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Fastener terminology EN–ZH glossary: essential screw & bolt vocabulary for procurement

2026-09-06

Compiled by JIALI Industrial (164.hk) — a Hong Kong fastener supplier specialising in screws, bolts, nuts and selection know-how.

Why a bilingual terminology glossary matters

In cross-border fastener procurement, terminology mismatches cause costly misunderstandings. For example, the Chinese term translated loosely as screw can map to screw, bolt or threaded fastener in English, while the two Chinese characters for bolt and screw are strictly distinguished in the Chinese national standard: a bolt mates with a nut, whereas a screw taps directly into the workpiece. Mastering a standard EN–ZH terminology glossary prevents specification drift in quotation and delivery — a vital skill for Hong Kong buyers interfacing with mainland factories or overseas suppliers. The commercial consequences are concrete. Consider a buyer who enquires in English for a set of M8 stainless screws and a mainland supplier, reading the term as the Chinese word for bolt, quotes hex head bolts with nuts. The buyer expected socket head cap screws, the price difference is material, and the delivery is unusable for the assembly in question. The rework costs a week and a rush order. A second common case is the distinction between fully threaded and part threaded parts. English uses full thread and partial thread, while Chinese has separate terms for a fully threaded screw and a partly threaded one, and a quotation that does not state which was offered will be produced to whichever the factory considers standard. A third case is the head style: the English term countersunk and the Chinese term for it are both used loosely to cover a range of geometries, including a raised countersunk head that sits proud of the surface and a flat countersunk head that sits flush, and the two are not interchangeable in a flush assembly. The practical conclusion is that a bilingual purchase specification should not rely on the English term alone. Writing the part name in both languages, giving the standard number, and stating the critical dimensions removes almost all of the ambiguity, at a cost of a few extra characters in the RFQ.

Common fastener terms — EN–ZH reference table

Head types: hex bolt and hexagon head bolt (外六角螺栓), socket head cap screw (內六角螺釘, DIN 912), flange bolt (法蘭面螺栓), countersunk screw (沉頭螺釘), pan head screw (盤頭螺釘), button head and round head counterparts (圓頭螺釘). Thread and pitch: coarse thread (粗牙), fine thread (細牙), pitch (牙距), full thread (全牙), partial thread (半牙), rolled thread against cut thread (搓牙 / 車牙), and thread run-out (螺紋收尾). Nuts and washers: hex nut (六角螺母, GB/T 6170), nylon insert lock nut (尼龍鎖緊螺母, DIN 985), flange lock nut (法蘭鎖緊螺母, DIN 6923), spring washer (彈簧墊圈), flat washer (平墊圈), and the distinction between a plain washer for load spreading and a hardened washer (硬化墊圈) for a high-strength joint. Surface finish: zinc-plated (鍍鋅), hot-dip galvanising (熱浸鍍鋅), black oxide (黑色氧化), Dacromet (達克羅), passivation (鈍化), and mechanical zinc or zinc-flake equivalents (機械鍍鋅 / 鋅鋁塗層). Drive types: hex socket (內六角), hexagon head (外六角), Phillips and Pozidriv (十字), Torx and hexalobular (星形), and the security variants of each. Fastener families: set screw or grub screw (緊定螺釘), stud (螺柱), threaded rod or all-thread (牙條 / 全牙螺杆), blind rivet (拉釘 / 抽芯鉚釘), self-tapping screw (自攻螺絲), self-drilling screw (自鑽螺絲 / 鑽尾螺絲), and the anchor family (膨脹螺栓 / 化學錨栓). Two of these terms behave differently in the two languages and deserve specific attention. In English, the word screw is used for a very wide range of threaded fasteners, including many that a Chinese technical document would call by a different name. In Chinese, the terms for bolt and screw carry a structural distinction about whether a nut is involved, so a translation that ignores it can move a part between two different product families. The word for rivet is another case: English distinguishes blind, solid, tubular and structural rivets, and a translation that uses the general term for rivet alone may not convey which of the four is intended, which matters because their setting tools and strength are entirely different. When in doubt, quote both the English term and the standard number, and attach a photograph of the part, since a photograph resolves more ambiguity than any glossary entry.

