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Fastener Glossary & Standards Reference for Buyers
Types, grades, ISO/DIN/ASTM/GB standards, finishes and procurement terms in one reference page for RFQs and drawings.
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A practical glossary of fastener terms, grades and standards used in international procurement. Use this page when you read drawings, RFQs or packing lists.
Common fastener types
- Hex bolt β hexagonal head, full or partial thread. Widely used in steel structures and machinery.
- Carriage bolt β round head with square neck; locks into wood or metal.
- Flange bolt β integrated flange acts as a washer; common in automotive and pipelines.
- Eye bolt β ring head for lifting and anchoring.
- Stud / double-end stud β threaded rod with two ends, often used in flanges and engines.
- Threaded rod (all-thread) β continuous thread, cut to length.
- Expansion bolt (wedge / sleeve) β expands in concrete or masonry; key for construction fixing.
- Chemical anchor β resin + stud for high-load concrete fixing.
- Drop-in anchor / drive anchor β embedded anchors for medium loads.
- Hex nut / flange nut / cap nut / castle nut β matching and locking hardware.
- Washer (flat / spring / fender) β load distribution and anti-looseness.
Materials and grades
- Carbon steel β most standard bolts; grades 4.8, 8.8, 10.9, 12.9 (metric property class).
- Stainless steel β A2-70 / A4-80 (ISO 3506), 304 / 316 (ASTM).
- Alloy steel β heat-treated for high strength (e.g. ASTM A325, A490).
- Brass / aluminum β corrosion or aesthetic applications.
Standards you will see on drawings
- ISO 4014 / 4017 β hex bolts (partial / full thread).
- ISO 4032 β hex nuts.
- DIN 933 / 931 / 934 β classic German hex bolt / nut series.
- ASTM A307 β carbon steel bolts for general use.
- ASTM A325 / A490 β structural bolts.
- GB/T 5782 / 5783 β Chinese hex bolt standards (often equal to ISO/DIN).
- ASME B18.2.1 β inch hex bolts.
Surface finish
- Zinc plated β standard indoor corrosion protection.
- Hot-dip galvanized (HDG) β thicker zinc for outdoor / structural.
- Dacromet / zinc-nickel β high corrosion resistance.
- Black oxide / plain β oil finish; needs secondary protection.
- Stainless passivation β restores stainless surface after forming.
Procurement terms
- MOQ β minimum order quantity. WT Bolts: MOQ from 1 kg on standard sizes.
- Lead time β production + packing time. Stock items ship fast; custom parts follow drawing confirmation.
- OEM / made to drawing β parts produced to your sample or CAD.
- Mill certificate (MTC) β material test report shipped with goods.
- Export packing β inner bags, cartons/pallets, clear labels, container loading checks.
How to choose a supplier
Confirm grade and standard on the RFQ, ask for MTC and packing method, and check whether stock or custom lead time matches your project window. WT Bolts supplies hex bolts, expansion bolts, anchor bolts, studs, nuts and custom fasteners with large stock and export-standard packing.
Need a quote? Visit wtbolts.com or email [email protected].
