Hangbo Alloy Group
Shanghai · Est. 2012
UNS N06054 / AWS A5.14 ERNiCrFe-7A — Modified high-chromium nickel-iron welding wire with boron and zirconium additions for improved ductility-dip-cracking (DDC) resistance, engineered for Inconel 690 nuclear steam generator welds and corrosion-resistant overlay cladding.
Inconel 52M — classified under AWS A5.14 as ERNiCrFe-7A and with UNS designation N06054 — is a modified, high-chromium nickel-iron welding filler metal developed specifically for welding Inconel 690 (UNS N06690) and for corrosion-resistant overlay of carbon and stainless steels. It is the improved successor to Inconel 52 (ERNiCrFe-7, UNS N06052).
The defining improvement in Inconel 52M is its controlled boron and zirconium micro-additions, which markedly reduce the tendency for ductility-dip cracking (DDC) in highly restrained nuclear welds. The chemistry still carries the elevated chromium level of 28.0-31.5% (roughly double that of ERNiCr-3 / Inconel 82), so the deposit retains outstanding resistance to primary water stress-corrosion cracking (PWSCC) — the life-limiting degradation mechanism in pressurized water reactor (PWR) steam generators. As the nuclear industry standardized on Inconel 690 tubing, Inconel 52M and 52MSS became the preferred fillers for alloy 690 components, especially automated narrow-groove tube-to-tubesheet joints.
For chemical processing, power generation, and offshore engineering, Inconel 52M also provides excellent oxidation resistance and good compatibility when joining nickel alloys to stainless or carbon steels. Hangbo Alloy Group supplies Inconel 52M as TIG rods, MIG wire, SAW/strip wire, and matching covered electrodes with full AWS/ASME certification.
Hangbo Alloy Group supplies modified nuclear-grade Inconel 52M TIG rods, MIG wire, strip/cladding wire, and ENiCrFe-7 covered electrodes — all with full material certification and traceability. Stock and mill orders available, with improved DDC resistance for restrained nuclear joints.
The chemical composition of Inconel 52M / ERNiCrFe-7A is controlled by AWS A5.14. Compared with the original ERNiCrFe-7, 52M tightens several limits and adds boron (B ≤ 0.005%) and zirconium (Zr ≤ 0.02%) — the micro-additions responsible for its improved ductility-dip-cracking resistance and cleaner, oxide-floater-free deposits.
| Element | AWS A5.14 Range (wt%) | Typical Value | Role in the Weld Deposit |
|---|---|---|---|
| Nickel (Ni) | Remainder | ≥58 | Austenitic matrix, corrosion resistance, crack resistance |
| Chromium (Cr) | 28.0 – 31.5 | 29.5 | Cr₂O₃ protective scale; SCC and oxidation resistance |
| Iron (Fe) | 7.0 – 11.0 | 9.0 | Thermal expansion matching Inconel 690 |
| Niobium (Nb) | 0.50 – 1.0 | 0.7 | Carbide stabilization, improved creep strength |
| Titanium (Ti) | ≤ 1.0 | 0.3 | Deoxidation, grain refinement |
| Aluminum (Al) | ≤ 1.10 | 0.4 | Deoxidation, oxide-scale adhesion |
| Carbon (C) | ≤ 0.04 | 0.02 | Controlled low level to preserve corrosion resistance |
| Manganese (Mn) | ≤ 1.0 | 0.5 | Deoxidation, sulfur control |
| Silicon (Si) | ≤ 0.50 | 0.25 | Wetting and fluidity; controlled to limit cracking |
| Copper (Cu) | ≤ 0.30 | 0.10 | Trace impurity limit (tighter than 52) |
| Cobalt (Co) | ≤ 0.12 | 0.05 | Residual control |
| Molybdenum (Mo) | ≤ 0.50 | 0.20 | Residual; minor strength contribution |
| Zirconium (Zr) | ≤ 0.02 | 0.01 | Improves DDC resistance, wetting, cleanliness |
| Boron (B) | ≤ 0.005 | 0.003 | Improves DDC resistance (modified grade) |
| Phosphorus (P) | ≤ 0.020 | 0.010 | Impurity control for ductility |
| Sulfur (S) | ≤ 0.015 | 0.008 | Impurity control for hot cracking resistance |
Key compositional insight: The chromium level in Inconel 52M is intentionally matched to Inconel 690 (29% Cr), shifting the weld metal's corrosion potential into the "passive" regime in high-temperature pure water. The boron and zirconium additions — absent from plain Inconel 52 — are the modification that suppresses ductility-dip cracking in the 700-1100°C range.
