Creep-resistant 9Cr-1Mo alloy steel · EN material no. 1.7386

X11CrMo9-1 (1.7386) Forgings: Rolled Rings, Discs, Tubesheets, Valve Bodies and Flanges

X11CrMo9-1 (EN material number 1.7386, also written X12CrMo9-1) is a 9 % chromium, 1 % molybdenum creep-resistant alloy steel used for pressure equipment operating at elevated temperature, typically in the 550-650 °C range. It is the European equivalent of ASTM A182 F9 (forgings), A335 P9 (pipe) and A213 T9 (tube), and is supplied to EN 10222-2 for pressure-purpose forgings. The grade is ferritic in the annealed condition and tempered-martensitic after normalizing and tempering, and it offers high resistance to creep, steam oxidation, sulfidic corrosion and high-temperature hydrogen attack.

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We manufacture X11CrMo9-1 / 1.7386 forgings to customer drawing: seamless rolled rings, discs and tubesheets, shells and cylinders, round and hollow bars, valve bodies and bonnets, nozzles, girth flanges and channel covers. Enquiries: +86 189 2135 9659 · sales@steelforgepieces.com.

Quick specification

Table 1. X11CrMo9-1 summary
Grade designation	X11CrMo9-1 (EN 10027-1)
Material number	1.7386 (EN 10027-2 / Werkstoff-Nr.)
Other designations	X12CrMo9-1, 12CrMo91 (DIN), 11CrMo9-1 (AFNOR), UNS K90941 / S50400
Alloy type	9Cr-1Mo ferritic / martensitic creep-resistant alloy steel
Governing standards	EN 10222-1 and EN 10222-2 (forgings for pressure purposes); EN 10216-2 (seamless tubes); EN 10253-2 (butt-welding fittings)
Delivery conditions	+I (isothermally annealed) or +NT (normalized and tempered)
Typical service temperature	Approx. 550-650 °C, subject to the design code
Main industries	Refining and petrochemical, power generation, boilers, pressure vessels, valves
Product forms supplied	Open-die forgings and seamless rolled rings
Manufacturer	Jiangyin Jiangnan Metal Co., Ltd., Jiangyin City, Jiangsu Province, China

Chemical composition of X11CrMo9-1

The composition limits below are those given in EN 10253-2 for grade X11CrMo9-1. Note that EN 10216-2:2014 applies a tighter sulphur limit of S ≤ 0.010 %; where a forging is ordered against EN 10222-2 or against an ASTM specification, the limits of that standard govern and are confirmed on the mill certificate.

Table 2. Chemical composition, % by mass (ladle analysis), X11CrMo9-1 per EN 10253-2
C	Si	Mn	P	S	Cr	Mo	Al	Cu
0.08-0.15	0.25-1.00	0.30-0.60	max 0.025	max 0.020	8.00-10.00	0.90-1.10	max 0.040	max 0.30

The 8-10 % chromium content with about 1 % molybdenum is what sets this grade apart. Chromium gives oxidation and sulfidation resistance; molybdenum gives solid-solution strengthening and creep resistance. Unlike P91 / X10CrMoVNb9-1 (1.4903), X11CrMo9-1 has no deliberate vanadium, niobium or nitrogen additions. Its creep strength is therefore well below P91, but its weldability and post-weld heat treatment requirements are less demanding.

Mechanical properties

Room-temperature properties depend on the delivery condition. +I denotes isothermal annealing, which produces a soft ferritic structure suited to heavy machining; +NT denotes normalizing and tempering, which produces tempered martensite and the higher strength level normally specified for pressure parts.

