How many markings are on the head of a Grade 5 bolt?
three markings
Grade 5. Hex heads with three markings are grade 5 fasteners. This grade is made from medium quality carbon steel.
What are the markings on a Grade 5 bolt?
Bolt Grade Markings and Strength Chart
| Head Marking | Grade and Material | Nominal Size Range (inches) |
|---|---|---|
| No Markings | Grade 2 Low or medium carbon steel | Over 3/4″ thru 1-1/2″ |
| 3 Radial Lines | Grade 5 Medium carbon steel, quenched and tempered | 1/4″ thru 1″ |
| Over 1″ thru 1-1/2″ |
What do the markings on the heads of bolts mean?
The markings on the heads of bolts serve two different purposes: The markings can indicate who manufactured the bolt. This will vary from manufacturer to manufacturer, but is usually one, two or three characters. The markings can identify the standard to which the bolt was made.
What is usually stamped on the head of a special bolt?
Fastener head markings usually accomplish two things: they identify the manufacturer of the fastener and the standard to which the fastener was made.
Is a Grade 5 bolt stronger than a Grade 8?
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.
What are Grade 5 bolts used for?
These bolts are generally used for non-critical joints and applications. A grade 5 bolt is distinguished by 3 radial lines and promises tensile strengths between 105,000 and 120,000 psi. They are most commonly found in automotive applications. This sought-after grade 8 bolt can be distinguished by six raised dashes.
Why do Grade 5 bolts have 3 marks?
The higher the grade, the stronger the bolt. English bolts have radial lines on their head to identify the grade, or strength class. The number of lines on the bolt head is 2 less than the actual grade. So, for example, a grade 5 bolt will only have 3 radial lines on its head.
Is a Grade 5 bolt strong?
Grade 5 bolts are hardened to increase strength and are the most common bolts found in automotive applications.
Will Grade 5 bolts rust?
Many other grades exist but are used far less often. Grade 2, 5, and 8 are usually plated with a slightly blue-ish or yellow zinc coating, or are galvanized, to resist corrosion.
Are Grade 5 bolts hard?
Grade 5 Bolts and fasteners are made of medium strength carbon steel and are specified under the Society of Automotive Engineers (SAE). with a minimum tensile strength of 120,000 psi in diameters through 1 in. and 105,000 psi for diameters over 1 in. through 1-1/2 in.