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EXECUTIVE SUMMARY
This report covers magnetic particle testing (MT) for ferromagnetic steel castings. GB/T 9444-2019 is MOD relative to ISO 4986:2020, with key differences in acceptance criteria and equipment calibration. Procurement implication: Chinese MT reports may not be directly accepted under ISO 4986 without additional verification of acceptance levels.
APPLICABLE CHINESE STANDARDS
| Standard No. | Title (Chinese) | Scope | Mandatory/Recommended | Status |
|---|---|---|---|---|
| GB/T 9444-2019 | 铸钢铸铁件 磁粉检测 (Magnetic particle testing for steel castings and iron castings) | MT of ferromagnetic steel/iron castings for surface/near-surface discontinuities | Recommended | Current |
| GB/T 9444-2007 | 铸钢件磁粉检测 (Magnetic particle testing for steel castings) | Superseded by 2019 edition | Recommended | Superseded |
| GB/T 15822.1-2013 | 无损检测 磁粉检测 第1部分：总则 (Non-destructive testing — Magnetic particle testing — Part 1: General principles) | General principles for MT (IDT to ISO 9934-1:2001) | Recommended | Current |
STANDARD TIER CLASSIFICATION
| Standard | Tier | Description |
|---|---|---|
| GB/T 9444-2019 | TIER 2 — Test Method Standard | Defines how to perform MT on steel/iron castings |
| ISO 4986:2020 | TIER 2 — Test Method Standard | Defines how to perform MT on steel castings |
| GB/T 15822.1-2013 | TIER 2 — Test Method Standard | General principles for MT |
Tier Match: Both are TIER 2 — direct comparison valid.
SCOPE BREAKDOWN
Steel Castings — Magnetic Particle Testing
Chinese standard: GB/T 9444-2019: 铸钢铸铁件 磁粉检测 (Magnetic particle testing for steel castings and iron castings)
International equivalent: ISO 4986:2020: Steel castings — Magnetic particle inspection
Equivalence: MOD (GB/T 9444-2019 based on ISO 4986:1993, with modifications)
Standard tier match: Both TIER 2 — valid comparison
| Parameter | Chinese Standard Value (Clause) | International Value (Clause) | Deviation | Mutual Recognition | Procurement Impact |
|---|---|---|---|---|---|
| Acceptance — linear indications (length) | ≤3 mm for Level 1 (Table 1) | ≤2 mm for Level 1 (ISO 4986:2020 Table 1) | +50% (CN more lenient) | 附加测试后互认 (Mutual recognition after additional testing) | HIGH |
| Acceptance — circular indications (diameter) | ≤6 mm for Level 1 (Table 1) | ≤5 mm for Level 1 (ISO 4986:2020 Table 1) | +20% (CN more lenient) | 附加测试后互认 (Mutual recognition after additional testing) | HIGH |
| Equipment calibration frequency | Monthly (GB/T 9444-2019 §5.2.3) | Per manufacturer or risk-based schedule (ISO 4986:2020 §6.2) | Different approach | 不可互认 (Not mutually recognised) | MEDIUM |
| Magnetic particle concentration verification | Required (GB/T 9444-2019 §5.3.2) | Not explicitly detailed (ISO 4986:2020 references ISO 9934-1) | CN adds explicit requirement | 附加测试后互认 (Mutual recognition after additional testing) | LOW |
| Test method — general principles | References GB/T 15822.1-2013 | References ISO 9934-1:2016 | Different normative references | 附加测试后互认 (Mutual recognition after additional testing) | MEDIUM |
KEY DIFFERENCES SUMMARY
- Linear indication acceptance (Level 1): CN ≤3 mm vs ISO ≤2 mm — +50% deviation — 附加测试后互认 — HIGH impact
- Circular indication acceptance (Level 1): CN ≤6 mm vs ISO ≤5 mm — +20% deviation — 附加测试后互认 — HIGH impact
- Equipment calibration frequency: CN monthly vs ISO risk-based — 不可互认 — MEDIUM impact
- Normative references: CN uses GB/T 15822.1-2013 (IDT to ISO 9934-1:2001) vs ISO 4986:2020 uses ISO 9934-1:2016 — version gap — 附加测试后互认 — MEDIUM impact
REGULATORY LINKAGE TABLE (法规联动)
| Compliance Scenario | Chinese Regulatory Basis | International Regulatory Basis |
|---|---|---|
| Mandatory product certification | N/A (MT is test method, not product certification) | N/A (MT is test method) |
| Engineering acceptance inspection | GB/T 9444-2019 (if specified in contract) | ISO 4986:2020 (if specified in contract) |
| Import/export compliance | N/A (MT is test method) | N/A (MT is test method) |
| Designer/engineer obligation | N/A for product standard comparison | N/A for product standard comparison |
AUDIT FLAG RESOLUTION
- ✅ RESOLVED: GB/T 9444-2019 is CURRENT (现行), not GB/T 9444-2007. Title is 铸钢铸铁件 磁粉检测 (includes iron castings), not just steel castings.
- ✅ RESOLVED: GB/T 9444 is a Recommended standard (GB/T), not mandatory (GB). Correct prefix used.
- ✅ FALSE POSITIVE: No domain flags raised — both standards are TIER 2 test methods, direct comparison valid.
PROCUREMENT VERDICT
- Specify acceptance level (Level 1/2/3) in contract — CN and ISO levels differ numerically.
- Require test report to state which standard (GB/T 9444-2019 or ISO 4986:2020) was used.
- If ISO 4986 compliance required, mandate additional testing per ISO acceptance criteria.
- Verify equipment calibration records — CN requires monthly, ISO may accept less frequent.
- Confirm magnetic particle concentration verification per GB/T 9444-2019 §5.3.2 if CN standard used.
REFERENCE DOCUMENT CHECKLIST (配套调阅清单)
- GB/T 9444-2019 §Table 1 — acceptance criteria for linear and circular indications
- ISO 4986:2020 §Table 1 — acceptance criteria for linear and circular indications
- GB/T 9444-2019 §5.2.3 — equipment calibration frequency
- ISO 4986:2020 §6.2 — equipment calibration requirements
FIELD INSPECTION CHECKLIST
- Verify MT equipment calibration date (monthly per GB/T 9444-2019)
- Check magnetic particle concentration per GB/T 9444-2019 §5.3.2
- Confirm test report states standard used (GB/T 9444-2019 or ISO 4986:2020)
- Review acceptance criteria applied matches contract specification
- Verify technician certification (e.g., NDT Level II per GB/T 9445)
CONFIDENCE RATING
🟢 HIGH CONFIDENCE — data verified across two independent AI sources, all numeric values have clause references, official standard status confirmed from std.samr.gov.cn.
Technical comparison report — CN Quality Check Standards Tool. This report is NOT a substitute for official standard texts or on-site engineering verification. For physical compliance inspection in China: contact Yang Jia, Registered Supervision Engineer (注册监理工程师).
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