Typical Materials Alloy 400 and Alloy K-500 for the Oil and Gas Industry

The process of oil and gas extraction is highly complex. Crude oil and natural gas are complex organic mixtures, and their compositions vary across different depositional locations. Crude oil is primarily composed of hydrocarbons, as well as sulfur, oxygen, and nitrogen compounds, while natural gas consists mainly of methane, ethane, and propane, with minor amounts of hydrogen sulfide and other components. Therefore, the materials used for the extraction equipment must possess resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking.

According to the International Energy Agency's "World Energy Outlook 2017", global energy demand is expected to increase by 30% by 2040. Although renewable energy sources such as wind and solar power have been developed and commercialized to some extent, oil and natural gas will continue to be the primary sources of global energy supply for a considerable period. In recent years, to ensure the long-term sustainable use of fossil fuels, the utilization of oil and gas reservoirs has been increased through deep drilling and secondary/tertiary recovery.

As oil and gas reserves continue to decline, the discovery of new deposits has become increasingly challenging, and the demands on materials processing technologies for oil and gas extraction will become more stringent. Both nickel alloys and specialty steels will continue to contribute to the world's energy and fuel supply, both now and in the future. Alloy 400 and Alloy K-500 are two typical materials suitable for the oil and gas industry.

Alloy 400

W.Nr.: 2.4360

UNS: N04400

Alloy 400 is a nickel-copper alloy with excellent corrosion resistance to a wide range of reducing media, as well as good mechanical properties. It has outstanding resistance to corrosion in non-aerated hydrofluoric acid, neutral, and alkaline salt solutions.

Alloy 400 can be used in the construction of uranium extraction and isotope separation equipment in nuclear fuel production. It is a standard material for equipment in salt solution concentration and crystallization, vinyl chloride monomer (VCM) production, MDI and TDI production, and petroleum refining. Alloy 400 is also used for the manufacture of feedwater heaters and steam generator heat transfer tubes, as well as casing and platform steel columns in offshore oil and gas production. This material has been certified for use in pressure vessels operating at temperatures between -10 to 425°C (18 to 797°F).

Material Characteristics

• Excellent resistance to stress corrosion cracking caused by chlorides

• Maintains excellent strength at low temperatures

• Easier to fabricate compared to other high-alloy materials

• Certified for use in pressure vessels from -10 to 425°C (14 to 797°F) according to VdTÜV Material Sheet 263, and up to 480°C (896°F) according to the ASME Boiler and Pressure Vessel Code

Chemical Composition Overview (%)

Corrosion Resistance

Alloy 400 has excellent corrosion resistance to neutral and alkaline salts, making it a standard material in the salt production industry for a long time. Alloy 400 is one of the few materials that can withstand contact with fluorides, hydrofluoric acid, and fluorine compounds. The material also has excellent resistance to corrosion in alkaline media. Compared to copper-based alloys, it performs very well in seawater and has superior resistance to atmospheric corrosion. Alloy 400 also has good resistance to non-aerated dilute inorganic acids, such as sulfuric and hydrochloric acids.

However, the corrosion rate of this alloy increases significantly under oxidizing conditions due to the lack of chromium. While Alloy 400 can resist stress corrosion cracking, it is susceptible to stress cracking in the presence of mercury or moist hydrofluoric acid vapors. If used in such conditions, a stress-relieving heat treatment is required.

Applications

Common applications of Alloy 400 include:

• Feedwater and steam generator heat transfer tubes in power plants

• Brine heaters and vapor recompression evaporators in salt production facilities

• Alkylation in sulfuric and hydrofluoric acid

• Heat exchangers in the chemical industry

• Plating equipment in mineral oil distillation plants

• Lining for splash zones on offshore platforms

• Impellers and pump shafts in ships

Alloy K-500

W.Nr.: 2.4375

UNS: N05500

Alloy K-500 is a nickel-copper alloy with the addition of aluminum and titanium to increase the strength of the alloy.

Compared to Alloy 400, the yield strength of Alloy K-500 is nearly doubled, and the tensile strength is also increased by about 50% after precipitation hardening, while maintaining excellent corrosion resistance.

Even at high temperatures, Alloy K-500 can still maintain excellent corrosion resistance and high strength. The alloy is non-magnetic and can be fabricated without the need for heat treatment, or can be worked in the solution-annealed or precipitation-hardened condition and then given subsequent heat treatment.

Material Characteristics

• Alloy K-500 has excellent corrosion resistance in many marine engineering and chemical industry applications

• Good resistance to stress corrosion cracking caused by chlorides

• Maintains high tensile strength up to 650°C (1,202°F) in the precipitation-hardened condition

• Good fatigue strength in the precipitation-hardened condition

• Remains non-magnetic down to -100°C (-148°F)

Chemical Composition Overview (%)

Corrosion Resistance

The corrosion resistance of Alloy K-500 is generally comparable to Alloy 400 under normal conditions. This alloy has excellent resistance to a wide range of media, from pure water to high-concentration salt and alkaline solutions. Alloy K-500 is almost immune to stress corrosion cracking caused by chloride ions. In the precipitation-hardened condition and under stresses approaching the yield strength, the material is susceptible to stress corrosion cracking in hot hydrofluoric acid vapor. Alloy K-500 has been proven to have good corrosion resistance in rapidly flowing seawater and marine atmospheres, but may experience pitting in stagnant or slow-moving seawater. Alloy K-500 also has good resistance to corrosive gas environments.

Applications

Alloy K-500 is widely used in the marine, offshore engineering, chemical, petrochemical, and shipbuilding industries.

Typical applications include:

• Valve seals, pump casings, and wear rings in seawater

• Pump shafts and propeller shafts

• Fastening elements/hardware, such as bolts in the splash zone and windward areas

• Armoring for towing cables

• Springs

• Components of drilling equipment in the oil industry

• Aircraft instrument components

Available Products:

Shanghai COCESS Special Alloys Co., Ltd. can produce and supply Monel 400 and Monel K-500 in the form of bars, plates, strips, pipes, capillary tubes, fittings, flanges, forgings, fasteners, and welding materials. Please contact us for more product details.