1.3817 specification summary
1.3817 is the European material number for X40MnCr18, an austenitic non-magnetizable steel supplied to Stahl-Eisen-Werkstoffblatt SEW 390. Its specified composition is 0.30–0.50 % C, ≤ 1.00 % Si, 17.0–19.0 % Mn, ≤ 0.060 % P, ≤ 0.030 % S, 3.00–5.00 % Cr, ≤ 1.00 % Ni and ≤ 0.10 % N. In the solution-annealed condition published values are 750–950 MPa tensile strength, a 0.2 % proof stress of at least 280 MPa, and, longitudinally, at least 35 % elongation with 85 J Charpy impact energy (20 % and 55 J transverse). It is the classic “18Mn-5Cr” family used for generator retaining rings, where extensive cold expansion can take the proof stress to an upper limit of about 1,200 MPa.
Jiangyin Jiangnan Metal Co., Ltd. forges 1.3817 into seamless rolled rings up to 6,000 mm outside diameter, forged rings and discs, shafts, sleeves, hollow bars, blocks and round, square and flat bars, up to 30 tonnes single-piece weight. Steel is melted at the works and, for ring and retaining-ring work, remelted on the 3 t or 6 t protective-atmosphere electroslag furnace. Minimum order is 10 kg with no minimum piece count, normal lead time is 20 to 60 days, and a complete enquiry is quoted within two working days. Contact sales@steelforgepieces.com or 0086-189-2135-9659.
Two points on this grade are often left off supplier datasheets. Magnetic-particle inspection cannot be used on it, and the 18Mn-5Cr family has a documented stress-corrosion-cracking history that limits where it should still be specified. Both are covered below under non-destructive examination and retaining rings and stress-corrosion cracking.
What forged products are available in 1.3817 / X40MnCr18?
Three routes cover the grade, chosen by geometry and quantity. Seamless ring rolling on the radial-axial mills produces rings from small bearing sizes up to 6,000 mm outside diameter, and is the normal route for retaining rings, rotor end rings and non-magnetic flange blanks. Open-die forging on the 6,300 t, 4,000 t and 2,000 t hydraulic presses covers shafts, blocks, hollow bars and large discs. Upset-and-punch forging handles short, heavy-section rings and hubs that fall outside the ring-mill envelope. Every piece is forged from a single ingot, with no welding, no casting and no purchased billet of unknown origin.
- Seamless rolled rings
- Forged rings
- Retaining ring and end-ring blanks
- Forged discs
- Tube sheets and covers
- Forged shafts and spindles
- Sleeves, bushes and hollow bars
- Round, square and flat bars
- Forged blocks and slabs
- Flange blanks
- Bolt and stud blanks
- Valve and instrument parts
Cleanliness matters more than near-net shape on this grade
1.3817 is not an expensive alloy by nickel-alloy standards, so profiling a die to the finished contour saves less than it would on a nickel forging. Internal soundness is the usual constraint instead. High-manganese ingots are prone to freckle and streak segregation, and retaining-ring stock is normally electroslag remelted for that reason. Allow for the remelt on any ring that will be ultrasonically examined to a tight class, and state it on the enquiry, because it affects both price and lead time.
What is 1.3817 (X40MnCr18)?
1.3817 is a solid-solution, high-manganese austenitic steel designed to be non-magnetizable while carrying high mechanical stress. The EN chemical-symbol name X40MnCr18 sets out the composition directly: 0.40 % carbon nominal (the “40”), manganese as the principal alloying element at 18 %, and chromium second. The behaviour of the steel in service follows from those three elements.
Manganese at 17–19 %
Manganese is a strong austenite stabiliser. At this level the face-centred-cubic structure is retained at room temperature and does not transform to ferromagnetic α′-martensite under cold deformation. A part can be cold expanded, drawn or straightened and still measure non-magnetic afterwards, which is what a generator retaining ring requires.
Carbon at 0.30–0.50 %
Carbon is a second austenite stabiliser and the main reason the grade work-hardens steeply. It also rules out treating 1.3817 as a corrosion-resistant steel. With 3–5 % chromium and carbon at this level there is no stable passive film, and chromium carbides will form at grain boundaries if the steel is held in the sensitising range.
Chromium at 3–5 %
Chromium at this level acts as a strengthener and gives some improvement in oxidation and general corrosion behaviour. It is not enough to passivate the surface. Parts needing corrosion resistance as well as non-magnetic behaviour should go on the 18Mn-18Cr grades or on a nitrogen-alloyed austenitic stainless such as Nitronic 50. Nitronic 50 is commonly cross-referenced in Europe to 1.3964, but the two are not a composition match: 1.3964 carries more nickel and molybdenum. Order against the designation your specification names.
Not hardenable by heat treatment
There is no quench-and-temper response. The delivery condition is solution annealed and water quenched, and strength above the annealed minimum comes from cold work. On rings that is done by cold expansion, which forms the ring to size and work-hardens it in the same operation.
