How to identify stainless steel bolts and head markings?
Stainless steel nuts and bolts have markings on them to help the user identify their properties. We have put together a quick guide below on how to decipher the code. The three marks you will most commonly find are as follows; the name of the manufacturer (or an abbreviated version) The grade of stainless steel, i.e. A2 or A4.
What do the markings on a bolt mean?
What do the markings on a bolt head 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.
How to identify a bolt?
They represent the following rifles:
- 351 is and A-Bolt II or I (original A-Bolt)
- 358 is the AB3
- 354 is and X-Bolt
How to identify grade 8 bolts?
You can identify Grade 8 bolts by the six evenly spaced radial lines on the head. These high strength bolts are made with a steel alloy containing an average of 18 percent chromium and 8 percent nickel, which makes them extremely strong but very brittle.
What do the numbers and letters on bolts mean?
Each grade has a specific bolt strength. No matter the system used to grade the bolts, the higher number means the stronger the bolt. For most home and automotive applications, you won't need anything more than a grade 8 bolt strength or metric class 10.9.
How do you read bolt markings?
Whether metric or standard, all bolts are sized by diameter, thread pitch, and length—in that order. So, for example, an SAE 1/2-16 x 2 bolt is ½" in diameter, has 16 threads per inch, and is 2" long. An M12-1.5 x 50 metric bolt is 12mm in diameter, has a thread pitch of 1.5mm, and is 50mm long.
What does 3 marks on a bolt mean?
SAE grade 5 fastenerThree radial lines will indicate an SAE grade 5 fastener, while six radial lines will indicate an SAE grade 8 fastener. These are the most common grades, but there are others.
What does 8.8 mean on a bolt head?
So, in English, a Property Class 8.8 bolt is a bolt with a nominal tensile strength of 800 MPa and a nominal yield strength that is 80% of that nominal tensile strength, so 640 MPa.
What does 7 on a bolt head mean?
The marks approximately correspond to the following property classes: Head Mark "4": 4.6, 4.8, 5.6, 5.8, 6.8. Head Mark "7": 8.8. Head Mark "8": 9.8. #2.
How can you tell if a bolt is a Grade 5?
Grade 5. Manufactured from medium carbon steel and hardened for greater strength and durability, 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 or those that require medium strength.
How can you tell the difference between Grade 5 and Grade 8 bolts?
Grade 8 / Grade G 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 jh on bolt head mean?
1:426:50Bolt Head Markings: What do they mean? | Fasteners 101 - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd typically three slashes is going to be grade. Five. Okay you see the JH. There that's aMoreAnd typically three slashes is going to be grade. Five. Okay you see the JH. There that's a manufacturer's marking.
What do notches on a nut mean?
Metric (Notches in the nuts of fittings indicate that they are metric - Cold Hose. Repair Hose Kits.
Is Grade 8 or 12.9 stronger?
Used in high stress environments, grade 12.9 fasteners are the highest class of metric cap screws. Where Grade 8 fasteners have a 150,000 psi tensile strength, 12.9 fasteners have a 180,000 psi tensile strength, making them more durable than the grade 5.
What is the strongest bolt grade?
grade 8Grade 9 Bolts Grade 9 structural bolts, also known as grade 9 hex cap screws, are one the strongest structural bolts that can be used today. While the typical grade 8 bolt has a tensile strength of 150,000 PSI, a grade 9 bolt has a tensile strength of 180,000PSI.
What does 4.6 mean on a bolt?
In 4.6, The first number 4 indicates 1/100 of nominal tensile strength . Hence the tensile strength = 400 Mpa. The second number indicates 10 times the ratio between lower stress(proof stress) and nominal tensile strength(yield stress ratio) means, 10 times the yield stress = 10 x 240/400 = 2400/400 = 6.
How to tell the strength of a bolt?
You can usually figure out the grade, or strength, of a bolt by looking at the markings on its head. English bolts (U.S.S. or S.A.E) are categorized by grade, from grade 2 to grade 8, where the grade represents inch strength. The higher the grade, the stronger the bolt. English bolts have radial lines on their head to identify the grade, ...
Why do English bolts have radial lines?
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.
How many radial lines are there on a grade 8 bolt?
A grade 8 bolt will have 6 radial lines on its head. Metric bolts are a bit more straight forward, usually having their strength class number stamped right on the bolt head. Some metric nuts also have the strength class number stamped on their face. The below diagram shows examples of English and Metric bolt and nut markings.
What are some common head markings on stainless steel bolts and screws?
If you look at the head of a stainless steel fastener, you might see a marking stamped onto the surface. These marks hold valuable information about the fastener and learning how to read them can help you decide if it’s the correct product for the job.
Is Stainless Steel magnetic?
No. Austenitic grades of stainless such as 304 and 316 are NOT magnetic in their raw, annealed state.
How can I tell if my stainless steel is 304 or 316?
The head marking 'A2' identifies 304 grad and 'A4' identifies 316 grade. However testing the stainless chemically is the only sure way of knowing the grade.
How do I guarantee that my fastener or fitting is stainless?
The only true way to ensure specification compliance is a material elementary analysis with an X-Ray Spectrometer. To be able to be classed as stainless it will have a chemical composition of at least 10.5% Chromium, and meet other requirements depending on what stainless steel grade it should be.
