What is the difference between high-strength nuts and general nuts, in fact, you only need to understand their standards and other characteristics to easily distinguish them. The so-called high-strength nut is a special bolt with high strength and high fatigue resistance used in special equipment or engineering. Of course, generally high-strength nuts are used with high-strength bolts to achieve better application.
We generally see that many bolts with M heads in the market are ordinary nuts, not high-strength nuts. The calibration side of the general hexagonal head nut is the following pattern M30, and M30 indicates the thread standard, that is, the inner diameter of the thread is 30mm. Grade 10 indicates the functional grade of the bolt, and tZn is the surface treatment method.
Other types of bolts also have their own expressions, but generally threaded bolts have to use the original functional grade of "M":
The functional level of the nut is divided into 3, 4, 4, 5, 5.8, 6, 8, 10, 12 so many levels from small to large. This symbolic method means taking 10 as an example. 10 indicates 1/100 of the tensile strength of the bolt, which means that the tensile strength of this grade of bolt must reach the level of 1000MPa, which may be higher than 1000MPa in practice.
GB/T3098.1 rules the smaller tensile strength of this grade of bolts must be greater than 1040MPa. After the decimal point, the yield strength ratio is indicated, that is, the bolt's (yield strength/tensile strength)=0.9, that is, the yield strength=1000*0.9=900MPa. The yield strength of this grade of bolt must be higher than 900MPa to be qualified.
Generally, we refer to the three grades of nuts of 8.8, 10.9, and 12.9 as high-strength nuts.
It should be noted that GB/T3098.1 does not give detailed values of yield strength for these three grades of bolts. This is because for high-strength bolts 0.8 and 0.9 are the smaller yields regulated by this grade. Strength ratio, because high-strength bolts are used for very important links, there is no spot on the market. It is necessary to make an order with the bolt manufacturer. Therefore, the detailed yield ratio is usually produced by the buyer with a detailed value.
Stainless steel screws are made of metal, and there are four main methods for metal corrosion protection, namely the nature of the material itself, the environment in which it is used, the interface between the material and the environment, and the design of improving the metal structure. If a complete corrosion-resistant alloy is used to manufacture stainless steel screws Unless there is a special requirement, it is not realistic in terms of economic concept, or the appearance of the screw is completely isolated from the environmental elements that will cause corrosion, which may not be feasible in practice, and it may be very difficult. Improved metal structure design can improve the impact of special circumstances under certain conditions, but the design of most stainless steel screws cannot be fully modified, and its maintenance function is not permanent. Therefore, this method cannot basically deal with the problem, as long as the interface is Anti-corrosion, that is, surface anti...
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