Austenitic Stainless · JIS G 4304
SUS 317J1 Forgings Seamless rolled rings, flanges, shafts, discs and bars in 18Cr-16Ni-5Mo stainless, melted and forged on one site.
SUS 317J1 is the molybdenum-rich end of the 317 family. Five percent molybdenum and sixteen percent nickel buy service life in liquor that eats 316L, which is why it turns up in bleach plant, phosphoric acid plant and chloride-bearing heat exchangers. We melt it in our own furnaces and forge it on presses up to 6,300 tonnes.
- Standard
- JIS G 4304
- Nominal
- 18Cr-16Ni-5Mo
- Structure
- Austenitic, non-magnetic
- Condition
- Solution annealed and quenched
- Max ring
- 6,000 mm outside diameter
- Max piece
- 30,000 kg
- Min order
- 10 kg, no minimum count
- Lead time
- 20 to 60 days
- Enquiries
- sales@steelforgepieces.com
SUS 317J1 in short. A Japanese austenitic stainless steel of nominal 18Cr-16Ni-5Mo. JIS G 4304 sets it at C 0.040 max, Si 1.00 max, Mn 2.50 max, P 0.045 max, S 0.030 max, Ni 15.00 to 17.00, Cr 16.00 to 19.00 and Mo 4.00 to 6.00. Solution treated it must reach 175 N/mm² proof stress, 480 N/mm² tensile and 40 % elongation at no more than 187 HBW. Japanese material references place it where SUS 317L and SUS 316L run out of margin: heat exchangers carrying chloride-bearing liquor, acetic acid plant, phosphoric acid plant and bleaching equipment. Jiangyin Jiangnan Metal Co., Ltd. melts and forges this grade at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, as rings to 6,000 mm outside diameter and single pieces to 30 tonnes. Contact sales@steelforgepieces.com or +86 189 2135 9659.
Chemical Composition
Limits below are the JIS G 4304 specification, not a typical analysis. Our melt shop aims the heat inside these bands and reports the actual figures on the certificate.
| Element | Limit | Function |
|---|---|---|
| Carbon, C | 0.040 max | Kept low to restrict carbide precipitation |
| Silicon, Si | 1.00 max | Deoxidation residual |
| Manganese, Mn | 2.50 max | Austenite stabiliser |
| Phosphorus, P | 0.045 max | Residual |
| Sulfur, S | 0.030 max | Residual |
| Chromium, Cr | 16.00 – 19.00 | Forms the passive film |
| Nickel, Ni | 15.00 – 17.00 | Austenite stability, well above 317L |
| Molybdenum, Mo | 4.00 – 6.00 | The addition that defines the grade |
| Iron, Fe | Balance | Matrix |
A warning about the figures circulating online. Several English-language grade databases publish an 18–20 Cr / 11–15 Ni / 3–4 Mo analysis under the name SUS 317J1. That is not what JIS specifies, and it appears to be plain SUS 317 data filed under the wrong heading. Two of those same sites also list a yield strength above their own tensile strength and a density range spanning a factor of two, so treat them with care. If a buyer hands you that chemistry on an enquiry, raise it before anyone cuts metal.
Mechanical Properties
Values are the JIS acceptance limits in the solution-treated condition. Heavy forged sections behave differently from bar stock, so where a project needs guaranteed properties at a stated depth we agree the test location and sampling plan at order stage.
| Property | Requirement |
|---|---|
| 0.2 % proof stress | 175 N/mm² min |
| Tensile strength | 480 N/mm² min |
| Elongation | 40 % min |
| Hardness, Brinell | 187 HBW max |
| Hardness, Rockwell B | 90 HRBS / HRBW max |
| Hardness, Vickers | 200 HV max |
Where The Grade Sits
SUS 317J1 is a Japanese designation with no AISI number of its own. The Dandong Foundry stainless grade comparison table pairs it with the Chinese grade 0Cr18Ni16Mo5, which lines up with the 18Cr-16Ni-5Mo chemistry. We are not aware of a published one-to-one European or UNS equivalent, and we would rather say so than invent one.
Buyers sometimes reach this page while cross-shopping UNS S31703 (317L) or UNS S31753 (317LN). Those are relatives, not substitutes. 317L runs leaner on both nickel and molybdenum; 317LN adds nitrogen for strength. Swapping between them is an engineering decision, not a purchasing one. Name the governing standard on the order and we will forge to it.
How We Make It
Most forging suppliers in China buy billet. We start a step earlier. Stainless and duplex grades go through the 25 t electric arc furnace, a ladle furnace for desulphurisation and alloy trim, then vacuum oxygen decarburisation where low carbon or tight nitrogen control matters. A grade like SUS 317J1, with its 0.040 % carbon ceiling and 6 % molybdenum ceiling, is exactly the case VOD exists for.
From there the steel is cogged under a 2,000, 4,000 or 6,300 tonne press, or punched and rolled on one of three radial-axial ring mills. Heat treatment runs through fourteen furnaces on site, including a 15 m deep well furnace for vertical quenching of long shafts. Nothing is subcontracted, so a part never leaves the works between the furnace and the inspection bay.
Heat Treatment and Machining Notes
SUS 317J1 is austenitic and cannot be hardened by heat treatment. It ships solution annealed and rapidly quenched, which puts the carbides back into solution after hot work and restores corrosion resistance. We set the exact soak temperature from the standard or specification governing your order rather than applying a blanket figure, because the right number differs between JIS, an ASTM equivalent and a client specification.
