Special steels and alloys for harsh operating conditions

When designing and operating equipment for various industries — whether chemical, oil and gas, or food — it is necessary to account for the effect of aggressive media and extreme temperatures on materials. Under such conditions, corrosion-resistant, heat-resistant, and high-temperature steels and alloys that retain their properties despite external influences are of particular importance.

Corrosion-resistant materials

Corrosion is one of the main problems faced by engineers in chemical, oil and gas, and other industries. Destruction of metals under the action of an aggressive external environment can lead to serious economic and environmental consequences. Therefore, the use of corrosion-resistant steels and alloys is not merely a choice but a necessity.

The main types of corrosion-resistant materials include:

1. Chromium steels
   • Examples: 12Kh13, 20Kh13.
   • Contain chromium, which forms a protective chromium oxide film on the surface that hinders corrosion.
   • The minimum chromium content for providing protection is 13%.
2. Austenitic steels
   • Examples: 12Kh18N9, 12Kh18N10T, 12Kh18N9SMR, 10Kh17N13M3T.
   • Contain nickel and chromium, which form a protective film.
   • Offer higher ductility and impact toughness compared with chromium steels.
3. Ferritic steels
   • Examples: 12Kh17, 08Kh17T.
   • Have a different chemical composition and structure compared with chromium and austenitic steels, but also offer elevated corrosion resistance.

Heat-resistant (oxidation-resistant) materials

In aerospace, rocket, and nuclear industries, where operating temperatures of assemblies and equipment can exceed 1000°C, ordinary materials lose their properties. Heat-resistant steels and alloys remain resistant to oxidation and retain functionality at extreme temperatures.

Main types of heat-resistant materials:

1. Nickel alloys
   • Examples: Kh20N80N, Kh15N60N.
   • Contain a high percentage of nickel that provides heat resistance.
2. Corundum ceramics
   • Consist of aluminum oxide and offer high heat resistance.
3. Iron-based alloys with chromium and aluminum
   • Examples: Kh15Yu5, Kh23Yu5, Kh23Yu5T.

High-temperature (creep-resistant) materials

Heat-resistant steels and alloys retain their mechanical properties under elevated loads and extreme temperatures, which is essential in power-plant engineering, aerospace, and space technology.

Examples of high-temperature materials:

1. Martensitic steels
   • Examples: 40Kh9S2, 15Kh11MF.
   • Known for high strength and hardness, but have comparatively low ductility.

Innovative and sought-after alloys

Inconel alloys are distinguished by high strength, corrosion resistance, and heat resistance, which makes alloys of this family sought after in various industries.

• Inconel 600
  • An alloy based on iron, nickel, and chromium that combines high resistance to stress-corrosion cracking with the ability to retain strength under elevated temperatures. 
  • Used in chemical and petrochemical industries, nuclear power, and automotive manufacturing.
• Inconel 625 
  • A niobium-stabilized Ni-Cr-Mo alloy with resistance to aggressive media, including crevice corrosion and pitting. 
  • Used in the aerospace and chemical industries, oil and gas production, and shipbuilding.
• Inconel 718 
  • An age-hardenable alloy that retains high strength up to 700°C and offers corrosion resistance and good weldability.
• Inconel 725
  • Has corrosion resistance similar to Inconel 625, but higher strength achieved by age hardening.
• Inconel C-276
  • An alloy with high resistance to reducing and mildly oxidizing media, as well as resistance to localized attack and stress-corrosion cracking. 
  • Used in chemical and oil-refining industries for operation in aggressive media.

The tensile strength of these alloys in the annealed condition is approximately 700–800 MPa, and after aging — 1,200–1,400 MPa.

Application areas

Modern technologies require materials that withstand extreme service conditions. Let us consider the main application areas of specialty Inconel-family alloys and their importance in various industrial sectors.

Aerospace technology

The aerospace industry places extremely high demands on materials. Inconel-type alloys have unique heat resistance and corrosion resistance, which makes them indispensable in manufacturing various propulsion-system components. They are used:

• in power turbines — withstand extreme temperatures while retaining strength and stability;
• in exhaust systems — help minimize thermal effects on other system components;
• in tooling for composite production — their strength and thermal resistance are needed when creating complex composite materials.

Such alloys are used in airplanes, helicopters, and spacecraft, where reliability and safety come first.

Automotive technology

The automotive industry also needs high-strength materials resistant to high temperatures. Continually tightening environmental regulations and rising requirements for engine efficiency promote wider use of specialty alloys. Application of such materials is especially important:

• in valves and ignition devices — ensure stable engine operation under extreme service conditions;
• in exhaust systems — resistance to high temperatures and corrosion helps extend system service life.

Thus, modern automobiles become more reliable and environmentally friendly thanks to the introduction of innovative materials.

Chemical and processing industries

Equipment for these industries must be designed taking into account exposure to various aggressive media in which ordinary materials quickly fail. Inconel-type alloys, distinguished by high corrosion resistance, are used:

• in process vessels — ensure equipment durability despite exposure to aggressive chemicals;
• in pipelines — materials resist corrosion and withstand high pressure and elevated temperatures;
• in pumps and valves — use of specialty alloys reduces the risk of leaks and accidents.

These materials make it possible to significantly improve the safety and efficiency of production processes.

Oil and gas industry

In the oil and gas sector, equipment operates under high temperatures, pressure, and aggressive media. Inconel-type alloys are used to produce:

• downhole tubing — withstand exposure to various gases and petroleum products;
• wellhead equipment — ensure reliable operation under extreme conditions;
• processing equipment — alloy corrosion resistance extends the service life of assemblies and units.

These alloys are especially sought after on offshore platforms and in deepwater wells, where equipment reliability requirements are highest.

Oil refining and petrochemical industries

Production processes in oil refining and petrochemistry require high-temperature corrosion-resistant alloys. They are used:

• in reactors and heat exchangers — resistance to high temperatures and chemical attack helps extend equipment service life;
• in pyrolysis tubes and headers — ensure stable system operation under extreme loads;
• in transfer pipelines — ensure reliable and safe transport of processed products.

Such materials help reduce the risk of process stoppages and accidents at continuous-cycle plants.

Power generation

The power industry, including thermal and nuclear power, also places high demands on materials used in production equipment. Inconel-type alloys are actively used:

• in land-based gas turbines — ensure long-term operation at high temperatures;
• in tubes in coal and gas plants — materials resist corrosion and temperature effects;
• in nuclear power plant equipment — high alloy corrosion resistance improves operational reliability and safety.

Where equipment reliability and long service life are critical factors, specialty steels and alloys play an indispensable role.

Products manufactured by PZPS

Petersburg Precision Alloys Plant produces a wide product range, including corrosion-resistant steels and heat-resistant materials such as:

• alloys analogous in chemical composition, structure, and properties to Inconel 625, Inconel 718, and Inconel C-276;
• corrosion-resistant steels 12Kh18N9, 12Kh18N10T, 12Kh18N9SMR, 10Kh17N13M3T;
• heat-resistant steels and alloys 20Kh13, KhN78T.

Thanks to continuous innovation and strict quality control, PZPS guarantees the reliability and durability of its products, making them an excellent choice for various industrial sectors. For ordering materials, developing new specialty alloys, or other manufacturing services, submit a request on the website or call the phone numbers listed. Our specialists will contact you and answer your questions in detail.

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