Material grades and standard abbreviations

Materials and grades: carbon steel (碳鋼), stainless steel (不鏽鋼), alloy steel (合金鋼), and brass (黃銅); strength classes 4.8, 8.8, 10.9 and 12.9 per ISO 898-1; stainless steel per ISO 3506 in grades A2 (304) and A4 (316). Common standard abbreviations: GB/T (China), DIN (Germany), ISO (International), ASTM (USA), JIS (Japan) and EN (Europe). Certifications and compliance terms: RoHS 2.0, REACH, SVHC, EN 10204 3.1 material certificate (材質證明書), PPAP for automotive submissions, and the ISO 9227 or ASTM B117 salt spray test. We recommend listing specs and standards bilingually on every RFQ to eliminate ambiguity in cross-language communication. A few of these abbreviations are worth expanding because they are routinely misread. EN 10204 is a standard defining the types of inspection documents, and the common 3.1 designation means a certificate issued by the manufacturer's independent inspection representative, which is a stronger statement than a simple certificate of conformity; buyers sometimes order 3.1 expecting a third-party laboratory report and receive something different. Similarly, REACH and RoHS are European regulations addressing different concerns, one on chemical substances in articles and the other on restricted substances in electrical equipment, and a fastener destined for an electrical enclosure may need both while a structural part generally needs only one. The distinction between a certificate of conformity and a material certificate also matters when a customer's own quality department inspects: a certificate of conformity states that the goods meet the specification, whereas a material certificate records the actual chemical composition and mechanical results of the heat, which is what an auditor usually wants to see. Salt spray references behave the same way: a report citing ISO 9227 or ASTM B117 should also state the duration and whether the endpoint is white or red rust, and a figure without those details cannot be compared with another supplier's figure. Where a purchase order crosses languages, writing the standard number in its original form and not translating it is the safest practice, because a translated standard number is easier to misread than a code.

Common pitfalls and how to avoid them in bilingual procurement

Pitfall one is relying on a single English term for a part that has several forms. Screw, rivet and washer all cover multiple products, and the specification should narrow the term with a standard number or a dimension. Pitfall two is translating the standard number. GB/T 5783 has no meaningful translation and should be quoted exactly; a translated version invites a mismatch. Pitfall three is omitting the thread type. A coarse thread and a fine thread of the same nominal diameter are different parts, and in a bilingual RFQ the pitch is often left implicit on the assumption that the default is understood, which it is not across suppliers. Pitfall four is confusing a material certificate with a certificate of conformity, and ordering the wrong one for a customer's own acceptance requirement. Pitfall five is translating a quotation back into the original language and treating the translation as the agreement. A quotation should be accepted in the language in which the specification was written, with the bilingual version attached as a reference rather than as the controlling document, so that there is no argument later about what a term meant. A practical workflow for cross-border enquiries is to keep a single bilingual template with fixed fields for part name in both languages, standard number, size and pitch, property class, material, finish, quantity and required documents; to attach a photograph or drawing to every line; and to state which language version controls in the event of a discrepancy. That last point is the one most often skipped and the one that resolves disputes fastest, because it removes the argument about meaning and returns the discussion to the goods themselves. For recurring items, adding the part to your own bilingual catalogue with a photograph removes the risk entirely for all future orders. Need a complete EN–ZH fastener terminology glossary or procurement template? Contact JIALI Industrial (164.hk) for a bilingual spec sheet and technical support.

Related Reading

• Fastener purchase contracts and drawing tolerances: getting the quality requirements right the first time
• Stainless bolts still rust? Passivation, corrosion testing and procurement essentials
• JIALI launches Stainless Steel zone with full 304 / 316 range

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