Table 3. Room-temperature mechanical properties of X11CrMo9-1 in the +I and +NT conditions
Property	+I (isothermally annealed)	+NT (normalized & tempered)
Tensile strength R_m (MPa)	460-640	590-740
0.2 % proof strength R_p0.2 (MPa), min.	210	390
Elongation at fracture A (%), longitudinal, min.	20	18
Impact energy KV at +20 °C (J), longitudinal, min.	40
Impact energy KV at +20 °C (J), transverse, min.	27

For comparison, ASTM A182 Grade F9 forgings are specified at R_m ≥ 585 MPa, R_p0.2 ≥ 380 MPa, elongation ≥ 20 % and reduction of area ≥ 40 %, with a hardness range of roughly 179-217 HB, which is close to the EN +NT condition. Acceptance is made against the ordered specification, so every forging is tested and certified to the standard named on the purchase order.

Equivalent and comparable grades

Table 4. International cross-reference for X11CrMo9-1 / 1.7386 (nearest equivalents; always confirm against the ordering standard)
Standard / region	Designation	Product form
EN (Europe)	X11CrMo9-1 / 1.7386	Forgings, tubes, bars, fittings
DIN (Germany, superseded)	X12CrMo9-1, 12CrMo91	Tubes, forgings
ASTM / ASME	A182 Gr. F9 · A336 Gr. F9	Forged flanges, fittings, valves, heavy forgings
ASTM / ASME	A335 Gr. P9 · A213 Gr. T9 · A369 Gr. FP9	Seamless pipe and tube
ASTM / ASME	A234 Gr. WP9 · A387 Gr. 9	Wrought fittings · plate
UNS	K90941 (forgings) · S50400 (pipe)	n/a
JIS (Japan)	STPA 26	Seamless tube
BS (UK, superseded)	BS 3604 Gr. 629-470	Pipe
Cast counterpart	ASTM A217 Gr. C12 · GX12CrMo9-1 (1.7389)	Castings

X11CrMo9-1 compared with neighbouring Cr-Mo grades

Buyers normally compare X11CrMo9-1 with the grades immediately above and below it in chromium content. The table below sets out how it differs from the 5 % Cr, 2.25 % Cr and vanadium-modified 9 % Cr grades in the same family.

Table 5. X11CrMo9-1 against the adjacent Cr-Mo creep-resistant grades
Grade	EN / material no.	ASTM forging grade	Nominal alloy	How it compares
X11CrMo5	1.7362	A182 F5	5Cr-0.5Mo	Lower chromium, so less oxidation and sulfidation resistance; used at lower temperatures.
11CrMo9-10	1.7383	A182 F22	2.25Cr-1Mo	Much lower chromium but tougher and easier to weld in heavy sections; the standard choice for hydroprocessing vessels up to about 550 °C.
X11CrMo9-1	1.7386	A182 F9	9Cr-1Mo	This grade. Good oxidation, sulfidation and hydrogen-attack resistance at 550-650 °C, with moderate creep strength.
X10CrMoVNb9-1	1.4903	A182 F91	9Cr-1Mo-V-Nb	Same chromium level, but with V, Nb and N added. Much higher creep strength, at the cost of tight heat treatment and PWHT control.
X20CrMoV11-1	1.4922	n/a	12Cr-1Mo-V	Higher chromium and carbon with vanadium; higher creep strength than X11CrMo9-1, historically used for European steam plant.

Heat treatment and delivery condition

X11CrMo9-1 is air-hardening: even moderate section sizes transform to martensite on still-air cooling, so an as-forged part is hard and must be heat treated before machining or service. The two standard delivery conditions are:

+I: isothermal annealing

Austenitize, then hold isothermally in the pearlite range and cool slowly. Produces a soft ferritic structure, typically in the range of about 180-210 HB, for heavy machining or for parts that will be heat treated after fabrication. Strength level: R_m 460-640 MPa.

+NT: normalizing and tempering

Normalize from approximately 930-980 °C, then temper at approximately 720-800 °C, giving tempered martensite and the pressure-part strength level R_m 590-740 MPa with R_p0.2 ≥ 390 MPa. Exact soak times and cooling rates are set by section thickness.

