1.5415

What 1.5415 steel is

1.5415 is the European steel number for 16Mo3, a weldable, molybdenum-alloyed steel for pressure purposes. The addition of roughly 0.25–0.35 % molybdenum raises creep rupture strength and resistance to temper embrittlement, which lets the steel hold its design stress at temperatures where plain carbon steel has already lost most of its strength.

The grade is defined in EN 10028-2 (flat products for pressure purposes) and, for forged products, in EN 10222-2 (steel forgings for pressure purposes, ferritic and martensitic steels with specified elevated temperature properties). Bars are covered by EN 10273 and seamless tubes by EN 10216-2. The former German designation under DIN 17155 was 15Mo3; drawings still specify 15Mo3 and it is ordered and supplied as 16Mo3 / 1.5415 today.

16Mo3 is a low-alloy ferritic steel, so it hot forges, machines and welds without difficulty, and it costs far less than the chromium-molybdenum grades (13CrMo4-5, 10CrMo9-10) that take over above roughly 550 °C. For boiler drums, steam-line fittings, heat exchanger tubesheets and reactor shells working in the 350–530 °C band, it is still the grade most buyers specify first.

Jiangyin Jiangnan Metal Co., Ltd. supplies 1.5415 as open-die and ring-rolled forgings only; the data below is the material data our forgings are ordered and certified against.

Chemical composition of 1.5415 (16Mo3)

Ladle analysis, percent by mass, to EN 10028-2:2003. Product analysis is permitted to deviate within the tolerances given in the standard.

Chemical composition of 1.5415 / 16Mo3 per EN 10028-2:2003, published by Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China.

Molybdenum is the only deliberate alloy addition in 16Mo3, and it is what makes the grade creep-resistant. Chromium, nickel and copper appear as residuals and carry maximum limits only. Sulphur is held to 0.010 % max, which matters for through-thickness ductility in thick tubesheets and for ultrasonic cleanliness.

Mechanical properties of 1.5415 (16Mo3)

Room-temperature properties depend on both the delivery condition and the nominal thickness of the product. +N is normalised; +QT is quenched and tempered.

Tensile strength, R_m

Yield strength, R_eH

Impact energy, KV

Elongation at fracture, A

Mechanical properties of 1.5415 / 16Mo3 per EN 10028-2, published by Jiangyin Jiangnan Metal Co., Ltd. For forgings, the acceptance values in EN 10222-2 apply and are agreed at order.

Test location matters on heavy forgings. Unless the enquiry says otherwise, we take test specimens at ¼ thickness (T/4) and sample the prolongation after the final heat treatment, in the orientation stated on the order.

Elevated temperature behaviour

Two practical points on heavy 1.5415 forgings at temperature:

• Section size drives properties. A 300 mm thick tubesheet does not cool at the same rate as a 60 mm ring, so the same heat can meet the thin-section values and miss the thick-section ones. Specify the governing thickness in the enquiry.
• Simulated post-weld heat treatment. If the forging will see a long PWHT cycle in the fabricator's shop, ask for test coupons in the simulated PWHT condition. Extra hours at 620–680 °C soften the material, and acceptance should be checked in the condition the part will actually be in.

Equivalent grades and cross references for 1.5415

Cross references are for identification only. Equivalent grades match in chemistry and general property level but not always in test temperature, impact requirement or delivery condition. The standard named on your order is the one we certify to; if a drawing calls out A182 F1 and the vessel code is EN 13445, tell us which document governs and we will confirm before rolling steel.

Forging and heat treatment of 1.5415

1.5415 forges readily over a wide temperature window and is not air-hardening, so heavy sections can be cooled in still air without cracking. Typical practice on our presses:

Values are shop practice, not acceptance criteria. Soak times, cooling media and holding temperatures are fixed in the approved heat treatment procedure for each order and recorded on chart.

Forging ratio and grain flow

For pressure parts we work to a minimum forging reduction ratio of 3:1 from the cast section, and higher on rings and shafts where grain flow has to follow the contour. Ring rolling gives circumferential grain flow, which is why a rolled ring outperforms a piece cut from plate in hoop-stressed service such as a girth flange or a shell course.

Welding 1.5415 (16Mo3)

16Mo3 is classed as a readily weldable low-alloy steel and is welded by SMAW, SAW, GTAW and GMAW using matching 1Mo consumables. The two controls that matter are preheat and post-weld heat treatment:

• Preheat: typically 150–250 °C, rising with thickness, restraint and carbon equivalent. Maintain interpass temperature within the same band.
• PWHT: typically 620–680 °C, held according to thickness, then controlled cooling. PWHT is normally mandatory on pressure-retaining welds in this grade.
• Consumables: low-hydrogen, matching Mo-alloyed filler; keep electrodes in a heated quiver.

Clad and weld-overlaid forgings are common in this grade, a stainless or nickel-alloy overlay on a 1.5415 tubesheet being the usual combination. The overlay goes on before final machining, and the base metal properties are verified after the full simulated heat treatment cycle.