Where the grade is used
Mill datasheets for this grade list it for non-magnetizable components in machine construction with high yield-strength requirements, specifically profile shapes and proof shafts for rotor forgings. The 0.5C-18Mn-4/5Cr family it belongs to is also the family from which several thousand generator retaining rings were forged over some thirty years. The non-magnetizable steel class more generally is used wherever a structural part sits inside or beside a magnetic circuit: rotor end components, transformer tanks and clamping structures, switchgear and high-voltage apparatus hardware, and non-magnetic profiles in electrical machine construction. A ferritic steel in any of those positions would concentrate stray flux, raise eddy-current heating and cost efficiency. Please state the application on the enquiry as well as the grade, so we can check one against the other.
What 1.3817 is not for
This grade is regularly mis-specified for chemical, food and refinery service on datasheets whose text was copied from austenitic stainless grades. It has no useful resistance to acids, chlorides or polythionic acid, and once cold worked to high strength it is susceptible to stress-corrosion cracking in moist environments. If the duty involves a corrosive medium, ask us for a different grade before placing the order.
What are the equivalent designations and standards for 1.3817?
The grade appears on drawings under several names. They describe the same material, and Jiangyin Jiangnan Metal accepts purchase orders under any of them, cross-certified on one mill test certificate.
| System or body | Designation | Notes |
|---|---|---|
| Germany, Werkstoff number | 1.3817 | The unambiguous wording for a purchase order |
| Europe, chemical-symbol name | X40MnCr18 | Used on EN-style certificates |
| Delivery specification | SEW 390 (1991-11) | Nichtmagnetisierbare Stähle — Technische Lieferbedingungen. A VDEh Stahl-Eisen-Werkstoffblatt, not a DIN or EN standard, and not superseded by one. Beware datasheets that cite “EN 10090” for this grade: EN 10090 is valve steels and alloys for internal combustion engines and has nothing to do with it |
| Common trade usage | 18Mn-4Cr, 18Mn-5Cr, “18/5” | Generic family name in the generator industry |
| Cold-worked variant | X40MnCr18K | The suffix K denotes the cold-worked (kaltverfestigt) delivery condition |
| Related, higher-nitrogen | 1.3813 / X40MnCrN19 | Nitrogen-alloyed development of the same family, higher proof stress |
| Related, higher-chromium | 1.3816 / X8CrMnN18-18 | The 18Mn-18Cr retaining ring grade that superseded 18Mn-5Cr: C ≤ 0.12, Cr 17.5–20.0, N 0.40–0.70. Not interchangeable. Some trader sites render the name as “X8CrMnN18-8”, which is wrong |
| United States, nearest family | ASTM A289 (50Mn18Cr5 type) | Alloy steel forgings for non-magnetic retaining rings. Closely related but not identical. Confirm carbon and chromium against the class limits before substituting |
| Permeability measurement | ASTM A342 | Test methods for permeability of weakly magnetic materials |
| Ultrasonic examination | ASTM A531 · EN 10228-3 · SEP 1921 | A531 is the practice written for turbine-generator retaining rings |
| Certification | EN 10204 3.1 / 3.2 | 3.1 as standard, 3.2 with third-party witness on request |
A note on ASTM A289
ASTM A289/A289M, Standard Specification for Alloy Steel Forgings for Nonmagnetic Retaining Rings for Generators, was withdrawn by ASTM in September 2023 without replacement. There is therefore no live ASTM specification a buyer can cite for these forgings, and any datasheet listing A289 as current is misleading. Projects and OEM specifications still invoke the last edition, 97(2018), by agreement. If your specification calls for A289, say on the enquiry that you are applying that edition, so the acceptance criteria are fixed before the order is placed rather than argued at inspection. The requirement in it that most affects price is that the steel be made by the electroslag remelting process, which this works has in-house.
What is the chemical composition of 1.3817?
The limits below are the SEW 390 requirements for X40MnCr18. Every heat forged here is verified twice: a ladle analysis taken at the furnace, then a product analysis on the forged part by optical emission spectrometry. Both results appear on the certificate. Because the steel is melted at this works rather than bought in as billet, the chemistry can be aimed at the forging it will become.
| Element | Min | Max | Function in the steel |
|---|---|---|---|
| Carbon (C) | 0.30 | 0.50 | Austenite stabiliser and solid-solution strengthener; drives the steep work-hardening rate |
| Silicon (Si) | — | 1.00 | Deoxidiser |
| Manganese (Mn) | 17.0 | 19.0 | Principal alloying element; holds the structure austenitic and non-magnetic through cold work |
| Phosphorus (P) | — | 0.060 | Impurity; segregates to grain boundaries |
| Sulfur (S) | — | 0.030 | Impurity; hot-shortness risk during forging |
| Chromium (Cr) | 3.00 | 5.00 | Strengthener and modest oxidation improver; too low to passivate |
| Nickel (Ni) | — | 1.00 | Residual; further austenite stabilisation |
| Nitrogen (N) | — | 0.10 | Interstitial strengthener; controlled, because higher-nitrogen variants are separate grades |
Reference chemistries published by European mills for their own versions of the grade sit near the middle of these bands, typically around 0.40 % C, 18.0 % Mn and 4.0 % Cr with silicon held to 0.80 % maximum. Customer specifications often narrow one or two bands, usually carbon for cold-expansion behaviour or phosphorus and sulfur for ring cleanliness. State the narrowed limits on the enquiry and they are applied at the furnace rather than screened at the end.