Welding note. Preheat and interpass control are mandatory for 9Cr-1Mo, and post-weld heat treatment at roughly 730 °C or above is normally required. Oxy-acetylene welding is not permitted. The exact preheat, PWHT temperature and hold time must follow the applicable construction code and the qualified welding procedure. The figures above are indicative and are confirmed against the specification named on the order.

X11CrMo9-1 forged products we manufacture

All parts are made to customer drawing or specification as open-die forgings or seamless rolled rings. Typical X11CrMo9-1 / 1.7386 items include:

Rings and cylindrical parts

Seamless rolled rings and forged rings
Sleeves, bushes and bushings
Shells, casings, cylinders and barrels
Forged pipe and tube sections, hollow bars
Round bars, blocks, hubs and housings

Discs and tubesheets

Forged discs and disks
Tubesheets, tube sheets and tube plates
Fixed, stationary and floating tubesheets
Clad, weld-overlaid and coated tubesheets
Front-end and rear-end heat exchanger components

Valve components

Valve bodies and valve blocks
Valve bonnets and closures
Valve stems and seat rings
Machined valve parts to drawing

Flanges, nozzles and shafts

Girth flanges and cover flanges
Channel covers
Long welding neck (LWN) flanges and nozzle necks
FVC-type self-reinforced nozzles
Forged shafts

Where X11CrMo9-1 is used

Refining and petrochemical. Hydroprocessing and catalytic reforming service, high-temperature piping and headers, and equipment exposed to hot hydrogen and sulphur-bearing streams, where the 9 % chromium level gives resistance to sulfidic corrosion and to high-temperature hydrogen attack.
Power generation and boilers. Superheater and reheater headers, steam collectors, main steam and hot reheat components, turbine parts and connectors operating in the 550-650 °C range.
Pressure vessels and heat exchangers. Tubesheets, channel covers, girth flanges, nozzles and shells for elevated-temperature service.
Valves and fittings. Bodies, bonnets and closures for high-temperature steam and process duty, commonly ordered as ASTM A182 F9.

Manufacturing route and inspection

A typical production route for an X11CrMo9-1 forging runs: steelmaking and refining → ingot or billet → open-die forging or ring rolling with a controlled forging reduction ratio → heat treatment to +I or +NT → rough or finish machining → testing and certification. Testing normally covers chemical analysis, tensile and impact testing on coupons representing the forging, hardness survey, ultrasonic examination to ASTM A388 or EN 10228-3, and magnetic particle or dye penetrant examination of machined surfaces. Material is released with an EN 10204 3.1 certificate; 3.2 certification with third-party inspection is available when specified on the order.

Frequently asked questions about X11CrMo9-1

What is X11CrMo9-1 steel?

X11CrMo9-1 is a European creep-resistant alloy steel containing nominally 9 % chromium and 1 % molybdenum, carrying EN material number 1.7386. It is used for pressure-retaining parts operating at elevated temperature, typically 550-650 °C, in refineries, petrochemical plants and power boilers. It is ferritic in the annealed condition and tempered-martensitic after normalizing and tempering.

What is the material number of X11CrMo9-1?

The EN material number (Werkstoff-Nummer) of X11CrMo9-1 is 1.7386. The grade is also encountered as X12CrMo9-1 and, in older German practice, as 12CrMo91.

What is the ASTM equivalent of X11CrMo9-1?

For forgings, the nearest ASTM equivalent is ASTM A182 Grade F9 (and A336 Grade F9 for heavy forgings). In pipe and tube form the equivalents are ASTM A335 Grade P9, A213 Grade T9 and A369 Grade FP9; the wrought fitting grade is A234 WP9 and the plate grade is A387 Grade 9. The UNS numbers are K90941 and S50400. These are nearest equivalents rather than identical specifications, so the ordering standard should always be stated on the purchase order.

What is the chemical composition of X11CrMo9-1?

