DK-Lok Documentation Chain: MTR, Heat Codes, and Test Records for Malaysian O&G Procurement

DK-Lok procurement in Malaysian O&G is a documentation question as much as a hardware question. Think of the paperwork as a chain of custody for the fitting itself — the Material Test Report (MTR), the laser-etched heat code, the API 598:2016 factory pressure-test record, and the NACE MR0175:2021 certificate are the four links that close out a DOSH audit on a critical fitting.

If you sign the PO without the documentation set called out, the chain you need at audit was never assembled at the source. This guide covers what arrives with an authorised DK-Lok order, how to specify the documentation level on the PO, and how the documentation set supports DOSH defensibility under the OSH (Amendment) Act 2022.

The Documentation Chain Overview

Four core documents travel with an authorised DK-Lok shipment into Malaysia. Each plays a defined role in the procurement audit trail, and together they form the chain that ties a fitting on a plant skid back to a certified manufacturing batch at the DK-Lok facility.

• Material Test Report (MTR). Mill-level certification of alloy chemistry and mechanical properties for the heat from which the fitting was machined.
• Heat code. Laser-etched alphanumeric code on the fitting body that maps to the MTR batch.
• Factory pressure-test record. API 598:2016 seat-leakage and shell-pressure test record for valves; ISO 5208:2015 for selected configurations.
• NACE MR0175:2021 certificate. For sour-service applications, the certification of compliance with the metallurgical and hardness controls for H₂S exposure.

On a routine procurement, the first three documents arrive with every shipment. The NACE certificate is supplied when sour service is specified on the PO.

Document	Issued by	Certifies	Required when
Material Test Report (MTR)	Certifying mill	Alloy chemistry + mechanical properties for the heat	Every critical-service shipment
Heat code	DK-Lok factory	Maps the fitting body back to its MTR batch	Every critical-service fitting / valve
Factory pressure-test record	DK-Lok factory	Shell-pressure + seat-leakage performance per API 598:2016 / ISO 5208:2015	Every valve
NACE MR0175:2021 certificate	DK-Lok factory, per heat lot	Sulfide-stress-cracking resistance for sour service	Sour service called out at PO stage

Material Test Report (MTR): The Foundation

The MTR is the foundational document in the chain. Issued by the certifying mill and carried through DK-Lok’s manufacturing process, it records:

• Alloy chemistry — element-by-element composition (Cr, Ni, Mo, C, S, P, etc.).
• Mechanical properties — tensile, yield, elongation, hardness.
• Heat number — the mill batch identifier that ties the MTR to the physical fitting.
• Mill name and certification stamp.
• Conformance statement against the applicable ASTM specification — typically ASTM A276:2017 for bar stock, ASTM A269:2022 or ASTM A213:2023 for seamless tubing feedstock.

For a Malaysian plant, the MTR is what allows the design engineer to verify the as-built alloy against the specification. If the design calls for SS316L with carbon content ≤0.030%, the MTR is the document that confirms it.

Heat Code Traceability

The heat code is the link between the physical fitting and its MTR. DK-Lok applies the code as a laser-etched alphanumeric stamp on the fitting body, typically 6 to 10 characters. The code maps to the manufacturing batch and the MTR for that batch.

On receipt, the verification step is to confirm the heat code on the fitting matches the MTR supplied with the shipment. The mapping is one-to-many — a single MTR covers all fittings machined from one heat — so multiple fittings on the same line item will share a heat code if they came from the same batch.

The heat code is what the DOSH auditor follows back through the documentation when a critical fitting is queried during an inspection. A complete chain reads: fitting on the skid → heat code → MTR → mill certificate.

API 598:2016 and ISO 5208:2015 Test Records

For valves, the factory pressure-test record certifies the body has been tested before shipment. API 598:2016 (Valve Inspection and Testing) is the reference for shell-pressure and seat-leakage testing across the DK-Lok valve range; ISO 5208:2015 covers selected configurations.

The test record contains:

• Serial or batch identifier.
• Shell-pressure test result — the body has held the specified hydrostatic pressure for the specified duration without leakage.
• Seat-leakage test result — the closed seat has held the specified test pressure with leakage below the threshold for the assigned API 598:2016 leak class.
• Test medium, temperature, and date.

Specify the test record explicitly on the PO. On a routine order, the record arrives with the shipment; on more compressed timelines, requesting the record after delivery extends the documentation gap that a DOSH auditor will note.

NACE MR0175:2021 Certificates for Sour Service

Sour service — process streams with H₂S partial pressure above the NACE MR0175:2021 threshold — requires materials selected and processed to specified hardness and metallurgical controls. The standard is the international reference for sulfide-stress-cracking-resistant materials in oilfield service.

For DK-Lok fittings supplied to sour service, the NACE certificate documents:

• The fitting material conforms to NACE MR0175:2021.
• Hardness measurement falls within the allowable range for the chosen material.
• Heat treatment is controlled to maintain compliance.

Simlecco handles sour-service orders by specifying NACE compliance on the order to DK-Lok and ensuring the certificate arrives with the consignment. Sour service should always be called out at PO stage — adding it after the fact is a retrofit problem rather than a routine procurement.

The NACE-versus-standard-316L question is itself a recurring debate on engineering forums. An Eng-Tips discussion on determining the H₂S threshold for NACE piping covers the partial-pressure rule, the wetted-versus-non-wetted parts distinction, and the project owner’s responsibility to declare sour service at the line list stage — useful background when a vendor questions whether NACE certification applies to a specific line item.

ISO 8434-1:2007 Tube Fitting Compliance

ISO 8434-1:2007 is the dimensional standard for metric 24° cone tube connectors — the geometry that allows a tube fitting from one ISO 8434-1-compliant manufacturer to physically mate with the cone-and-thread of another. DK-Lok fittings are designed to ISO 8434-1:2007 dimensional compliance for the metric range.