Melting route
Carbon, alloy and high-manganese grades run through the 25 t electric arc furnace, are refined in a 25 t or 50 t ladle furnace, and are vacuum-decarburised where the specification calls for it. For ring stock and any part that will be ultrasonically examined to a tight acceptance class, the electrode is remelted on the 3 t or 6 t protective-atmosphere electroslag furnace. The melting route actually used is reported on the certificate.
What are the mechanical properties of 1.3817?
1.3817 is not hardenable by heat treatment. The solution-annealed rows below are the commonly published requirements for bar and forgings in the solution-treated condition, split by test direction because the longitudinal and transverse figures differ. Several supplier datasheets quote the longitudinal figures without saying so. The cold-worked row is included because retaining rings and similar high-duty parts are usually ordered in that condition.
| Condition | Test direction | Tensile strength Rm | Proof stress Rp0.2 | Elongation A | Impact KV |
|---|---|---|---|---|---|
| Solution annealed and water quenched standard supply | Longitudinal | 750–950 MPa | ≥ 280 MPa | ≥ 35 % | ≥ 85 J |
| Transverse | 750–950 MPa | ≥ 280 MPa | ≥ 20 % | ≥ 55 J | |
| Cold expanded / cold worked rings | By agreement | — | up to ≈ 1,200 MPa | reduced | by agreement |
Two qualifications apply. The values above hold for a limited ruling section, about 100 mm for bars and forgings and about 20 mm for flat products; heavier sections are agreed at order, which on a large ring or a heavy shaft should be settled at enquiry stage. And 175 ksi (1,200 MPa) is the upper limit of proof stress attainable in the manganese-chromium ring alloys through extensive cold expansion, not a typical delivery value. Rings were supplied across a range of strength grades, and what a given ring reaches depends on its section, the expansion ratio and the acceptance criteria in force. Results for every forging are reported on the EN 10204 certificate, tested on coupons taken from the same heat and heat-treatment batch.
Selecting on strength
The annealed proof stress of 280 MPa is low, and the grade is not chosen for its annealed strength. The design case is the cold-worked condition, where the practical limit comes from the stress-corrosion-cracking behaviour described below rather than from the capacity of the steel. Where a part needs non-magnetic behaviour together with a high proof stress and reasonable environmental resistance, the 18Mn-18Cr grade (1.3816 / X8CrMnN18-18) is the current choice, and we forge it as well. State the required strength level on the enquiry and we will confirm which grade meets both requirements before the drawing is issued.
Physical and magnetic properties of X40MnCr18
| Property | Value | Condition and remarks |
|---|---|---|
| Density | ≈ 7.80 g/cm³ | Room temperature; use for forging weight estimates |
| Modulus of elasticity | ≈ 190–195 GPa | Room temperature, typical. Lower than the 200–210 GPa of ferritic steel, as with other high-manganese austenites. Do not substitute the carbon-steel figure in a stiffness calculation |
| Structure | Austenitic, FCC | Stable at room temperature and through cold deformation |
| Relative permeability μr | < 1.01 | SEW 390 sets this as the defining limit for a non-magnetizable steel; solution-annealed material sits close to 1.00. Cold work, residual straightening stress and surface condition all move the figure, so state the limit, the method (ASTM A342) and the measuring points on the order |
| Response to cold work | Stays austenitic | Unlike 304 or 316, heavy cold deformation does not produce ferromagnetic α′-martensite, so permeability stays low after cold expansion or drawing |
| Magnetic-particle inspection | Not applicable | The steel is non-magnetic; specify liquid penetrant instead |
| Corrosion resistance | Low | Not a stainless steel; protect in service and in transit |
Weight check
At 7.80 g/cm³ a 1.3817 ring weighs within about half a percent of the same geometry in carbon steel. Ring weight in kilograms = π/4 × (OD² − ID²) × H × 7.80 × 10⁻⁶, with all dimensions in millimetres. Forged parts are priced on input weight rather than finished weight, so add the machining allowance, the test-coupon allowance and the cropping loss before comparing quotations.
How is 1.3817 forged and heat treated?
1.3817 is hot worked from about 1150 °C and finished above roughly 950 °C. Below that the steel work-hardens quickly, press loads climb and the risk of surface cracking rises. After the last blow the part must be solution annealed in the range 1000–1100 °C and quenched, normally in water; mill practice for this grade commonly sits at 1000–1050 °C. The anneal dissolves grain-boundary carbides and restores a fully austenitic structure. A part that skips it will still pass a tensile test, having lost both toughness and its permeability margin.
Practical forging notes
- Sulfur control. With 18 % manganese the steel is sensitive to hot shortness. Keep sulfur to the low end of the band and use a clean, sulfur-free furnace atmosphere.
- Reduction ratio. A forging ratio of 4:1 or better, worked incrementally with reheats as needed, is the normal target for ring and shaft work in this grade.
- Cooling after forging. Heavy sections should not be left to air-cool slowly from forging heat. The solution anneal and rapid quench are part of the specification.
- Straightening. Straightening or sizing after the anneal puts cold work back into the part. Where permeability or hardness is limited, control the amount and re-verify afterwards.
