Summary
X3CrNiMo13-4 (EN material number 1.4313) is a low carbon, soft martensitic stainless steel containing nominally 12 to 14% Cr, 3.5 to 4.5% Ni and 0.3 to 0.7% Mo with maximum 0.05% C. It is the European equivalent of UNS S41500, ASTM A182 F6NM and AISI 415, and the wrought counterpart of the cast grade CA6NM.
The low carbon content limits chromium carbide formation, so the grade has better toughness and weld behaviour than conventional martensitic stainless steels such as 1.4021 or 410. Quench and temper treatment gives a 0.2% proof strength from 520 MPa in the +QT650 condition up to 800 MPa in +QT900. Normal applications are hydro turbine components, pump and compressor parts, valve bodies, stems and seats, and oilfield equipment, over a service range of about -60 to +350 degrees C.
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, produces X3CrNiMo13-4 forgings to EN 10250-4, EN 10222-5 and ASTM A182 F6NM and ships worldwide with EN 10204 3.1 certification. Tel +86-189-2135-9659, email sales@steelforgepieces.com.
1. Grade Overview
Soft martensitic 13Cr-4Ni stainless steel, used where martensitic strength has to be combined with sub-zero toughness.
X3CrNiMo13-4 belongs to the soft martensitic family, developed to correct the main weakness of plain 13% chromium steels. High carbon gives hardness in those grades but reduces toughness and makes welding difficult. Here the carbon is held to 0.05% maximum and about 4% nickel is added to maintain a fully martensitic, hardenable structure, which raises ductility and notch toughness and keeps impact values usable below zero. The molybdenum addition of 0.3 to 0.7% improves pitting resistance compared with plain 13Cr grades. Surface condition has a strong effect on corrosion performance, and polished surfaces are recommended where the best resistance is required.
Selection against other grades
Against 410 and 420 martensitic grades, 1.4313 offers higher toughness and easier fabrication. Against duplex grades such as 2205, it costs less and is easier to forge in heavy sections, but it has lower chloride pitting resistance. Against 17-4 PH, it avoids age hardening and is more readily produced in very large forged sections, which is one reason the 13Cr-4Ni type is standard for large hydro turbine parts.
Corrosion resistance is moderate and the grade is intended for media with low chloride content. For seawater, high chloride or aggressive sour conditions we normally quote duplex F51, super duplex F55 or Inconel 625 instead. Send us the service conditions and we will confirm the correct material before you order.
2. Equivalent and Cross Reference Grades
Designations generally accepted as the same or closely comparable soft martensitic 13Cr-4Ni material.
| Region / Standard | Designation | Remarks |
|---|---|---|
| EN (Europe) | X3CrNiMo13-4 / 1.4313 | EN 10088-1, -2, -3; EN 10250-4; EN 10222-5; EN 10272; EN 10028-7 |
| USA, UNS | S41500 | Wrought equivalent |
| USA, ASTM / ASME | A182 F6NM | Forged flanges, fittings, valves and parts for piping |
| USA, AISI | AISI 415 | Informal designation derived from S41500 |
| USA, cast | CA6NM / UNS J91540 | Cast counterpart for turbine runners and pump casings |
| France, AFNOR | Z6CN13-04, Z4CN13-4 | Comparable |
| Sweden, SS | SS 2385 (SS 2384 also quoted) | Published sources differ, confirm at order |
| United Kingdom, BS | 425C11 | Comparable, wider carbon tolerance |
| China, GB | 04Cr13Ni5Mo, 0Cr13Ni5Mo | Comparable |
| Japan, JIS | SCS5 | Cast, molybdenum not specified |
| Switzerland | X5CrNi13-4 | Comparable |
Equivalents are given for guidance only. Composition limits differ between standards, so the specification stated on the purchase order governs the supply.
3. Chemical Composition
Note the difference between the EN and ASTM windows, in particular for nickel and molybdenum.
| C | Si | Mn | P | S | Cr | Ni | Mo | N |
|---|---|---|---|---|---|---|---|---|
| max 0.05 | max 0.70 | max 1.50 | max 0.040 | max 0.015 | 12.0 - 14.0 | 3.5 - 4.5 | 0.30 - 0.70 | max 0.020 |
| C | Si | Mn | P | S | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|
| max 0.05 | max 0.60 | 0.50 - 1.00 | max 0.030 | max 0.030 | 11.5 - 14.0 | 3.5 - 5.5 | 0.50 - 1.00 |
F6NM permits up to 5.5% nickel and requires a minimum of 0.50% molybdenum, so a heat certified to EN 1.4313 is not automatically acceptable as F6NM. Where a project calls for both, the heat must fall inside both windows. State this at enquiry stage and the dual certification will be confirmed on the order.
