ISO 3506-1

EXECUTIVE SUMMARY

This report compares ISO 3506-1:2020 (stainless steel bolts, screws, studs) against its Chinese adoption GB/T 3098.6-2023. Both are TIER 1 product standards with MOD equivalence — property class system and steel grades align, but China adds domestic reference standards and formatting per GB/T 1.1-2020. Procurement implication: fasteners certified to GB/T 3098.6-2023 are generally acceptable for ISO 3506-1 applications, but verify proof stress values and test methods before cross-certification.

APPLICABLE CHINESE STANDARDS

STANDARD TIER CLASSIFICATION

SCOPE BREAKDOWN

Bolts, screws and studs (螺栓、螺钉和螺柱)

Chinese standard: GB/T 3098.6-2023: 紧固件机械性能 不锈钢螺栓、螺钉和螺柱

International equivalent: ISO 3506-1:2020: Fasteners — Mechanical properties of corrosion-resistant stainless steel fasteners — Part 1: Bolts, screws and studs with specified grades and property classes — 2020 edition

Equivalence: MOD

Standard tier match: Both TIER 1 — valid comparison

KEY DIFFERENCES SUMMARY

• Test method references — GB/T 3098.6-2023 cites GB/T 3098.1-2010; ISO 3506-1:2020 cites ISO 898-1. Different test apparatus tolerances may apply. Verdict: 附加测试后互认 (Mutual recognition after additional testing). Impact: MEDIUM.
• Formatting/terminology — GB/T 3098.6-2023 follows GB/T 1.1-2020 drafting rules; no technical deviation. Verdict: 直接互认 (Direct mutual recognition). Impact: LOW.
• Normative references — China adds domestic standards not in ISO text; affects compliance documentation. Verdict: 附加测试后互认 (Mutual recognition after additional testing). Impact: LOW.

REGULATORY LINKAGE TABLE (法规联动)

AUDIT FLAG RESOLUTION

• ✅ RESOLVED: GB/T 3098.6-2023 is CURRENT (现行) per std.samr.gov.cn — no supersession note required. Both drafts correctly identified 2023 edition.
• ✅ RESOLVED: ISO 3506-1:2020 is current edition (supersedes 2009). Both drafts agree.
• ⚠️ UNRESOLVED: Exact clause numbers for tensile/proof stress tables in GB/T 3098.6-2023 — verify against official text Table 3.
• ⚠️ UNRESOLVED: Hardness values for A4-80 — verify against both standards' Table 4.

PROCUREMENT VERDICT

• Confirm GB/T 3098.6-2023 certificate matches required property class (e.g., A4-80).
• Request test reports citing GB/T 3098.6-2023 test methods; verify equivalence to ISO 898-1 methods.
• For EU export, ensure CE marking per EN ISO 3506-1 — GB/T certification alone insufficient.
• Verify hardness values against official Table 4 of both standards before cross-certification.
• Specify nut/set screw/tapping screw standards (GB/T 3098.15/16/21) if full assembly procured.

REFERENCE DOCUMENT CHECKLIST (配套调阅清单)

• GB/T 3098.6-2023 § Table 3 — tensile/proof stress values
• GB/T 3098.6-2023 § Table 4 — hardness values
• ISO 3506-1:2020 § Table 3 — tensile/proof stress values
• ISO 3506-1:2020 § Table 4 — hardness values
• GB/T 3098.6-2023 § 8 — test method references

FIELD INSPECTION CHECKLIST

• Verify grade marking (e.g., A4-80) stamped on fastener head.
• Confirm material certificate matches steel grade (A1–A5, C1–C4, F1).
• Spot-check hardness with portable tester against Table 4 values.
• Verify batch test reports cite GB/T 3098.6-2023, not superseded editions.
• Confirm no surface defects (cracks, seams) per visual inspection requirements.

CONFIDENCE RATING

🟡 MEDIUM — core data (property classes, steel grades, tensile/proof stress) verified across two independent AI sources; ≤3 parameters (hardness, exact clause numbers, test method equivalence) flagged for official text confirmation.