---
title: "1.3813 (X40MnCrN19) Non-Magnetic Steel Forgings"
description: "1.3813 / X40MnCrN19 non-magnetic steel to SEW 390: composition, delivery conditions, permeability limits, forging and NDT practice. Rings and bars to drawing."
canonical: "https://www.steelforgepieces.com/Stainless-Steel/1.3813.html"
manufacturer: "Jiangyin Jiangnan Metal Co., Ltd."
address: "No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China"
telephone: "+86 189 2135 9659"
email: "sales@steelforgepieces.com"
grade: "1.3813 / X40MnCrN19 / X40MnCrN19K"
standard: "SEW 390 (1991-11)"
date_modified: "2026-09-21"
language: "en"
---

# 1.3813 (X40MnCrN19) Non-Magnetic Steel Forgings

Open-die forged rings, seamless rolled rings, discs, shafts, bars, sleeves and bushings in
1.3813 non-magnetisable austenitic manganese steel, made to drawing at Jiangyin Jiangnan
Metal Co., Ltd. in Jiangyin, Jiangsu Province, China, with solution treatment, permeability
testing and EN 10204 3.1 or 3.2 certification.

## At a glance

| Item | Value |
| --- | --- |
| Material No. | 1.3813 |
| Designation | X40MnCrN19 |
| Group | Non-magnetisable austenitic Mn-Cr-N steel |
| Standard | SEW 390 (1991-11) |
| Nominal composition | 0.4 C, 18 Mn, 4 Cr, 0.1 N |
| Relative permeability | max. 1.01 quenched, max. 1.03 cold worked |
| Rp0.2 | 295 to 490 MPa depending on delivery condition |
| Stainless | No, 3 to 5 percent Cr only |
| Manufacturer | Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, China |

## 01 What 1.3813 is, and what it is not

1.3813 (X40MnCrN19) is a non-magnetisable austenitic manganese-chromium-nitrogen steel to
SEW 390, with 0.30 to 0.50 percent carbon, 17.0 to 19.0 percent manganese, 3.00 to 5.00
percent chromium and 0.080 to 0.120 percent nitrogen. Manganese and nitrogen, not nickel,
hold the structure austenitic, so the steel stays non-magnetic: relative permeability is at
or below 1.01 after solution annealing and quenching, and at or below 1.03 after cold working.

It is not a stainless steel. EN 10020 sets the boundary for stainless at 10.5 percent
chromium, and 1.3813 carries 3 to 5 percent. Several trader data sheets describe it as rust
and acid resistant. That wording is a loose translation of the German group heading, and the
chemistry does not support it.

The reason the grade exists is electromagnetic, not structural. A ferromagnetic part inside a
strong alternating field heats through eddy current and hysteresis losses and distorts the
field the equipment depends on. A fully austenitic steel with permeability close to 1.0 does
neither.

Composition places 1.3813 in the 18Mn-4Cr to 18Mn-5Cr family, which was the standard material
for generator rotor retaining rings through roughly 1960 to 1980. Schmiedewerke Krupp-Kloeckner
recorded around 18,000 retaining rings produced over thirty years from a steel of 0.5 percent
carbon, 18 percent manganese, 4.5 percent chromium and 0.1 percent nitrogen, which is the top of
the SEW 390 carbon band and not its nominal 0.40 percent. The changeover to the 18Mn-18Cr
replacement began in the mid 1970s, with the new alloy in service from 1978.

## 02 Chemical composition

Heat analysis limits to SEW 390. Iron is the balance. Nickel and molybdenum are not alloyed
to this grade and are not specified.

| C | Si | Mn | P | S | Cr | N | Fe |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 0.30 to 0.50 | max. 0.80 | 17.00 to 19.00 | max. 0.100 | max. 0.030 | 3.00 to 5.00 | 0.080 to 0.120 | Balance |

A second set of limits circulates for this grade and it is not an error, it is a different
document. Data sheets quoting Mn 18.0 to 20.0, Si max. 0.50, P max. 0.050 and S max. 0.015 are
reproducing TLV 9384.01, a turbine builder technical delivery specification, which also carries
its own mechanical requirements. The table above is SEW 390. Both are legitimate and they are
not interchangeable, so name the document your drawing invokes. Jiangyin Jiangnan Metal melts
its own steel, so the limits you need are set at the furnace rather than argued about on an
incoming billet certificate.

