Differences Between High-Temperature Alloy Steel and Ordinary Bearing Steel
In the bearing industry, material selection directly determines bearing performance and service life. This is especially true under high-temperature conditions, where the differences between high-temperature alloy steel and ordinary bearing steel are key factors affecting equipment stability.
Many mechanical engineers and procurement personnel are often confused when choosing bearings—what exactly are the differences between these two materials in terms of composition, high-temperature resistance, and application scenarios? This article provides a comprehensive analysis from core dimensions to help you accurately distinguish between high-temperature alloy steel bearings and ordinary bearing steel bearings.
I. Different Chemical Compositions Define the Fundamental Material Differences
The essential differences between the two materials originate from their chemical composition, which is also the root cause of the special properties of high-temperature alloy steel.
| Ordinary Bearing Steel | Primarily high-carbon chrome steel, with the most typical grade being GCr15. Its chemical composition contains about 0.95%–1.05% carbon and 1.30%–1.65% chromium, with the remainder being iron and small amounts of impurities. This composition aims to improve hardness, wear resistance, and contact fatigue strength, meeting transmission needs at normal or moderately elevated temperatures (usually not exceeding 200°C). Production cost is relatively low, making it the most widely used bearing material in the industrial field. |
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| High-Temperature Alloy Steel | Based on ordinary bearing steel but with the addition of significant amounts of heat-resistant alloying elements such as nickel, molybdenum, tungsten, and cobalt. Some grades also include strengthening elements such as titanium and aluminum. |
II. Significant Differences in High-Temperature Resistance and Applicable Temperature Range
High-temperature resistance is the most intuitive distinction between the two materials and directly determines their application boundaries—this is the fundamental reason behind the term “high-temperature alloy steel.”
| Ordinary Bearing Steel | Has relatively weak high-temperature resistance. When working temperature exceeds 200°C, its hardness decreases significantly—from HRC60–64 at room temperature to below HRC50—resulting in reduced wear resistance and load-bearing capacity. At temperatures above 300°C, the material softens and creeps noticeably, and the bearing may seize, wear rapidly, or even fracture. |
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| High-Temperature Alloy Steel | Offers excellent high-temperature resistance. Depending on the grade, it can operate stably at 500°C–1000°C for prolonged periods. This capability comes from alloy elements forming dense oxide films and strengthening phases that effectively resist high-temperature structural degradation, making these steels the core choice for high-temperature environments. |
III. Differences in Mechanical Properties to Suit Various Working Conditions
Beyond high-temperature performance, the two materials also differ significantly in mechanical properties under both normal and high-temperature conditions, enabling them to match different load and operating requirements.
| Ordinary Bearing Steel | Has advantages in hardness and wear resistance. The tensile strength of GCr15 at room temperature can exceed 1600 MPa, and its contact fatigue life can surpass 1000 hours. It is suitable for high-frequency, high-load transmission at room temperature, such as in automotive wheel bearings, machine tool spindle bearings, and more. |
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| High-Temperature Alloy Steel | Although its room-temperature mechanical properties are somewhat inferior to ordinary bearing steel (for example, GH4169 has a tensile strength of about 1275 MPa at room temperature), its advantages at high temperatures are remarkable. This enables high-temperature alloy steel bearings to withstand high temperatures, high pressures, and severe vibrations in complex conditions such as aerospace engines, metallurgical furnace rollers, and chemical reactors. |
IV. Different Application Scenarios — Precise Matching Is Key
Based on the performance differences above, the application boundaries of the two materials are clear. Improper substitution may cause equipment failure or unnecessary cost increases.
| Ordinary Bearing Steel | Used mainly in “normal-temperature, general-purpose” scenarios, covering most industrial fields such as automobiles, home appliances, machine tools, and textile machinery. Its excellent cost-performance ratio makes it the preferred choice for mass production. |
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| High-Temperature Alloy Steel | Focuses on “high-temperature, special-condition” scenarios, and is widely used in aerospace, petrochemicals, metallurgy, thermal power generation, and similar industries. |
V. How to Choose? Match Material to Working Conditions to Avoid Risks
In summary, the essential difference between high-temperature alloy steel and ordinary bearing steel lies in “specialized materials” versus “general-purpose materials.” The core criteria for selection include:
| Working Temperature | Choose high-temperature alloy steel when temperature exceeds 200°C |
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| Load Intensity | High load under high temperature requires high-temperature alloy steel |
| Environmental Complexity | Prefer high-temperature alloy steel when high temperature, corrosion, and vibration coexist |
Using high-temperature alloy steel bearings in normal-temperature conditions may lead to unnecessary cost increases; conversely, applying ordinary bearing steel in high-temperature environments can severely reduce equipment life and even cause safety hazards. Therefore, precisely matching working conditions with material type is the core principle of bearing selection.
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