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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.
How do you identify a Grade 5 bolt?
Grade 5 bolts are case hardened, meaning the bolt has been heated enough to hardened the outside of the bolt but not enough to harden the inside portion. Grade 5 bolts are identified by 3 evenly spaced radial lines on the head.
What does 8.8 on a bolt mean?
A property class (PC) is the metric equivalent of a grade in inch series terminology. So, in English, a PC 8.8 bolt is a bolt with a nominal tensile strength of 800 MPa and a nominal yield strength that is 80% of the bolt’s nominal tensile strength, or 640 MPa.
What is the strongest bolt grade?
Grade 8 Bolts A grade 8 bolt is the highest grade SAE bolt. Grade 8 bolts have a minimum tensile strength of 150,000 PSI.
Is Grade 8 or 12.9 stronger?
A head with no markings is Grade 2, one with 3 lines spaced 120 degrees is Grade 5, and 6 lines spaced at 60 degree intervals is Grade 8.Table 1. Grade/Class Strength Metric Class 10.9 Similar to Grade 8. Metric Class 12.9 The highest metric class for strength, it exceeds Grade 8.
Whats stronger Grade 8 or Grade 5 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.
Is Grade 8 the strongest bolt?
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.
Does M8 mean 8mm?
Hole Sizes for Metric Bolts The defined diameter of metric bolts is actually slightly larger than the actual diameter of the bolt shaft. So an M8 bolt would have a shaft diameter that’s slightly under 8mm which means that the bolt should fit through an 8mm hole.
What do letters on bolts mean?
The markings can identify the standard to which the bolt was made. For instance, if a bolt head contains three radial lines, then it’s a Grade 5 bolt. If it contains five radial lines, then the bolt is Grade 8.
What does 4.8 mean on a bolt?
For example, a bolt with a performance grade of 4.8 means: The nominal tensile strength of bolt material is 400 MPa. The yield-strength ratio of bolt material is 0.8. The nominal yield strength of bolt material is 400 x 0.8=320 MPa.
Will Grade 8 bolts rust?
Grade 8 Steel Bolts 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. Grade 8 bolts that are not galvanized or plated with yellow zinc, however, are cheaper.
What grade are black bolts?
The colour black, referred to the fact the steel used to make the bolts was not finished with any corrosion protection, although zinc plating is a common finish for durability. The grade 4.6, relates to the strength of the bolts.
Are stainless bolts stronger than Grade 8?
Stainless steel bolts are rated for corrosion resistance. Bolt strength is rated in PSI (pounds per square inch). A stainless steel bolt has the same PSI rating as a grade 5 bolt (125,000 PSI). A grade 8 bolt has a stronger rating with a PSI of 150,000.
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.
How hard is a Grade 5 bolt?
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.
What is a Grade 10 bolt?
Class 10. This is a metric nut grading similar to the SAE grade 8 classification, which is used in conjunction with Class 10.9 bolts. This strength of nut is used in automotive, and structural industries, as well as in high temp applications.
Are stainless steel screws stronger than zinc?
Though some Zinc alloys can be very strong, overall stainless steel is stronger. However, zinc is a heavy element, and when alloyed with other metals it provides better corrosion resistance, stability, dimensional strength and impact strength.
What does 12.9 mean on a bolt?
High tensile Grade 12.9 Hex Bolts Grade 12.9 Hex Bolts are high strength bolts with 1100MPa minimum yield strength and 1220MPa minimum tensile strength.
Can you weld a Grade 8 bolt?
If you weld a Grade 8 bolt, you could soften it to the strength that Grade 5 possesses. No matter how little heat you use, heating the bolt in uncontrolled conditions will weaken it.
What does M12 mean?
The first half (M12), is the size measurement (metric) taken across the outside diameter of the thread (which in this case is 12mm). The second half is the thread pitch, which is the measurement of threads/inch (which in this case is 1.75).
What size nut fits a 8mm bolt?
Yes, most likely you want an M8 x 1.25 nut, assuming you want a nut that fits on the bolt nicely.
Is 5/16 The same as M8?
Well, quick answer is no. They are not the same and they are not interchangeable, although they can work under certain circumstances. The most important part is understanding the meaning of M8 and 5/16 to refer to the size of a metric screw or bolt, so then we can see why they aren’t the same thing!.
What are the different bolt grades?
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. No matter the system used to grade the bolts, the higher number means the stronger the bolt.
What does M14 mean on a bolt?
M14 means it is metric with a 14mm outside diameter.
How can you tell if a bolt is metric or standard?
Telling the difference between a metric and imperial bolt is easy. If the bolt has lines on the head its standard or imperial. If the bolt has numbers on the head then its metric.
