Valve body materials: cast iron, ductile iron, carbon steel and stainless steel
What the body has to withstand
The valve body is the pressure boundary: it sets the temperature and pressure envelope, the corrosion behaviour against the medium, and usually the largest share of the valve’s weight and cost. Body material is therefore one of the first selection decisions — before size, connection or actuation — because it constrains everything downstream, including which executions exist for a duty at all.
A material choice is always a pairing of medium and conditions. Water at ambient temperature, saturated steam, weak acids and abrasive slurries push the decision in different directions, and the same alloy that is unremarkable in chilled water can be the wrong answer in hot chloride-bearing media. This page explains the common body material groups and how to read them in a catalogue.
The four common groups in industrial valve catalogues
Across the valve model pages published in this catalogue, provenance-backed body material fields fall into four broad groups plus a corrosion-endurance special case. The table counts identifier pages whose spec table lists each group, so it reflects what this catalogue actually publishes rather than a general industry claim.
| Material group | Typical published grades | Published model pages listing the group |
|---|---|---|
| Cast iron (grey) | Cast iron / gray cast iron | 36 |
| Ductile (nodular) iron | Ductile iron, GGG50, nodular cast iron | 43 |
| Carbon & low-alloy steel | WCB, carbon steel, A105, LCB, WC6, F22 | 82 |
| Stainless steel | CF8, CF8M, CF3M, SS304, SS316, F304L, F316L | 82 |
| Duplex stainless steel | Duplex stainless steel | 15 |
Iron vs steel vs stainless: the practical differences
Grey cast iron is the economical answer for low-pressure water and non-aggressive duties; it is rigid but brittle, so it is unsuitable where thermal shock or mechanical impact is expected. Ductile (nodular) iron keeps iron’s cost profile but adds elongation and impact resistance, which is why water-works valves — butterfly, check, diaphragm, balancing — are commonly published in ductile iron bodies.
Cast carbon steel (WCB in ASME nomenclature) serves higher pressure and temperature duties than irons — steam, oil and gas process lines — and forged grades (A105) extend the same family to small-bore high-pressure valves. Low-temperature carbon steel (LCB) and the chrome-moly grades (WC6, F22) move the envelope toward low service temperatures and higher creep-range temperatures respectively.
Stainless bodies (CF8/CF8M cast, SS304/SS316 wrought designations, their low-carbon L variants) are selected for corrosion resistance: CF8M is the cast grade commonly paired with 316-type chemistry, and molybdenum content is what improves pitting behaviour in chloride-bearing media. For strongly corrosive or abrasive media, lined executions — rubber or PTFE lining over a ductile iron body — shift the corrosion duty from the body to the lining, which is the standard approach in diaphragm and pinch valves.
How this shows up on the product pages
Every valve model page in this catalogue renders its spec table only for fields that carry collected evidence, and body materials are the most widely covered field: 131 of the published model pages list provenance-backed body materials. Where an execution page offers a material choice — for example body_materials listing "Cast Iron, WCB, SS304, SS316" — the list is the published option set for that execution, not a statement that every combination is in stock.
The family and category pages carry the same fields at family level where the pack provides them. When a spec cell shows an unverified or "confirm at RFQ" state, the material for that exact configuration has not been established by the collected evidence — the correct move is to state the requirement in the inquiry rather than assume.
What to state in an inquiry
So the quoted body matches the duty, state: medium and concentration, temperature range (minimum and maximum, including upset), design pressure and class, and any specification that governs the body (an ASTM/ASME or EN grade call-out). With those four or five lines, matching a published execution — or identifying that the duty needs a lining or an upgrade — is a confirmation step, not a guess.