ERNi-1 is a nickel-based filler metal designed for welding pure nickel materials (such as industrial pure nickel Nickel 200 and 201). It is also widely used in the connection of dissimilar metals such as nickel and stainless steel. Its unique chemical composition and process characteristics make it a key welding material in the fields of chemical industry, nuclear power, mechanical electronics, etc. The following analyzes the core value of ERNi-1 from three aspects: application scenarios, performance advantages and research progress.
1. The main application scenarios of ERNi-1
Welding of pure nickel materials
Pure nickel (such as N6 alloy) is widely used in chemical equipment, electronic components, etc. due to its excellent corrosion resistance and high temperature performance. However, pure nickel is prone to defects such as pores and cracks when welding. ERNi-1 significantly improves the quality of welds by supplementing alloying elements (such as Al and Ti) and refining grains, and is suitable for processes such as plasma arc welding (PAW) and tungsten inert gas welding (GTAW).
Dissimilar metal connection
ERNi-1 can be used for welding nickel and stainless steel. For example, in nuclear reactor equipment, nickel-based alloys are welded on the surface of stainless steel substrates (such as SS316H) to improve corrosion resistance. In addition, it is also used as a transition layer for BFe30-1-1 composite steel plate welding, effectively blocking the diffusion of Fe elements and ensuring weld performance.
2. Performance advantages of ERNi-1
Deoxidation and nitrogen fixation
The Al (1.5%) and Ti (2.0-3.5%) elements in ERNi-1 form Al₂O₃ and TiO₂ deoxidation products in the welding heat cycle, and combine with nitrogen to form TiN and AlN particles, reducing the tendency of CO and nitrogen pores and improving the density of the weld.
Grain refinement and mechanical property improvement
TiN particles (melting point 2950°C) act as heterogeneous nucleation cores to promote grain refinement during molten pool crystallization. The average grain size is reduced from 125.8 μm of PAW joint to 54.8 μm, the tensile strength is increased by 11.6%, and the elongation is increased by 85.5%. In addition, TiN can "pin" austenite grain boundaries, inhibit grain boundary migration, and enhance creep resistance.
Corrosion resistance optimization
In 6% FeCl₃ solution, the corrosion rate of ERNi-1 filled weld (2.6908 g/m²·h) is lower than that of ordinary PAW weld (2.8820 g/m²·h), but still slightly higher than that of the substrate (2.3458 g/m²·h), indicating that its corrosion resistance is better than that of unfilled weld.
3. Process control and research progress
The importance of composition regulation
Although Al and Ti have significant deoxidation effects, excessive amounts will lead to large-sized inclusions (such as TiO₂ up to 20 μm), which will damage the toughness of the weld. Studies have shown that the Ti content needs to be strictly controlled in the range of 2.0-3.5% to ensure the deoxidation and nitrogen fixation effects while avoiding the formation of brittle phases.
Welding process adaptability
ERNi-1 is compatible with a variety of welding methods, including plasma arc welding (PAW) and tungsten inert gas welding (GTAW). Compared with unfilled PAW, the process parameter range of the filler wire is wider and the welding process is more stable.
4. Industry application cases
Nuclear power equipment: ERNi-1 is used for cladding of stainless steel substrates to ensure the high temperature and corrosion resistance of nuclear reactor vessels.
Chemical equipment: In the welding of pure nickel N6 reactors, ERNi-1 effectively avoids thermal cracks and pores, extending the life of the equipment.
Conclusion
ERNi-1 welding wire solves the problem of pure nickel and dissimilar metal welding through alloy element optimization and microstructure regulation, becoming an ideal choice for high temperature and corrosive environments. In the future, with the refinement of welding technology and innovation of material design, the application potential of ERNi-1 will be further released.
