Stainless steel parallel head hexagon socket bolts are classified according to the hardness of the screw wire, tensile force, yield strength, etc., that is, the grade of the hexagon socket bolt, and the grade of the hexagon socket bolt. Different product materials require different grades of hexagon socket bolts to correspond to them. All hexagon socket bolts have the following grades: stainless steel parallel head hexagon socket bolts are divided into ordinary and high strength according to the grade strength. Ordinary hexagon socket bolts refer to grade 4.8, and high-strength hexagon socket bolts refer to grades 8.8 and above, including grades 10.9 and 12.9. Class 12.9 hexagon socket bolts generally refer to knurled, natural black hexagon socket head screws with oil.

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