Knowledge

Alloy 59 (ASTM B575 N06059) is a high-purity nickel-chromium-molybdenum alloy, renowned for its outstanding corrosion resistance and high-temperature stability, making it a crucial material in the chemical, energy, and other industries. The following is a detailed analysis of its specific properties and applications. ​​​​​​​

 

Core Performance Analysis

 

Corrosion resistance performance

Corrosion resistance in mixed acid media

Outstanding performance in a mixed environment of sulfuric acid and hydrochloric acid: corrosion rate in boiling 40% sulfuric acid ≤ 0.05mm/year, corrosion rate in 10% hydrochloric acid at 60℃ ≤ 0.15mm/year. Its corrosion resistance is significantly better than that of Hastelloy C-276 and C-22. The core advantage lies in its high chromium content of 22-24% and molybdenum content of 15-16.5%, which can form a dense passive film and effectively resist chloride ion erosion.

Resistance to pitting and crevice corrosion

Critical pitting temperature (CPT) ≥ 100℃, critical crevice corrosion temperature (CCT) ≥ 80℃, ranking among the top in similar alloys. In a wet hydrogen sulfide environment containing 5000ppm Cl⁻, the stress corrosion cracking resistance life exceeds 5000 hours, suitable for harsh conditions with high chloride and hydrogen sulfide content.

Adaptability to extreme environments

Passed NACE MR0175/ISO 15156 Grade VII certification, can be stably applied in environments containing H₂S, CO₂ and other acidic gases, and can withstand pressure vessel conditions from -196℃ to 450℃, covering scenarios from deep cold to medium-high temperatures.

 

-Mechanical Properties-

Mechanical properties at room temperature

Tensile strength ≥ 690 MPa, yield strength ≥ 340 MPa, elongation ≥ 40%, with high strength and excellent toughness, meeting the comprehensive requirements for mechanical properties of structural components.

High-temperature stability

It maintains excellent mechanical properties at 800°C: tensile strength ≥ 690 MPa, yield strength ≥ 340 MPa, elongation ≥ 40%, suitable for load-bearing or sealing parts in high-temperature oxidation environments.

Low-temperature toughness

No embrittlement occurs at -196°C, with excellent low-temperature toughness, meeting the usage requirements of cryogenic equipment (such as liquefied natural gas facilities).

 

 

- Machining and Welding Performance -

Hot working process

The hot working temperature range is 1180-950℃. After processing, water cooling or rapid air cooling should be adopted. The solution treatment temperature should be controlled at 1100-1180℃ to ensure the alloy achieves the best corrosion resistance.

Cold working points

The work hardening rate is higher than that of austenitic stainless steel. It is recommended to use low cutting speed with heavy feed rate. When the cold rolling deformation exceeds 15%, solution treatment should be carried out to restore performance.

Welding characteristics

ERNiCrMo-13 welding wire is recommended, and pulsed argon arc welding technology should be used. No stress relief treatment is required after welding, and there is no risk of intergranular corrosion. The welding processability is excellent.

 

 

- Typical Application Fields -

The chemical and petrochemical industry

Reactor and Storage Tanks

Corrosion-resistant reactors widely used in acetic acid and acetic anhydride production, as well as storage containers for highly corrosive media such as sulfuric acid and hydrochloric acid. In the acetic acid synthesis process, their outstanding resistance to intergranular corrosion can extend the service life of equipment by 3 to 5 times, significantly reducing maintenance costs.

Catalyst System

In environments involving acidic chloride catalysts such as ethylene oxide production, it can effectively resist pitting corrosion caused by chloride ions, ensuring the long-term stable operation of the catalyst reaction system.

Pickling Equipment

Suitable for mixed acid pickling lines in the steel industry, it can withstand the corrosion of a 10-20% HCl and FeCl₃ mixed solution, with an annual corrosion rate of ≤0.1 mm, meeting the strict requirements of the pickling process for equipment corrosion resistance.

 

 

 

The field of energy and environmental protection

Flue gas desulfurization (FGD)

It is applied to key components such as scrubbers, reheaters, and wet gas fans, and can withstand the corrosion of sulfurous acid solutions with a pH of 2-5 and chloride ions. Its service life is more than 10 times longer than that of 316L stainless steel, significantly reducing the frequency of equipment replacement.

Hydrogen energy storage and transportation

In the 2024 Beijing Daxing Hydrogen Energy Demonstration Zone project, Alloy59 was successfully used in the high-pressure hydrogen storage tanks and gas transmission pipelines of hydrogen energy logistics vehicles, assisting in completing a 1,300-kilometer cross-provincial transportation task and reducing carbon emissions by over 350 tons, highlighting its reliability in the field of new energy storage and transportation.

Geothermal equipment

For geothermal well environments containing H₂S and CO₂, its corrosion resistance is superior to that of duplex stainless steel, and it can withstand high-temperature fluids up to 200°C, making it suitable for the complex working conditions of geothermal resource development.

 

The Pulp and Paper Industry

Cooking and bleaching equipment

It can withstand the corrosion of cooking liquor containing ClO₂ and NaOH. In a 10% NaOH and NaClO mixed solution at 70℃, the corrosion rate is ≤ 0.02 mm/year, ensuring the long-term stable operation of papermaking equipment in a strongly oxidizing environment.

 

Marine and Ship Engineering

Seawater treatment system

It is used as pretreatment equipment for reverse osmosis membranes and can withstand seawater corrosion with 20000 ppm Cl⁻, with an annual corrosion rate of less than 0.01 mm, meeting the water treatment requirements in marine environments.

Marine diesel engine cleaning machine

In a humid environment with NaCl water mist, its resistance to pitting corrosion is superior to that of Hastelloy C-276, and the equipment maintenance cycle is extended to 2 years, reducing the operation and maintenance costs of ships.

 

- Competitive Advantage and Selection Recommendations -

Compared with Hastelloy C-276:

Alloy 59 has a higher molybdenum content (15-16.5% vs 15-17%), a 30% lower corrosion rate in reducing acids, and a cost reduction of 10-15%.

Alternative options:

In scenarios where the requirement for Cl⁻ resistance is not high, it can partially replace Inconel 625, but it should be noted that its high-temperature strength is slightly lower.

Customer case:

A petrochemical enterprise replaced the original 316L material of the hydrochloric acid regeneration tower with Alloy 59, reducing the annual maintenance cost from $500,000 to $120,000 and reducing the downtime by 80%.

 

Market Dynamics and Sales Strategies

Industry Trends:

Driven by the hydrogen energy industry, global demand for Alloy 59 is expected to increase by 18% by 2025, mainly for hydrogen storage equipment and pipelines in hydrogen refueling stations. Its reliability in H₂S/CO₂ environments is particularly emphasized.

 

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