Abstract

Purchasing manager or quality control engineer are often faced with a batch of SSAW steel pipe and a factory test certificate (MTC), which is the “birth certificate” of each steel pipe, and it is full of terms such as “heat number” or “API 5L Grade X 52” Understanding this document is very important for verifying whether your SSAW pipeline meets project standards and ensuring the safety of the project.

welder working on ssaw pipeline installation.

 

This guide breaks down a typical MTC for steel pipe into simple steps. Using industry standards such as API 5L, we’ll decode each part, so that you can cross-check the microphone as required to avoid errors that do not conform to SSAW pipeline.

Deconstructing the typical SSAW pipeline MTC

MTC organizes quality data in a logical way. The following is a step-by-step decomposition of each key part.

1. Title information: the “Backbone of Traceability”

This top tracks your SSAW tube from production to delivery, and answers: “Who made it and which batch did it come from?”

· Manufacturer information: Includes the name and address of the factory and ISO 9001 certification. Check this with the pre-approved suppliers to avoid counterfeiting.

· MTC number: a unique ID for the certificate-save it for future reference.

· HeatNo. A code for a single molten steel batch. All SSAW tubes from the same furnace have the same chemical composition, which is the most important traceability sign.

· Lot numbers group steel pipe from the same production lot. A failed pipeline in a batch may require a comprehensive re-inspection.

Important reason: For infrastructure projects, tracing SSAW pipeline to heat/lot allows you to quickly isolate defective batches.

2. Product Specifications: Does It Match Your Needs?

This section defines your SSAW pipe‘s identity, aligned with standards like API 5L—the global benchmark for energy-sector steel pipe.

Major inspection:

· Standard Reference: Look for “API 5L” or EN 10204. API 5L outlines the requirements for strength, welding and corrosion( https://www.api.org/products-and-services/standards).

Note: API 5L version 46th is widely used, and its update ensures the safety and interoperability of steel pipes.

· Grade: indicates strength. -e.g., API 5L Gr. B (low strength, yield value ≥ 245 MPa) is used for water pipelines or X 52 (medium strength, yield value ≥ 355 MPa) is used for oil/gas pipelines.

· Dimensions:

Outer Diameter (OD): Ensures fitting compatibility.

Wall thickness (WT): it affects the bearing capacity (API 5L sets the minimum value, for example, for a 24-inch outer diameter, X 52 needs to be ≥ 6.35 mm)

Length: usually 6-12m-to be confirmed according to the installation plans.

Professional tip: mismatch (e.g., Ordered X 52 and got gr. It means that the SSAW pipeline will perform poorly).

3. Chemical Composition: What Drives Steel Performance?

This section lists the factors affecting the strength, weldability and corrosion resistance of steel pipes, which are in line with API 5L.

Element API 5L X52 Limit Function in steel pipe Influence
Carbon (c) ≤ 0.26% Increase strength Too much damage to solderability; Too little will weaken the power.
Manganese (Mn) 1.35-1.65% Enhance toughness Prevent cold brittle fracture
Silicon (Si) ≤ 0.40% Increase the production intensity Exceeding 0.40% will reduce the ductility
Phosphorus (P) ≤ 0.030% Harmful impurity Cause shortness of coldness
Sulfur(S) ≤ 0.030% Harmful impurity Causes thermal embrittlement in the welding process

Authoritative Note: the latest version of API 5L updated the impurity limits to improve the durability of SSAW pipe, which was confirmed in the official release notes of the standard.

4. Mechanical Properties: Can the Pipe Withstand Stress?

These metrics measure SSAW pipe behavior under pressure—defined by API 5L:

1. Yield strength: Stress (X52 ≥ 355MPa) at which permanent deformation starts. Exceeding it will lead to collapse.

2. Tensile Strength: the maximum stress before fracture (X52 ≥ 485 MPa). Prevent power surge.

3. Elongation rate: stretching before breaking (X52 ≥ 22%). Higher elongation can prevent welding cracks.

Important reasons: the low yield strength is at risks of failure; There is a risk of cracking at low elongation.

5. Testing Results: Proof of Quality

MTCs confirmed that the steel tube passed the key tests:

A. Hydrostatic Test

Check the leakage by filling the SSAW pipe with water and applying 1.5 times the working pressure for 60-120 seconds. This is mandatory by API 5L unless an alternative is approved.

B. Non-Destructive Testing (NDT)

· Detect hidden defects:

· Ultrasonic test: check the weld.

· Magnetic particle testing (MT): Surface cracks were found.

Visual inspection (VI): dent/rust was found.

For example, “100% ultrasonic flaw detection of weld; 20% magnetic particle flaw detection of end-no defects” to confirm the quality.

Conclusion

Commitment of MTC bridges supplier and performance of SSAW pipeline. Decoding each part can ensure compliance, avoid rework and reduce security risks such as emergencies. Always cooperate with suppliers who provide complete and compliant microphones for steel pipes-never sacrifice quality for the sake of cost.

FAQ

Q 1: What’s the difference between the 1: EN 10204 3.1 and 3.2 microphones?

3.1: issued by the manufacturer’s QC (without the supervision of the third party).

3.2: verification by an independent inspector (witness test).

(Source: https://landingpage.bsigroup.com/LandingPage/Standard?UPI=000000000030027046)

Q 2: Why is a “Heat Number” important?

A Heat Number identifies a molten steel batch—all SSAW pipe from it has identical chemistry. It enables tracing defective batches and ensures project consistency.

Q 3: What if MTC data does not match the pipeline tag?

1. Immediately stop using the steel pipe.

2. Use photos to record the mismatch.

3. Contact the supplier to correct; If it is not solved, the delivery is refused.