What does 8.8 mean on a bolt head?
By Daniel Johnston
If you have ever looked a metric hex bolt you might notice the markings 8.8, 10.9 or 12.9 this does not mean grade 8,10 or 12. The grade 8.8 refers to the tensile strength which is generally 116,000 psi, grade 10.9 is generally 150,000 and grade 12.9 is generally 175,000 psi.
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Hereof, what does 8.8 Bolt mean?
8.8- This type of grade is often referred to as the structural grade for bolts. When a bolt has a grading of S, it means that it can withstand a stress of 45 to 49.9 metric tonnes per 6.45 cm². This grading, which is typically stamped on the head of the bolt, has the same tensile strength as a grade 8.8 bolt.
what size is a 8.8 Bolt? Bolt Grade Markings and Strength Chart
| Grade and Material | Nominal Size Range (inches) |
|---|---|
| Class 8.8 Medium carbon steel, quenched and tempered | 16mm - 72mm |
| Class 10.9 Alloy steel, quenched and tempered | 5mm - 100mm |
| Class 12.9 Alloy steel, quenched and tempered | 1.6mm - 100mm |
In this manner, what do the markings on the head of a bolt mean?
The lines on the head of a bolt indicate its grade. SAE J429 (Society of Automotive Engineers) bolts have radial lines, whereas ASTM (American Society for Testing and Materials) uses a combination of letters and numbers to indicate the grade.
Is 8.8 high tensile?
Grade 8.8 high tensile steel is often referred to as the structural grade for bolts. It is the most common form of high tensile material and is usually stocked in plain finish or zinc. It can be plated in many other coatings. There are a wide range of products available from stock in high tensile steel.
Related Question AnswersIs a 10.9 Bolt stronger than Grade 8?
Zinc plated for moderate corrosion resistance. 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.What does 12.9 on a bolt head mean?
The 12.9 is the Class head marking under ASTM F568M standard for Bolts of a high grade (1220 MPa), being Alloy steel, quenched and tempered. ASTM F568M is an ASTM International standard for metric bolts, screws and studs that are used in general engineering applications.What does 10.9 on bolt head mean?
If you have ever looked a metric hex bolt you might notice the markings 8.8, 10.9 or 12.9 this does not mean grade 8,10 or 12. The grade 8.8 refers to the tensile strength which is generally 116,000 psi, grade 10.9 is generally 150,000 and grade 12.9 is generally 175,000 psi.How much weight can a 3/8 bolt hold?
SAE Bolt Strength| Bolt Safe Working Loads (lbs) (Safe tensile load at 6,000 psi load) (Safe shear strength at 7500 psi load) | ||
|---|---|---|
| BoltDia(in) | NF Thread Grade 2 Iron Bolt | |
| 1/4 | 200 | 370 |
| 5/16 | 340 | 575 |
| 3/8 | 510 | 830 |
What is the strongest bolt grade?
The strongest commercial-quality bolt is grade 8, marked by six raised dashes; its medium-carbon alloy steel has been quenched and tempered to achieve a tensile strength of 150,000 psi.What do you mean by tensile strength?
Tensile strength. The tensile strength of a material is the maximum amount of tensile stress that it can take before failure, for example breaking. There are three typical definitions of tensile strength: Yield strength - The stress a material can withstand without permanent deformation.What are the different grades of bolts?
The most common grading system used for bolts in the U.S. is the SAE system, but you can find metric grading systems as well. There are several grades of bolts but the three common grades for SAE are 2, 5 and 8. The common class (grades) for metric are 5.8, 8.8, 10.9 and 12.9. Each grade has a specific bolt strength.What does M stand for in bolt sizes?
metricWhat is a #10 screw?
The term 10-32 comes from Unified and American Screw Threads for Bolts, Nuts, and Machine Screws standards published by ANSI B1. 1-1974. The number “10” is simply a size designator with no numerical meaning. The number “32” refers to 32 threads per inch.What do bolt size numbers mean?
The number 1 or number larger than one, or number one or number larger than one followed by a fraction, is the diameter of the shaft. The number following the hyphen is the number of threads per inch; that is, the number of threads on the shaft itself, per inch of shaft length.What is tensile strength of a bolt?
The tensile strength of a grade 8 bolt is 150,000 pounds per square inch. Tensile strength is the maximum load in tension (stretching) that a part can carry without breaking.How can you tell if a bolt is metric?
The metric screw thread is identified by the capital letter M, followed by the nominal diameter. Metric threads are measured by the distance between two adjacent threads in millimeters (pitch). Threads on a standard (inch based) fastener are measured by counting the number of threads per inch.What is the difference between Grade 2 and Grade 5 bolts?
Grade 2 – bolts manufactured from low or medium carbon steel. Grade 5 – bolts manufactured from medium carbon steel. Grade 8 – bolts manufactured from medium carbon alloy steel.Are Grade 8 bolts the strongest?
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.How can you tell if a bolt is high tensile?
To identify this grade, look out for an '8.8' stamp or a set of three radial lines on the head of the bolt. Most often, customers looking for a high tensile bolt may just be looking for the 8.8 grade.How do you calculate tensile strength?
Divide the the applied load by the cross-sectional area to calculate the maximum tensile stress. For example, a member with a cross-sectional area of 2 in sq and an applied load of 1000 pounds has a maximum tensile stress of 500 pounds per square inch (psi).What is a high tensile strength?
Answered Mar 1, 2017. Tensile strength is the resistance of a material to breaking under tension. So, if an object has high tensile strength, it essentially means that it can resist a lot of tension before if breaks.What grade bolt has the highest shear strength?
They are commonly used at high stress points in connecting devices.- 12.9 Bolts. A 12.9 bolt is one of the highest grade of bolts produced.
- 12.9 Shear Strength. The minimum tensile strength of a 12.9 bolt is 1220 MPa.