The phosphorus ceiling of 0.100 percent in SEW 390 is a standard limit, not a target, and it is
loose by the standards of any rotating or highly stressed component. Normal practice is far
below it. TLV 9384.01 sets 0.050 percent, and tighter can be agreed.

SEW 390 is a Stahl-Eisen-Werkstoffblatt issued by the German steel industry association, not a
DIN or EN standard, and there is no EN designation for this grade. Data sheets writing it as
DIN EN X40MnCrN19 are inventing a reference that does not exist.

What each element does:

- Manganese, 17 to 19 percent: the austenite stabiliser, doing the job nickel does in a 300
  series stainless, keeping the structure austenitic at room temperature so no ferrite or
  martensite forms to carry magnetism.
- Nitrogen, 0.080 to 0.120 percent: interstitial solid solution strengthening and further
  austenite stabilisation. Nitrogen is the single line separating 1.3813 from 1.3817 on paper.
- Carbon, 0.30 to 0.50 percent: more solid solution strengthening and austenite stability, and
  the reason the steel must be quenched from solution temperature rather than cooled slowly.
- Chromium, 3 to 5 percent: strength and a small improvement in oxidation behaviour, not
  corrosion resistance. At this level no passive film forms.

## 03 Mechanical properties by delivery condition

1.3813 is strengthened by cold work, not by hardening. An austenitic steel has no phase
transformation to quench into, so quenching from 1000 to 1050 degrees Celsius softens it and
puts the carbides back into solution. Strength above the solution annealed level comes from
deformation, which is why SEW 390 lists three delivery conditions rather than a hardness range.

| Condition | Rp0.2, MPa | Rm, MPa | A5, percent | Impact, DVM | Permeability mu-r |
| --- | --- | --- | --- | --- | --- |
| Solution annealed and quenched | min. 295 | 740 to 930 | min. 45 | min. 124 J | max. 1.01 |
| Warm-cold worked | min. 390 | 830 to 1030 | min. 40 | min. 124 J | max. 1.01 |
| Cold worked | min. 490 | 830 to 1030 | min. 35 | min. 103 J | max. 1.03 |

Impact energy for this grade is quoted on the DVM specimen, not the ISO-V Charpy specimen.
The two are not interchangeable and a DVM figure should not be compared directly against a
Charpy V-notch requirement on a drawing. The neighbouring grade 1.3817 is published with
ISO-V values instead.

The trade-off that decides the order: cold work buys about 195 MPa of yield strength over the
solution annealed condition, and costs the 1.01 permeability class. If a drawing demands both
maximum strength and the tightest permeability, one of the two has to give.

Purpose-built retaining rings reach far higher figures than any row above, up to roughly 1200
MPa yield, by heavy cold expansion of a ring over a mandrel. That is a dedicated process route
for one product, not a delivery condition orderable against SEW 390.

## 04 Physical and magnetic properties

| Property | Value | Comment |
| --- | --- | --- |
| Density | 7.85 to 7.90 kg/dm3 | Walzwerke Einsal 7.85, Basedo Steel approximately 7.9 |
| Modulus of elasticity | approx. 191 000 MPa | Lower than ferritic steel, normal for high manganese austenite |
| Electrical resistivity | approx. 0.70 ohm.mm2/m | High, part of why eddy current losses stay low |
| Relative permeability, quenched | max. 1.01 | Solution annealed and water quenched |
| Relative permeability, warm-cold worked | max. 1.01 | Strength raised without losing the 1.01 class |
| Relative permeability, cold worked | max. 1.03 | Cold deformation raises permeability |
| Magnetic behaviour | Paramagnetic | Fully austenitic, no ferrite, no martensite |

A generic modulus of 210 GPa appears on several aggregator pages for this grade. That is the
default value those templates print for every steel. The figure to use for deflection
calculations is approximately 191 GPa.