The welding parameters above are indicative. Qualified WPS/PQR to EN ISO 15614-1 or ASME IX governs on any real job.

1.5415 forgings we manufacture

Every item below is produced from 1.5415 (16Mo3) by open-die forging or ring rolling at our Jiangyin works, then heat treated, tested and machined to the customer's drawing.

Rings, shells and hollow sections

• Seamless rolled ringsRing-rolled, circumferential grain flow, for girth flanges and shell courses
• Forged ringsUpset and punched, small quantities and odd sections
• Sleeves, bushes and bushingsBored and turned to drawing
• Hollow bars and cylindersTrepanned or expanded, long lengths
• Barrels, shells, casings and casesHeavy-wall pressure bodies
• Pipes and tubularsForged and bored, thick wall, non-standard sizes
• Hubs and housingsNear-net contour forgings

Discs, tubesheets and plates

• Forged discs and disksSolid or bored, upset from billet
• Tubesheets and tube platesFront, rear, fixed, stationary and floating tubesheets
• Clad and overlaid tubesheetsWeld overlay or explosion-clad face on a 1.5415 base
• Channel coversFlat and self-reinforced

Flanges and nozzles

• Girth flangesRolled ring, machined to EN 1092-1 or ASME B16.5 / B16.47
• Long welding neck nozzlesLWN, forged from solid or ring
• Self-reinforced nozzlesFVC type nozzle necks
• Cover flanges and blindsSolid forged, machined both faces

Valve and shaft components

• Valve bodies and blocksForged blocks and near-net bodies
• Valve bonnets and closuresPressure-retaining, tested to EN 10204 3.1
• Valve stems and seat ringsBar-forged, straightened and stress relieved
• ShaftsStepped, flanged and plain, up to long lengths
• Round barsForged and peeled or rough-turned

Shell-and-tube heat exchanger sets

We supply matched sets for shell-and-tube exchangers in 1.5415: stationary and floating tubesheets, girth flanges, channel covers, shell courses and nozzle necks, forged from the same heat where the specification calls for it, so the whole set carries one certificate and one heat-treatment record.

Sizes and forging capacity

Sizes outside this table are often still possible. On heavy work the heat treatment furnace and the machining envelope usually run out before the press does. Send the drawing and we will confirm before quoting.

Supply condition

• As forged, rough machined with test prolongation, or finish machined to drawing
• Normalised (+N), normalised and tempered, or quenched and tempered (+QT)
• Clad, weld-overlaid or coated faces on request
• Preservation and seaworthy packing for export

Testing and certification

1.5415 is a pressure-purpose grade, so test results and certificates go out with every order. Standard scope on our forgings:

Certificates are issued to EN 10204 3.1 as standard. EN 10204 3.2 certification with a third-party inspector (TÜV, Lloyd's, BV, SGS, DNV or the customer's own inspector) is available when specified on the order. Material traceability is by heat number and piece number, stamped and recorded from steel making through to final machining.

Confirm any code requirement at enquiry stage, whether PED 2014/68/EU, AD 2000-Merkblatt W0, ASME Section VIII or GB 150. It changes the test plan and the mill we buy the ingot from.

Where 1.5415 forgings are used

• Power generation. Boiler drums and headers, steam-line fittings, valve bodies and turbine-side pipework operating in the 350–530 °C range.
• Petrochemical and refining. Reactor shells, coke drum components, hydrogen service vessels and high-temperature separators.
• Heat exchangers. Tubesheets, girth flanges, channel covers and shell courses for shell-and-tube exchangers, often with a corrosion-resistant overlay on the process side.
• Pressure vessels. Nozzle necks, long welding neck flanges, blind covers and manway forgings on vessels built to EN 13445, ASME VIII or GB 150.
• Valves and fittings. Forged bodies, bonnets, closures and seat rings for elevated temperature steam and process duty.

How to order 1.5415 forgings

Send a drawing or a sketch with dimensions to sales@steelforgepieces.com. To quote accurately we need five things:

1. Grade and standard as written on your drawing: 1.5415, 16Mo3, 15Mo3 or the equivalent you work to
2. Dimensions and quantity, and whether the price should be as-forged, rough machined or finish machined
3. Delivery condition: +N, normalised and tempered, or +QT
4. Test and certificate requirements, including any third-party inspection
5. Design code, if the part is pressure-retaining

Quotations are normally returned within one working day. Typical lead time is 25–45 days from order confirmation depending on size, heat treatment cycle and machining scope.

Frequently asked questions about 1.5415

Related grades

Grades commonly compared with or substituted for 1.5415 on the same enquiry:

• 42CrMo4
• AISI 4140
• 1.7225
• 34CrNiMo6
• AISI 4340
• 1.6582
• 18CrNiMo7-6
• AISI 8620
• 17-4PH
• Inconel 625
• Incoloy 800H
• Inconel 718