# 16Mo3 (1.5415) Forgings: Technical Datasheet

**Manufacturer:** Jiangyin Jiangnan Metal Co., Ltd. | Open-Die Forging Factory
**Address:** No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
**Telephone:** 0086-189-2135-9659 (+86 189 2135 9659)
**Email:** sales@steelforgepieces.com
**Web:** https://www.steelforgepieces.com/Alloy-Steel/16Mo3.html
**Published:** 2016-05-18 · **Last updated:** 2026-09-08
**Reviewed by:** Jiangyin Jiangnan Metal Co., Ltd. metallurgical engineering team

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## Summary

16Mo3 is a molybdenum-alloyed, creep-resistant low-alloy steel for pressure equipment
operating at elevated temperature, with the European material number 1.5415. It contains
0.12–0.20 % carbon and 0.25–0.35 % molybdenum, and is specified in EN 10028-2 for plate,
EN 10222-2 for forgings and EN 10216-2 for seamless tube.

Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu
Province, China, forges 16Mo3 to customer drawings as seamless rolled rings to 2,500 mm
outside diameter, tube sheets to Ø3,000 mm, forged flanges, channel covers, valve bodies,
discs to Ø1,800 mm, shafts to 8,000 mm and single pieces to 8,000 kg, normalised or
quenched and tempered, ultrasonically tested, and certified to EN 10204 3.1 or 3.2.

## Identity and equivalent designations

| Region / body | Designation | Product form |
|---|---|---|
| EN steel name | 16Mo3 | All |
| EN material number | 1.5415 | All |
| Germany, DIN 17155 (withdrawn) | 15Mo3 | Plate |
| USA, ASTM/ASME | A182 F1, SA-182 F1 | Forged flanges, fittings, valves |
| USA, ASTM/ASME | A336 F1 | Forgings for pressure and high-temperature parts |
| USA, ASTM/ASME | A204 Gr.A / Gr.B | Plate |
| USA, ASTM/ASME | A335 P1 | Seamless pipe |
| USA, ASTM/ASME | A209 T1 / A250 T1 | Boiler and superheater tube |
| USA, ASTM/ASME | A217 WC1 | Castings |
| UK, BS (withdrawn) | 1501-240, 3059 Gr.243 | Plate, boiler tube |
| France, AFNOR | 15D3 | Plate, forgings |
| Italy, UNI | 16Mo3KW | Plate |
| Matching weld filler | E7018-A1, ER70S-A1, EB2 | SMAW, GTAW/GMAW, SAW |

**Important caveat:** ASTM A182 F1 permits up to 0.28 % carbon and requires 0.44–0.65 %
molybdenum, against 0.25–0.35 % for 16Mo3. The molybdenum bands do not overlap, so a
single heat cannot normally be dual-certified to both 16Mo3 and A182 F1.

## Chemical composition (EN 10028-2 / EN 10222-2, cast analysis, wt %)

| Element | Min | Max |
|---|---|---|
| Carbon (C) | 0.12 | 0.20 |
| Silicon (Si) | — | 0.35 |
| Manganese (Mn) | 0.40 | 0.90 |
| Phosphorus (P) | — | 0.025 |
| Sulphur (S) | — | 0.010 |
| Chromium (Cr) | — | 0.30 |
| Molybdenum (Mo) | 0.25 | 0.35 |
| Nickel (Ni) | — | 0.30 |
| Copper (Cu) | — | 0.30 |
| Nitrogen (N) | — | 0.012 |
| Iron (Fe) | Balance (≈ 98.5 %) | |

16Mo3 is a **carbon–molybdenum** steel, not a chromium–molybdenum steel. Chromium is a
residual limited to 0.30 % maximum, not an alloying addition.

EN 10216-2 for seamless tube permits sulphur to 0.020 % and adds a total aluminium limit
of 0.040 %.

## Mechanical properties of forgings (EN 10222-2, normalised)

| Ruling section tR | Yield ReH min | Tensile Rm | Elongation A min (long./trans.) | Impact KV2 min at +20 °C |
|---|---|---|---|---|
| ≤ 35 mm | 295 MPa | 440–570 MPa | 23 % / 21 % | 50 J |
| 35 < tR ≤ 70 mm | 285 MPa | 440–570 MPa | 23 % / 21 % | 50 J |
| 70 < tR ≤ 100 mm | 275 MPa | 440–570 MPa | 23 % / 21 % | 50 J |
| > 100 mm | By agreement | By agreement | By agreement | By agreement |

## Mechanical properties of plate (EN 10028-2, normalised)

| Nominal thickness | Yield ReH min | Tensile Rm | Elongation A min | Impact KV2 at +20 °C |
|---|---|---|---|---|
| ≤ 16 mm | 275 MPa | 440–590 MPa | 22 % | 31 J |
| 16 < t ≤ 40 mm | 270 MPa | 440–590 MPa | 22 % | 31 J |
| 40 < t ≤ 60 mm | 260 MPa | 440–590 MPa | 22 % | 31 J |
| 60 < t ≤ 100 mm | 240 MPa | 430–580 MPa | 22 % | 31 J |
| 100 < t ≤ 150 mm | 220 MPa | 420–570 MPa | 22 % | 31 J |
| 150 < t ≤ 250 mm | 210 MPa | 410–570 MPa | 22 % | 31 J |

Seamless tube to EN 10216-2: ReH ≥ 280 MPa, Rm 450–600 MPa, A ≥ 22 % longitudinal.