Per EN 10253-2: carbon 0.08-0.15 %, silicon 0.25-1.00 %, manganese 0.30-0.60 %, phosphorus max 0.025 %, sulphur max 0.020 %, chromium 8.00-10.00 %, molybdenum 0.90-1.10 %, aluminium max 0.040 % and copper max 0.30 %. EN 10216-2:2014 restricts sulphur further to max 0.010 %.

What are the mechanical properties of X11CrMo9-1?

In the normalized and tempered (+NT) condition, tensile strength is 590-740 MPa with a minimum 0.2 % proof strength of 390 MPa and minimum elongation of 18 %. In the isothermally annealed (+I) condition, tensile strength is 460-640 MPa with a minimum proof strength of 210 MPa and minimum elongation of 20 %. Minimum impact energy at +20 °C is 40 J longitudinal and 27 J transverse.

Is X11CrMo9-1 the same as P91?

No. P91 corresponds to X10CrMoVNb9-1 (material number 1.4903) and contains deliberate additions of vanadium, niobium and nitrogen that X11CrMo9-1 does not have. Both are 9Cr-1Mo-base steels, but P91 has substantially higher creep strength; X11CrMo9-1 is the earlier, plainer 9Cr-1Mo grade with lower creep strength and less demanding welding and post-weld heat treatment requirements.

What is the maximum service temperature of X11CrMo9-1?

The grade is generally specified for continuous service in the region of 550-650 °C. The permissible design temperature for a given component is set by the applicable design code and the allowable stress tables for the ordered specification, not by the grade alone.

Can X11CrMo9-1 be welded?

Yes, with controls. Preheat and interpass temperature control are required, oxy-acetylene welding is not permitted, and post-weld heat treatment at approximately 730 °C or above is normally mandatory because the steel air-hardens. Welding must follow a qualified procedure under the governing construction code.

Who supplies X11CrMo9-1 forgings?

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin City, Jiangsu Province, China that manufactures X11CrMo9-1 / 1.7386 forgings to customer drawing: seamless rolled rings, discs, tubesheets, shells, bars, valve bodies, nozzles, girth flanges and channel covers. The works is at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Enquiries: +86 189 2135 9659 or sales@steelforgepieces.com.

What information is needed to quote an X11CrMo9-1 forging?

To return an accurate quotation we need: the drawing or dimensions (outside diameter, inside diameter, height or thickness), the quantity, the ordering standard and grade (for example EN 10222-2 X11CrMo9-1 +NT, or ASTM A182 F9), the required delivery condition, the machining state (as-forged, rough machined or finish machined), the testing and NDT scope, and the certificate type required (EN 10204 3.1 or 3.2).

About the manufacturer

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory based in Jiangyin City, Jiangsu Province, China, in the Yangtze River delta forging cluster between Wuxi and Shanghai. The works produces open-die forgings, seamless rolled rings, forged flanges and forged bars in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, including X11CrMo9-1 (1.7386) and the related grades listed below. Parts are made to customer drawing and certified to the ordering standard.

Table 7. Manufacturer contact details
Company	Jiangyin Jiangnan Metal Co., Ltd.
Business type	Open-die forging factory / forged component manufacturer
Address	No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone / WhatsApp	+86 189 2135 9659
Email	sales@steelforgepieces.com
Website	www.steelforgepieces.com

Standards referenced on this page

EN 10222-1, Steel forgings for pressure purposes: general requirements for open die forgings
EN 10222-2, Steel forgings for pressure purposes: ferritic and martensitic steels with specified elevated temperature properties
EN 10216-2, Seamless steel tubes for pressure purposes with specified elevated temperature properties
EN 10253-2, Butt-welding pipe fittings: non-alloy and ferritic alloy steels with specific inspection requirements
ASTM A182 / A336 / A335 / A213 / A234 / A387, corresponding American specifications for 9Cr-1Mo products
EN 10204, Types of inspection documents for metallic products

Technical data compiled by Jiangyin Jiangnan Metal Co., Ltd. from the standards listed above. Values are given for guidance; the specification named on the purchase order governs acceptance.
Last reviewed 19 September 2026.