Many users do not know the difference between high-strength nuts and general nuts. In fact, they can easily distinguish them by understanding their standards and other characteristics. The so-called high-strength nuts are special bolts with high strength and high fatigue resistance used in special equipment or projects. Of course, generally high-strength nuts are used with high-strength bolts to achieve better use.
We generally see that many bolts with M-heads in the market are general nuts, not high-strength nuts. Grade 10 indicates the performance level of the bolt, and tZn is the surface treatment method.
Other types of bolts also have their own expressions, but generally the threaded ones have the "M" functional level of the original bolt: The functional grades of nuts are divided into 3, 4, 4, 5, 5.8, 6, 8, 10, 12 from small to large. This symbol method means that 10 is used as an example to indicate 1/100 of the tensile strength of the bolt, which means that the tensile strength of the bolt of this grade must reach the level of 1000MPa, which may be higher than 1000MPa in practice. GB/T3098.1 rules that the minimum tensile strength of this grade of bolts must be greater than 1040MPa. The yield ratio after the decimal point 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 bolts must be higher than 900MPa to be considered qualified.
Generally, we refer to the nuts of the three grades 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, because for high-strength bolts 0.8 and 0.9 are the smaller yield strengths specified by the grade. Strength ratio, because high-strength bolts are used for very important links, there is no spot for sale on the market, it is necessary to book with the bolt manufacturer, so the specific yield ratio is generally produced by the buyer putting forward specific values.
