Industry Solutions

Petroleum Refinery Pipes

Chrome-moly and high-alloy pipe solutions for CDU, VDU, hydrotreaters, hydrocrackers, and FCC units — engineered for HTHA resistance, creep strength, and sulfidic corrosion service.

API 941 Compliant NACE MR0103 Certified Seamless & Welded Full PWHT Documentation
Overview

Alloy & Chrome-Moly Pipes for Petroleum Refineries

Refinery piping operates across a uniquely hostile spectrum: atmospheric distillation at 360°C, vacuum units at 420°C, hydrotreaters under hydrogen partial pressures exceeding 200 bar, and catalytic reformers pushing 550°C. Each unit operation requires a tightly controlled material selection strategy guided by API 941 (Nelson Curves) to prevent high-temperature hydrogen attack (HTHA) and creep failure. Metinox Overseas has deep experience supplying chrome-moly alloys, austenitic stainless steels, and duplex grades to refinery EPC contractors and operators worldwide.

Where We Deliver

Key Applications & Grade Rationale

Key Applications

  • Crude distillation unit (CDU) transfer lines and atmospheric tower internals
  • Vacuum distillation unit (VDU) piping — high vacuum with sulfidic corrosion risk
  • Hydrotreater and hydrocracker reactor inlet/outlet piping under H₂ partial pressure
  • Catalytic reformer (CCR/semi-regen) piping and separator systems
  • Fluid catalytic cracking (FCC) regenerator and main fractionator piping
  • Amine gas treating unit (AGT) absorber and regenerator pipework
  • Sulphur recovery unit (SRU / Claus plant) process lines
  • Overhead corrosion circuits — naphthenic and HCl acid service

Why These Grades?

1¼Cr–½Mo (P11/T11) Entry-level chrome-moly; used in hydrotreaters and steam lines up to 540°C — sits safely above the carbon steel HTHA curve.
2¼Cr–1Mo (P22/T22) Workhorse alloy for hydrocracker reactors and high-temperature/high-pressure hydrogen service; superior creep rupture strength.
9Cr–1Mo–V (P91/T91) Ultra-high strength martensitic grade for steam superheat and FCC regenerator air preheater circuits.
SS 317L / 317LMN Superior to 316L in sulfuric acid and polythionic acid environments — selected for amine regenerator overhead systems.
Monel 400 (UNS N04400) Exceptional resistance to naphthenic acid in straight-run crude units — critical for high-TAN crude processing.
Product Range

Recommended Products & Grades

Product Recommended Grades Ideal Application
Alloy Steel Pipes P5, P9, P11, P22, P91 Hydrotreaters, hydrocrackers, reformers, steam piping
Stainless Steel Pipes SS 316L, SS 317L, SS 321H, SS 347H Overhead corrosion circuits, amine units, high-temp service
Monel Pipes 400 & K500 Alloy 400, Alloy K-500 High-TAN crude service, naphthenic acid units
Duplex Steel Pipes UNS S31803, S32205 Seawater-cooled condensers, amine reboiler bundles
Carbon Steel Pipes ASTM A106 Gr.B, A53 Low-temperature utility and condensate lines
Why Choose Us

Key Benefits

Complete PWHT & Charpy Documentation

Chrome-moly pipes supplied with impact, hardness, and post-weld heat treatment records.

PTA Risk Awareness

Polythionic acid sensitisation risk identified proactively — right grade recommended before it becomes a problem.

High-H₂ NACE MR0103 Compliance

Pipes for high hydrogen-partial-pressure service supplied with full NACE MR0103 compliance documentation.

Fast TAR Turnaround

Ready stock for critical path items during planned shutdowns — minimise downtime on turnarounds.

Expert Guidance

Why Metinox Overseas — FAQs

Why Metinox Overseas?

  • Approved vendor to EIL, BPCL, HPCL, IOCL refinery turnaround procurement
  • Chrome-moly pipes supplied with complete PWHT and Charpy impact data
  • Polythionic acid (PTA) risk awareness — we recommend the right grade proactively
  • High-H₂ service pipes with NACE MR0103 compliance documentation
  • Fast turnaround for critical path items during planned shutdowns (TAR)
What is HTHA and how do I select pipe grades to avoid it?
High Temperature Hydrogen Attack occurs when atomic hydrogen diffuses into carbon steel at elevated temperatures and pressures, reacting with carbon to form methane — causing internal decarburisation and fissuring. API 941 (Nelson Curves) defines safe operating zones for various steel grades. At ≥260°C and significant H₂ partial pressure, carbon steel must be upgraded to 1¼Cr–½Mo (P11) or higher chrome-moly grades.
Why does Monel 400 outperform stainless steel in high-TAN crude units?
Naphthenic acids (TAN >0.5 mgKOH/g) preferentially attack the passive oxide film on stainless steels in the 220–400°C range at high fluid velocities. Monel 400 forms a highly adherent oxide layer chemically inert to naphthenic acid attack, making it the preferred material for transfer line piping in high-TAN crude distillation circuits.

Refinery Turnaround Approaching?

We stock P11, P22, P91 and stainless grades for emergency procurement with full documentation.

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