Black Nuts And Bolts High Tensile Grade 10.9 12.9 Fasteners Lug Nut

The black nuts and bolts are commonly used in tires/wheels or the other vehicle equipment. The fasteners are usually with heat treatment and galvanization. Ever Hardware provides the custom made black nuts and bolts and customizable packaging.

Heat treating is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve the desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, normalizing, and quenching. It is noteworthy that while the term heat treatment applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding.
The symbol for the property classes of hex bolts, screws, and studs consists of two numbers separated by a decimal point. 8.8, 10.9, 12.9, 14.9 etc.
Take the whole number before the decimal point. This number, when multiplied by a hundred, gives you the nominal tensile strength in newtons per millimeter squared.
The digit following the decimal point, multiplied by ten, gives you the yield stress ration, or the percentage ratio between the lower yield stress and the nominal tensile strength.
If you now multiply the first number by 10 times the second number you will arrive at the notional yield stress in newtons per millimeter squared.
The main characteristic property of Nuts is the thread stripping strength (proof stress).
The property classes of nuts are designated by a number which indicates the maximum appropriate property class of bolt with which they should be fitted. Therefore nut property classes are the same as the bolt designation initial number.
Internationally, mechanical stress is expressed in newtons per square area, in bolting N/mm2. Common practice overseas is to use the unit megapascal (MPa), which corresponds directly to N/mm2. For example 1,200 N/mm2 = 1,200 MPa.

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