Chromium-free welding consumable
AssigneeThe Ohio State University
InventorsGerald S. Frankel, John C. Lippold
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Abstract
A chromium-free welding consumable and a method of welding stainless steel to reduce the presence of chromium emissions. The consumable is made from an alloy that reduces the emission of chromium during a welding process, and include predominantly nickel, with between approximately five and ten weight percent copper, up to approximately two percent by weight of ruthenium and up to five percent non-copper alloying ingredients. Welding consumables made from the alloy are particularly well-suited for welding austenitic stainless steels, such as type 304 stainless steel. The method involves using chromium-free weld filler material with a stainless steel base material.
Claims21
A substantially chromium-free welding material for welding a stainless steel base metal, said material comprising:
- between approximately 1 weight percent and 2 weight percent ruthenium;
- between approximately 5 weight percent and approximately 10 weight percent copper;
- and
- a balance of nickel and up to 5 weight percent other alloying ingredients such that upon welding said stainless steel base metal, fumes from a weld pool produced by said welding contain substantially no hexavalent chromium.
A substantially chromium-free nickel-based welding consumable comprising up to approximately 10 weight percent copper, between approximately 1 weight percent and approximately 2 weight percent ruthenium and up to 5 weight percent other alloying ingredients such that said device is defined by a corrosion potential at least as high as a stainless steel workpiece to which said consumable is configured to be joined, a breakdown potential greater than the workpiece and a repassivation potential greater than the workpiece.
A method of welding a stainless steel base material, said method comprising:
- providing a chromium-free welding consumable comprising up to approximately 10 weight percent copper, between approximately 1 weight percent and approximately 2 weight percent ruthenium and a balance of nickel and up to 5 weight percent other alloying ingredients;
- and
- welding said base material with said welding consumable to produce a welded composition such that fumes from a weld pool produced by said welding contain a substantial reduction in hexavalent chromium concentration relative to that produced using a chromium-containing welding consumable.
The method of claim 19, wherein said up to approximately 2 weight percent aluminum, up to approximately 2 weight percent titanium comprise approximately 0.5 weight percent of each.
Dependencies are inferred from the claim text.