Permeability is a property of the finished part, not of the heat. It is set by how the steel
was worked and treated, it can be disturbed by local cold deformation during machining or
straightening, and a mill certificate for chemistry alone will not satisfy it.

## 05 Forging and heat treatment

| Operation | Temperature | Cooling |
| --- | --- | --- |
| Hot forming, forging and ring rolling | 850 to 1050 C | Air, then solution treat |
| Solution annealing | 1000 to 1050 C | Water or air |
| Hardening by quench and temper | Not applicable | Austenitic, no transformation to harden |

Production route: melt (EF, LF, VOD), forge at 850 to 1050 C, solution treat at 1000 to 1050 C,
quench in water or air, machine, then test by UT, PT and permeability measurement.

The forging window is narrow, and the lower figure is a finish temperature rather than a soak
temperature. Above about 1050 degrees Celsius a high manganese, high carbon austenite is prone
to grain coarsening and hot shortness; let the piece fall below about 850 degrees Celsius and it
work hardens so rapidly that the press stalls and the surface tears. Heavy sections need reheats,
not one long pass.

The quench after solution treatment is not optional. With 0.30 to 0.50 percent carbon and 3 to
5 percent chromium in solution, slow cooling through roughly 600 to 900 degrees Celsius
precipitates chromium carbides on the austenite grain boundaries, costing toughness and
ductility and potentially starting a magnetic response at the boundaries.

SEW 390 permits water or air cooling from solution temperature, and that permission is easy to
misread. In a steel carrying up to 0.50 percent carbon, air cooling will not reliably suppress
carbide precipitation through a heavy section; it is realistic for thin product only. Water
quenching is the normal route for forgings, and section thickness decides whether the centre of
a heavy piece cools fast enough.

Machining behaves like any strongly work hardening austenitic steel: positive rake, rigid
set-up, deliberate depth of cut, no dwelling in the cut. Welding is not a routine operation on
this grade because high carbon combined with a Cr-Mn austenite gives both sensitisation and
hot cracking risk.

## 06 Corrosion behaviour

1.3813 has no meaningful corrosion resistance and will rust. Chromium at 3 to 5 percent is
below the level at which a passive chromium oxide film forms. Forgings are normally shipped
with rust preventive oil and sealed packing, and parts in service need paint, plating or a dry
environment.

The 18Mn-4Cr to 18Mn-5Cr family carries a documented stress corrosion cracking history in
humid service.
Retaining rings made from this family failed in service in Germany, Sweden and elsewhere from
the late 1970s onward, attributed to stress corrosion cracking in the presence of moisture,
and the industry response was a new alloy, not better sealing. If the application
combines high sustained stress with any chance of condensation, chlorides or damp hydrogen,
this is the wrong grade.

## 07 1.3813 against 1.3817 and 1.3816

| Item | 1.3813 X40MnCrN19 | 1.3817 X40MnCr18 | 1.3816 X8CrMnN18-18 |
| --- | --- | --- | --- |
| C | 0.30 to 0.50 | 0.30 to 0.50 | max. 0.12 |
| Si | max. 0.80 | max. 1.00 | max. 1.0 |
| Mn | 17.00 to 19.00 | 17.00 to 19.00 | 17.5 to 20.0 |
| Cr | 3.00 to 5.00 | 3.00 to 5.00 | 17.5 to 20.0 |
| N | 0.080 to 0.120 | max. 0.100 | 0.40 to 0.70 |
| Ni | Not specified | max. 1.00 | max. 1.00 |
| P | max. 0.100 | max. 0.060 | max. 0.06 |
| Rp0.2, quenched | min. 295 MPa | min. 280 MPa | min. 930 MPa, cold expanded |
| Impact specimen | DVM | ISO-V | ISO-V |
| SCC in humid service | Susceptible | Susceptible | Resistant |
| Product standard | SEW 390 | SEW 390 | SEW 390, ASTM A289 |

1.3816 figures are the composition published for that grade, alongside the ASTM A289 Grade 1
minimum yield. The two are close but not the same document: A289 calls for C max. 0.10, S max.
0.015, Ni max. 2.00 and N 0.45 to 0.80, so material certified to 1.3816 is not automatically
compliant with A289 and the reverse is equally true. ASTM A289/A289M was withdrawn by ASTM in
2023 with no replacement, and it remains in wide use as a reference specification for existing
generator fleets.

