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. Grade 9 bolts are ideal for heavy-duty applications and are also often used in heavy machinery such as bulldozers.

Besides, What is strength of bolt?

The yield strength of a bolt can be defined as the tensile force that will produce a certain amount of permanent deformation within a specific fastener. … Proof load is the limit of the elastic range of the bolt. Designing for the use of bolts according to proof load can help prevent plastic deformation.

Keeping this in mind, Are bolts hardened steel? This is a standard hardware grade steel. It is the cheapest and the most common grade of steel fastener. Unless there is a manufacturer’s mark, Grade 2 bolts will have no head markings. These are hardened to increase the strength and are most commonly found in automotive applications.

What is the strongest bolts 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.

What is the shear strength of a bolt?

The shear strength of a bolt is a measurement of the minimum amount of force needed to break the bolt into two pieces. The shear strength of a metal bolt is approximately 0.6 times its tensile strength. A bolt commonly shears where its head meets the threads.

What is bolt shear strength?

The shear strength of a bolt is a measurement of the minimum amount of force needed to break the bolt into two pieces. The shear strength of a metal bolt is approximately 0.6 times its tensile strength. A bolt commonly shears where its head meets the threads.

What does 8.8 mean on a bolt?

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.

How do you find the bearing strength of a bolt?

Bearing strength at bolt holes. At edges, Lc = 1.25 – hole diameter/2 = 1.25 – (3/4 + 1/16)/2 = 0.844 in. At other holes, s = 2.5 in, Lc = 2.5 – (3/4 +1/16) = 1.688 in. At edges, Lc = 1.25 – hole diameter/2 = 1.25 – (3/4 + 1/16)/2 = 0.844 in.

Are bolts case hardened?

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 kind of steel are bolts?

Carbon steel is the most common type of steel used in fastener production. Grades 2, 5, and 8 are typically the standard for carbon-steel based screws and bolts, with alloyed carbon steel being a higher-end variation on these metals.

What is the hardest bolt grade?

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.

Is there a grade 12 bolt?

Do Grade 12 bolts exist? No SAE Grade 12 exists. On the metric side, there are no grades, only property classes. The highest strength property class is 12.9 which requires a tensile strength of approximately 1200 MPa and a yield strength of about 1080 MPa.

What is the strongest nut and 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.

How do you calculate shear load on a bolt?

Calculate the shear stress using the formula F ÷ (d x (t1+t2)) if the bolt connects two plates where each plate is subjected to a force (F) in opposite directions. This load case is called single shear.

How do you calculate shear strength?

RE: Calculating Shear Strength of a Material? Ultimate shear strength is commonly estimated to be 0.6*UTS. The 0.57*TYS is probably taken from the von Mises/distortion energy/octahedral shear stress criterion, and it should be stated as shear yield strength = 0.577*tensile yield strength.

What is the best bolt for shear strength?

Grade 8 bolts exhibit greater tensile, yield, and shear strength as well as greater fatigue resistance and, just as important, are capable of greater torque specs and therefore much greater pre-load and clamping strength.

How do you calculate bolt shear force?

Use a ruler or digital calipers to measure the thickness of each part of the bolted assembly. Label each thickness t1, t2, t3, and so on. Calculate the shear stress using the formula F ÷ (d x (t1+t2)) if the bolt connects two plates where each plate is subjected to a force (F) in opposite directions.

What is the difference between 8.8 and 10.9 bolts?

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.

What’s the difference between 4.6 and 8.8 bolts?

Category 4.6/S refers to commercial bolts of Property Class 4.6 conforming to AS 1111.1 tightened using a standard wrench to a ‘snug-tight’ condition. Category 8.8/S refers to any bolt of Property Class 8.8, tightened using a standard wrench to a ‘snug- tight’ condition in the same way as for category 4.6/S.

What is class 8.8 steel?

Mechanical properties

Grade, material & condition Nominal thread diameter size range [mm] Tensile strength (min) [MPa]
Class 8.8 Medium carbon steel; quench and tempered 17–72 830
Class 8.8

low carbon


Low carbon boron steel

; quench and tempered
Class 8.8.3 Atmospheric corrosion resistant steel; quench and tempered

How is bolt torque calculated?

The widely recognized engineering formula, T= K x D x P (to be explained later in this article), was used to provide the chart’s values, but it must be understood that every bolted joint is unique and the optimum tightening torque should be determined for each application by careful experimentation.

What is bearing strength of a material?

In essence, bearing strength is the maximum stress load that the unit can “bear” or hold before the structure fails. But bearing strength can also be measured in terms of tensile, compression, and flexural strength, plus bearing hardness.

What is a case hardened bolt?

The case hardened or through hardened grade 8 bolt has been really cooked. Not only is the outside crispy, but you would be hard pressed to put a fork in it as it has been hardened by heat treatment all the way through. It is made with medium alloy steel.

Are bolts tempered?

Grade 8 alloy steel bolts have a tempering temperature of 800° F, which allows their use at higher temperatures.

Are all bolts heat treated?

Since nearly all fasteners are heat treated, it is useful to understand the types of heat treatments used in the fastener industry. It is important to note that the heat treatment of steel and alloy fasteners is different than for aluminum fasteners.