Is Grade 8 or 8.8 stronger?

Synopsis: The similarity in names is purely coincidental and the Metric Class 8.8 is not as strong as the Inch Grade 8. As you can see from the table below, a metric Class 8.8 is the equivalent of a Grade 5, not a Grade 8.

What is grade 8.8 steel equivalent to?

Class 8.8 is approximately equivalent to SAE J429 Grade 5, ASTM A449 & IFI 100/107 Gr. B (locknuts only) Class 10.9 is approximately equivalent to SAE J429 Grade 8 and ASTM A354 Grade BD & IFI 100/107 Gr.

Is Grade 8 the strongest bolt?

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 there a higher grade than Grade 8?

Bolt Grade Numbers

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, the higher number means the stronger the bolt.

Is Grade 8.8 or 12.9 stronger?

The mechanical difference between the 12.9 and 8.8 is yield strength (roughly 90% of 1200 MPa vs 80% of 800 MPa). That means the 12.9 can be stretched further (i.e. torqued to some higher value) before it yields, which of course increases the clamp force.

Strongest Bolt? Grades Explained & Dyno Tested For Science

Is 8.8 equivalent to Grade 8?

The similarity in names is purely coincidental and the Metric Class 8.8 is not as strong as the Inch Grade 8. As you can see from the table below, a metric Class 8.8 is the equivalent of a Grade 5, not a Grade 8.

Is a 10.9 bolt stronger than Grade 8?

They are very similar. Grade 8 is an SAE designation. 10.9 is a metric designation. But the two systems yield the same holding strength.

When not to use Grade 8 bolts?

Compatibility: Grade 8 fasteners may not be compatible with all materials. For example, if they are used to fasten soft materials such as aluminum or brass, the threads may strip or the fasteners may fail due to the lack of sufficient gripping power.

Which is stronger 8.8 or Grade 5?

So a Property Class 8.8 bolt or screw is a medium-strength fastener that's roughly the same strength as an SAE J429 Grade 5 fastener.

What does TBF 8.8 mean on a bolt?

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.

Is a 12.9 bolt stronger than Grade 8?

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.

Are titanium bolts stronger than Grade 8?

Titanium. Made from aircraft grade titanium 6AL-4V (grade 5), the outstanding benefits are that we roll the threads to produce greater fatigue strength and reduce galling. These bolts are in excess of 120,000psi ultimate tensile strength, suitable to replace both Grade 5 and Grade 8 steel bolts.

What is the strongest grade bolt you can buy?

Commercial-grade 8 bolts are the strongest option available. They're made from medium carbon alloy steel and have markings that include six raised dashes. The psi of the bolt is 150,000, meaning that it can withstand great deals of pressure because of the way it was quenched and tempered.

Are 8.8 bolts strong?

In terms of strength, 8.8 is equivalent to Grade 5, 10.9 is equivalent to grade 8. There are also 12.9 metric bolts, which are a little stronger than 10.9, and are a higher alloy steel.

What is the strength of a 8.8 bolt?

In the case of a 8.8 grade bolt the first figure signifies that the Tensile Strength is at least 800MPa. The second figure signifies that the fastener will begin to yield at 80% of the Ultimate Tensile Strength, i.e. at least 640MPa.

Can you weld grade 8.8 bolts?

The mechanical properties of 8.8 bolts are produced by heat treatment. Consequently, the application of heat during the welding process will change the mechanical properties to such an extent that the bolt will no longer conform to the property class 8.8. The rule is that heat treated bolts should never be welded.

Will a Grade 8 bolt break?

Grade 8 bolts are designated as a 150 ksi. This means its tensile strength or the resistance it has before it is subject to breaking under tension is equal to 150,000 lbs. per square inch. In comparison, a Grade 5 bolt is weaker as its tensile is 120 ksi, placing it at 120,000 lbs.

Can you cut a Grade 8 bolt?

The hardness rating of a bolt is indicated on the head. This is a Grade 8 bolt, which is harder to cut than a Grade 5 or Grade 3 bolt. The best way to shorten a bolt is to thread a nut equal in size to the hexagon of the bolt. This is a 7/16-inch hex head.

Will Grade 8 bolts rust?

Black oxide is in fact a controlled chemical oxidation process that equates to black rust. If you ever buy grade 8 bolts or screws that are black oxided, you will notice that they are often oil coated. This is to prevent them from rusting! So yes, they will rust.

Why are Grade 8 bolts yellow?

Steel fasteners are commonly available in 4 grades: Grade 2, Grade 5, Grade 8, and Alloy Steel. 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.

Can I drill a hole in a Grade 8 bolt?

Grade 8 bolts are softer than Rc 40 and normally present no problem in drilling. Drill thru with a 1/8" drill first to lessen the required thrust on the larger drill. I'd use 135* split points for all drilling. Cobalt wouldn't hurt if you have them handy, but HSS should work fine.

Are higher grade bolts more brittle?

2) The material must be susceptible - generally the higher the tensile strength/hardness of the fastener, the greater is the risk from this type of brittle fracture.

Is a Grade 5 or Grade 8 bolt 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.

What grade 8.8 bolt for suspension?

SAE Grade 5 (Metric 8.8): Made out of quenched and tempered medium carbon steel, Grade 5 bolts are significantly stronger than Grade 2 and have proof of load around 600M Pa. This means that they are used on more substantial components like key brackets, steering and suspension components.