What is the hardness of a Grade 8 bolt?

Materials - Medium Carbon Steel Bolts in SAE J429 (Grades 2, 5 and 8)
GradeNominal size, inchesCore hardness, Rockwell
2¾ - 11/2 inchB70 to B100
5¼ - 1 inchC25 to C34
1 - 1-1/2 inchesC19 to C30
8¼ - 1-1/2 inchesC33 to C39

How many marks are on a Grade 8 bolt?

Bolt Grade Markings and Strength Chart
Head MarkingGrade and MaterialMechanical Properties
Min. Tensile Strength (psi)
3 Radial LinesGrade 5 Medium carbon steel, quenched and tempered120,000
6 Radial LinesGrade 8 Medium carbon alloy steel, quenched and tempered150,000
  • What is a grade 8.8 bolt?

    The first digit relates to the ultimate strength of the material, whilst the second is the ratio of yield stress to ultimate strength. Thus grade 4.6 bolts have an ultimate material strength of 400N/mm2 and the uield (or proof) stress is 60% of the ultimate strength.
  • What is stronger grade 5 or 8 bolt?

    Grade 8 bolts have been hardened more than grade 5 bolts. Thus they are stronger and are used in demanding applications such as automotive suspensions. Grade 8 bolts have 6 evenly spaced radial lines on the head. Grade G is roughly equivalent to Grade 8.
  • What does 12.9 mean on a bolt?

    12.9 grade steel means that a component manufactured form this grade of steel has 12X100 N/mm^2 tensile strength and 9 is a multiplier means 90% of 1200 = 1080 N/mm^2 is the yield strength of the grade. Similarly we also have grade 8.8 , 10.9 , 6.8 also.

Is a 10.9 Bolt stronger than Grade 8?

Also known as A-2 stainless, 18-8 is the most common grade of stainless steel for general use. A tempered medium carbon steel. Class 10.9 is stronger than class 8.8, and is commonly found in high strength automotive applications. Class 10.9 is similar to grade 8.
  • Are Grade 8 bolts rust proof?

    According to K-T Bolt Manufacturing Inc., Grade 8 bolts "are used in demanding applications such as automotive suspensions. Grade 8 bolts have 6 evenly spaced radial lines on the head." Unlike stainless steel, which is highly resistant to corrosion, steel, however reinforced, will oxidize over time and rust.
  • What is the difference between metric and standard bolts?

    M 10 x 1.5 is a metric bolt with a 10 mm nominal diameter and 1.5 mm pitch. The standard American bolt is defined by the inch system designation. For both metric and standard bolts, the head size is the distance across the flats. For standard bolts, the head size is measured in inches or fractions of an inch.
  • What element is molten in hot dip galvanization of fasteners?

    Hot-dip galvanization is a form of galvanization. It is the process of coating iron and steel with zinc, which alloys with the surface of the base metal when immersing the metal in a bath of molten zinc at a temperature of around 840 °F (449 °C).

Updated: 26th August 2018

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