- Home
- Welding Consumables
- High Temperature Alloys Welding Wire
- Inconel X750 Welding Wire
Inconel X750 Welding Wire Supplier in Mumbai, India
Nicorex Alloys is an ISO 9001 and ISO 14001 certified supplier, stockist, and importer of Inconel X-750 welding wire based in Mumbai, India. We supply precipitation-hardened filler wire with the base metal manufactured to AMS 5698 (No. 1 Spring Temper) and AMS 5699 (Spring Temper), designated UNS N07750 / W.Nr 2.4669.
Inconel X-750 (Alloy X-750) is a nickel-chromium precipitation-hardenable filler. It consists of approximately 70% Ni, 15.5% Cr, 7% Fe, 2.5% Ti, 1.0% Nb, and 0.7% Al. The alloy gains its strength from γ′ Ni₃(Al,Ti) precipitates supplemented by minor γ″ Ni₃Nb from the niobium content. X-750 stands apart as the definitive alloy for high-temperature springs and fasteners. Its stress-relaxation resistance at temperatures up to 704°C (1300°F) is unmatched among nickel alloys, while oxidation resistance extends to 982°C (1800°F). Outstanding chloride-ion stress corrosion cracking (SCC) resistance makes X-750 the standard material for nuclear reactor hold-down springs and bolting in primary water service. The alloy is NACE MR0175 / ISO 15156-3 listed for sour oil and gas environments. GTAW (TIG) is the preferred welding process; preheat is not required, and interpass temperature must stay at or below 93°C (200°F).
Every coil and cut length from Nicorex Alloys ships with EN 10204/3.1B mill test certificates, full heat-lot traceability, and PMI reports. Key industries include nuclear power (PWR/BWR reactor internals), aerospace (gas turbine springs and fasteners), rocket propulsion, oil and gas sour service, and high-temperature spring and bellows fabrication.
Inconel X-750 Filler Wire Specifications
The specifications of Inconel X-750 filler, including standard, equivalent designations, welding process, and other important details, are covered in the table below:
| Property | Value |
|---|---|
| AWS Classification | A5.14 ERNiFeCr-2 |
| UNS Number | N07718 |
| Welding Processes | GTAW (preferred), GMAW (micro-fissuring risk) |
| Polarity | TIG: DCEN MIG: DCEP |
| Shielding Gas | 100% Ar (GTAW); Ar or Ar/He (GMAW — no pure CO₂) |
| TIG Cut Lengths | 0.76–4.70 mm (0.030–0.187 in) |
| MIG Spools | 0.76–2.40 mm (0.030–0.094 in) |
Chemical Composition of Inconel X-750 Welding Wire (%)
Nicorex Alloys supplies Inconel X-750 matching filler wire conforming to the AMS 5698 composition limits.
| Element | Nickel (Ni) | Chromium (Cr) | Iron (Fe) | Titanium (Ti) | Niobium + Tantalum (Nb+Ta) | Aluminium (Al) | Manganese (Mn) | Silicon (Si) | Carbon (C) | Cobalt (Co) | Copper (Cu) | Sulfur (S) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Requirement | 70.0 min (Balance) | 14.0–17.0 | 5.0–9.0 | 2.25–2.75 | 0.70–1.20 | 0.40–1.00 | 1.0 max | 0.50 max | 0.08 max | 1.0 max | 0.50 max | 0.01 max |
| Typical | ~72.0 | 15.5 | 7.0 | 2.50 | 1.0 | 0.70 | 0.25 | 0.20 | 0.04 | 0.20 | 0.10 | 0.003 |
Titanium (2.25–2.75%) combined with aluminium (0.40–1.00%) gives a total Ti+Al of approximately 3.2%: lower than Waspaloy (4.4%), making X-750 somewhat easier to weld than Waspaloy but harder than solid-solution alloys. Niobium (0.70–1.20%) forms supplementary γ″ plus NbC carbides; unlike Inconel 718, where 5% Nb is the primary strengthener, its role in X-750 is secondary. Sulfur at 0.01% max is tighter than ERNiCr-3 (0.03% max), critical for nuclear SCC resistance.
Mechanical Properties of Inconel X-750 Weld Deposits
Inconel X-750 filler wire produces weld deposits that achieve the following properties after age-hardening. Values vary with the PWHT option selected.
