How can stainless steel bearing clamping ring washer achieve both high strength and corrosion resistance through material selection and heat treatment processes?
Publish Time: 2026-01-26
As a critical axial positioning and preload element, the stainless steel bearing clamping ring washer must withstand continuous loads and vibration impacts, and is often exposed to harsh environments such as humidity, salt spray, acids, alkalis, or high temperatures. Therefore, its performance must simultaneously meet the requirements of "high strength" to ensure clamping reliability and "high corrosion resistance" to ensure long-term service safety. This seemingly contradictory goal is achieved through the synergistic effect of scientific stainless steel material selection and precise heat treatment processes.
1. Material Selection: Precise Matching from Austenitic to Precipitation-Hardening Stainless Steel
While ordinary 304 or 316 austenitic stainless steels possess excellent corrosion resistance, their strength is relatively low, making it difficult to meet high preload requirements. One option is martensitic stainless steel, which, after quenching and tempering, can achieve a hardness of HRC 58 or higher and a tensile strength exceeding 1800 MPa, suitable for high-load conditions. Another option is precipitation-hardening stainless steel, which combines the corrosion resistance of austenitic steel with the high strength of martensitic steel. Taking 17-4PH as an example, it contains precipitation-strengthening elements such as copper and niobium. After solution treatment and aging heat treatment, its strength is increased to over 1300 MPa, while retaining corrosion resistance close to that of 304. This type of material becomes an ideal choice that balances strength, toughness, and corrosion resistance.
2. Heat Treatment Process: Finding a Balance Between Strengthening and Passivation
Heat treatment is key to releasing the potential of materials. For martensitic stainless steel, a vacuum quenching + cryogenic treatment + low-temperature tempering process is employed: the vacuum environment prevents oxidation and decarburization, cryogenic treatment promotes the transformation of residual austenite, and tempering eliminates internal stress and stabilizes the microstructure. For precipitation hardening steel, the solution treatment temperature and aging parameters are strictly controlled—insufficient solution treatment leads to coarse precipitates, reducing strength; excessive aging causes chromium depletion at grain boundaries, weakening corrosion resistance. Advanced manufacturers ensure the dispersed distribution of precipitates through precise temperature control and atmosphere protection, strengthening the matrix while maintaining the integrity of the surface passivation film.
3. Surface Passivation and Micro-treatment: Strengthening the Natural Protective Barrier
Even with high-quality stainless steel, embedded iron filings or surface scratches generated during processing can still damage the passivation film, leading to pitting corrosion. Therefore, finished products need to undergo nitric acid or citric acid passivation treatment to remove free iron ions and promote the regeneration of the chromium-rich oxide film. Some high-end products further employ shot peening or micro-arc oxidation technology to increase surface compressive stress and density without changing dimensions, significantly enhancing fatigue resistance and corrosion resistance.
4. Microstructure Control: Avoiding Sensitization and Intergranular Corrosion
During welding or improper heat treatment, stainless steel is prone to sensitization in the 450–850°C range, leading to chromium carbide precipitation at grain boundaries and causing intergranular corrosion. To mitigate this risk, clamping ring washers are often made of low-carbon or titanium/niobium-stabilized steel, or the cooling rate of the heat treatment is controlled throughout the process to avoid the sensitization temperature range. Metallographic testing shows that high-quality products have clear grain boundaries and no carbide precipitation, ensuring long-term stability in chloride ion environments.
In summary, stainless steel bearing clamping ring washer, through a four-pronged technical approach of "optimized alloy system—precise heat treatment—surface passivation strengthening—microstructure control," constructs a strong and corrosion-resistant metallic structure at the atomic scale. It is not only a small part for mechanical connections but also an invisible guardian of the safe operation of high-end equipment, demonstrating the wisdom of modern materials engineering in combining rigidity and flexibility.
