ISO 15608 Material Groups

EN ISO 15608 Material Group 42 such as Monel 400 alloy:
Nickel-copper alloys (Ni-Cu) with Ni ≥ 45 % and Cu ≥ 10 %

Alloy 400 is a single-phase, solid solution, nickel-copper alloy.

Corrosion resistance of Monel 400

Alloy 400 has excellent resistance to neutral and alkaline salts and has long been the standard material for salt production systems.

Alloy 400 is one of the few materials which can be used in contact with fluorine, hydrofluoric acid and hydrogen fluoride or their compounds. The material has a very high resistance to alkaline media. Its behavior in seawater is also excellent compared to copper-based alloys with an increased resistance to cavitation. Alloy 400 can be used in contact with highly diluted mineral acids, such as sulfuric and hydrochloric acid, provided that they are not ventilated.

Weldability of Monel 400

Alloy 400 is It has to be ensured that work is performed using targeted heat application and low heat input e.g. max. 8 kJ/cm at TIG-Welding. The interpass temperature should not exceed 150 °C.

Typical material in group 42

EN ISO 15608 Material Group 43 such as Hastelloy C-276:
Nickel-chromium alloys (Ni-Cr-Fe-Mo) with Ni ≥ 40 %

Nickel-chromium alloys

The corrosion-resistant nickel-chromium alloys such as Inconel 625 are widely used by the chemical processing industries. The need for reliable performance leads to their acceptance and growth in the areas of energy, health and environmental, oil and gas, pharmaceutical and flue gas desulfurisation industries. The attributes of nickel-chromium alloys include high resistance to uniform attack, outstanding localised corrosion resistance, excellent stress corrosion cracking resistance, and ease of welding and fabrication

Hastelloy C-276

Belongs to this group of highly corrosion-resistant nickel-chromium-molybdenum-tungsten alloys. Hastelloy C-276 is characterized by high resistance to crevice corrosion, pitting and stress-crack corrosion in oxidizing and reducing media.
The material exhibits good resistance to numerous corrosive media, including strong oxidizing agents such as iron(III) chloride and copper(II) chloride and hot media, e.g. sulfuric acid, nitric acid, phosphoric acid, chlorine (dry), formic acid and acetic acid.
It also exhibits good resistance in wet chlorine gas, sodium hypochlorite and chlorine dioxide solutions.

Typical materials in group 43

ISO 15608 Material Group 44: Nickel-molybdenum alloys (Ni-Mo) with Ni ≥ 45 % and Mo ≤ 32 %

The corrosion-resistant nickel-based alloys find extensive use in the chemical processing, pharmaceutical, oil & gas, petrochemical and pollution control industries in which highly corrosive environments are very common.

High molybdenum alloying

Molybdenum is a very important alloying element in high performance nickel-based alloys. Molybdenum also acts in conjunction with chromium to provide resistance to localized corrosion attack such as pitting and crevice corrosion. In the case of high temperature alloys, additions of molybdenum are often used to impart resistance to damage caused by high temperature creep.

These alloys fall into two basic classes:

• corrosion-resistant alloys (N10675, N10276)
• high temperature alloys (N10242)
  The high temperature alloys can be further subdivided into two categories:
  • solid-solution strengthened
  • age-hardenable (N10242)

Typical materials in group 44

EN ISO 15608 Material Group 45 such as alloy 825:
Nickel-iron-chromium alloys (Ni-Fe-Cr) with Ni ≥ 31 %

Nickel-Iron-Chromium alloys composition such as alloy 825

The high nickel content is sufficient for resistance to chloride-ion stress-corrosion cracking. The nickel, in conjunction with the molybdenum and copper, also gives outstanding resistance to reducing environments such as those containing sulfuric and phosphoric acids. As an austenitic, nickel-base alloy, the material is ductile over a wide range of temperatures from cryogenic to well in excess 538°C . Fabricability is typical nickel-base alloys, with the material readily formable and weldable by a variety of techniques.

Applications of Nickel-Iron-Chromium alloys such as alloy 825

The main applications are chemical processing, pollution control, oil and gas recovery, acid production, pickling operations also for

• pipes, tubes and fittings in the oil and gas extraction, e. g. in heat exchangers, evaporators, washers, immer- sion pipes in sea water cooled heat exchangers, offshore piping 
• Components in sulfuric acid pickling plants like heating coils, vessels, boilers, baskets and chains 
• Heat exchangers, evaporators, washers, immersion pipes in phosphoric acid production 
• Food industry 

Alloy 825: High Corrosion Resistance

Nickel-Iron-Chromium alloys have a high level of corrosion resistance. In both reducing and oxidize environments, the alloy resists general corrosion, pitting, crevice corrosion, intergranular corrosion, and stress-corrosion cracking.

Typical materials in group 45

EN ISO 15608 Material Group 46 such as alloy 617:
Nickel-chromium-cobalt alloys (Ni-Cr-Co) with Ni ≥ 45 % and Co ≥ 10 %

Features of Nickel-chromium-cobalt alloys such as Alloy 617

These alloys are solid-solution-strengthened nickel-cobalt-chromium-silicon alloys with outstanding resistance to various forms of high-temperature corrosion attack. They have an excellent resistance to sulfidation and chloride attack in both reducing and oxidizing atmospheres. The alloys also have exceptionally good resistance to oxidation, hot corrosion, carburisation, metal dusting, nitridation, and corrosion attack by low melting point compounds such as those formed by phosphorus, vanadium, and other impurities.

The combination of high strength and oxidation resistance at temperatures over 980°C makes Alloy 617 an attractive material for such components as ducting, components of power-generating plants, combustion cans, and transition liners in both aircraft and land-based gas turbines. That characteristic, combined with good resistance to oxidizing and carburizing atmospheres, makes the alloy especially suitable for long-term, high-stress use at elevated temperatures. Alloy 617 has excellent weldability.

Applications of Nickel-chromium-cobalt alloys

The alloys are especially suited for applications in high temperature corrosive environments generated by combustion of low grade fuels or processing of chemical feed stocks with corrosive contaminants such as sulfur, chlorine, fluorine, vanadium, phosphorus, and others. The alloys are capable of withstanding temperatures up to 1200 °C.  It is widely used in recuperators, heat exchangers and waste heat recovery systems. Alloys are also suitable for utility boilers, sulfur plants, high-temperature furnaces, kilns, calciners, resource recovery units, cement kilns, pulp and paper recovery boilers, coal gasification systems, and fluidized-bed combustion systems.

Typical materials in group 46

EN ISO 15608 Material Group 47:
Nickel-iron-chromium-copper alloys (Ni-Fe-Cr-Cu) with Ni ≥ 45 %

Typical materials in group 47

ISO 15608 Material Group 48:
Nickel-Iron-Cobalt alloys (Ni-Fe-Co-Cr-Mo-Cu) with 31 < Ni ≥ 45 % and Fe ≥ 20 %

Invar 36 alloy is a free machining 36% nickel iron alloy possessing a rate of thermal expansion approximately one-tenth that carbon steel at temperatures -150 °C up to 204 °C. It has a low coefficient of thermal expansion, making it useful for applications where dimensional stability is required. It is also known for its high strength and corrosion resistance.

Typical materials in group 48