API 602 vs API 600 — When to Use Forged

API 600 covers cast steel gates typically NPS 2 and above flanged. API 602 covers compact forged gates for small-bore high-pressure (often Class 800 SW/NPT).

Do not substitute face-to-face or ends across standards. RFQ A105 Class 800 forged when the manifold is screwed/SW Class 800.