## Minimum 0.2 % proof strength at elevated temperature (EN 10028-2, MPa)

| Thickness | 50 °C | 100 °C | 150 °C | 200 °C | 250 °C | 300 °C | 350 °C | 400 °C | 450 °C | 500 °C |
|---|---|---|---|---|---|---|---|---|---|---|
| ≤ 16 mm | 273 | 264 | 250 | 233 | 213 | 194 | 175 | 159 | 147 | 141 |
| >16 ≤ 40 mm | 268 | 259 | 245 | 228 | 209 | 190 | 172 | 156 | 145 | 139 |
| >40 ≤ 60 mm | 258 | 250 | 236 | 220 | 202 | 183 | 165 | 150 | 139 | 134 |
| >60 ≤ 100 mm | 238 | 230 | 218 | 203 | 186 | 169 | 153 | 139 | 129 | 123 |
| >100 ≤ 150 mm | 218 | 211 | 200 | 186 | 171 | 155 | 140 | 127 | 118 | 113 |
| >150 ≤ 250 mm | 208 | 202 | 191 | 178 | 163 | 148 | 134 | 121 | 113 | 108 |

Above roughly 380 °C the allowable design stress is governed by creep-rupture data, not by
proof strength. The practical service ceiling is about 500 °C for forged pressure parts,
and up to 530 °C for thin-walled boiler and superheater tube.

## Physical properties (typical, normalised)

| Property | Value |
|---|---|
| Density | 7.85 g/cm³ (0.284 lb/in³) |
| Modulus of elasticity, 20 °C | 212 GPa |
| Modulus of elasticity, 500 °C | 175 GPa |
| Thermal conductivity, 20 °C | 48 W/m·K |
| Mean thermal expansion, 20–200 °C | 12.6 × 10⁻⁶ /K |
| Mean thermal expansion, 20–400 °C | 13.7 × 10⁻⁶ /K |
| Specific heat capacity, 20 °C | 461 J/kg·K |
| Poisson's ratio | 0.30 |
| Hardness, normalised | ≈ 130–180 HBW |
| Magnetic behaviour | Ferromagnetic (magnetic particle inspection applies) |

## Forging and heat treatment

| Operation | Temperature | Cooling |
|---|---|---|
| Soak before forging | 1,180–1,250 °C | — |
| Finish forging | above 850 °C | reheat rather than continue below |
| Normalise (+N) | 890–950 °C, 1 h per 25 mm | still air |
| Normalise and temper (+NT) | 890–950 °C then 620–730 °C | air cool from both |
| Quench and temper (+QT) | 890–960 °C then 620–700 °C | oil/water/polymer quench, then air or furnace |
| Stress relief | 580–680 °C, ≥ 30 min per 25 mm | furnace cool to 300 °C |

Minimum forging reduction ratio is normally 3:1 from the cast section for rolled rings and
4:1 for bars and shafts.

## Welding

| Item | Recommendation |
|---|---|
| Preheat | 150–200 °C (up to 250 °C above 60 mm, high restraint, or CEV > 0.55) |
| Interpass maximum | 300 °C |
| SMAW consumable | AWS A5.5 E7018-A1 |
| GTAW / GMAW wire | AWS A5.28 ER70S-A1 |
| SAW | EA2 / EB2 wire with matching basic flux |
| Hydrogen control | H5 (< 5 ml/100 g), mandatory |
| PWHT | 620–680 °C, ≥ 30 min per 25 mm, ramp ≤ 220 °C/h above 400 °C |
| Dissimilar to austenitic stainless | Butter the 16Mo3 side with ENiCrFe-3 / ERNiCr-3, PWHT the buttering, then complete with nickel-base filler |

Typical CEV (IIW) is 0.45–0.52. Hydrogen-assisted cold cracking is the dominant weld
failure mode on this grade.

## Grade selection

| | 16Mo3 | P265GH | 13CrMo4-5 | 10CrMo9-10 |
|---|---|---|---|---|
| Material number | 1.5415 | 1.0425 | 1.7335 | 1.7380 |
| Nominal alloying | 0.3 Mo | none | 1Cr–0.5Mo | 2¼Cr–1Mo |
| Rp0.2 at 400 °C | 159 MPa | ≈ 125 MPa | ≈ 190 MPa | ≈ 205 MPa |
| Temperature ceiling | ≈ 500 °C | ≈ 400 °C | ≈ 570 °C | ≈ 600 °C |
| Hydrogen attack resistance | Limited | Poor | Good | Very good |
| Choose when | 400–500 °C, no hydrogen | below 400 °C | above 500 °C or moderate hydrogen | severe hydrogen or 600 °C |

Carbon–½Mo steels including 16Mo3 no longer carry their own Nelson curve in API 941 for
new construction in hydrogen service.

