Understanding Weld Overlay: Stellite, Inconel, and Stainless Options

May 9, 2026

A comparison of common weld overlay materials — Stellite, Inconel, and stainless steel — with guidance on selecting the right overlay for your valve or component application.

What is Weld Overlay?

Weld overlay (also called hardfacing or cladding) deposits a layer of corrosion-resistant or wear-resistant material onto a base metal. It's commonly used on valve seats, gates, and other high-wear surfaces.

Stellite 6

Best for: High-temperature wear resistance
Hardness: 38-45 HRC as-deposited
Common use: Valve seats, gate faces

Inconel 625

Best for: Corrosion resistance in harsh environments
Hardness: 25-35 HRC
Common use: Valve bodies, chemical process equipment

309/316 Stainless

Best for: General corrosion protection at lower cost
Hardness: 80-90 HRB
Common use: Carbon steel vessels, pipe sections

Documentation Requirements

All weld overlays should be accompanied by WPS/PQR documentation, welder qualification records, and overlay thickness verification.