The 1.3817 column understates that grade in one respect. SEW 390 splits its requirements by test
piece orientation: A5 minimum 35 percent longitudinal against 20 percent transverse, and ISO-V
impact minimum 85 J longitudinal against 55 J transverse.

How to choose:

- 1.3813 over 1.3817 when the drawing asks for the higher yield strength, because the nitrogen
  addition is what provides it. 1.3817 has the tighter phosphorus limit and a nickel allowance.
- 1.3816 over both for a new generator retaining ring, or for any highly stressed non-magnetic
  part exposed to moisture. The 18Mn-18Cr alloy was developed because the 18Mn-5Cr family
  cracked, and it replaced it across the industry.
- 1.3813 remains the right call for non-magnetic structural and machine parts in dry or
  protected service, and for replacement parts matching an existing 18Mn-5Cr specification.

## 08 Inspection and testing

Magnetic particle inspection does not apply to 1.3813, because the material is not
ferromagnetic. ASTM E709 is written for ferromagnetic materials, and at a relative permeability
capped at 1.03 no usable leakage field can be produced. Surface examination has to be liquid
penetrant to ASTM E165 or EN ISO 3452-1, or eddy current. A drawing note calling for MT on this
grade is an error carried over from a ferritic part.

That applies to 1.3813, not to austenitic steels in general: duplex and
austenitic-ferritic grades, and austenitic castings containing delta ferrite, can often be
magnetic particle tested.

EN 10228 has no part that covers this steel. Part 3 is titled for ferritic and martensitic steel
forgings. Part 4 looks like the answer, but its scope is limited to forgings made from austenitic
and austenitic-ferritic stainless steels, and 1.3813 is not stainless; Part 4 also excludes
turbine rotor and generator forgings by name. Citing EN 10228-4 on a 1.3813 order will be queried at
inspection.

The route that fits is the ASTM pair. ASTM A388/A388M, Standard Practice for Ultrasonic
Examination of Steel Forgings, is the general practice and carries no ferritic restriction.
ASTM A745/A745M, Standard Practice for Ultrasonic Examination of Austenitic Steel Forgings, is
written to be applied to forgings examined under A388 and adds the technique requirements that
coarse austenitic grain demands. It says austenitic steel, not austenitic stainless steel, so it
covers 1.3813.

| Requirement | Method and reference | Note |
| --- | --- | --- |
| Volumetric | Ultrasonic to ASTM A388/A388M with ASTM A745/A745M | EN 10228-3 is ferritic; EN 10228-4 is limited to stainless grades |
| Surface | Liquid penetrant to ASTM E165 or EN ISO 3452-1 | Magnetic particle does not apply, the steel is not ferromagnetic |
| Magnetic | Relative permeability to ASTM A342/A342M | Measure on the finished part |
| Chemistry | Optical emission spectrometry, ASTM E415 | Verified at the furnace, melt number traced to the part |
| Tensile and impact | ASTM A370 or ISO 6892 | Confirm DVM or ISO-V specimen on the order |
| Grain size | ASTM E112 | Relevant after the narrow-window forging schedule |
| Certification | EN 10204 3.1 as standard, 3.2 on request | 3.2 witnessed by BV, DNV, LR, SGS, TUV or your inspector |

Melting at Jiangyin Jiangnan Metal runs through the electric arc furnace with ladle refining
and vacuum oxygen decarburisation, and through protective atmosphere electroslag remelting
where a cleaner ingot is specified. Because the steel is melted on site, the nitrogen level can
be aimed at the middle of the 0.080 to 0.120 percent band instead of accepted as delivered.

