Requirements for the use of blackened bolts
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Recently, our company has started using blackened bolts in place of ordinary galvanized bolts. However, I noticed that just a few days after their use, some parts of these blackened bolts began to rust. I also searched for information online on this topic and found that the corrosion resistance of blackened bolts is relatively lower compared to galvanized bolts. The main advantage of blackened bolts over the commonly used galvanized bolts is their higher precision in thread engagement, which results in less additional friction during tightening. On the other hand, the surface of ordinary galvanized bolts is relatively rough, resulting in higher friction between the threads; therefore, a greater torque is required during tightening to achieve the desired effect. But I would like to consult experts in this field: blackened bolts have poor corrosion resistance, and our company is located near the coast. I wonder if there are any risks associated with using them just because of their high fitting accuracy Blackened bolts simply have an oxide layer on their surface; there are certain things to keep in mind when using them, such as whether they should not be struck, and whether protective measures like applying butter to their surface are necessary.
I’m not quite sure; you use galvanized bolts. Is it to prevent bolt corrosion, since galvanized bolts can protect against mild corrosion? I’m not sure which type of blackened bolt you’re referring to; take a look at the bolt standards – they will list the bolts you need, making it easier to purchase them. If you think black bolts are not effective, it is recommended to use 304 material bolts. Remember, the material of the nuts and studs cannot be the same
The last edit to this post was made by Keep running on 2015-12-31 at 21:27. Severe corrosion protection in coastal areas is a problem; bolts used in pipelines are generally galvanized, while equipment usually uses blackened bolts. For those that need to be removed frequently, butter or wax oil can be used for sealing
Stainless steel bolts tend to seize, which makes them difficult to remove
Different materials can effectively prevent such things from happening
The bolts used in chemical production must certainly have certain anti-corrosion properties. As I’ve already explained, galvanized bolts provide anti-corrosion protection, and their performance is better than that of bolts treated with blackening processes. Another point concerns the use of bolts made of 304 material. Our manufacturing process involves high-temperature and high-pressure reactions, and I feel that the stiffness of 304 bolts is not sufficient; moreover, the temperature at some of the connection points falls within the range that causes sensitization in austenitic stainless steel. I have some questions: 1. What precautions should be taken when using blackened bolts? I noticed that after about ten to fifteen days of use, some parts of the blackened bolts we have started to rust. This is the case even in winter, and the situation is likely to worsen as the weather gets warmer. 2. What are the specific advantages of blackened bolts compared to ordinary galvanized bolts? 3. The requirements for using blackened bolts, or in other words, the areas where they can be applied – as mentioned earlier, they are only suitable for use in equipment.
Hello, our company produces a special tape for protecting bolts from corrosion; it is easy to apply, simple to remove, and comes at a very low price
Bro, your post seems quite suspiciously promotional – the same sentence appears more than 10 times in this forum. If you’re really trying to help people analyze and solve problems, that would be great. Not every situation can be resolved with the same phrase.
I encountered a client with a similar problem: the equipment was used outdoors, and the fasteners were blackened bolts and nuts. The material is 35CrMoA. It started to rust after being used for a short time, and later the customer became furious, claiming that our quality was poor. Of course, the device itself is excellent; the only complaint is regarding the fasteners... There is a reason for choosing certain fasteners – galvanized fasteners are subject to usage restrictions according to the HG standards. When the contents of the tank are high-risk materials, special requirements are placed on the fasteners; specialized, high-strength... must be used.
Bolt anti-corrosion solution: UV-curing bolt anti-corrosion adhesive
What should I do to remove this adhesive?