Grade dossier
317L Stainless Steel for Welded Corrosion-Resistant Equipment
The low-carbon 317 variant combining 3-4% molybdenum with improved resistance to weld sensitization for fabricated chemical and process equipment.
Identity before substitution
Define the grade, product and condition together
A familiar grade name is not a complete purchase specification. Product form, controlling standard, dimensions, condition, finish, certification and service environment determine whether the delivered material is suitable.
Composition control
ASTM A240/A240M flat-product chemistry
Limits are not heat analysis targets
The table summarizes grade limits commonly used for plate, sheet and strip. Pipe, tube, bar, forgings and cast products can be governed by different specifications. Always place the product standard and edition on the purchase order.
| C | 0.030 max |
|---|---|
| Mn | 2.00 max |
| Si | 0.75 max |
| P | 0.045 max |
| S | 0.030 max |
| Cr | 18.00-20.00 |
| Ni | 11.00-15.00 |
| Mo | 3.00-4.00 |
| N | 0.10 max |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 515 MPa min |
|---|---|
| 0.2% yield strength | 205 MPa min |
| Elongation | 40% min |
| Hardness | 95 HRBW max |
Selection indicators
| Density | about 8.0 g/cm3 |
|---|---|
| Typical producer chemistry | about 18.5Cr-14.5Ni-3.1Mo |
| Corrosion position | More molybdenum than standard 316L |
| Welding note | Low carbon reduces sensitization risk; procedure control still matters |
Values depend on product form, thickness, test orientation, condition and governing edition. Use the mill test certificate and the purchase specification for acceptance, not a web table alone.
Selection boundary
Where 317L belongs and where to escalate
Grade selection is an environmental decision, not a popularity contest. Review the complete medium, temperature, geometry, fabrication, cleaning and inspection requirements.
Good reasons to evaluate it
Chemical-processing vessels and piping after media review
Pulp and paper process equipment
Dyeing and selected acid-handling systems
Welded equipment requiring S31703 certification
Reasons to stop and review
Claiming universal seawater resistance
Using 317L when deposits and crevices remain uncontrolled
Confusing 317L with 317 or 317LMN
RFQs that omit media concentration and temperature
Fabrication route
Protect properties through cutting, forming and welding
Select filler for composition, dilution and corrosion service.
Remove heat tint and restore the specified surface condition.
Use exposure-specific test data where failure consequence is high.
Confirm product availability, thickness and certificate scope early.
Supply definition
Product form changes the applicable requirements
Do not send an RFQ that names only the grade. State form, governing standard, dimensions, tolerances, finish, edge or end condition, quantity, certification and inspection.
Plate, sheet and strip to ASTM A240/A240M
Billet and bar under applicable standards
Pipe and tube under product-specific specifications
Forgings, fittings and welded process equipment
Certificate checkpoint
Request heat identity, chemical analysis, mechanical results and compliance to the exact product specification. Add PMI, corrosion testing or supplementary examination only when the application requires it.
Interactive selection check
Test 317L against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 317L stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 317L replace another grade?
Only after checking the governing standard, composition, mechanical properties, corrosion exposure, fabrication route and certification. A commercial name is not a substitution approval.
Does the table apply to every product form?
Not automatically. The values shown use flat-product requirements as a reference. Other forms can use different product standards, dimensions and tests.
What should a 317L RFQ include?
Product form, standard and edition, UNS or EN designation, dimensions, tolerances, finish, quantity, service, fabrication, certificate and inspection requirements.
Sources, scope and RFQ
Use traceable grade data, then specify the actual product
ASTM A240/A240M requirements for UNS S31703 flat product
Alleima 3R64 official 317L/S31703 datasheet
Outokumpu Ultra 317L official grade identity and typical chemistry
Applicable product-form specification and project corrosion data