Fastener Export Inspection and Acceptance Guide

Fastener Export Inspection and Acceptance Guide

Fastener export acceptance centers on dimensions, threads, mechanicals and finishes, with inspection items and sampling per product standards and customer requirements. Standardized inspection cuts batch returns and protects delivery quality. This guide covers common items, sampling and acceptance points—final standards follow the order agreement.

Export inspection combines factory checks and third-party preshipment inspection, usually around packing completion, per the agreed sampling plan.

Dimension and Thread Inspection

Check head diameter, width across flats, length and head height per drawing and standard tolerances. Threads use GO/NO-GO gauges—GO runs smoothly, NO-GO stops properly—with checks on form, pitch and surface for cross-threading, burrs and missing threads.

Use calibrated gauges and controlled measurement conditions. Sample proportionally, record per item, and use results as the batch decision base.

Mechanical Testing

Bolts are checked by class for hardness and tensile strength—Rockwell or Vickers hardness, tensile by test machine. Nuts check proof load and hardness; washers check hardness and spring properties. High-strength parts watch hydrogen embrittlement, with delayed fracture tests when needed.

Mechanical tests need a representative sample count; reports record values and judgment. Requirements follow the applicable standards per material and grade.

Finish and Corrosion Inspection

Finish checks cover appearance, thickness, adhesion and salt spray. Appearance—no blistering, peeling, base metal exposure or major color difference; thickness by gauge per standard sampling; adhesion by cross-cut or bending; salt spray per agreed duration and class—neutral salt spray commonly in the 24-96h reference range.

Salt spray is time-consuming; validate the process before batches, with preshipment checks on appearance and thickness plus supplier reports and third-party review when required.

Sampling Plans and AQL

Preshipment uses attribute sampling per GB/T 2828.1 (ISO 2859-1), accepting or rejecting batches by AQL (e.g. 0.65, 1.0, 1.5, 2.5). Sample size follows lot size and inspection level; customers may set stricter plans.

Sample across packing units to avoid masking local defects. Keep records, nonconformance handling and re-inspection traceable.

Shipping Documents and Acceptance

Export documents include packing list, invoice, material certificates and inspection reports per order and destination. Reports note batch, standard basis and results for customer and customs verification. Arrange third-party certificates early.

Disputes are judged by sealed samples, drawings and agreed standards; clean documents and complete records resolve issues quickly and protect both parties.