Retaining rings: why 18Mn-5Cr was replaced by 18Mn-18Cr
Generator retaining rings hold the rotor end windings against centrifugal force and are among the most highly stressed components in a turbine generator. From the middle of the twentieth century the usual material was the cold-expanded 18Mn-5Cr steel of which 1.3817 is a member, chosen because it is non-magnetic and can be work-hardened to a very high proof stress. Most supplier datasheets for the grade stop there, which leaves out what happened next.
From the late 1970s a pattern of failures emerged. The hardened 18Mn-5Cr alloy is tough in a conventional fracture-toughness test but susceptible to stress-corrosion cracking in water, damp hydrogen and chlorides, which are the conditions that arise when moisture condenses on a ring during a shutdown or when stator cooling water leaks. Published counts of in-service failures differ. A 1994 worldwide assessment documented nine failures of 18/5 rings; a later industry account puts the figure at more than thirty. A ring that bursts destroys the stator winding and the iron behind it, so the consequence of a failure weighs more heavily than its frequency.
The response was a non-ferromagnetic alloy with far more chromium, 18Mn-18Cr (1.3816 / X8CrMnN18-18 and equivalents), developed through the 1980s and adopted progressively for new and replacement rings. It gives comparable strength with considerably better resistance to stress-corrosion cracking in the presence of moisture, and its service record since has been good. It is not immune. There are scattered reports of stress-corrosion cracking in 18Mn-18Cr rings where halides, chlorides and copper ions are present. Generator rebuilds now normally replace 18Mn-5Cr rings with 18Mn-18Cr instead of re-qualifying the old material.
Choosing between 1.3817 and 18Mn-18Cr
1.3817 remains correct for non-magnetic components in dry, controlled environments: transformer and switchgear structures, apparatus hardware, rotor components that are not exposed to moisture, and replacement parts for existing machines built to the original specification. For a new generator retaining ring, send us the machine and the service environment. In most cases 18Mn-18Cr is the grade we would recommend, and we will say so before quoting. For a like-for-like replacement on an older unit, state the original drawing and specification so the replacement matches what the machine was designed around.
1.3817 compared with the grades it competes against
The usual question is whether a cheaper austenitic stainless will do, or whether the job needs a higher-chromium non-magnetic grade. The table sets out the alternatives we most often quote against 1.3817.
| Property | 1.3817 X40MnCr18 |
1.3813 X40MnCrN19 |
1.3816 X8CrMnN18-18 |
Nitronic 50 S20910 / XM-19 |
AISI 304 S30400 |
|---|---|---|---|---|---|
| Carbon, % | 0.30–0.50 | ≈ 0.40 | ≤ 0.12 | ≤ 0.06 | ≤ 0.08 |
| Manganese, % | 17.0–19.0 | ≈ 19 | 17.5–20.0 | 4.0–6.0 | ≤ 2.0 |
| Chromium, % | 3.00–5.00 | ≈ 4 | 17.5–20.0 | 20.5–23.5 | 18–20 |
| Nitrogen, % | ≤ 0.10 | alloyed | 0.40–0.70 | 0.20–0.40 | — |
| Non-magnetic after cold work | Yes | Yes | Yes | Yes | No — forms martensite |
| Proof stress, annealed | ≥ 280 MPa | ≥ 390 MPa (hot-cold formed) | high | ≥ 380 MPa | ≥ 205 MPa |
| Proof stress, cold worked | up to ≈ 1,200 MPa | ≥ 600 MPa, Rm 850–1,250 MPa | very high | moderate | moderate |
| Corrosion resistance | Low | Low | Moderate | High | Good, not chloride |
| SCC resistance in moist service | Poor when cold worked | Limited | Good | Good | Poor above 60 °C in chlorides |
| Specify it when… | A non-magnetic structural part in a dry environment, or a like-for-like replacement | Higher annealed proof stress is needed in the same family | New generator retaining rings and moisture-exposed rotor parts | Non-magnetic and corrosion-resistant | General service where magnetic behaviour does not matter |
The 304 row is included because it is a common source of error. Austenitic stainless steels of the 304 and 316 type measure non-magnetic in the annealed condition, but they form strain-induced martensite when cold worked, bent or heavily machined, and the permeability then climbs. They are not a substitute for a non-magnetizable steel where a permeability limit appears on the drawing.
Machining, welding and non-destructive examination
Machining
1.3817 machines like other heavily work-hardening austenitic steels, with the carbon and manganese together giving a steep hardening rate. Use rigid setups and sharp, positive-rake carbide tooling. Keep a heavy positive feed so the tool cuts beneath the work-hardened layer rather than rubbing on it, run modest cutting speeds, flood with coolant and avoid dwelling. A tool that stops cutting glazes the surface, and the next pass then has to cut harder material. Where a bore above roughly Ø100 mm is needed, a trepanned or forged-hollow blank saves both material and drilling time against a solid forging.
Welding
Fusion welding of 1.3817 is not normal practice and is not recommended for load-carrying joints. With carbon at 0.30–0.50 % the heat-affected zone forms carbides and loses both toughness and permeability margin, and a weld on a cold-worked part removes the cold work that provides its strength in that area. Where a joint cannot be avoided, treat it as a special process: qualify the procedure, allow for a post-weld solution anneal, and re-verify permeability and mechanical properties afterwards. Raise it at enquiry stage so it can be planned.
