Hastelloy C22 forged fittings are highly versatile and durable components made with a nickel-chromium-molybdenum alloy resistant to corrosion and oxidation. Welding these fittings requires the right process, parameters, and materials to ensure the welds are strong, reliable, and defects-free. The first step is to preheat the component by bringing it up slowly to 500°F (260°C). This helps reduce thermal stresses while helping the workpiece reach a temperature suitable for welding. Next, ensure that dirt or rust has been removed from the surface before using an Orbital machine or TIG welder with a thoriated tungsten electrode tip and argon gas shielding. As you weld Hastelloy C22 forged fittings, use filler material containing no more than 5% iron content to prevent cracking in the weld joint due to brittleness. Finally, for proper post weld cleaning, use pickling acid followed by quickly rinsing it off so as not to cause any damage to its surfaces. These steps will help guarantee successful welding when dealing with hastelloy c22 forged fittings.
What is Hastelloy C22 Forged Fittings?
Hastelloy C22 Forged Fittings are a form of forged fitting made with the Hastelloy C22 alloy, composed of nickel, chromium, molybdenum and tungsten. This combination allows for exceptional strength at elevated temperatures while remaining highly corrosion-resistant in oxidizing and reducing environments. Hastelloy C22 Forged Fittings stand up well against most organic chemicals, consisting of acids like sulfuric acid, among other more complex solutions. These fittings offer superior performance in many applications, such as oil & gas processing lines, petrochemical plants and power generation systems.
How to Properly Weld Hastelloy C22 Forged Fittings
Choosing the Right Welding Method:
To select the right welding method for Hastelloy C22 forged fittings, consider the material’s properties. Hastelloy C22 is a nickel-chromium-molybdenum alloy with excellent corrosion resistance to oxidizing environments and superior stress corrosion cracking resistance. The best welding methods for this alloy are those that produce minimal distortion and residual stresses, such as shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), or gas metal arc welding (GMAW). When selecting a filler material, use an AWS A5.14 ERNiCrMo-3 specification for maximum weld strength and corrosion resistance.
Choosing the Right Welding Filler Metal:
The correct filler metal for Hastelloy C22 forged fittings depends on the welding process and base metal properties. A high alloy, the low interstitial austenitic stainless steel filler metal, is often recommended to produce a weld with match strength and corrosion resistance to that of Hastelloy C22. Alternatively, nickel-based alloys such as Inconel 625 are suitable depending on the deposition rate and heat input requirements.
Maintaining the Correct Heat Input:
Heat input is important for Hastelloy C22 forged fittings. It is essential to ensure proper preheat and interpass temperatures to avoid cracking and other forms of material degradation. The preheat temperature should be between 400-700°F (205-371°C). Interpass temperatures should not exceed 1400°F (760°C) to prevent overheating. Additionally, use a low heat input rate during welding with an amperage rating of up to 350 amperes for a single-pass weld or 600 amps maximum for multiple passes. Proper maintenance of the correct heat input during welding Hastelloy C22 forged fittings will help extend the life of your component and reduce the risk of failure.
Post-Weld Treatment:
Hastelloy C22 forged fittings must be heat treated to restore the corrosion resistance, and strength lost due to welding. This should be done by slowly reheating the component to a temperature of 1250°C (2282°F) for 2-3 hours, followed by rapid or air cooling. All post-weld treatments must be carried out under strictly controlled conditions to maintain the integrity of the material.
Conclusion:
Welding Hastelloy C22 forged fittings is a highly specialized process that requires precision, skill, and attention to detail. Proper pre-weld, selecting the appropriate welding method and filler metal, maintaining the right heat input, and carrying out the post-weld treatment is critical to achieving high-quality results. These guidelines will ensure Hastelloy C22 forged fittings deliver optimal performance, longevity, and durability.