Introduction

ASTM B668 Seamless Nickel Alloy Pipe is the standard specification for iron-nickel-chromium-molybdenum alloy seamless pipe and tube intended for general corrosive service. This specification covers two primary grades: UNS N08028 (Alloy 28 / Sanicro 28 / W.Nr. 1.4563) and UNS N08029 , available in cold‑finished or hot‑finished conditions.

UNS N08028 seamless pipe (Alloy 28) is the most widely used grade within this standard. It is a copper-bearing nickel alloy (0.6–1.4% Cu) with high chromium (26–28%) and nickel (30–34%) content, offering excellent corrosion resistance in sulfuric acid, phosphoric acid, and chloride‑containing environments. This general corrosive service alloy is commonly specified for chemical processing, heat exchangers, and process piping systems. UNS N08029 seamless tube is a lower‑alloyed variant offering reliable performance for less demanding industrial applications.

Note: All products are supplied in the solution‑annealed condition, which optimizes corrosion resistance and fabricability.

Available in cold‑finished and hot‑finished forms, 1/2″ to 12″ NPS, with custom size, large diameter, and Schedule 40/80 options.

Specifications & Process Options

Applications

1. Chemical Processing & Sulfuric Acid Service

• UNS N08028 seamless pipe for chemical processing – reactors, distillation columns, heat exchangers handling sulfuric acid, phosphoric acid, and chloride‑contaminated streams.

• Sanicro 28 pipe for sulfuric acid service delivers excellent resistance across a wide concentration range, outperforming 316L and many higher alloys.

• UNS N08029 seamless pipe for industrial applications serves less aggressive chemical environments where a general corrosive service nickel alloy pipe is required.

• ASTM B668 nickel alloy pipe for heat exchangers used in condenser tubing and reboiler bundles where high temperatures and corrosive media combine.

2. Process Piping & Chloride Environments

• Iron-nickel-chromium-molybdenum alloy pipe for process piping systems handling mixed acids, chlorides, and organic compounds without localized attack.

• Alloy 28 seamless tube resists pitting and crevice corrosion in high‑chloride environments, making it suitable for brine handling and coastal process plants.

• ASTM B668 seamless tube for general industrial service provides reliable long‑term performance in chemical transfer lines and reactor feed systems.

3. Oil & Gas / General Industrial Corrosive Service

• UNS N08028 pipe for oil and gas industry – topside chemical injection lines, produced water handling, and amine service piping in wet CO₂ and moderate H₂S environments.

• Corrosion resistant alloy pipe for chemical plants maintains integrity in sour service and high‑temperature process streams.

• Cold‑finished nickel alloy seamless pipe offers excellent surface finish and dimensional accuracy for critical industrial applications.

Why Choose Us as Your ASTM B668 Pipe Supplier?

We are a trusted ASTM B668 seamless nickel alloy pipe, Alloy 28 seamless pipe supplier, UNS N08028 seamless pipe manufacturer, China‑based, serving clients worldwide. All products meet ASTM B668 / ASME SB668 with full mill test certificates and NDT.

What we offer:

• Forms: Seamless pipe, seamless tube, hollow bar, fittings, flanges

• Sizes: 1/2″ to 6″ OD; Schedule 40–SCH160; custom diameters and wall thicknesses

• Grades: UNS N08028 (Alloy 28 / Sanicro 28 / W.Nr. 1.4563) , UNS N08029

• Standards: ASTM B668 / ASME SB668; also B622, B444, B423, B163

• Customization: Cut‑to‑length, special bevel ends, coatings, cold‑finished or hot‑finished

• Quality: EN 10204 3.1, PMI, full traceability, hydrostatic testing

• Global supply: Export to chemical, oil & gas, power, and heat exchanger industries

Contact us for size chart, pricing, or a quote on UNS N08028 Alloy 28 Seamless Pipe, ASTM B668 Nickel Alloy Tube, or custom requirements.

FAQ – ASTM B668 Nickel Alloy Pipe & Tube

Q: How does Alloy 28 compare to Alloy 926 for chemical processing?
A: UNS N08028 seamless pipe excels in concentrated sulfuric and phosphoric acid service, while Alloy 926 seamless tube with 6% molybdenum is better suited for high‑chloride seawater environments.

Q: What is the difference between UNS N08028 and UNS N08029?
A: UNS N08028 seamless pipe has higher nickel (30–34%) and chromium (26–28%) with copper addition for superior acid resistance; UNS N08029 seamless tube is a lower‑alloyed grade for less demanding general corrosive service.

Q: Is Alloy 28 suitable for sour gas service?
A: Yes, for moderate H₂S and CO₂ service. For extreme sour conditions, higher alloys like C‑276 are recommended.

Q: Why is Alloy 28 considered a "general corrosive service" alloy?
A: It provides balanced resistance across sulfuric acid, phosphoric acid, and chloride environments, making it a versatile choice for chemical processing and heat exchanger applications.

XI’AN MONO TECHNOLOGY CO.,LTD. is one of ASTM B668 Seamless Nickel Alloy Pipe & Tube other Superalloy, Nickel alloy, High Temperature Alloy pipe manufacturers, suppliers, factory, company, exporter, seller, brands, import, buy, best, high-quality from China, in accordance with ASTM, ASME, DIN, ISO,JIS standard.pls contact us freely for your RFQ to info@monokj.com