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Proof Load vs Yield vs Tensile Strength in Bolts Explained

Three Numbers, Three Different Questions When a bolt datasheet lists proof load, yield strength and tensile strength, it is answering three different questions: how much load can this bolt take without changing at all (proof), where does it start to stretch permanently (yield), and where does it finally break (tensile). Confusing them leads to two

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Pre-Shipment Fastener Inspection: Complete Checklist for Importers

Why Pre-Shipment Inspection Exists Once a container of fasteners leaves the port, discovering a wrong grade or a bad coating costs you the freight twice — once going and once coming back. Pre-shipment inspection (PSI) is the buyer’s last cheap chance to verify the goods, and for a technical product like fasteners it is not

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How to Choose a Fastener Manufacturer in China: 10-Point Checklist

Why the Checklist Matters China produces more fasteners than the rest of the world combined — which means for every serious manufacturer there are a dozen trading companies with a polished website and no factory behind it. The difference shows up six months later, in thread tolerances, coating thickness and heat-treatment consistency. This checklist is

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Fastener Corrosion Classes C1–C5: Choosing the Right Finish

Why Corrosion Classes Decide Your Fastener Finish The same zinc-plated bolt that lasts decades inside a heated office would be rusted scrap on an offshore platform within a year. Engineers handle this with the corrosivity categories C1–C5 (and CX) from ISO 12944-2, which classify environments by how aggressively they attack steel. Match your fastener finish

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