Forged vs Cast Valves: Which Is Right for Your Application?

 September 19, 2026  Novel Valves Engineering Team  Forged Valves

When reviewing valve specifications, engineers frequently encounter the choice between forged steel and cast steel valves. Both materials can produce reliable, high-quality valves — but each has distinct advantages in terms of material properties, applicable sizes, pressure ratings, and economics.

Understanding when to specify forged versus cast valves prevents over-specification (paying for forged valves where cast would suffice) and under-specification (using cast valves in critical service where only forged is acceptable).

1. How Forging and Casting Differ

Casting Process

In casting, molten steel is poured into a mold and solidified. The process allows complex shapes in large sizes but can introduce internal porosity, shrinkage voids, and inclusions in the solidified metal — which must be detected by NDT (radiography, UT) and repaired by welding.

Forging Process

In forging, solid steel billets are mechanically deformed under high pressure (hammered or pressed) into the desired shape while at elevated temperature. This compresses and aligns the grain structure of the steel — creating a denser, stronger, more uniform material with no internal porosity.

2. Key Differences

Parameter	Forged Valves	Cast Valves
Material Integrity	Superior — no internal porosity	Good — requires NDE inspection
Strength	Higher tensile & impact strength	Lower (but adequate for most service)
Size Range	Small — typically NPS ½" to 2"	All sizes — NPS ½" to 60"+
Pressure Class	Class 800# to 2500# (small sizes)	Class 150# to 2500# (all sizes)
Applicable Standard	API 602, API 608	API 600, API 6D, API 609
Material Grade (CS)	A105, A182 F11/F22	WCB, WC6, WC9
Material Grade (SS)	A182 F316, F304	CF8M, CF8
Cost (small sizes)	Competitive / lower	Higher (pattern + foundry cost)
Cost (large sizes)	Very high / impractical	More economical
Lead Time	Short (raw material availability)	Longer (foundry cycle)

3. When to Specify Forged Valves

• Small sizes (NPS ½" to 2"): For small sizes, forging is more economical than casting and provides superior material quality
• High-pressure service (Class 800# and above): Forged valves handle extreme pressure with greater confidence in material integrity
• Critical service: High-pressure steam, hydrogen, HF acid, toxic media where internal defects cannot be tolerated
• Instrument valve applications: Small bore, high-pressure, where forged body is standard practice
• Subsea applications: Where radiographic inspection of castings would be required anyway

4. When to Specify Cast Valves

• Large sizes (NPS 2" and above): Forging becomes impractical and uneconomical at large sizes
• Standard pressure classes (150# to 600#): Cast valves with proper NDE are fully adequate
• Non-critical service: Water, utility steam, cooling water, HVAC
• Volume procurement: Cast valves offer better pricing at large quantities and large sizes

5. Novel Valves Forged Valve Range

Novel Valves manufactures forged steel gate valves, globe valves, check valves, and ball valves per API 602 and API 608 — in sizes NPS ½" to 2", pressure classes 800# to 2500#. Available in A105 (carbon steel), A182 F316 (SS 316), A182 F11/F22 (alloy steel), and various exotic alloys.