For effective operation at extremely high temperatures, properties such as heat resistance and heat resistance are critical for precision alloys and steels. This is especially important for plant components that are subject to significant mechanical loads. This includes aircraft engines, gas turbines, thermal power plants, industrial pumping furnaces, as well as equipment at refineries and petrochemical plants.
Heat resistance (scale resistance) is determined by the ability of metals to resist chemical corrosion at elevated temperatures in a dry gaseous environment. This is due to the formation of oxide films on the metal surface, which act as a protective barrier. For example, iron (Fe) with oxygen (O2) at temperatures up to 560—600°C, forms densely bound oxide-resistant Fe oxide films2O3 and Fe3O4, which makes it difficult for metal atoms (cations) and oxygen (anions) to diffuse. However, at higher temperatures (above 600°C), these films break down, and a layer of loose FeO oxide forms on the metal surface, which contributes to intensive oxidation of steels and iron-based alloys.
One of the key factors affecting the heat resistance of materials is their chemical composition, since it determines the protective properties of oxide films. Table 1 compares the oxide resistance of several chemical elements — pure metals.
Table 1 - Heat resistance of metals in air at operating temperatures
The heat resistance of a material is determined by its ability to maintain its strength at high temperatures. The main indicators of heat resistance include long-term strength and creep strength, which must meet the operating conditions of finished products or structures.
Choosing a heat resistance criterion for precision alloys and steels depend on the planned service life of a machine or mechanism made from this material. Table 2 shows the recommended service lives of heat-resistant structures depending on their purpose.
Table 2 - Service life of heat-resistant structures
The history of superalloys began in 1929, when scientists Bedford and Pilling made changes to the chromium-nickel alloy. By adding to it titanium (Ti) et aluminum (Al), they were able to significantly increase the material's creep resistance. Interestingly, superalloys were discovered shortly before jet engines were developed. The first prototypes of aircraft with turbine engines, created in England and Germany in the 1930s, required new materials that could withstand extreme operating conditions: high temperatures and increased loads.
For a long time, superalloys were produced only for the military industry as the main material for creating jet engines. But in the middle of the last century, similar materials became in demand in other industries, in particular, for the manufacture of various drive devices (gas pipeline pumps, gas turbines for power plants). From the 1950s to the 1960s, intensive development of heat-resistant superalloys began around the world, which led to improved technologies and increased production volumes. Over time, these materials have become an integral part of the aviation and energy industries, ensuring reliability and durability under the most extreme operating conditions.
One of the key requirements for superalloys is the minimum content harmful contaminants, such as sulfur (S), phosphorus (P), lead (Pb), bismuth (Bi) and tellurium (Te). And the main goal of researchers and engineers in this field is to increase reliability and economic efficiency by reducing the use of expensive alloying elements at temperatures up to 680°C. Promising areas of development include the use of materials based on nickel (Ni).
One of the types products The St. Petersburg Precision Alloy Plant is corrosion-resistant steels 12X18N9, 12X18H10T, 12X18N9SMR (EP-414). They undergo strict quality control at every stage of production, which makes it possible to ensure that they meet the highest standards.
For purchase questions cold rolled strip from corrosion-resistant steels and precision alloys, please contact specified phone or leave applications on the site.
The company is actively engaged in development of production heat-resistant and heat-resistant chromium-nickel alloys (KhN53BMTYU, an analogue of the foreign NN 718 alloy) and molybdenum-chromium-nickel alloys, which is facilitated by work research center.
You can find out about the terms of cooperation and the technical capabilities of the PZPS Research Center by calling +7 812 740-76-87 or writing to nic@pzps.tech. Our specialists will contact you as soon as possible and answer all your questions in detail.