Non-destructive examination
Magnetic-particle inspection cannot be used on this grade
1.3817 is austenitic and non-magnetic, so magnetic-particle examination will not work on it. Specifying MT on the drawing adds nothing and stops the order at the inspection stage. Specify liquid penetrant to ASTM E165 / E1417 for surface examination instead.
For volumetric examination, note that the usual austenitic-forging practice is not the one for this application. ASTM A745/A745M states that ultrasonic examination of non-magnetic retaining ring forgings should be made to ASTM A531/A531M rather than to A745. A531 is the practice written for turbine-generator retaining rings. European work is normally placed against EN 10228-3 or SEP 1921, and general austenitic forgings against ASTM A388/A388M. Coarse-grained austenitic forgings attenuate and scatter ultrasound, so expect a lower test frequency and a calibration block cut from the same grade and heat-treatment condition. State the practice and the acceptance class on the enquiry. One class either way can decide whether a ring is accepted or scrapped.
Production capability: 1.3817 forging manufacturer
Jiangyin Jiangnan Metal Co., Ltd. has operated as an integrated melting works and open-die forging plant in Zhouzhuang Town, Jiangyin, Jiangsu Province since 1997. It employs 460 people, including 9 senior engineers, 32 intermediate engineers and 140 technicians. Melting, forging, ring rolling, heat treatment, machining and testing are all on one site, so a certificate traces a part back to its melt number instead of stopping at a purchased billet. The works holds CCS, BV, DNV, LR and NK classification society approvals and exports to North America, Europe, the Middle East and Asia-Pacific.
| Operation | Equipment | Capability for 1.3817 |
|---|---|---|
| Primary melting | 25 t electric arc furnace, 25 t and 50 t ladle furnaces, 30 t and 60 t VOD | Maximum heat size 60 t; chemistry aimed at the forging at the furnace |
| Remelting | 3 t and 6 t protective-atmosphere electroslag furnaces (IGESR) | ESR ingot for ring and retaining-ring stock, as A289-type specifications require |
| Open-die forging | 6,300 t, 4,000 t and 2,000 t hydraulic presses; 5 t to 750 kg hammers | Shafts, blocks, hollow bars and heavy discs to 30 t single-piece weight |
| Ring rolling | Radial-axial mills, 6 m, 3 m and 1 m | Seamless rolled rings from OD 50 mm to OD 6,000 mm |
| Heat treatment | 14 furnaces, including two 15 m well-type furnaces and three high-temperature car-bottom furnaces | Solution annealing 1000–1100 °C with chart recording; quench tank alongside the door; long shafts quenched vertically |
| Machining | Vertical lathes to Ø5,000 mm swing, horizontal lathes to 14 m, CNC deep-hole drilling to Ø1,600 × 10,000 mm | As-forged, proof-machined or finish-machined to drawing |
| Chemistry | Optical emission spectrometer, infrared carbon–sulfur analyser, handheld PMI | Ladle and product analysis, both reported on the certificate |
| Mechanical testing | 600 kN and 300 kN universal testing machines, pendulum impact tester with low-temperature bath | Tensile to ASTM A370 / ISO 6892; Charpy V-notch to −60 °C |
| Non-destructive examination | Digital ultrasonic flaw detectors, penetrant line, industrial endoscope | UT to ASTM A531 / A388 / EN 10228-3; PT to ASTM E165 (MT not applicable) |
| Metallography | Microscope, mounting press, polisher; CNC wire-cut EDM for specimens | Grain size to ASTM E112; macroetch and cleanliness ratings on request |
Minimum order 10 kg
No minimum piece count. A single small part can be quoted, and so can a one-off large ring, which is unusual for a plant running a 6,300 t press.
Lead time 20 to 60 days
Lower end where the steel goes straight from the arc furnace to the press. Upper end where electroslag remelting, witnessed testing or tight UT classes are involved.
Quotation in 2 working days
From a complete enquiry. Incomplete enquiries need a round of questions first, which is the usual reason a price takes longer.
Made to order
Jiangyin Jiangnan Metal is a manufacturer, not a stockist or trading company. Every forging is produced to a customer drawing or specification from steel melted at the works.
What testing and certification is supplied with 1.3817 forgings?
Standard supply is an EN 10204 3.1 mill test certificate issued by our own quality department, listing the heat number, ladle and product chemistry, the melting route, the solution-annealing cycle used, tensile and hardness results, the dimensional report and NDE results. EN 10204 3.2 certificates witnessed by BV, DNV, Lloyd's Register, SGS, TÜV or your own inspector are available on request.
Tests available on request
Relative permeability to ASTM A342 · grain size to ASTM E112 · macroetch to ASTM E381 · non-metallic inclusion rating to ASTM E45 or ISO 4967 · Charpy V-notch at ambient or low temperature · hardness mapping on heavy sections · positive material identification before shipment · ultrasonic examination to a nominated practice and class.
