GB/T 90.1-2023 Fasteners - Acceptance inspection
1 Scope
This document specifies an inspection procedure to be used by the purchaser where no prior agreement exists. It also specifies a reference acceptance procedure for acceptance or rejection of an inspection lot, when no agreement can be reached between the purchaser and the supplier, or where conformance to specification is disputed.
It applies to inspection lots of bolts, screws, studs, nuts, pins, washers, rivets and other related fasteners.
This document applies to fasteners not intended for high volume machine assembly, special-purpose applications or specially engineered applications requiring more advanced in-process control and lot traceability.
For in-process control or final inspection by the manufacture and sorting, see GB/T 90.3.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection (GB/T 2828.1-2012, ISO 2859-1:1999, IDT)
GB/T 3099.4 Terminology of fasteners - Control, inspection, delivery, acceptance and quality (GB/T 3099.4-2021, ISO 1891-4:2018, MOD)
GB/T 3358.2 Statistics - Vocabulary and symbols - Part 2: Applied statistics (GB/T 3358.2-2009, ISO 3534-2:2006, IDT)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2828.1, GB/T 3099.4 and GB/T 3358.2 and the following apply.
3.1
inspection lot
quantity of fasteners of the same designation received from the same supplier at the same time and of the same manufacturing lot number
3.2
characteristic
dimensional element, mechanical, physical or functional property or other recognizable product feature for which limits are specified
Example: Head height, body diameter, tensile strength or hardness
3.3
acceptance quality limit
AQL
acceptable percentage of non-conforming fasteners in an inspection lot (3.1) corresponding to a specific probability of acceptance defined in the AQL index
Note: AQL95 is the percentage of non-conforming fasteners where the inspection lot has a 95% chance of being accepted by the purchaser under the sampling plan; in other words, the supplier’s risk of rejection is less than 5%.
3.4
limiting quality
LQ
percentage of non-conforming fasteners in an inspection lot (3.1) corresponding to a specific probability of acceptance defined in the LQ index
Note 1: LQ10 is the percentage of non-conforming fasteners where the inspection lot has a 10% chance of being accepted by the purchaser under the sampling plan; in other words, the purchaser’s risk of accepting the lot is less than 10%.
Note 2: For a given sampling plan, limiting quality (LQ) and acceptance quality limit (AQL) are linked in the corresponding operating characteristic (OC) curve.
4 Symbols
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols
5 Incoming acceptance inspection procedures for fasteners
6 Result of inspection and disposition
Annex A (informative) Sampling plans basics
Annex B (informative) Operating characteristic of sampling plans
Bibliography