Physical properties of the Inconel 52M deposit are similar to those of Inconel 690 base metal due to the closely matched, high-chromium chemistry. Values below are typical/representative for the ERNiCrFe-7A deposit.
| Property | Value | Notes |
|---|---|---|
| Density | ~8.19 g/cm³ | Similar to Inconel 690 |
| Melting Range | ~1340 – 1380 °C | Depends on exact composition |
| Thermal Expansion (20–1000°C) | ~15.5 × 10−6 /°C | Matches Inconel 690 |
| Thermal Conductivity (at 20°C) | ~12 W/(m·K) | Low; requires controlled heat input |
| Electrical Resistivity | ~1.15 μΩ·m | Typical nickel-alloy value |
| Magnetic Properties | Non-magnetic (austenitic FCC deposit) | |
| Crystal Structure | Face-Centered Cubic (FCC) | |
| Property | Typical Value | AWS A5.14 Minimum |
|---|---|---|
| Tensile Strength (Rm) | 552 – 700 MPa | ≥ 552 MPa |
| Yield Strength (Rp0.2) | 330 – 360 MPa (typ.) | — (not specified) |
| Elongation (A) | 30 – 45% | ≥ 30% |
| Hardness | 180 – 230 HV | — |
Note: The AWS A5.14 specification sets minimum tensile strength (552 MPa) and elongation (30%); yield is not specified and is given here as typical. Actual mechanical properties depend on welding process, heat input, shielding gas, and dilution from base metal. Nuclear specifications often impose additional qualification testing beyond AWS minimums.
The Inconel 52M weld deposit retains good strength and oxidation resistance at elevated temperatures. It is suitable for service up to approximately 1150°C in oxidizing atmospheres, although its primary nuclear applications operate at 280–340°C. At these reactor temperatures, the key requirement is long-term stress-corrosion-cracking resistance rather than high-temperature strength.
| Parameter | GTAW | GMAW | SAW / Strip |
|---|---|---|---|
| Process polarity | DCEN | DCEP | DCEP |
| Shielding gas / flux | Ar or Ar-He | 98% Ar / 2% O₂ or Ni-alloy mix | Neutral/basic Ni-alloy flux |
| Typical heat input | 0.5 – 1.5 kJ/mm | 0.8 – 1.8 kJ/mm | 1.0 – 2.0 kJ/mm |
| Interpass temperature | ≤ 150 °C (300 °F) | ||
| Preheat | Generally not required for Ni alloys / austenitic SS; 50–100°C for thick carbon steel cladding | ||
Like many Ni-Cr-Fe alloys, the ERNiCrFe-7 family can be susceptible to ductility-dip cracking at roughly 700–1100°C if heat input is excessive or restraint is high. Inconel 52M reduces this tendency through:
Contact Hangbo Alloy Group for certified ERNiCrFe-7A TIG rods, MIG wire, SAW/strip wire, and ENiCrFe-7 covered electrodes. Improved DDC resistance for restrained nuclear joints, competitive pricing, fast delivery, full mill test reports.
The high chromium content of the Inconel 52M deposit gives it excellent corrosion resistance in oxidizing environments and high-temperature aqueous media:
Hangbo Alloy Group supplies Inconel 52M / ERNiCrFe-7A in the following product forms, manufactured to AWS A5.14 / ASME SFA-5.14 specifications:
| Product Form | Applicable Standard | Typical Size Range |
|---|---|---|
| TIG Rods / Cut Lengths | AWS A5.14 ERNiCrFe-7A | Diameter 0.8 – 3.2 mm; lengths 915 / 1000 mm |
| MIG Wire (spools) | AWS A5.14 ERNiCrFe-7A | Diameter 0.8 – 1.6 mm; spools 5 – 15 kg |
| SAW / Strip Wire | AWS A5.14 ERNiCrFe-7A | Diameter 2.4 – 3.2 mm; strip 0.4-0.8 mm × 30-120 mm |
| Covered Electrodes | AWS A5.11 ENiCrFe-7 | Diameter 2.4 – 4.8 mm (Inconel 152M) |
All products are supplied with EN 10204 Type 3.1 material certificates including chemical analysis, mechanical test results, and AWS/ASME conformance declarations. Nuclear-grade lots with full traceability and additional NDT are available on request.