For interface design — where a Malaysian plant is integrating instrumentation hookups that span multiple manufacturers — ISO 8434-1:2007 compliance is the assurance that the fittings will mate dimensionally. For HP and sour service, however, the discipline is to standardise on a single manufacturer and validate the complete assembly per NACE MR0175:2021. ISO 8434-1:2007 is a mating-geometry standard, not a service-rated joint qualification.

The Procurement Workflow

Specifying the documentation set on the PO is the single most effective procurement control. The following should appear on every PO for DK-Lok fittings or valves on critical service:

• Part numbers and configurations against the design specification.
• Body material per ASTM A276:2017 (or applicable ASTM reference) and seat material as specified.
• Pressure-temperature rating at actual operating conditions, not room-temperature MAWP.
• MTR required with shipment, tied to heat code on the fitting body.
• API 598:2016 test records (for valves) per serial or batch.
• NACE MR0175:2021 certificate (for sour service) per shipment.
• ISO 15848-1:2015 fugitive-emissions class (for stem-sealed valves) where required.

Specifying the documentation level at PO stage avoids the post-delivery scramble that produces incomplete audit trails.

DOSH Audit Defensibility

Under the OSH (Amendment) Act 2022, site management must demonstrate that critical-service equipment meets the design specification. The audit conversation on a critical fitting typically runs through four questions, and the documentation set answers each:

1. What is the fitting on this line? Answered by the procurement record — part number, configuration, line tag.
2. What is the alloy? Answered by the MTR — chemistry and mechanical properties certified by the mill.
3. How does the fitting tie back to the MTR? Answered by the heat code on the fitting body matching the heat number on the MTR.
4. Has the body been pressure-tested? Answered by the API 598:2016 test record for valves; the MTR-plus-design-rating combination for fittings.

Principal liability under the OSH (Amendment) Act 2022 reaches RM500,000 per offence. The cleanest defence is a documentation set that closes out each question without gaps — which is the routine output of an authorised procurement workflow.

What Arrives with an Authorised Simlecco Shipment

Every authorised Simlecco shipment on critical service includes the documentation set described above. Specifically:

• Original DK-Lok packaging with manufacturing batch label and country-of-origin marking.
• Laser-etched heat code on each fitting or valve body.
• The matching MTR for the heat code, naming the certifying mill and the ASTM reference.
• API 598:2016 seat-leakage and shell-pressure test records for valves, by serial or batch.
• NACE MR0175:2021 certificate when sour service is specified on the PO.
• Shipping document tying the consignment to DK-Lok’s Korea facility.

This is the documentation set the DOSH auditor expects to see on a critical-service line item. It is also the documentation set the design engineer needs to verify the as-built configuration against the specification.

Lead Time and Local Stock

Direct import of DK-Lok fittings and valves from Korea to a Malaysian plant runs roughly 12 weeks on sea freight for specialty configurations. Air freight reduces the calendar lead time but at 8–15× the unit shipping cost — which on most procurement budgets is reserved for emergencies.

Simlecco holds local stock of common DK-Lok configurations at the Selangor warehouse — twin-ferrule tube fittings across the popular sizes in SS316L, needle valves, gauge-root valves, instrument ball valves, and 2V/3V/5V manifolds. For inventoried part numbers, dispatch is typically within a business day with the documentation set assembled from the on-hand records. For non-inventoried configurations, a delay on the direct-import path applies.

The procurement case for ordering through the authorised channel is the combination of: documented chain to the manufacturing batch, local stock against project schedule, and the documentation set assembled on dispatch rather than reconstructed after the fact.

Frequently Asked Questions

What does an MTR include, and how do I read it?

An MTR includes alloy chemistry by element, mechanical properties (tensile, yield, elongation, hardness), the heat number, the mill name and certification stamp, and a conformance statement against the applicable ASTM specification. Read it by confirming the heat number matches the code on the fitting, the chemistry meets the design requirement (e.g. carbon ≤0.030% for SS316L), and the conformance statement names the correct ASTM reference (ASTM A276:2017 for bar stock, ASTM A269:2022 or ASTM A213:2023 for tubing feedstock).

How is the heat code applied, and where do I find it?

DK-Lok laser-etches the heat code on the fitting body. The location depends on the configuration — typically on a flat machined surface large enough to carry the 6 to 10-character code. The same code is referenced on the MTR supplied with the shipment.

When do I need a NACE MR0175:2021 certificate?

Specify NACE MR0175:2021 compliance whenever the process stream contains H₂S above the partial-pressure threshold defined in the standard, or whenever the project specification calls for it independent of the calculated partial pressure. Specify the requirement on the PO — adding NACE compliance after delivery is a retrofit problem, not a documentation request.

What is the typical lead time on a documentation request?

On a routine consignment from Simlecco local stock, the documentation set is assembled on dispatch — the MTR, heat code, test records, and applicable certificates ship with the order. For non-inventoried configurations on direct import, the documentation set is consolidated as the shipment is prepared, on the same 12-week timeline as the hardware.

Documentation Specification Checklist

For a PO covering DK-Lok fittings or valves on critical service, specify each of the following:

Talk to Simlecco

Simlecco is the authorised DK-Lok distributor for Malaysia, supplying direct customers and an authorised dealer network. We ship every order on critical service with the documentation set — MTR, heat code, API 598:2016 test records, NACE MR0175:2021 certificates where applicable — assembled on dispatch. For projects requiring documented chain of custody, click the WhatsApp button on this page to speak with our technical team, or fill in the contact form and we will respond within one business day.

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