## 09 Product forms and working envelope

| Product | Limit | Set by |
| --- | --- | --- |
| Seamless rolled rings | up to OD 6000 mm | 6 m radial-axial ring rolling mill |
| Rings below ring mill range | from OD 50 mm | Upset and punch route |
| Discs and blocks | up to 5000 mm diameter machined | 5000 mm vertical turning lathe |
| Shafts | up to 14 000 mm turned length | Horizontal lathe, 15 m well furnace for vertical quench |
| Bored cylinders | up to 1600 x 10 000 mm | CNC deep-hole drilling machine |
| Single piece weight | up to 30 000 kg | 6300 t press, 60 t maximum heat size |
| Minimum order | 10 kg | No minimum piece count |

These are plant limits, not a promise for every grade. For 1.3813 the practical ceiling on a
heavy section is usually the quench rather than the press.

## 10 What to send with an enquiry

| No. | Item | Example |
| --- | --- | --- |
| 1 | Grade and any composition restriction | 1.3813 / X40MnCrN19, Mn 17.0 to 19.0, P max. 0.100 |
| 2 | Delivery condition | Solution annealed and quenched, or cold worked class |
| 3 | Permeability requirement | mu-r max. 1.01, measured to ASTM A342 on the finished part |
| 4 | Dimensions or drawing, and section thickness | OD 900 x ID 620 x H 180 mm, PDF or STEP |
| 5 | Testing | UT to ASTM A388 with A745, PT to ASTM E165, impact specimen type |
| 6 | Certificate and destination port | EN 10204 3.2 witnessed by DNV, Rotterdam |

Quotations normally return within two working days. Lead time runs 20 to 60 days. Minimum
order is 10 kg with no minimum piece count.

## 11 Frequently asked questions

**What is 1.3813 steel?**

1.3813, designation X40MnCrN19, is a non-magnetisable austenitic manganese-chromium-nitrogen
steel to SEW 390, containing 0.30 to 0.50 percent carbon, 17.0 to 19.0 percent manganese, 3.00
to 5.00 percent chromium and 0.080 to 0.120 percent nitrogen. Manganese and nitrogen rather
than nickel hold the structure austenitic, so the steel stays paramagnetic with a relative
permeability at or below 1.01 in the solution annealed and quenched condition.

**Is 1.3813 a stainless steel?**

No. EN 10020 requires at least 10.5 percent chromium for a steel to be classified as stainless,
and 1.3813 contains 3 to 5 percent. It has no meaningful corrosion resistance and will rust in
humid storage or service.

**Why is 1.3813 non-magnetic?**

Its structure is fully austenitic, a face centred cubic phase with no ferromagnetic response,
and manganese at 17 to 19 percent together with nitrogen at 0.08 to 0.12 percent keeps it
austenitic down to room temperature. There is no ferrite and no martensite to carry magnetism.

**What are the mechanical properties of 1.3813?**

SEW 390 gives three delivery conditions at room temperature. Solution annealed and quenched:
Rp0.2 minimum 295 MPa, Rm 740 to 930 MPa, A5 minimum 45 percent, DVM impact minimum 124 J.
Warm-cold worked: Rp0.2 minimum 390 MPa, Rm 830 to 1030 MPa, A5 minimum 40 percent, DVM impact
minimum 124 J. Cold worked: Rp0.2 minimum 490 MPa, Rm 830 to 1030 MPa, A5 minimum 35 percent,
DVM impact minimum 103 J.

**Can 1.3813 be hardened by quenching and tempering?**

No. It is austenitic and has no phase transformation to harden, so quenching from the solution
annealing range of 1000 to 1050 degrees Celsius softens the steel rather than hardening it.
Strength above the solution annealed level is produced by cold or warm-cold deformation.

**Why must 1.3813 be quenched after solution annealing?**

With 0.30 to 0.50 percent carbon and 3 to 5 percent chromium held in solution, slow cooling
precipitates chromium carbides on the austenite grain boundaries. That reduces toughness and
ductility and can produce a local magnetic response at the boundaries. Water quenching from
1000 to 1050 degrees Celsius is the normal route.

