Published notes
Valve Pressure Class Is Not a Working Pressure
How a pressure class is read against material group and temperature, and what a forging certificate can and cannot prove.
API Spec 20C, API Q1 & NORSOK M-650
What the three documents actually cover, which one is a licence and which one is an audit, and what they change for an oil and gas or offshore order. For: buyers writing a specification, and engineers checking whether a supplier’s paperwork will pass.
Material Test Certificates: EN 10204 3.1 vs 3.2
What a material test certificate contains, what the difference between 3.1 and 3.2 is, which fields are worth checking, and what ships with a Longrui order. For: anyone doing goods-in inspection or building a supplier file.
Forging Quality Control
The inspection and test plan behind a forging: what is checked at each stage, with which instrument, and what record it leaves before dispatch. For: quality engineers auditing a process, and buyers comparing two suppliers’ inspection plans.
Forging vs Casting
How the two routes differ in grain structure, porosity and fatigue, which grades pair up across ASTM specifications, and when to specify a forging. For: design engineers choosing a process, and buyers asked to justify the price difference.
More technical pages
- Closed die or open die forging: how to choose — tooling economics, draft and shape limits, size range.
- Verifying a material certificate: 10 checks — what to check at goods-in, and what PMI cannot prove.
Forging capacity behind these notes
Three multi-directional presses of 6,000 T, 3,000 T and 2,000 T, forged parts from 5 to 520 kg, machining to Ø600 × 1,000 mm, and heat treatment in-house — the figures these notes are written from are on the capability page.
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