Many users can't tell the difference between high-strength nuts and ordinary nuts. In fact, it's very easy to distinguish them just by understanding their standard and other characteristics. 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, the general high-strength nuts are used with high-strength bolts to achieve better use.
We generally see in the market that many bolts with m-head are general nuts, not high-strength nuts. The calibration side of general hexagon nuts is M30, and M30 indicates the thread standard, that is, the inner diameter of thread is 30mm, grade 10 indicates the application function grade of bolts, and TZN is the appearance treatment method.
Other types of bolts also have their own expressions, but generally the threaded bolts should use "m" as the initial bolt function level:
The functional grades of nuts are divided into 3, 4, 4, 5, 5.8, 6, 8, 10 and 12. This symbol method means taking 10 as an example, 10 indicates 1 / 100 of the tensile strength of the bolt, that is to say, the tensile strength of the bolt of this grade must reach 1000MPa grade, which may be higher than 1000MPa in practice.
According to GB / t3098.1, the smaller tensile strength of bolts of this grade is necessary to be greater than 1040mpa. The yield ratio indicated after the decimal point, 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 before it is qualified.
Generally, we call the nuts of 8.8, 10.9 and 12.9 high strength nuts.
It should be noted that GB / t3098.1 does not give the detailed values of the bending strength of the three grades of bolts. This is because for high-strength bolts, 0.8 and 0.9 are smaller bending strength ratios regulated by the grade. Because high-strength bolts are used for very important links, there is no spot sale on the market, so it is necessary to order from the bolt manufacturer, Therefore, the detailed yield ratio is usually produced by the buyer's detailed value.
