Chemical components

Product Description

ERNiCrFe-7A is a nuclear-grade nickel-chromium-iron solid welding wire compliant with ASME SFA A5.14/A5.14M standards (AWS A5.14 ERNiCrFe-7A, UNS N06054), specifically designed for Inconel 690 (UNS N06690) and similar nickel-chromium-iron alloys in nuclear power applications. Featuring a high-purity composition with 28.0-31.5wt.% chromium, 7.0-11.0wt.% iron, and strict impurity control (C≤0.04wt.%, P≤0.02wt.%, S≤0.015wt.%), it excels in high-temperature and radiation environments. With additions of 0.5-1.0wt.% niobium, ≤1.0wt.% titanium, and ≤0.005wt.% boron, it provides enhanced ductility-dip cracking resistance. Compatible with GTAW (TIG), GMAW (MIG), and PAW processes, it supports welding of nuclear-grade alloys, dissimilar metal joints, and corrosion-resistant surfacing in critical nuclear island components.

Features

▪ Superior Nuclear-Grade Performance: Offers exceptional resistance to stress corrosion cracking in pure water and radiation environments at temperatures up to 350°C. The high chromium content (28.0-31.5wt.%) provides outstanding oxidation resistance, while Nb and B additions significantly reduce ductility-dip cracking susceptibility compared to standard ERNiCrFe-7. Weld metal exhibits tensile strength of 598-675MPa at room temperature and maintains ≥485MPa at 350°C, with elongation ≥38.5% in welded and heat-treated conditions.
▪ Enhanced Ductility-Dip Cracking Resistance: Optimized alloy design with controlled Nb (0.5-1.0wt.%), B (≤0.005wt.%), and Ti (≤1.0wt.%) additions inhibits M₂₃C₆ precipitation and reduces DDC sensitivity. This formulation minimizes oxide floaters and inclusions, ensuring excellent weld integrity in thick-section, high-restraint applications. The weld metal microstructure shows carbide precipitates (1-5μm) distributed at grain boundaries and grains without harmful Laves phase formation.
▪ Excellent Weldability: Ensures smooth weld formation with stable arc characteristics and clean metal transfer. The ultra-low impurity design (P≤0.02wt.%, S≤0.015wt.%) minimizes hot cracking tendency. Compatible with DCEN (GTAW), DCRP (GMAW) polarity using pure argon shielding gas. Interpass temperature control ≤150°C is recommended, and post-weld heat treatment (608°C/40h) maintains mechanical properties while optimizing microstructure.

Applications

▪ Ideal for nuclear power and extreme environment applications, ERNiCrFe-7A is widely used in:
▪ Nuclear Power Industry: Critical nuclear island components including steam generator tubes, reactor pressure vessels, pressurizers, and residual heat removal heat exchangers. Specifically designed for third-generation nuclear power plants with technology maturity level 8, meeting all design and manufacturing requirements for AP1000 and other advanced PWR reactors.
▪ High-Temperature Chemical Processing: High-temperature reactor vessels, heat exchangers, and components exposed to oxidizing acids, chlorides, and corrosive media. Used in hydrogenation units, acid service equipment, and environments requiring exceptional stress corrosion cracking resistance at elevated temperatures.
▪ Dissimilar Metal Welding: Critical for joining Inconel 690 alloys to carbon steels, stainless steels, and other nickel-based alloys in nuclear and petrochemical applications. Enables reliable transitions between dissimilar materials with different thermal expansion coefficients and corrosion resistance requirements.
▪ Advanced Manufacturing and Aerospace: High-end manufacturing applications demanding exceptional high-temperature strength, oxidation resistance, and long-term stability in aggressive environments. Serves as the preferred choice for cutting-edge nuclear technologies including Generation IV reactors (HTGR, SFR) and next-generation power generation equipment.