**Can magnetic particle inspection be used on 1.3813 forgings?**

No, because the material is not ferromagnetic. ASTM E709 is written for ferromagnetic
materials, and with relative permeability capped at 1.03 no usable leakage field can be produced.
Surface examination has to be liquid penetrant testing to ASTM E165 or EN ISO 3452-1, or eddy
current. This applies to 1.3813 and not to austenitic steels in general: duplex and
austenitic-ferritic grades, and austenitic castings containing delta ferrite, can often be
magnetic particle tested.

**Which ultrasonic standard applies to 1.3813 forgings?**

ASTM A388/A388M applied together with ASTM A745/A745M. A388 is the general practice for
ultrasonic examination of steel forgings, and A745 adds the technique requirements for austenitic
steel forgings, where coarse grain scatters and attenuates the beam. Neither part of EN 10228
fits: Part 3 is written for ferritic and martensitic forgings, and Part 4 covers austenitic and
austenitic-ferritic stainless steel forgings while also excluding turbine rotor and generator
forgings by name.

**What is the difference between 1.3813 and 1.3817?**

Nitrogen. Both are non-magnetisable austenitic Mn-Cr steels with 0.30 to 0.50 percent carbon,
17.0 to 19.0 percent manganese and 3.00 to 5.00 percent chromium, but 1.3813 specifies nitrogen
at 0.080 to 0.120 percent while 1.3817 caps it at 0.100 percent without a lower limit. The
nitrogen raises the proof strength, so 1.3813 is specified at minimum 295 MPa in the quenched
condition against minimum 280 MPa for 1.3817.

**Is 1.3813 suitable for generator retaining rings?**

Its composition is that of the 18Mn-4Cr to 18Mn-5Cr family that was the standard retaining ring
material from the 1960s until the 1980s. That family was replaced across the industry by the
18Mn-18Cr alloy, grade 1.3816 and specification ASTM A289, after stress corrosion cracking
failures in the presence of moisture. For a new retaining ring the answer is 1.3816.

**Does cold working 1.3813 affect its magnetic permeability?**

Yes. SEW 390 allows a relative permeability of at most 1.01 in the solution annealed and
quenched condition and in the warm-cold worked condition, but at most 1.03 after cold working.
The cold worked strength class of minimum 490 MPa cannot be combined with the tightest
permeability requirement.

**Who supplies 1.3813 forgings?**

Jiangyin Jiangnan Metal Co., Ltd. forges 1.3813 to customer drawings at No.1 Chengxiqiao Road,
Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The works has melted and forged on one
site since 1997, holds CCS, BV, DNV, LR and NK approvals, and supplies rings, seamless rolled
rings, discs, shafts, bars, sleeves and bushings with EN 10204 3.1 or 3.2 certification.
Enquiries: sales@steelforgepieces.com or +86 189 2135 9659.

**What is the minimum order quantity and lead time for 1.3813?**

Minimum order is 10 kg with no minimum piece count. Normal lead time runs 20 to 60 days from
order confirmation.

## 12 Sources

Chemical and mechanical data is taken from SEW 390 as published by German mills and
stockholders carrying the grade, principally Walzwerke Einsal and Basedo Steel, cross-checked
against the trader data sheets circulating for X40MnCrN19. Where sources disagree, the
disagreement is stated and not resolved silently. The retaining ring history is drawn from
the published record of 18Mn-5Cr service failures and the development of the 18Mn-18Cr
replacement alloy.

Values for a specific order are confirmed on the inspection certificate for that order, which
is the document that governs, not this page.

Citation: Jiangyin Jiangnan Metal Co., Ltd. "1.3813 (X40MnCrN19) Non-Magnetic Steel Forgings."
steelforgepieces.com, reviewed 21 September 2026.
https://www.steelforgepieces.com/Stainless-Steel/1.3813.html

## Contact

Jiangyin Jiangnan Metal Co., Ltd.
Integrated melting works and open-die forging factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone: +86 189 2135 9659
Email: sales@steelforgepieces.com
Hours: Monday to Saturday, 08:00 to 17:30 China Standard Time, UTC+8