Documentation package
EN 10204 3.1 or 3.2 certificate · heat-treatment chart for the annealing batch · UT and PT reports with the acceptance criteria stated · dimensional inspection report against the drawing · marking record carrying heat number, grade, drawing number and works number · packing list, photographs and shipping marks.
Non-conformance handling
An out-of-specification finding is reported in writing within 24 hours. You receive the finding and the proposed disposition, whether rework, re-anneal, regrade or scrap, before anything is done to the part. Records are retained for ten years so a claim can be traced back to the melt.
How to specify a 1.3817 forging order
An enquiry carrying the seven items below can be priced within two working days. Each missing item costs about a day in emails.
| # | Item | Example |
|---|---|---|
| 1 | Grade wording | 1.3817 / X40MnCr18 to SEW 390, or your own company specification |
| 2 | Drawing or dimensions | OD 1,200 × ID 900 × H 260 mm, or PDF / DWG / DXF / STEP |
| 3 | Delivery condition | Solution annealed and water quenched, or cold worked to a stated proof stress |
| 4 | Magnetic requirement | Relative permeability ≤ 1.01, measured to ASTM A342, at stated locations |
| 5 | Melting route | EAF + LF, or ESR remelted, if your specification requires it |
| 6 | Testing and NDE | UT practice and acceptance class; PT per ASTM E165; grain size; impact temperature |
| 7 | Certification and commercial | EN 10204 3.1 or 3.2 with inspection body; quantity; required date; Incoterm and destination port |
Drawing callout template
MATERIAL: 1.3817 / X40MnCr18, non-magnetizable steel per SEW 390
MELTING: EAF + LF (+ ESR remelt where specified); route to be reported
CONDITION: Solution annealed 1000-1100 C, water quenched
(+ cold expanded to Rp0.2 >= xxx MPa, rings only)
MECHANICAL: Rm 750-950 MPa, Rp0.2 >= 280 MPa, A >= 35%, Z >= 40%,
KV >= 85 J transverse, in the solution annealed condition
MAGNETIC: Relative permeability <= 1.01 per ASTM A342, measured at
[state locations]; report every reading
NDE: UT per ASTM A531 (retaining rings) or ASTM A388 / EN 10228-3
(state class); PT per ASTM E165 Type I Method C
-- MT NOT APPLICABLE, MATERIAL IS NON-MAGNETIC
GRAIN SIZE: ASTM E112, [state requirement]
CERTIFICATION: EN 10204 3.1 (3.2 with third-party witness if required)
MARKING: Heat number, grade, drawing number, low-stress stamp or vibro-etchSpecification errors that cost money on 1.3817 orders
- Requesting magnetic-particle inspection. The steel is non-magnetic, so MT cannot be carried out. Specify liquid penetrant instead, or the order stops at the inspection stage.
- Calling up ASTM A745 for a retaining ring. That practice points non-magnetic retaining ring forgings to ASTM A531 instead. Naming the wrong one leaves the acceptance criteria open until after the part is made.
- Leaving the permeability requirement off the drawing. Where a permeability limit matters to the machine, it needs to be stated, measured and reported at named locations. The grade name alone is not a guarantee.
- Omitting the post-forge solution anneal from the specification. The forging will pass its tensile test while failing on toughness and permeability. State the anneal temperature and the quench.
- Treating 1.3817 as corrosion resistant. It is not a stainless steel. Datasheets listing it for acid, food or refinery service have copied text from an unrelated grade. Protect the part in service and specify a preservative for sea freight.
- Specifying 18Mn-5Cr for a new moisture-exposed retaining ring. Given the stress-corrosion-cracking record, this should be a deliberate engineering decision rather than a repeat of an old drawing. Contact us before the drawing is issued.
Frequently asked questions about 1.3817 / X40MnCr18
What is 1.3817 steel?
1.3817 is the European material number for X40MnCr18, an austenitic non-magnetizable steel supplied to SEW 390. It contains 0.30–0.50 % carbon, 17.0–19.0 % manganese and 3.00–5.00 % chromium, with silicon and nickel to 1.00 % maximum and nitrogen to 0.10 % maximum. The high manganese content keeps the structure austenitic at room temperature and through cold work, so the steel stays non-magnetic. It is used for generator retaining rings and rotor components, transformer and switchgear structures, and high-voltage apparatus hardware. Jiangyin Jiangnan Metal Co., Ltd. forges this grade into rings, discs, shafts, sleeves, blocks and bars.
Is 1.3817 magnetic?
No. 1.3817 is an austenitic, face-centred-cubic steel. SEW 390 defines a non-magnetizable steel as one with a relative permeability below 1.01, and solution-annealed 1.3817 sits close to 1.00, which makes it effectively transparent to a magnetic field. Unlike AISI 304 and 316, it does not transform to ferromagnetic α′-martensite when cold worked, so it stays non-magnetic after cold expansion, drawing or heavy machining, where 304 in the same condition becomes weakly ferromagnetic. Permeability still drifts with condition, so where a limit matters, state it on the drawing together with the measurement method (ASTM A342) and the measuring points. Because the steel is non-magnetic, magnetic-particle inspection cannot be used on it; specify liquid penetrant testing instead.
What is the chemical composition of X40MnCr18?
