filler, WPS, PMI targets or certificate language without confirming S31703 requirements for the actual product and joint.
Specification boundary
Standards, Temperature and Approval
Product and project approval
ASTM A240/A240M can govern 316L and 317L flat product, while pipe, tube, bar, fittings and forgings require their applicable material and dimensional standards. The purchase-order edition, design code, process corrosion basis, welding specification and authorized material reviewer control acceptance.
Temperature boundary
This page provides no universal temperature or concentration threshold for 316L or 317L. Temperature changes acid corrosion, chloride activity, evaporation, cleaning severity and stress-corrosion risk; contaminants, deposits, crevices, flow, weld heat tint and shutdown chemistry can change the result. Use project-specific data and authorized corrosion review.
Commercial comparison
Cost and Availability Factors
Quote 316L and 317L on one RFQ with the same product form, dimensions, tests and documents. This page does not represent current stock, price or lead time.
Cost factors
- Current nickel and molybdenum inputs plus heat availability for S31603 or S31703 in the required form.
- Dimensions, finish, tolerances, forming, machining, welding consumables, production yield and surface restoration.
- MTC, PMI, corrosion or supplementary testing, NDE, sample approval, inspection and witness points.
- Quantity, mill minimum, matching components, packing, freight, Incoterm, delivery window and requalification work.
Inputs for a like-for-like quotation
- UNS S31603 or S31703, product form, current material and dimensional standards, design code and substitution policy.
- Dimensions, quantity, delivery condition, finish, surface acceptance, tolerances and edge or end preparation.
- Process and cleaning chemistry, concentration, contaminants, chlorides, pH, temperature, deposits, crevices and flow.
- Fabrication drawing, weld procedure and consumable basis, heat-tint removal, pickling, passivation and finish restoration.
- MTC type, heat traceability, PMI, corrosion or other tests, NDE, inspection, packing, destination and Incoterm.
Continue the specification
Related Grades, Standards and Applications
Grade references
316L Stainless Steel Sheet
316/316L stainless sheet for chloride and chemical service in 2B, BA and brushed finishes. Common inquiry range 0.3–6.0 mm, 1000/1219/1500 mm, cut to size.
View details →
316L Stainless Steel Seamless Pipe
Seamless 316L ASTM A312 pipe, pickled and annealed. Common inquiry range NPS 1/8–24, Sch 5S–XXS, 6 m or cut-to-length, with quoted tests and heat identity.
View details →
Buyer questions
Frequently Asked Questions
Is 317L stronger than 316L?
The displayed ASTM A240 engineering summaries do not show identical minimums: 317L is listed higher in the summarized annealed flat-product values. Use the current standard, product form and design code rather than treating that difference as a general structural upgrade.
How much more does 317L cost?
There is no fixed premium or lead-time rule. Molybdenum content, product form, size, mill route, quantity and testing affect the delivered quotation; compare 317L and 316L for the same specification and procurement date.
Can a 316L weld procedure be reused for 317L?
Do not assume so. The engineer and welding specification must confirm base-metal grouping, consumable chemistry, dilution, heat input, qualification range, corrosion basis and post-weld surface treatment for the actual joint.
Published by Tsingshan (Shandong) Iron & Steel Co., Ltd..Sources, update policy and technical limitations.
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