| Standard | Description |
|---|---|
| AWS A5.14 / A5.14M | Specification for Nickel and Nickel-Alloy Bare Welding Electrodes and Rods — ERNiCrFe-7A |
| ASME SFA-5.14 / SFA-5.14M | ASME Boiler & Pressure Vessel Code equivalent |
| ASME IX | Qualification: F-No. 43 |
| UNS N06054 | Unified Numbering System designation |
| ISO 18274 | Welding consumables — solid wire and rods for fusion welding of nickel and nickel alloys (Ni-Cr-Fe family) |
| AWS A5.11 / A5.11M | Specification for Nickel and Nickel-Alloy Covered Welding Electrodes — ENiCrFe-7 (Inconel 152M) |
| NRC / 10 CFR 50 | Nuclear reactor construction and repair consumables |
| Property | Inconel 52 ERNiCrFe-7 | Inconel 52M ERNiCrFe-7A | Inconel 52MSS (7A family) |
|---|---|---|---|
| UNS | N06052 | N06054 | N06054 (family) |
| AWS | ERNiCrFe-7 | ERNiCrFe-7A | ERNiCrFe-7A |
| Chromium % | 28 – 31.5 | 28 – 31.5 | 28 – 31.5 |
| B + Zr additions | No | Yes (DDC control) | Yes (optimized) |
| DDC resistance | Good | Improved | Best (automated NGW) |
| Oxide floaters | Standard | Resistant | Resistant, optimized |
| Typical use | General 690 welds, cladding | Restrained 690 welds, DDC-prone | Automated tube-to-tubesheet NGW |
| Min tensile | ≥ 552 MPa | ≥ 552 MPa | ≥ 552 MPa |
Selection guide: Choose Inconel 52 (ERNiCrFe-7) for general Inconel 690 welding and overlay where restraint is modest. Choose Inconel 52M (ERNiCrFe-7A) when ductility-dip-cracking resistance and oxide cleanliness matter — the default for most modern nuclear and high-integrity joints. Choose Inconel 52MSS for automated narrow-groove tube-to-tubesheet welding and specialized strip cladding in nuclear steam generators.
Inconel 52M — classified under AWS A5.14 as ERNiCrFe-7A and UNS N06054 — is a modified, high-chromium nickel-iron welding filler metal developed for welding Inconel 690 (UNS N06690) and for corrosion-resistant overlay of carbon and stainless steels. It is the improved successor to Inconel 52 (ERNiCrFe-7): it carries small, controlled additions of boron and zirconium that markedly reduce the tendency for ductility-dip cracking (DDC) in highly restrained nuclear welds, while still matching the high-chromium (28-31.5%) chemistry that gives outstanding resistance to stress-corrosion cracking in high-temperature pure water.
AWS A5.14 composition limits for ERNiCrFe-7A (UNS N06054) are: Nickel remainder, Chromium 28.0-31.5%, Iron 7.0-11.0%, Niobium 0.50-1.0%, Titanium ≤1.0%, Aluminum ≤1.10%, Carbon ≤0.04%, Manganese ≤1.0%, Silicon ≤0.50%, Copper ≤0.30%, Cobalt ≤0.12%, Molybdenum ≤0.50%, Phosphorus ≤0.02%, Sulfur ≤0.015%, Zirconium ≤0.02%, Boron ≤0.005%, Others ≤0.50%. The controlled B and Zr additions — absent from the original ERNiCrFe-7 — are what give 52M its improved DDC resistance.
Minimum all-weld-metal tensile properties of ERNiCrFe-7A are: tensile strength ≥552 MPa (≥80,000 psi) and elongation ≥30% (4d). Yield strength of a typical deposit is about 330-360 MPa (typical, not specified by AWS). The deposit is fully austenitic, non-magnetic, and highly ductile. Actual values depend on welding process, heat input, shielding gas, and dilution from the base metal.
Ductility-dip cracking occurs in the heat-affected and weld-metal regions of Ni-Cr-Fe alloys at roughly 700-1100°C when reheated or restrained. Inconel 52M reduces this tendency through controlled boron and zirconium micro-additions that modify grain-boundary behavior and wetting, plus tighter control of aluminum, niobium, and impurity elements. This makes 52M preferred over Inconel 52 for highly restrained, automated narrow-groove tube-to-tubesheet welds in nuclear steam generators, where DDC is a primary failure risk.
