Dynamic Fabrication routinely works with exotic metals like Hastelloy. We provide hastelloy welding services in fabrication of prototype and short production runs for special applications. If you have a project requiring hastelloy welding we are experienced in welding and fabricating these materials.
Hastelloy Welding Techniques
The registered trademark name, Hastelloy, is applied as the prefix name to more than twenty different highly corrosion resistant metal alloys produced by Haynes International, Inc. These superalloys, or high performance alloys, developed by Haynes International, are nickel-based steel alloys that exhibit traits that include high resistance to uniform attack, localized corrosion/oxidation resistance, stress corrosion cracking resistance and ease of welding and fabrication. Alloys of identical chemical and mechanical properties are available from other manufacturers and offer excellent alternatives to the various Hastelloy® brand alloys. Click here is a PDF specification sheet explaining the corrosion resistant properties of hastelloy.
The corrosion-resistant superalloys are widely used by the chemical processing, aerospace, and industrial gas turbine and marine industries. Additionally, due to their reliable performance, areas of energy, health and environmental, oil and gas, pharmaceutical and flue gas desulfurization industries are increasingly using them.
The welding characteristics of corrosion resistant nickel-based alloys are similar in many ways to those of the austenitic stainless steels. They should present no special welding problems, if proper techniques and procedures are followed.
Quality Hastelloy Welding
To ensure quality hastelloy welding, welding procedure specifications are usually required for code fabrication. When developing a procedure, take into account:
- Welding process
- Joint design
- Base and filler materials
- Electrical characteristics
- Preheat/interpass control
- Postweld heat treatment
Any modern welding power supply with adequate output and controls can be used for common fusion welding. Generally, weld heat input is controlled in the low to moderate range. Stringer bead welding techniques-with some electrode/torch manipulation-are preferred. Wide weave beads are not recommended.
Nickel-based alloys generally exhibit sluggish welding and shallow penetration characteristics; so, the possibility of incomplete fusion increases. Care must be used to ensure that sound welds are achieved. Nickel-based alloys have a tendency to crater crack; so, grinding of starts and stops is recommended.
Cleanliness is critical when welding nickel-based alloys. Contamination by grease, oil, lead, sulfur, or other low melting point elements can lead to severe cracking problems. The welding surface and adjacent areas should be cleaned thoroughly with an appropriate solvent such as 99.9% isopropanol (IPA). Prior to any welding, all foreign matter-grease, cutting fluids, crayon markings, scale-should be removed.
Characteristics of Hastelloy
- High resistance to uniform attack
- Outstanding localized corrosion resistance
- Excellent stress corrosion cracking resistance
- Good resistance to acids such as sulfuric, nitric, hydrochloric, hydrofluoric and chromic
- Ease of welding and fabrication
- High resistance to oxidation at elevated temperatures
Applications For Hastelloy Alloys
- Hastelloy Nickel Alloy Chemical Processing Industry
- Oil and gas production
- Components where exposure to high mechanical stress and sea water are required
- Components exposed to flue gas or flue gas desulfurization plants