4. Mechanical Properties at Room Temperature
Three standard quench and temper conditions. The QT number is the minimum tensile strength in MPa.
| Condition | Tensile Rm (MPa) | Proof Rp0.2 (MPa) | Elongation A (%) | Impact KV (J) | Hardness |
|---|---|---|---|---|---|
| +A, soft annealed | max 1100 | - | - | - | max 320 HBW |
| +QT650 | 700 - 850 | min 520 | min 15 | min 70 | - |
| +QT780 | 780 - 980 | min 620 | min 15 | min 70 | - |
| +QT900 | 900 - 1100 | min 800 | min 12 | min 50 | - |
| +QT to EN 10028-7 | 780 - 980 | min 650 | min 14 | min 70 | - |
| Sour service | Special heat treatment required | max 23 HRC | |||
Values vary with product form and the governing standard. For flat products to EN 10088-2 the +QT650 tensile range is listed as 700 to 800 MPa, while bar and forged sections are commonly quoted as 700 to 850 MPa. Published impact data for the +QT condition gives 50 to 70 J at +20 degrees C and 40 J at -20 degrees C. Testing is carried out to the standard stated on your order and actual results are reported on the 3.1 certificate.
5. Elevated Temperature and Physical Data
| Condition | 100 C | 150 C | 200 C | 250 C | 300 C | 350 C |
|---|---|---|---|---|---|---|
| +QT650 | 500 | 490 | 480 | 470 | 460 | 450 |
| +QT780 | 590 | 575 | 560 | 545 | 530 | 515 |
| +QT900 | 720 | 690 | 665 | 640 | 620 | - |
| Property | Value |
|---|---|
| Density | 7.7 g/cm3 |
| Modulus of elasticity | 195 GPa at 100 C, 185 GPa at 200 C, 175 GPa at 300 C, 170 GPa at 400 C |
| Coefficient of thermal expansion | 10.5 x 10-6 /K at 100 C, 10.9 at 200 C, 11.3 at 300 C, 11.6 at 400 C |
| Magnetic response | Ferromagnetic |
| Service temperature range | -60 to +350 C, with some datasheets quoting practical use to about 300 C |
6. Heat Treatment and Forging Data
| Operation | Temperature | Cooling and notes |
|---|---|---|
| Forging and hot rolling | about 1150 C | Air cool. Finish above the martensite range and avoid heavy reduction at low finishing temperature |
| Soft annealing, +A | 600 - 650 C | Air or furnace cool, gives max 320 HBW for machining |
| Hardening, austenitising | 950 - 1050 C | Oil or air quench |
| Tempering to +QT650 | 650 - 700 C, then 600 - 620 C | Double temper, gives the toughest and lowest strength condition |
| Tempering to +QT780 | 550 - 600 C | Balance of strength and toughness |
| Tempering to +QT900 | 520 - 580 C | Highest strength condition |
The second, lower temperature cycle used for +QT650 conditions the reverted austenite that gives this family its sub-zero toughness. Prolonged exposure near 475 C should be avoided, since soft martensitic grades are susceptible to embrittlement in that range.
7. X3CrNiMo13-4 Forged Products
Open-die forged and ring rolled to drawing.
| Forged form | Typical end use |
|---|---|
| Round bars and shafts | Pump shafts, valve stems, turbine shafts |
| Square, rectangular, flat and hex bars | Machined blocks, bases, guides |
| Hollow bars, sleeves, bushes, cylinders | Bushings, housings, hubs, casings, barrels |
| Seamless rolled rings | Turbine rings, bearing rings, retaining rings |
| Flanges, discs, plates, blocks | A182 F6NM piping flanges, blind discs, tube sheets |
| Valve components | Valve bodies, bonnets, seats, seat rings, stems, gates, balls |
| Pump and compressor parts | Impellers, casings, diffusers, wear rings |
| Hydro turbine components | Runner parts, guide vanes, wicket gates |
Supply conditions include as forged and rough machined, +A annealed, or fully heat treated to +QT650, +QT780 or +QT900. Surface options are black as forged, rough turned, peeled, ground or polished. Machining to finished drawing dimensions is available. Send the drawing with the required dimensions, standard and QT condition and we will confirm feasibility, weight and lead time.
