CRA Pipes – Weld Overlay Pipes

Author：admin
Date：2025-09-10
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CRA clad pipes and weld overlay pipes are closely related — and often overlap in terminology — there are important distinctions based on how the corrosion-resistant alloy (CRA) is applied, and how the pipe is manufactured or referred to in industry:

Key Differences: CRA Clad Pipe vs. Weld Overlay Pipe

Feature	CRA Clad Pipe	Weld Overlay Pipe
Definition	A general term for a pipe with a corrosion-resistant alloy bonded to a base pipe	A specific type of CRA clad pipe where CRA is applied using welding
Bonding Method	Can be weld overlay, explosion bonding, or hot roll bonding	Exclusively weld overlay using welding techniques (GTAW, GMAW, SAW)
CRA Application	CRA layer is bonded by any means	CRA layer is welded onto the inner (or sometimes outer) surface
Thickness of CRA Layer	Typically, thinner (e.g., 1.5mm–3mm) in explosion bonded or hot-rolled	Can be thicker, depending on welding passes (e.g., >3mm)
Base Pipe Source	Often produced from clad plate rolled into pipe or clad mechanically	Often starts from seamless or welded carbon steel pipe then overlay welded
Common Uses	High-volume, cost-sensitive projects (long pipelines, deep sea)	Custom spools, elbows, fittings, heavy-wall or small batch jobs
Standards Reference	API 5LD, ASTM B432, DNV-ST-F101	ASME IX, API RP 582, NACE MR0175 (for welding procedures)
Visual Appearance	Smooth, like solid pipe, often rolled from clad plate	Has visible welding beads/layers internally
Flexibility / Geometry	Limited to simple shapes (pipes, reducers, tees)	Very flexible — used for nozzles, elbows, vessels, bends