Inconel 52M is supplied as solid wire for GTAW (TIG) and GMAW (MIG), and as strip for electro-slag (ESW) and submerged-arc (SAW) strip cladding. Matching covered electrodes are classified ENiCrFe-7 (Inconel 152M). GTAW/GMAW use argon or argon-helium shielding; GMAW often uses pulsed-spray transfer with 98% Ar / 2% O₂ or proprietary nickel-alloy blends. The filler is also noted for excellent resistance to oxide 'floaters' and inclusions.
Key standards: AWS A5.14 / A5.14M — ERNiCrFe-7A; ASME SFA-5.14 / SFA-5.14M (ERNiCrFe-7A); ASME IX F-No. 43; UNS N06054; ISO 18274 (Ni-Cr-Fe wire family); and the matching covered electrode AWS A5.11 ENiCrFe-7 (Inconel 152M). It is qualified for nuclear pressure-boundary welding under ASME and is used in NRC-licensed plants for Inconel 690 components.
Primary applications: nuclear steam generator tube-to-tubesheet welding of Inconel 690 tubing; Inconel 690 tube repair and replacement; dissimilar metal welds between Inconel 690 and carbon/low-alloy or stainless steels; corrosion-resistant overlay/cladding of reactor pressure vessel nozzles, heads, and flanges; and chemical/petrochemical equipment handling oxidizing acids and high-temperature water. Its main advantage is matching the SCC resistance of Inconel 690 base metal with better DDC resistance than Inconel 52.
Inconel 52 is the original AWS A5.14 ERNiCrFe-7 (UNS N06052) composition. Inconel 52M (ERNiCrFe-7A, UNS N06054) is the modified version with controlled B and Zr additions for improved ductility-dip-cracking resistance and better oxide-floater resistance. Inconel 52MSS is a further refinement optimized for automated narrow-groove tube-to-tubesheet welding and strip cladding in nuclear steam generators, with optimized arc stability, wetting, and crack resistance. All three share the high-chromium ERNiCrFe-7 family chemistry and ASME IX F-No. 43.
For GTAW, use DCEN polarity, pure argon or argon-helium shielding gas (flow 12-20 L/min), and low to moderate heat input (0.5-1.5 kJ/mm). For GMAW, use pulsed-spray transfer with 98% Ar / 2% O₂ or proprietary nickel-alloy shielding gas; heat input 0.8-1.8 kJ/mm. For SAW/strip cladding, use neutral or mildly basic nickel-alloy fluxes matched to the wire. Interpass temperature should be kept below 150°C (300°F) to minimize ductility-dip cracking. No preheat is required on nickel alloys or austenitic stainless steels.
Hangbo Alloy supplies Inconel 52M as TIG rods (0.8-3.2 mm), MIG wire on spools (0.8-1.6 mm), SAW/strip wire (2.4-3.2 mm wire; strip 0.4-0.8 mm thick, 30-120 mm wide), and covered electrodes ENiCrFe-7 / Inconel 152M (2.4-4.8 mm). All forms can be supplied with AWS/ASME certification and full traceability.
Inconel 52M is a premium modified nuclear-grade filler. Typical pricing is $60-140/kg depending on product form, diameter, certification level, and current raw-material markets. Nuclear-grade lots with EN 10204 3.1/3.2 certificates are at the upper end. Lead times range from 4-8 weeks for standard sizes and 8-14 weeks for certified nuclear lots. Contact serena@hangboalloy.com for a competitive quote.
Yes. The high chromium content (~29%) gives Inconel 52M excellent oxidation resistance and outstanding resistance to primary water stress-corrosion cracking in nuclear steam generators. It also resists caustic and nitric acid environments. For strongly reducing hydrochloric or sulfuric acids, Hastelloy-type fillers are preferred.
Yes. Inconel 52M is commonly used for dissimilar metal welds between Inconel 690 or Inconel 600 and carbon steel, low-alloy steel, or austenitic stainless steel. The nickel-rich austenitic deposit accommodates thermal expansion mismatch and provides a corrosion-resistant transition. Applications include nuclear safe-end welds, petrochemical transition joints, and power plant repairs.
Hangbo Alloy Group is a global manufacturer and supplier of nuclear-grade nickel welding consumables, including Inconel 52M / ERNiCrFe-7A TIG rods, MIG wire, strip/cladding wire, and ENiCrFe-7 covered electrodes, with full AWS/ASME certification and traceability. Request a quote at serena@hangboalloy.com or call +86 166 2109 2936 (WhatsApp available).
