There are many factors influencing the safest and most secure bolted connections. To help you achieve the best possible results, we have come up with ten tips to ensure bolt safety. Please note that this is generally recommended and does not necessarily apply to all bolt applications.
Select the correct combination of bolt size and grade
For bolt applications, the bigger the size is, the better. Similarly, compared to low-grade bolts, high-grade bolts do not mean performance improvements. The combination of the two is the key.
Bolt size and strength level can bring positive and negative impact on the bolt load. If you can find the ideal combination, and the correct tightening of the bolt connector, the load will be to ensure that the bolt connection is an important factor. You can choose larger but lower strength bolts, or select smaller but higher strength bolts. Both of these options may be appropriate.
For the joint to create elastic force, to eliminate the problem of loose bolt
Thread loosening is one of the main causes of bolt loosening. There are three major causes of thread relaxation: rough or irregular surface subsidence; relaxation, that is, the polymer or composition and other texture becomes compact; creep, that is, under stress and high temperature, the material displacement or deformation. These three causes can cause the preload loss, resulting in a problem with the bolt connector.
Today, bolts have to withstand higher temperatures and loads, and more and more equipment components are made of synthetic materials, plastic and aluminum, which is the reason for the increasing number of thread loosening problems.
To solve this problem, you need to start from two aspects: to avoid thread loosening, the screw surface needs to be smooth and hard, but also to improve the flexibility of the bolt connection, such as the use of Nord-Lock X-series washers or Superbolt multi-push pushers. Superbolt multi-thrust pretensioner and Nord-Lock's multi-function wedge lock technology can improve the flexibility of the joint, the thread relaxation effect to a minimum.
Choose the correct lubrication method
For the bolt connection, how to emphasize the role of lubrication are not excessive. Lubrication minimizes friction unevenness while reducing torque load ratio. Lubrication also makes installation and removal easier and extends bolt life.
For bolt lubrication, it is important to choose the appropriate lubrication method according to the application. Some of the parameters that should be considered include: chemical composition, health and environmental effects, operating temperature range and coefficient of friction, and should consult with the lubricant manufacturer for recommended use.
Focus on life cycle costs
In the project design phase, a common problem is, in the end should choose low-cost solutions to keep the current lowest cost, or should choose high-quality solutions to achieve long-term cost savings? Initial costs should not be the only focus to be considered. Wise investment in the early stages of the project can bring significant cost savings in the later stages.
The coating can make the bolts more secure
Coating thickness may be only a few microns, but it can improve the performance of fasteners in a variety of ways, including resistance to corrosion, reduce friction, enhance the appearance value. There are a variety of coating solutions to choose from, where galvanized treatment is the most cost-effective and simplest. If the method can not achieve satisfactory results, but also the use of zinc alloy. If more protection is required, it is recommended to use multiple layers of zinc dust.
For the specific application, in the end the choice of which coating? First, the coating should be selected according to the degree of corrosion protection, and because the lubricant can compensate for the lack of friction performance, and then according to the required friction characteristics of choice, and finally consider the appearance of the effect.
Coating has a variety of functions, but some of the features are more important
Cheap counterfeit goods everywhere, bolt products are no exception. If you choose genuine, you get the product after a long time market test, to ensure excellent performance and quality. Like many products, the bolt solution is also a penny. The purchase of genuine prices is high, but because of reliable product performance, can reduce maintenance / repair costs, resulting in long-term cost savings.
And professional experience of deep business cooperation
There are countless fastening solutions. Even if some programs are widely used, it may not be possible to meet the requirements of a particular temperature or pressure range. Therefore, it is important to choose a partner to help you achieve a high degree of material stability and choose an ideal fastening solution.
Product recall or brand image damage may be significant. For example, when I see the leak caused by the ventilation system, I would have thought that it was not the company's choice of fastening solution. To achieve high quality standards, they need to work with the industry experienced business cooperation, and compared to rapid profit, such enterprises pay more attention to quality.
Corrosion should be considered at the beginning of the design of the bolt connection
Some people say that life has only two things to determine, that is, death and tax. In fact, you can also add a third: corrosion. Any metal material made of steel material as long as the exposure to oxygen and water, will eventually rust decomposition.
In a certain period of time, corrosion is inevitable, but there are ways to delay the deterioration of corrosion. One of the methods is cathodic protection, that is, sacrificing zinc and other secondary metals to delay corrosion, and the other is non-cathodic protection.
If the bolts must be reused, be sure to use the lubricant
Whether to reuse bolts is a common problem. It is particularly convenient to re-use fasteners for on-site operations compared to spare parts of all sizes and grades. In addition, re-use costs are lower.
However, it is difficult to determine whether the used fasteners are damaged, if damaged, may lead to problems. It is necessary to determine whether the bolts can be reused. If signs of corrosion are found, reuse should be avoided wherever possible. If you can see the thread damage, should also avoid repeated use.
But in some cases there may be no choice but to reuse the damaged bolt as a temporary solution. If it is necessary to reuse, be sure to use the lubricant. Lubricants can resist corrosion to some extent. If the thread is damaged, the lubricant also helps to achieve the necessary clamping force before the opportunity to install the new bolts.
Preload and fastening
Select the correct tool and order of operation
The preload level determines the bearing capacity of the bolted joints. Therefore, it is necessary to determine the level of preload required to reach the bolted connection and then reach the preload by means of appropriate fastening and fastening.
The preload must be at an appropriate level to avoid movement or separation of the clamping parts, but should be embedded within the modulus limit of the material to avoid fitting the butt surface and thread peeling.
Distinguish between the static and dynamic bearing capacity of the screw is also critical; the screw can withstand a higher static load but can withstand a lower dynamic load. Therefore, a higher level of preload should be maintained, thereby reducing the impact of dynamic loads on the joints.
When tightening, the ideal tool should be selected and the fastening operation should be completed in a reasonable order to ensure the level of preload required by the design engineer.