8. Applications
The main markets for X3CrNiMo13-4 are hydropower, oil and gas, and rotating equipment. Published supplier data lists valves, pumps, compressors, centrifuges, hydroelectric machines, turbines, reactor technology, shipbuilding and chemical plant, together with turbine, pump and compressor parts for the oil, chemical, metallurgical and energy industries at both high and low temperatures. Martensitic chromium nickel stainless steels of the 13Cr-4Ni type are widely used in hydro turbines, with the cast version CA6NM applied to runners and the forged version used where larger sections and higher integrity are needed.
Typical components
In hydropower: runner blades, crowns and bands, guide vanes, wicket gates, shafts and sleeves, where cavitation resistance and the ability to weld repair matter more than chloride resistance. In oil and gas: forged valve bodies and bonnets, seats, stems, wellhead and oilfield equipment, with the special maximum 23 HRC heat treatment where sour service applies. In rotating equipment: pump impellers, casings, wear rings, compressor and centrifuge parts. In process and power plant: chemical plant components, feedwater and boiler circuit parts, and dies and tooling for pressure die casting.
9. Welding, Machining and Corrosion
Welding
Published datasheets do not fully agree on this grade, so the position should be understood before fabrication is planned. Cutting carbon to 0.05% maximum greatly reduces hardening in the heat affected zone, which is why 13Cr-4Ni material is routinely welded and weld repaired in hydro turbine workshops, and why suppliers list F6NM as a construction material for turbines and power plant. Other datasheets state that 1.4313 is not suitable for welding. In practice the grade welds far better than conventional martensitic stainless steels but is not a freely weldable austenitic. Preheat, a qualified procedure, matched or over alloyed filler and post weld tempering below the original tempering temperature are normally required to restore heat affected zone toughness. Qualify the procedure on production representative thickness.
Machining
Machine in the annealed condition, maximum 320 HBW, wherever the design allows, then heat treat and finish. In +QT900 the material is noticeably harder on tooling. Rigid setups, sharp positive rake carbide, generous coolant and avoidance of dwell or rubbing are the usual requirements.
Corrosion
Resistance is moderate and suited to media with low chloride content. Surface finish has a strong influence on performance in service, and polishing of critical surfaces is recommended. The grade is not a substitute for duplex or super austenitic alloys in seawater.
10. Inspection and Documents
Standard supply is with an EN 10204 3.1 mill test certificate covering chemical composition, mechanical properties and the results of the tests carried out. Dimensional inspection is performed before despatch and marking is applied in accordance with the governing standard or your own marking instruction.
Testing available on request
Ultrasonic testing to EN 10228-3, ASTM A388 or SEP 1921, magnetic particle and dye penetrant inspection, Charpy V notch impact testing at sub-zero temperature, intergranular corrosion testing, hardness survey, hardness limited to maximum 23 HRC for sour service to NACE MR0175 and ISO 15156, positive material identification, and third party witness inspection by an independent body or your own inspector. Confirm the required test scope at enquiry so that it is priced and scheduled with the order.
Company
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Production covers forged bars, seamless rolled rings, flanges, discs, sleeves and machined components in carbon, alloy, tool and stainless steels and nickel alloys. Enquiries: +86-189-2135-9659, sales@steelforgepieces.com.
11. Frequently Asked Questions
Answers to the questions most often raised at enquiry stage.
Is X3CrNiMo13-4 the same as F6NM and UNS S41500?
What is the difference between X3CrNiMo13-4 and CA6NM?
What strength can be obtained from 1.4313?
Can X3CrNiMo13-4 be welded?
Is the grade suitable for sour service to NACE MR0175?
What is the service temperature range?
Is X3CrNiMo13-4 magnetic?
Which shapes can you forge in this grade?
What certification and lead time do you provide?
Who supplies forged X3CrNiMo13-4 in China?
Request a Quotation for X3CrNiMo13-4 Forgings
Send your drawing, the governing standard (EN 10250-4, EN 10222-5 or ASTM A182 F6NM), the required QT condition, quantity and test scope. Our engineers reply with price, lead time and a manufacturing feasibility note, normally within one working day.
Email sales@steelforgepieces.com Tel +86-189-2135-9659Related Grades
Page reviewed by the technical department of Jiangyin Jiangnan Metal Co., Ltd. Data is compiled from EN 10088-2, EN 10088-3, EN 10028-7 and ASTM A182 together with published mill datasheets for 1.4313 and F6NM. Values are for guidance and the purchase specification governs the supply.