Per SEW 390 for X40MnCr18: carbon 0.30–0.50 %, silicon 1.00 % maximum, manganese 17.0–19.0 %, phosphorus 0.060 % maximum, sulfur 0.030 % maximum, chromium 3.00–5.00 %, nickel 1.00 % maximum and nitrogen 0.10 % maximum, balance iron. Mill reference chemistries for the grade sit near the middle of these bands at approximately 0.40 % carbon, 18.0 % manganese and 4.0 % chromium. See Table 2 for the role of each element.
What are the mechanical properties of 1.3817?
In the solution-annealed and water-quenched condition the published values are a tensile strength of 750–950 MPa, a 0.2 % proof stress of at least 280 MPa, and — longitudinally — elongation of at least 35 % with Charpy impact energy of at least 85 J. Transverse requirements are lower: at least 20 % elongation and 55 J. The values apply to bars and forgings up to roughly 100 mm ruling section; heavier sections are agreed at order. 1.3817 is not hardenable by heat treatment, so strength above the annealed level comes only from cold work, and 175 ksi (1,200 MPa) is the upper limit of proof stress attainable in this family through extensive cold expansion rather than a typical delivery value.
At what temperature is 1.3817 forged and annealed?
Hot working starts from about 1150 °C and should finish above roughly 950 °C. After forging the part must be solution annealed in the range 1000–1100 °C and quenched, normally in water; mill practice for this grade commonly sits at 1000–1050 °C. The anneal dissolves grain-boundary carbides and restores a fully austenitic structure. A forging that is not re-annealed can still pass its tensile test while having lost toughness and permeability margin.
What is the difference between 1.3817 and 1.3816 (18Mn-18Cr)?
1.3817 is the 18Mn-4/5Cr type with 0.30–0.50 % carbon and only 3–5 % chromium. 1.3816 (X8CrMnN18-18) is the 18Mn-18Cr type: carbon capped at 0.12 %, chromium 17.5–20 % and nitrogen alloyed to 0.40–0.70 %. The important practical difference is stress-corrosion cracking. Cold-worked 18Mn-5Cr is susceptible to SCC in moist environments, which caused a series of generator retaining ring failures from the late 1970s onwards; 18Mn-18Cr was developed in response and has been the standard retaining ring material since the 1990s. They are not interchangeable, and substituting one for the other needs end-user approval in writing.
Can 1.3817 be welded?
Fusion welding is not normal practice for this grade and is not recommended for load-carrying joints. With carbon at 0.30–0.50 % the heat-affected zone forms carbides and loses toughness and permeability margin, and welding a cold-worked part locally destroys the cold work that gives it its strength. Where a joint is unavoidable, qualify the procedure, plan for a post-weld solution anneal, and re-verify permeability and mechanical properties. Flag the requirement at enquiry stage.
Which ultrasonic standard applies to 1.3817 forgings?
It depends on the part. ASTM A745/A745M, the usual practice for austenitic steel forgings, states that non-magnetic retaining ring forgings should be examined to ASTM A531/A531M instead, that being the practice written for turbine-generator retaining rings. General austenitic forgings are examined to ASTM A388/A388M, and European work to EN 10228-3 or SEP 1921. Coarse-grained austenitic material attenuates ultrasound, so expect a lower test frequency and a calibration block from the same grade and heat-treatment condition. State the practice and the acceptance class on the enquiry.
Which forged shapes are available in 1.3817?
Jiangyin Jiangnan Metal Co., Ltd. supplies 1.3817 as seamless rolled rings from OD 50 mm to OD 6,000 mm, forged rings and retaining-ring blanks, forged discs and tube sheets to Ø5,000 mm machined, forged shafts to 14,000 mm turned length, sleeves, bushes and hollow bars bored to Ø1,600 × 10,000 mm, forged blocks and slabs, flange and bolt blanks, and round, square and flat bars. Maximum single-piece weight is 30 tonnes, set by the 60 t heat size and the 6,300 t press.
What certification is supplied with 1.3817 forgings?
Standard supply is an EN 10204 3.1 mill test certificate listing heat number, ladle and product chemistry, the melting route, the solution-annealing chart, tensile and hardness results and NDE results. EN 10204 3.2 certificates witnessed by BV, DNV, Lloyd's Register, SGS, TÜV or your own inspector are available on request, as are permeability measurement to ASTM A342, grain size to ASTM E112, non-metallic inclusion ratings and positive material identification reports. The works holds CCS, BV, DNV, LR and NK classification society approvals.
How do I request a quotation for 1.3817 forgings, and what is the lead time?
Send the drawing or finished dimensions, quantity, specification, delivery condition, any permeability limit and the certificate level to sales@steelforgepieces.com, or call, WhatsApp or WeChat 0086-189-2135-9659. A complete enquiry is normally quoted within two working days. Minimum order is 10 kg with no minimum piece count. Normal lead time is 20 to 60 days: the lower end where the steel runs straight from the arc furnace to the press, the upper end where electroslag remelting, witnessed inspection or a tight ultrasonic class is involved.
Does Jiangyin Jiangnan Metal melt its own steel, or buy billet?