Aged Condition (Equalised + Precipitation Treated)
| Property | Typical Value |
|---|---|
| Ultimate Tensile Strength | 1172–1276 MPa (170–185 ksi) |
| Yield Strength, 0.2% Offset | 793–896 MPa (115–130 ksi) |
| Elongation | 15–25% |
| Hardness | 302–363 BHN (per AMS 5667) |
Annealed Condition (Before Ageing)
| Property | Typical Value |
|---|---|
| Ultimate Tensile Strength | 896–1000 MPa (130–145 ksi) max |
| Elongation | 25–35% |
Stress-relaxation resistance is the defining mechanical property of X-750. At temperatures up to 700°C, X-750 maintains bolt preload and spring force far longer than any other nickel alloy, which is why it is preferred for nuclear reactor spring applications. Per AMS 5668 (triple heat treatment), X-750 achieves a minimum 100-hour rupture life at 732°C (1350°F) under 310 MPa (45 ksi). X-750 also maintains excellent toughness at cryogenic temperatures, supporting rocket engine and LNG service.
Filler Metal Selection & Base Metal Compatibility for Inconel X-750
Nicorex Alloys stocks matching X-750 composition wire and alternative fillers for welding X-750 base metal. Filler selection depends on whether age-hardened weld strength is required.
Matching filler:
| Base Metal | ASME P-No. | Recommended Filler | AWS / AMS | Application / Notes |
|---|---|---|---|---|
| Inconel X-750 | 43 | X-750 matching | AMS 5698 | X-750 to X-750; use when age-hardened weld deposit strength is required |
Alternative fillers for X-750 base metal:
| Base Metal | ASME P-No. | Recommended Filler | AWS / AMS | Application / Notes |
|---|---|---|---|---|
| Inconel X-750 | 43 | ERNiFeCr-2 (FM 718) | AWS A5.14 / AMS 5832 | Age-hardenable; per Special Metals recommendation for X-750 |
| Inconel X-750 | 43 | ERNiCr-3 (FM 82) | AWS A5.14 | Solid-solution; no PWHT needed; preferred for dissimilar joints |
| Inconel X-750 | 43 | ERNiCrFe-5 (FM 69) | AWS A5.14 | Historical filler for X-750; used in Special Metals weld testing |
Dissimilar joint filler recommendations:
| Base Metal | ASME P-No. | Recommended Filler | AWS / AMS | Application / Notes |
|---|---|---|---|---|
| X-750 to stainless steel | 43 / 8 | ERNiCr-3 (FM 82) | AWS A5.14 | Standard choice for Ni-alloy to austenitic SS dissimilar joints |
| X-750 to carbon steel | 43 / 1 | ERNiCr-3 (FM 82) | AWS A5.14 | Ni-alloy filler bridges the CTE mismatch between X-750 and carbon steel |
| X-750 to Inconel 600 / 601 | 43 / 43 | ERNiCr-3 (FM 82) or matching X-750 | AWS A5.14 | Both alloys are P-No. 43; FM 82 preferred for solid-solution ductility |
| X-750 to Inconel 718 | 43 / 43 | ERNiFeCr-2 (FM 718) | AWS A5.14 / AMS 5832 | Matching 718 filler preserves age-hardening response across the joint |
If using matching X-750 filler, the entire weldment must undergo X-750 PWHT. If the mating material cannot tolerate the ageing temperature, use ERNiCr-3 (no PWHT required).
Recommended Welding Parameters for Inconel X-750
Nicorex Alloys supplies Inconel X-750 welding wire primarily for GTAW (TIG). Welding X-750 demands careful control due to strain-age cracking susceptibility.
| Parameter | Process / Value | Polarity | Shielding Gas | Notes |
|---|---|---|---|---|
| GTAW (TIG) | Preferred Process | DCEN | 100% Argon | Minimum heat input, use back purge |
| GMAW (MIG) | Controlled Use | DCEP | Ar / Ar-He | Control heat to avoid cracking |
| SMAW | – | – | – | No electrode available |
Premium Industrial Materials
Get Inconel X-750 Wire
at Competitive Prices
Industries and Applications of Inconel X-750 Welding Filler Wire
Nicorex Alloys supplies Inconel X-750 welding wire to fabricators in nuclear, aerospace, and oil and gas industries where high-temperature spring and fastener performance is critical.
- Hold-down springs, guide tube support pins, CRDM springs, fuel assembly springs and bolting, jet pump beams. X-750 is the standard spring material for nuclear reactor internals. Its stress-relaxation resistance, SCC resistance in primary water, and radiation tolerance are unmatched.
