Chapter 5: Material Traceability & MTC (Material Test Certificate)

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📌 5.1 What is Material Traceability?

Material Traceability is the ability to track and verify the identity, composition, origin, and certification of materials used in fabrication and construction.

🔎 Why it matters:

Ensures compliance with design codes (e.g., ASME, API)

Prevents mix-up of materials (e.g., carbon steel vs. stainless steel)
Allows rejection of defective or uncertified materials
Enables root-cause analysis in case of failure

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📋 5.2 Key Terms in Traceability

Term	Meaning
Heat Number	A unique code stamped on metal that traces it to a specific batch/melt in the steel mill
MTC (Mill Test Certificate)	A certificate issued by the material manufacturer providing chemical & mechanical properties
Material Identification	Process of matching actual material with the drawing/spec requirement using MTC or testing
Batch Number	Similar to heat number for non-metallics like paints, gaskets, bolts

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📄 5.3 Contents of a Material Test Certificate (MTC)

🔍 Usually conforming to EN 10204 Type 3.1 or 3.2, an MTC includes:

Material Grade (e.g., SA 516 Gr 70)

Heat Number
Chemical Composition (% C, Mn, Si, etc.)
Mechanical Properties (Yield, UTS, Elongation)
Impact Test Results (CVN)
Standards followed (ASME, ASTM, DIN)
Manufacturer’s stamp and signature

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🛠 5.4 Practical Example: Using MTC in Pressure Vessel Manufacturing

Step-by-Step:

1. Review drawing → Material Spec: SA 516 Gr 70, Thickness: 12 mm

2. Verify MTC → Check heat number, grade, thickness, and properties

3. Match Heat Number on MTC with physical plate marking

4. Stamp Accepted if matches; Reject if deviation found

5. Maintain Traceability Log in QA file

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🧰 5.5 Field Application: Traceability Marking

➤ Marking done using:

Paint/Marker (temporary)

Low-stress stamps (permanent)
Barcodes/QR codes in advanced plants

🔧 On-Site Tip: Use color-coded tags for carbon steel (blue), stainless (green), alloy (red), etc.

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📦 5.6 Material Receiving Inspection

When material is delivered to site or workshop:

1. Check Packing Slip vs PO

2. Visual Check for damage

3. Check Heat Numbers stamped on material

4. Cross-check MTC with drawing

5. Tag/Color Code for storage

6. Log into Material Traceability Register

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🛑 5.7 What if Material Fails Traceability?

Material is quarantined and marked as "Hold"

Investigated and reported in NCR (Non-Conformance Report)
Replaced or retested if applicable
Client approval required for acceptance or rejection

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🧪 5.8 Real-World Case Study: Pipeline Burst due to Material Mix-up

Scenario: A pipeline carrying oil ruptured in a refinery.
Root Cause: Low-grade carbon steel used instead of alloy steel.
Result:

USD 3 million in damage

Downtime of 2 weeks
Contractor blacklisted
Poor MTC verification during inspection stage

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🧠 Summary

Material Traceability ensures the right material is used as per code/spec

MTC is a key document for QA/QC and must be diligently reviewed
Heat number is essential for traceability from origin to final product
Failure to verify material can cause financial, safety, and legal issues

Quiz: Material Traceability & MTC (Material Test Certificate)

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Q1. What is the primary purpose of a Heat Number?
A) Measure material weight
B) Identify welding technique
C) Trace material batch and origin
D) Assign work shift of production
🟩 Correct Answer: C

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Q2. An MTC is usually issued by:
A) Quality Inspector
B) Client Representative
C) Material Manufacturer
D) Site Engineer
🟩 Correct Answer: C

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Q3. In an MTC, tensile strength, yield strength, and elongation fall under:
A) Chemical Composition
B) Visual Inspection
C) Mechanical Properties
D) Dimensional Test
🟩 Correct Answer: C

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Q4. Which EN standard governs the format and type of MTCs?
A) EN 1901
B) EN 10204
C) EN 13504
D) EN 9001
🟩 Correct Answer: B

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Q5. What type of MTC is usually issued for certified material traceable to inspection?
A) Type 2.1
B) Type 2.2
C) Type 3.1
D) Type 4.1
🟩 Correct Answer: C

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Q6. What happens when the heat number on a material does not match the one on the MTC?
A) Material is accepted with comment
B) It can be re-tested and used without issue
C) It is rejected or quarantined for investigation
D) No action is required
🟩 Correct Answer: C

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Q7. Which is not typically found in a Material Test Certificate?
A) Chemical analysis
B) Mechanical testing
C) Welding WPS
D) Heat number
🟩 Correct Answer: C

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Q8. In traceability, what method is least permanent for marking materials?
A) Paint marker
B) Low-stress stamping
C) Barcode tagging
D) Engraving
🟩 Correct Answer: A

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Q9. Why is material traceability critical in pressure vessel fabrication?
A) For cost-saving only
B) To reduce man-hours
C) To ensure compliance with design and safety standards
D) To avoid visual inspection
🟩 Correct Answer: C

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Q10. A traceability logbook is maintained to:
A) Track staff working hours
B) Record heat treatment times
C) Maintain records of all materials and their status
D) Store daily weather conditions
🟩 Correct Answer: C