Jiangyin Jiangnan Metal melts its own. The works runs a 25 t electric arc furnace with 25 t and 50 t ladle furnaces and 30 t and 60 t vacuum oxygen decarburisation units, plus 3 t and 6 t protective-atmosphere electroslag remelting furnaces for clean ring stock. Maximum heat size is 60 tonnes. This matters for 1.3817 in particular: high-manganese ingots are prone to freckle and streak segregation, and retaining-ring specifications require the electroslag remelting route, which this plant has in house rather than subcontracted.
Cite this page
This page is maintained as a technical reference by our engineering team. If you use the data in a specification, report or tender document, please cite it as:
Jiangyin Jiangnan Metal Co., Ltd. (2026) "1.3817 / X40MnCr18 Non-Magnetic
Steel Forgings: composition, properties, forging and heat treatment."
Updated 21 September 2026.
https://www.steelforgepieces.com/Stainless-Steel/1.3817.htmlCorrections and additions are welcome. If you have measured data for 1.3817 that contradicts anything here, write to sales@steelforgepieces.com and we will review the page and credit the correction.
Standards and references
Composition, property, heat-treatment and inspection data on this page are drawn from the published standards and industry references below. Values on any individual certificate are our own test results, traceable to calibrated equipment.
- SEW 390 (edition 1991-11), Nichtmagnetisierbare Stähle — Technische Lieferbedingungen (Non-magnetizable steels, technical delivery conditions), Stahl-Eisen-Werkstoffblatt, Verein Deutscher Eisenhüttenleute.
- ASTM A289/A289M, Standard Specification for Alloy Steel Forgings for Nonmagnetic Retaining Rings for Generators, ASTM International (withdrawn September 2023 without replacement; last edition 97(2018)).
- ASTM A531/A531M, Standard Practice for Ultrasonic Examination of Turbine-Generator Steel Retaining Rings, ASTM International.
- ASTM A745/A745M, Standard Practice for Ultrasonic Examination of Austenitic Steel Forgings, ASTM International. See the scope clause referring non-magnetic retaining ring forgings to A531.
- ASTM A388/A388M, Standard Practice for Ultrasonic Examination of Steel Forgings; EN 10228-3; SEP 1921.
- ASTM A342/A342M, Standard Test Methods for Permeability of Weakly Magnetic Materials, ASTM International.
- ASTM E165 / E1417, liquid penetrant testing; ASTM E112, grain size; ASTM E45 and ISO 4967, non-metallic inclusion content; ASTM A370 and ISO 6892, mechanical testing.
- EN 10204, Metallic products — Types of inspection documents, CEN, Brussels.
- Electric Power Research Institute, Materials for Generator Retaining Rings: A State-of-the-Art Review, on cold-expanded 18Mn-5Cr strength levels and stress-corrosion behaviour.
- Orita, K., Ikeda, Y., Iwadate, T. and Ishizaka, J., “Development of 18Mn-18Cr Non-magnetic Retaining Ring,” ISIJ International, vol. 30 (1990), no. 8, pp. 587 ff.
- Moore, W., “Damage Mechanisms Found in Generator Rotor 18Mn18Cr Retaining Rings,” Proceedings of the ASME 2016 Power Conference, POWER2016-59101.
- Speidel, M. O., Non-magnetic steels for generator end bells and their resistance to stress corrosion and hydrogen embrittlement, 1981.
- SIJ Metal Ravne, steel selector datasheet for the 1.3817 / X40MnCr18 grade (physical properties and solution-annealing practice).
- ASM Handbook, Volume 14A, Metalworking: Bulk Forming, ASM International, Materials Park, OH.
Standards are referenced without an edition number because editions change; for procurement, always cite the revision in force at the contract date. Data on this page is published in good faith for engineering guidance and does not constitute a warranty of fitness for a particular purpose.
Request a quotation for 1.3817 / X40MnCr18 forgings
Sales and engineering
Jiangyin Jiangnan Metal Co., Ltd.Open-die forging factory and integrated melting works
No.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China, 214423
Telephone, WhatsApp and WeChat: 0086-189-2135-9659
Email: sales@steelforgepieces.com
Enquiries are handled in English and Chinese, Monday to Saturday, 08:00 to 17:30 China Standard Time (UTC+8). Technical questions on chemistry, heat treatment, permeability or inspection scope are answered by an engineer on site.
Send with your enquiry
- Drawing or finished dimensions, and quantity
- Grade wording: 1.3817 / X40MnCr18 to SEW 390, or your specification
- Delivery condition, and any cold-worked strength level
- Permeability limit and where it is to be measured
- UT practice and acceptance class; PT requirement
- Certificate level and inspection body if witnessed
- Required delivery date, Incoterm and destination port
Related grades we forge
Non-magnetic and austenitic grades in the same family, and the corrosion-resistant alternatives: Nitronic 50, Nitronic 60, Nitronic 40, Nitronic 33, Nitronic 32, Nitronic 30, 904L, ASTM A182 F51, ASTM A182 F53, ASTM A182 F55, A286 and AISI 330. The full range is in the stainless and special steel index.
Forged in the same grades: forging rings, forged disks, forged cylinders, forged tubes, forged valve seat rings, forging crankshafts, forging steel products and forging pieces.