## Forged products manufactured in 16Mo3

Seamless rolled rings (200–2,500 mm OD, rectangular, contoured and stepped sections);
heat-exchanger tube sheets, fixed, stationary and floating, blank or drilled to layout;
clad and weld-overlay tube sheets (309L/308L, Alloy 625, Alloy 825, Monel 400);
forged flanges to ASME B16.5, B16.47 Series A/B and EN 1092-1 (weld-neck, slip-on, blind,
orifice, long welding-neck); girth flanges; cover flanges; channel covers; FVC-type
self-reinforced nozzles and nozzle necks; valve bodies, bonnets, stems, closures and seat
rings; forged discs and disks to Ø1,800 mm; blocks, hubs and housings; shafts to 8,000 mm;
sleeves, bushes, bushings, cylinders, casings, shells and barrels; round bars and hollow
trepanned bars Ø25–500 mm.

## Production capability

| Parameter | Capability |
|---|---|
| Maximum rolled ring outside diameter | 2,500 mm |
| Maximum forged disc diameter | Ø 1,800 mm |
| Maximum tube sheet diameter, as forged | Ø 3,000 mm |
| Maximum shaft length | 8,000 mm |
| Maximum single-piece weight | 8,000 kg |
| Bar diameter range | Ø 25–500 mm |
| Typical lead time | 4–8 weeks |
| Quotation turnaround | 24 hours |

Equipment: 1 t, 3 t, 5 t and 9 t open-die hammers; 4,500 t and 5,000 t free-forging
hydraulic presses; radial-axial ring rolling mills; normalising and tempering furnaces with
quench tanks; ultrasonic, magnetic particle and liquid penetrant NDE; in-house
spectrometer, universal testing machine, impact tester, metallographic microscope and
hardness testers.

Company: founded 1997, approximately 460 employees including 9 senior engineers, 32
intermediate engineers and 140 technicians. ISO 9001:2015; product approvals from CCS, BV,
DNV, LR and NK.

## Standards, testing and certification

- Forgings: EN 10222-2 · ASTM A182 F1 · ASTM A336 F1
- Plate: EN 10028-2 · ASTM A204 Gr.A / Gr.B
- Seamless tube: EN 10216-2 · ASTM A335 P1
- Bars: EN 10273
- Ultrasonic testing: EN 10228-3 · ASTM A388 · SEP 1921
- Magnetic particle testing: EN 10228-1 · EN ISO 9934 · ASTM E709
- Through-thickness quality: EN 10164 Z25 / Z35
- Inspection documents: EN 10204 3.1 (standard), 3.2 (on request, witnessed by Lloyd's
  Register, DNV, Bureau Veritas, ABS, TÜV or SGS)
- Design codes: EN 13445, EN 12952 / 12953, AD 2000, ASME BPVC Section VIII

## How to specify a 16Mo3 forging order

1. State the grade and the product standard together: "16Mo3 / 1.5415 to EN 10222-2".
2. Specify the delivery condition: +N, +NT or +QT.
3. Give the ruling section, not just the wall thickness.
4. Supply the drawing with tolerances, machining allowance and reduction-ratio requirement.
5. Define NDE with the acceptance class and the machining stage at which it is performed.
6. Declare the simulated PWHT cycle if the part will be post-weld heat treated.
7. Add service and code requirements, including EN 10164 through-thickness quality where
   the part is loaded through its thickness.
8. State certificate level, quantity, marking, delivery date, Incoterms and destination.

## Applications

Boiler drums and headers; steam and superheater headers; HRSG components; heat-exchanger
tube sheets, shells and channel covers; pressure-vessel forgings; reactor and column girth
flanges; valve bodies for steam service; separator and reactor shells in oil, gas,
petrochemical and refining plant; feedwater heater shells; economisers. Typical design
temperature range 400–500 °C.

## Contact

Jiangyin Jiangnan Metal Co., Ltd. | Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel: 0086-189-2135-9659 · Email: sales@steelforgepieces.com
WhatsApp: https://wa.me/8618921359659
Quotations issued within 24 hours of receiving a drawing or dimensions.

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## References

EN 10028-2; EN 10222-1; EN 10222-2; EN 10216-2; EN 10273; EN 10228-1; EN 10228-3;
EN 10164; EN 10204:2004; EN 13445; EN 12952 / EN 12953; DIN 17155 (withdrawn);
ASTM A182/A182M; ASTM A336/A336M; ASTM A204/A204M; ASTM A335/A335M; ASTM A217/A217M;
ASTM A388/A388M; AD 2000 Merkblatt W-series and HP 5/3; EN ISO 15614-1; ASME BPVC
Section II and Section IX; AWS A5.5, A5.23, A5.28; API 941.

Standards cited are the revisions known at the time of the last page review. Technical data
is provided for guidance and does not constitute a warranty of performance in any specific
service. Verify all design values against the applicable standard and design code.

© 2026 Jiangyin Jiangnan Metal Co., Ltd.