To evaluate the quality system of fastener suppliers, three key factors should be considered: whether there is a formal system certificate (ISO/IATF), whether on-site traceability and testing can be truly carried out (rather than just presenting documents), and whether key processes, especially heat treatment and thread testing, are controlled. Below is a set of practical methods for document review → on-site audit → fastener special focus → traffic light judgment.

📁 1、 Initial review of documents/qualifications (desktop screening)

Focus points of review items

ISO 9001:2015 must be within its validity period and cover the scope of “fastener production/processing”. It is not applicable only to trading companies (traders should refer to their factory inspection system)

IATF 16949/AS9100 (Automotive/Aviation) Critical Safety Component Selection with this certification

Can the EN 10204 material certificate be issued with a 2.1/2.2 or 3.1 certificate

Testing equipment ledger+calibration certificate. Tensile machines, hardness testers, spectrometers, salt spray boxes, and thread gauges must be within the calibration cycle

Main customer list/cooperation period with long-term supporting well-known machine manufacturers/large factories experience bonus points

⚠️ Just looking at certificates is not enough – many small factory certificates have been helped by consulting companies and must be combined with the site.

🏭 2、 On site Second Party Audit – Special Focus on Fasteners

① Raw material control

• ✅ Each batch of raw materials comes with a quality assurance certificate (furnace number, steel number ML40Cr/35K/SUS304, etc.)

– ✅ Warehouse re inspection or at least verification of material identification (color code/label)
• ❌ No furnace number traceability, mixed placement of different steel grades

② Heat treatment (the most critical step)

Is there a continuous mesh belt furnace with carbon potential control and automatic curve recording

Whether to conduct hardness sampling and tensile testing after tempering (or core hardness/re tempering test)

-8.8/10.9/12.9 levels must have traceable heat treatment batch records

💡 If there is no self owned heat treatment outsourcing, the qualification of the outsourcing factory and the entry verification record must be reviewed.

③ Thread and dimension inspection

• Use thread gauges (GO/NO GO) for full inspection or AQL sampling inspection

-Key dimensions (length, opposite edge, rod diameter) have initial inspection and patrol records
The thread gauge has usage frequency/cycle management during the calibration period

④ Surface treatment control

Galvanized/Dacromet with thickness testing records (XRF or weight method)

• Salt spray test frequency (per batch/week/per furnace) and non-conforming disposal process

⑤ Identification and traceability

• Mark the bolt head with grade lettering (8.8/A2-70, etc.) → Consistent with the material grade

The finished product packaging label includes: specification, grade, batch number, furnace number, quantity, and production date

• Can achieve one-way/two-way traceability from shipment batch to heat treated batch to raw material furnace number

⑥ Nonconforming Products and Corrective and Preventive Actions (CAPA)

• Unqualified product area, clearly marked

Root cause analysis and rectification verification records for substandard/mixed materials

🚦 3、 Simplified determination of traffic lights (for supplier grading)

Suggestions for using level features

🟢 Qualified Class A ISO9001 effective+complete heat treatment/testing records+complete material reports+traceability+no major abnormalities in the past year as the main supplier of critical/safety components

🟡 Conditional Class B has ISO but weak testing/traceability, or only traders (forced to enter the factory)+minor defects have been rectified for non critical parts/auxiliary materials, with a deadline for rectification

🔴 Unqualified/frozen without valid system certificate, refusal to provide report, no heat treatment control, failed to rectify due to previous failures, suspended/blacklisted

📋 4、 Three ‘killer questions’ that can be asked on the spot by auditors/quality control personnel

1. Adjust the quality assurance certificate, heat treatment records, and tension report of the raw materials for last month’s grade 8.8 M12 bolts. → Unable to retrieve=Serious non-compliance
When was the last calibration of the thread gauge? How many times has it been used
3. “If a customer discovers a batch of bolts labeled 8.8 but actually 4.8, how do you trace and recall them?” → Check if there is a real traceability drill/record

💬 Summary of Procurement/Quality in One Sentence

Evaluate the quality system of fastener suppliers, with a focus on the validity of ISO9001/IATF certificates, traceability of raw material furnace numbers, control and recording of heat treatment processes, thread and performance sampling capabilities, and the ability to provide material and mechanical performance reports along with the goods. Suggest conducting a second party on-site audit and tracking quarterly KPIs. “