How to distinguish between high-strength nuts and ordinary nuts?

Many customers can't figure out the difference between high-strength nuts and ordinary nuts. In fact, it is very simple to justify them by mastering their specifications and other characteristics. The high-strength nuts are specially made bolts with high toughness and high fatigue resistance that are commonly used in machinery and equipment or engineering projects. Naturally, high-strength nuts are all used with high-toughness bolts to achieve stronger use effects.

We generally see many bolts with M-heads in shopping malls, which are all general nuts, not high-strength nuts. The calibration of hexagonal head nuts is generally used to indicate the thread standard for M30 during the following layout M30, that is, the nominal diameter of the external thread. It is 30mm, grade 10 indicates the application level of the bolt, and tZn is the surface treatment method.

Other forms of bolts also have their own expressions, but generally those with external threads need to start with "M" at the beginning of the bolt's action level:

The action 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 type of marking means that 10 is used as an example to indicate 1/100 of the tensile strength of the bolt. In other words, the tensile strength of the bolt must reach the level of 1000MPa, and the actual activity may be higher than 1000MPa.

The minimum tensile strength of this level of bolts in GB/T3098.1 standard must exceed 1040MPa. The yield ratio after the decimal place is indicated, that is, the bolt's (yield compressive strength/tensile strength) = 0.9, that is, the yield strength = 1000*0.9 = 900MPa, the yield compressive strength of this level of bolts must be higher than 900MPa. meet the target.

Generally, we call the nuts of the three levels of 8.8, 10.9, and 12.9 as high-strength nuts.

It should be noted that GB/T3098.1 does not have a detailed standard value of yield compressive strength for these three levels of bolts, because for high-toughness bolts, 0.8 and 0.9 are all standard for this level. Smaller yield-strength ratio, since high-toughness bolts are used for very critical connections, there is currently no spot transaction on the market, and must be ordered from the bolt manufacturer. Therefore, the detailed yield-strength ratio is generally specified by the buyer. value to produce.