- Turbine exhaust bellows, seal rings, retaining rings, high-temperature springs, bolts, and studs at 500–700°C. X-750 provides the relaxation resistance needed to maintain preload through thermal cycling.
- Thrust chamber components, turbopump springs, and structural fasteners for liquid-fuelled rocket engines, serving from cryogenic propellant temperatures to hot-gas temperatures.
- Wellhead springs, valve springs, and high-strength fasteners for sour (H₂S) environments.
- Forming tools, extrusion dies, heat-treating fixtures, and thermocouple protection tubes.
Storage & Handling of Inconel X-750 Welding Wire
Nicorex Alloys supplies Inconel X-750 (AMS 5698) welding wire with proper packaging. X-750 filler wire is bare (uncoated). No re-baking is required.
Store at 15–25°C, below 60% RH, in original sealed packaging, away from carbon steel storage. Shelf life is indefinite if the packaging remains sealed. Handle with clean, lint-free gloves and dedicated stainless steel tools. Wipe with acetone or IPA if surface contamination is suspected.
The five elemental poisons for all nickel alloy fillers apply: S, Pb, Zn, Cu, and low-melting-point metals (Sn/Bi/Sb). X-750 is susceptible to HAZ liquation cracking and strain-age cracking, so cleanliness is even more critical than for solid-solution fillers. For nuclear-grade X-750, maintain full heat-lot traceability and chain-of-custody documentation.
Available Forms & Packaging of Inconel X-750 Welding Wire
Nicorex Alloys stocks Inconel X-750 wire in standard forms for welding and spring applications.
| Form | Diameter | Packaging |
|---|---|---|
| TIG Cut Lengths (rods) | Standard welding diameters | 914 mm (36″) lengths |
| MIG Spools | Standard diameters | GTAW preferred over GMAW |
| Coils | Per specification | For spring manufacturing and welding |
| Custom Cut Lengths | As required | Per project specification |
All Inconel X-750 wire is supplied with MTC 3.1 per EN 10204 certifying conformance to AMS 5698 or AMS 5699.
How to Order Inconel X-750 Welding Wire from Nicorex Alloys
Nicorex Alloys is a stockist and importer of Inconel X-750 (AMS 5698) welding wire in Mumbai, India. Provide these details for a quotation:
- Specification: AMS 5698 (No. 1 Spring Temper) or AMS 5699 (Spring Temper).
- Form: TIG rod, MIG spool, or coil.
- Diameter: Per project specification.
- Temper: No. 1 Spring Temper (AMS 5698) or Spring Temper (AMS 5699).
- Quantity: In kg or number of units. Single-heat if required.
- Heat/Lot Traceability: Required for nuclear and aerospace applications.
- Testing & Certification: MTC 3.1 per EN 10204 (standard). Additional: chemical re-verification (verify Co for nuclear), mechanical testing, third-party inspection.
- PWHT Intent: State which ageing schedule will be applied (AMS 5667/5668/5670).
- Nuclear/Aerospace OEM Requirements: Specify at order stage.
- Packaging: Sealed tubes, spools, or coils. Vacuum-sealed if required.
- Delivery: Domestic India or international export.
Frequently Asked Questions — Inconel X-750 Welding Wire
What is the Difference between the Matching X-750 Filler (AMS 5698) and ERNiFeCr-2 (FM 718) for Welding X-750?
Both can weld X-750 base metal, but they differ metallurgically. AMS 5698 (matching X-750) has ~70% Ni, 15.5% Cr, 7% Fe, 2.5% Ti, 1% Nb, strengthened by γ′ Ni₃(Al,Ti). ERNiFeCr-2 (FM 718) has ~52% Ni, 19% Cr, 18% Fe, 5% Nb, 3% Mo, strengthened by γ″ Ni₃Nb. Matching X-750 filler gives the closest composition match for corrosion compatibility. ERNiFeCr-2 delivers higher weld deposit strength but has different corrosion behaviour.
When NOT to Use Inconel X-750 Welding Wire?
Do not specify X-750 for service above 704°C (1300°F) where high strength is needed. γ′ overaging causes strength loss. Do not use X-750 filler when PWHT is impossible. Use ERNiCr-3 (FM 82) or ERNiCrMo-3 (FM 625) solid-solution filler. SAW is not recommended. X-750 has no molybdenum, so it is unsuited for reducing-acid service. Use ERNiCrMo-3 (625) or ERNiCrMo-4 (C-276).