01
Environment
Oil and gas or process systems with project-defined sour-service considerations
RTI application authority
Alloy Components for Sour-Service Applications
Sour-service procurement requires the project to define the environment and acceptance requirements before an alloy or product route can be reviewed. RTI helps buyers capture the relevant service details, NACE MR0175 / ISO 15156 requirement where applicable, material and product-form standard, dimensions, inspection plan, testing, certificates, marking, and documentation without suggesting universal compliance from an alloy name.
Quick engineering snapshot
Service context before material selection.
These controlled signals help start a technical conversation. Final component and alloy approval stays with the governing project specification and responsible engineering authority.
| Specification | Verified value | Unit |
|---|---|---|
| Environment | Oil and gas or process systems with project-defined sour-service considerations | - |
| Corrosion focus | Sour-service risks depend on the actual environment and may involve hydrogen-related damage mechanisms, general corrosion, local attack, and the interaction of material, hardness, stress, and process conditions. | - |
| Temperature consideration | The applicable project service envelope, temperature, pressure, fluid composition, water condition, and product form need to be reviewed together against the required sour-service standard. | - |
| Pressure and containment | Pressure class, temperature rating basis, flange geometry, facing, gasket, bolting, bore, material route, and piping class should be confirmed for the ordered connection. | - |
| Common component route | project sour-service piping class, material restriction, pressure class, facing, and joint detail / product form, bore, schedule, end preparation, fitting geometry, and traceable material route | - |
Operating environment
The component is only as well specified as the service around it.
The technical environment map keeps corrosion, temperature, pressure, product details, inspection, and documentation in the same decision path.
Technical environment map
Marine process envelope
02
Corrosion
Sour-service risks depend on the actual environment and may involve hydrogen-related damage mechanisms, general corrosion, local attack, and the interaction of material, hardness, stress, and process conditions.
03
Temperature
The applicable project service envelope, temperature, pressure, fluid composition, water condition, and product form need to be reviewed together against the required sour-service standard.
04
Pressure
Pressure class, temperature rating basis, flange geometry, facing, gasket, bolting, bore, material route, and piping class should be confirmed for the ordered connection.
05
Release
Specification, inspection, traceability, and delivery documentation
Corrosion and temperature
Review the mechanism, then confirm the material route.
Corrosion performance changes with the actual medium, temperature, geometry, fabrication, and operating conditions. The alloy name does not replace service-specific engineering review.
Mechanism first
Sour-service risks depend on the actual environment and may involve hydrogen-related damage mechanisms, general corrosion, local attack, and the interaction of material, hardness, stress, and process conditions.
Temperature changes the decision
The applicable project service envelope, temperature, pressure, fluid composition, water condition, and product form need to be reviewed together against the required sour-service standard.
Geometry and fabrication matter
Crevices, stagnant zones, weld details, insulation interfaces, gasket selection, and cleaning practice should be reviewed alongside the nominal alloy grade.
Commonly considered alloys
Comparison paths for an informed specification review.
These material pages provide technical information. They are not a substitute for the project material selection process or an approved substitution.
Inconel 625 / UNS N06625
Nickel alloy benchmark for severe corrosion, seawater, and elevated-temperature review.
Super Duplex 2507 / UNS S32750
Super duplex benchmark for chloride-rich and seawater-related applications.
Stainless Steel 316L / UNS S31603
Low-carbon molybdenum-bearing stainless benchmark for controlled process service.
Flanges and pipe fittings
Connection details control the commercial outcome.
For each component, keep material, product-form standard, dimensional standard, pressure class, facing, bore or schedule, testing, and document release separated and clear.
Flanges
Flange selection should confirm project sour-service piping class, material restriction, pressure class, facing, and joint detail, pressure class, facing, bore, gasket system, bolting, machining, and any drawing-controlled details before quotation.
Pipe fittings
Elbows, tees, reducers, caps, stub ends, and forged fittings should align product form, bore, schedule, end preparation, fitting geometry, and traceable material route before a purchase order is released.
Material route
Material grade, product-form standard, dimensional standard, inspection plan, marking, packing, and document release are separate controls. They should be written separately in the RFQ.
Relevant standards
Use the right document for the right control.
Product material standard, component dimensional standard, test-certificate route, and project specification each answer a different procurement question.
NACE MR0175 / ISO 15156 Guide
Sour-service review and order-specific documentation control.
ASME B16.5 Flange Guide
Flange size, class, facing, and RFQ controls.
ASME B16.9 Fittings Guide
Buttwelding fitting dimensions and procurement controls.
Material Traceability Guide
Heat number, MTC, PMI, marking, and dossier control.
Quality and inspection
Traceability belongs in the RFQ, not at dispatch.
PMI, MTC, EN 10204 3.1, TPI attendance, test records, markings, and release documentation should be aligned with the actual project and ordered product form.
PMI and grade segregation
Define the PMI method, sampling plan, acceptance criteria, and record format when alloy identity is critical to the service or project quality plan.
Material certificates
Request MTC and EN 10204 3.1 documentation when manufacturer-issued inspection records are required, then reconcile heat number, grade, product form, standard, test results, and final marking.
Inspection plan
The purchase order should identify the required review standard, material and product-form scope, certificate, PMI, hardness or other evidence where specified, marking, ITP, TPI, and release dossier.
Order-specific testing
Testing and acceptance must follow the applicable project requirements and standard edition. The RFQ needs to define what evidence is required for the ordered product form.
Procurement guidance
Build an RFQ an engineer can approve.
A complete enquiry reduces clarification cycles and makes inspection, documentation, packing, and delivery expectations visible from the start.
Design basis
State the fluid or process medium, concentration or contaminants where relevant, design and upset temperatures, design pressure, corrosion allowance, and governing project specification. Final material selection remains an engineering approval.
Commercial scope
State the sour-service requirement, governing document and edition, service conditions available for review, material and product standards, tests, certificates, inspection points, packing, and destination.
Document release
Agree document requirements, review points, TPI attendance where required, marking, protective facing covers, packing method, and destination requirements before production release.
No unapproved substitution
Do not treat similar alloy names as interchangeable. Any substitution needs the engineering authority to compare service, product standard, dimensions, tests, and documentation requirements.
Related RTI pathways
Continue the specification review.
Use material data pages, product pages, and engineering guides together when preparing a technical quotation.
Inconel 625 / UNS N06625
Nickel alloy benchmark for severe corrosion, seawater, and elevated-temperature review.
Super Duplex 2507 / UNS S32750
Super duplex benchmark for chloride-rich and seawater-related applications.
Stainless Steel 316L / UNS S31603
Low-carbon molybdenum-bearing stainless benchmark for controlled process service.
Engineering FAQs
Common sour service procurement questions.
Answers frame the information that belongs in the RFQ and do not replace formal design review or the project specification.
Structured RFQ
Prepare a cleaner component enquiry
Capture material, standard, dimensions, quantity, inspection, documentation, packing, and destination before the technical quotation is prepared.
Technical quotation
Define your sour service component package.
Share the service context, material, product, dimensions, pressure class, facing, testing, documents, destination, and drawing or datasheet details. RTI will use the information to structure the technical quotation pathway.
