A grade 8 bolt is the highest grade SAE bolt. Grade 8 bolts have a minimum tensile strength of 150,000 PSI. As a comparison, the ASTM A325 bolt is roughly equivalent to the SAE grade 5. A grade 8 bolt would be one that meets ASTM A490 standards.
Is a 10.9 bolt stronger than grade 8?
Class 10.9 is stronger than class 8.8. It is commonly found in high strength automotive applications. Class 10.9 is similar to grade 8. A low carbon steel for general use.
Is a 12.9 bolt stronger than grade 8?
Inch fasteners—those commonly used in North America—will have a grade or ASTM rating. Property class (often just “class”) specifies metric fasteners.
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. |
Is there 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.
Is grade 8 or Grade 5 stronger?
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.
How strong is a Grade 8 bolt?
The nominal size of the grade 8 bolts can be from 1/4″ to 1 1/2″. The minimum yield strength of this grade bolt is 130,000 psi. A maximum of 120,000 psi of tensile force (proof load) can be applied to grade 8 bolts.
What grade bolt is the strongest?
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.
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.
What is harder than a grade 8 bolt?
Grade 9 bolts are ideal for heavy-duty applications and are also often used in heavy machinery such as bulldozers. Not only are these bolts considerably stronger than they’re grade 8 counterparts, but they are also considerably more resistant to corrosive elements as they are made with yellow zinc chromate.
What is the shear strength of a grade 8 bolt?
Shear strength of a grade 8 bolt in good condition is 91,000 psi.
What are grade 8 bolts used for?
Grade 8 fasteners are considered hi-strength / high-tensile fasteners and are used in many highly industrial applications such as machinery, valves, pumps, vessels, motors, tractors, and even tanks… Although it may seem like a bolt is a bolt, there are significant differences in how each bolt is manufactured.
What are the strongest screws?
The world’s strongest bolts are stainless. BUMAX® Ultra has proven itself as the world’s strongest bolt – in various highly-demanding critical fastener applications around the world where standard fasteners are simply inadequate.
How strong is grade A?
Grades of Bolts – Bolt Grade Markings & Bolt Strength Chart
| Bolt Grade Markings & Strength Chart – Metric Steel Bolts | ||
|---|---|---|
| Head Marking | Grade/Specification | Tensile Strength min (MPa) |
| Class 10.9 | 1040 (150,000 psi) | |
| Class 12.9 | 1220 (176,000 psi) | |
| Usually stamped A-2 or A-4 | A2 & A4 Stainless | 500 Min 700 Typical |
How hard is it to break a grade 8 bolt?
Determining the Load a Grade 8 Bolt Can Carry
For example, a 1/2-inch grade 8 bolt with 13 threads per inch has an effective stress-carrying cross section of 0.1419 square inches, so its breaking load would be 0.1419 (area subject to stress) x 150,000 (tensile strength) = 21,285 pounds.
Do Grade 8 bolts bend or break?
Stronger tensile strength and more brittle is pretty much standard as you make harder steel alloys. Yes, from the point a Grade 8 bolt starts to bend to the point it fails will be less than a Grade 5.
Are all Grade 8 bolts the same?
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 strong is a Grade 8?
150 ksi
Grade 8 (SAE J429) is a medium carbon alloy steel with one of the highest tensile strengths available. With a minimum tensile strength of 150 ksi and a minimum yield of 130 ksi, Grade 8 has a higher tensile and yield strength than other steel grades such as Grade 5 and B7.
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.
How much torque can a Grade 8 bolt take?
US Recommended Bolt Torque
| Size | Recommended Torque | |
|---|---|---|
| Grade 2 | Grade 8 | |
| 7/8″ | 129 | 454 |
| 1″† | 188 | 682 |
| * Sizes from #4 to #10 are in lb-in. Sizes from 1/4″ up are in lb-ft. † Fine thread figures are for 1″-14. Grade 2, 5, and 8 values are for slightly lubricated bolts. |
What is the hardest bolt you can buy?
Grade 8 is the hardest, Grade 5 is medium, and Grade 2 is the softest. This is the most common grade of steel fastener and is the least expensive. Grade 2 bolts have no head marking, although sometimes a manufacturer’s mark is present. This grade of bolt is made from low or medium carbon steel.
What does 8.8 on a bolt mean?
Class 8.8 – Medium carbon steel, quenched and tempered.
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