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WCB vs CF8M: Choosing Valve Body Materials

VTXFLOW Engineering Team · 2026-07-17

WCB and CF8M are the two most ordered valve body materials in export trade. Choosing between them is usually simple once you know what each does — and expensive when you guess wrong.

WCB — the carbon steel workhorse

ASTM A216 WCB is cast carbon steel: strong, weldable and economical. It handles water, steam, oil, gas and non-corrosive process media from -29°C up to about 425°C. For general refinery, power and pipeline service it is the default — the majority of API 600 gate valves and floating ball valves ship in WCB.

CF8M — stainless for corrosion and temperature extremes

ASTM A351 CF8M is the cast equivalent of 316 stainless steel. The molybdenum addition resists chlorides, organic acids and marine atmospheres, and the material stays tough from -196°C (see our cryogenic range) up to roughly 538°C. Specify it for chemical processing, seawater, food-adjacent utilities and anywhere product purity or pitting resistance matters.

The cost equation

CF8M bodies typically cost 60–100% more than WCB. That premium buys corrosion life, not strength — pressure ratings at moderate temperatures are similar. Paying it for clean water service wastes budget; skipping it on chloride service destroys the valve in months.

Quick reference

  • Steam, oil, gas, utility water: WCB
  • Chemicals, chlorides, seawater, cryogenics: CF8M
  • Higher temperature carbon service (up to 595°C): WC6 / WC9 alloy steel
  • Severe sour service: add NACE MR0175 requirements to either

All VTXFLOW valves are available in WCB, CF8, CF8M, CF3M, LCB and duplex grades with EN 10204 3.1 certificates traceable to the heat.

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