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Multi-method to prevent 65Mn spring circle white point problem
The 65Mn spring washer, made from high-strength steel wire, is widely used in various applications due to its excellent elasticity and durability. In China, 65Mn is one of the most commonly used materials for spring washers. However, this material has a significant drawback: poor corrosion resistance. To improve its anti-rust performance, it is typically coated with zinc or cadmium. Unfortunately, these surface treatments can lead to hydrogen embrittlement, which weakens the mechanical properties of the washer and may cause cracking or failure under stress.
To address this issue, many industries are now considering replacing 65Mn with stainless steel materials that do not require such coatings. This change helps eliminate the risk of hydrogen embrittlement while maintaining the required elastic performance. For example, the Shanghai Spring Washer Factory has successfully developed stainless steel spring washers using 1Cr18Ni9Ti, a type of austenitic stainless steel known for its corrosion resistance and strength. These washers have been adopted in the aerospace industry, where reliability is critical. Recent reports show that they perform well without issues like hydrogen embrittlement, poor elasticity, or rust.
In addition, some aviation manufacturers have started using stainless steel spring washers in their key projects, and no quality problems have been reported so far. Our institute also tested stainless steel washers on a critical model, and they performed reliably. Based on these successful cases, it's recommended that other products suffering from hydrogen embrittlement issues should consider replacing 65Mn with stainless steel alternatives.
Currently, there are limited types of stainless steel spring washers available in China that meet the required standards. Some existing options include QJ2963.2-1997, which replaces GB/T93-1987, and QJ2963.3-1997, which replaces GB/T859-1987. These alternatives offer better corrosion resistance and reduce the need for galvanization or cadmium plating. While most commercially available spring washers are still made from 65Mn, efforts are being made to promote the use of stainless steel in more applications.
In cases where corrosion resistance is not a major concern, or when the washer operates in a controlled environment (such as inside a sealed compartment), it’s advisable to avoid galvanizing or cadmium plating. Instead, alternative anti-rust methods like oiling or surface oxidation can be used to prevent hydrogen embrittlement.
Another effective way to prevent loosening of threaded fasteners is by using rubber-proof anti-loose technology instead of traditional spring washers. With advancements in adhesive technology, products like Loctite and Iron Anchor have been successfully applied to thread connections. Some aviation manufacturers have already replaced spring washers with thread-coated rubber solutions, and no quality issues have been reported after testing and real-world use.
Our institute also implemented this technology in a key project, and the results were positive. The process involves applying adhesive to the threads before assembly. Although this method requires more steps—such as cleaning parts and controlling screwing speed—it allows for greater flexibility in choosing thread strength based on specific connection requirements. Overall, it provides a reliable and efficient alternative to traditional spring washers.