Dilution control in hardfacing severe service components

A method for forming a wear- and corrosion-resistant coating on an industrial valve component comprising:

• a) applying a cobalt-based dilution buffer layer having a thickness between about 0.005 and about 0.03 inch to an iron-based valve component body substrate selected from the group consisting of a valve body, a ball of a ball-and-ring valve assembly, a seat of a ball-and-ring valve assembly, a gate valve component body, a V-ball valve component body, a wedge valve component body, wedge valve guides, and a valve seat body, said applying comprising slurry coating of a cobalt-based alloy powder followed by sintering to fuse the powder together and to the substrate;
• b) applying by welding a cobalt-based build-up layer over the cobalt-based dilution buffer layer to integrate the build-up layer and the dilution buffer layer into an integral cobalt-based wear- and corrosion-resistant layer;
• and
• c) cooling the component to room temperature.

An industrial component comprising:

• an iron-based substrate body;
• and
• a cobalt-based layer over a surface of the substrate and securely bonded directly to the substrate body with no metal layer between the cobalt-based layer and the substrate body;
• wherein the cobalt-based layer has a thickness of at least about 0.055 inch;
• and
• the cobalt-based layer has an average level of iron dilution from the iron-based substrate into the cobalt-based layer of less than 5 wt % iron at a level spaced 0.06 inch from the substrate surface.