On the lathe it behaves like other high-nickel austenitics. It work hardens the moment the tool dwells, so the answer is positive rake geometry, a rigid setup, heavy coolant and a feed that never stops once it starts. Chips come off long and stringy, so chip breakers earn their keep. Where a customer wants the part proof-machined before ultrasonic inspection, we allow for that in the forging envelope.
Shapes We Forge In This Grade
Rings and Discs
Seamless rolled rings, contoured rings, forged rings, retaining rings, valve seat rings, solid discs, tube sheets and vessel covers.
Shafts and Bars
Stepped shafts, eccentric shafts, spindles, pinion shafts, round bar, flat bar, square bar and gear blanks.
Flanges and Hollows
Weld neck, blind, slip-on, lap joint and orifice flanges, plus sleeves, bushings, couplings and cylinders bored from solid.
Valve and Vessel Parts
Valve bodies, bonnets, stems, blocks, nozzles and manifolds for ball, gate, globe, check and plug valves.
Size Envelope
These limits are set by the machines on the floor, not by a sales estimate. If your part falls outside them, say so early and we will tell you straight whether it is possible.
| Form | Limit | Set by |
|---|---|---|
| Seamless rolled rings | OD 50 – 6,000 mm | 6 m, 3 m and 1 m radial-axial ring mills |
| Forged shafts | to 14,000 mm turned | C61160 lathe, 15 m well furnace for vertical quench |
| Discs, tube sheets, blocks | to 5,000 mm dia | 5,000 mm vertical turning lathe |
| Bored cylinders, hollow shafts | 1,600 mm dia × 10,000 mm | CNC deep-hole drilling machine |
| Single piece weight | to 30,000 kg | 60 t heat size, 6,300 t press |
| Order quantity | from 10 kg | No minimum piece count |
Testing and Certification
Every forging carries chemical analysis, mechanical test results and a dimensional report under EN 10204 3.1. Where a project calls for an independent witness, EN 10204 3.2 certification is arranged with the third party of your choice. Ultrasonic examination follows EN 10228-3, SEP 1921 or ASTM A388, whichever the order nominates, and parts are proof-machined first where the geometry needs it for clean coupling.
Supplementary testing is quoted on request: intergranular corrosion testing, ferrite measurement, positive material identification, impact testing and hardness survey. The works holds CCS, BV, DNV, LR and NK approvals, and 460 staff including 9 senior engineers and 32 intermediate engineers.
Ordering
Send a drawing to sales@steelforgepieces.com. Without one, outside diameter, inside diameter, height or length, quantity, governing standard and any supplementary tests are enough for a budget price. Quotations normally go back within one working day. Minimum order is 10 kg with no minimum piece count, and lead time runs 20 to 60 days depending on section, heat treatment cycle and machining.
Questions We Get Asked
What is SUS 317J1 stainless steel?
A Japanese austenitic stainless steel of roughly 18Cr-16Ni-5Mo. The high molybdenum and nickel put it above SUS 317L and SUS 316L, and Japanese material references list it for heat exchangers handling chloride-bearing liquor, acetic acid plant, phosphoric acid plant and bleaching equipment.
Is SUS 317J1 the same as 317L?
No. SUS 317J1 carries 15 to 17 % nickel and 4 to 6 % molybdenum, well above 317L. A widely published grade comparison table pairs SUS 317J1 with the Chinese grade 0Cr18Ni16Mo5, which matches the 18Cr-16Ni-5Mo chemistry.
What size SUS 317J1 forgings can you make?
Rolled rings run from 50 mm up to 6,000 mm outside diameter on the radial-axial mills. Shafts are turned up to 14,000 mm long, discs and tube sheets up to 5,000 mm diameter, and bored cylinders up to 1,600 mm diameter by 10,000 mm. The heaviest single piece is 30 tonnes, set by the 60 t heat size and the 6,300 t press.
Do you melt SUS 317J1 yourselves or buy billet?
We melt it. Stainless grades run through the electric arc furnace, the ladle furnace and vacuum oxygen decarburisation on the same site as the presses and ring mills, so the certificate traces back to the melt number rather than stopping at a purchased billet.
Can the grade be hardened by heat treatment?
No. Austenitic grades gain strength only from cold work. SUS 317J1 is supplied solution annealed and quenched.
What certification comes with the forgings?
EN 10204 3.1 as standard and EN 10204 3.2 third-party certification on request. Ultrasonic testing follows EN 10228-3, SEP 1921 or ASTM A388 as nominated. The works holds CCS, BV, DNV, LR and NK approvals.
What is the minimum order and lead time?
The minimum order is 10 kg with no minimum piece count. Lead time runs 20 to 60 days depending on section size, heat treatment cycle and machining.
Where These Figures Come From
Composition and mechanical limits are the JIS G 4304 values as published by susjis.info and by the Caishuku material database, which cites JIS G 4304-2005. The 0Cr18Ni16Mo5 pairing comes from the Dandong Foundry stainless grade comparison table. Plant capacities are our own. Reproduced for reference; the current edition of the applicable standard governs.
Published by Jiangyin Jiangnan Metal Co., Ltd. Reviewed by our forging and quality engineering staff. Last checked 4 October 2026. Markdown version: SUS-317J1.md