What is the difference between Grade 2 and Grade 5 bolts?

Asked by: Chris Marley

Grade 2 is a standard hardware grade steel. This is the most common grade of steel fastener and is the least expensive. Except a possible manufacturer’s mark,Grade 2 bolts have no head marking. Grade 5 bolts are hardened to increase strength and are the most common bolts found in automotive applications.

Is Grade 5 bolt stronger than Grade 2?

Bolt Grade Markings



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 are Grade 5 bolts used for?

Grade 5. Manufactured from medium carbon steel and hardened for greater strength and durability, 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 or those that require medium strength.

Are Grade 2 bolts strong?

Grade 2 hex head bolts are made from low to medium strength carbon steel and offer a tensile strength of 60,000 to 74,000 psi, depending on the diameter.

What grade bolts are the best?

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 much weight can a grade 2 bolt hold?

Clamp Load

What grade are Home Depot bolts?

Grade 8 – Bolts – Fasteners – The Home Depot.

Are Grade 5 bolts rust proof?

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.

Are stainless steel bolts stronger than Grade 5?

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 the strongest stainless steel bolt grade?

BUMAX® Ultra – the world’s strongest bolt



Since its launch in 2014, the BUMAX® Ultra range has proven that it is capable of exceeding tensile strengths of between 1 500 to 1 700 MPa on various applications, with good corrosion resistance and an operating range of between -50 and 400°C.

How do you tell what grade a bolt is?

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.

What is the shear strength of a Grade 5 bolt?

For example, an SAE grade 5 hex cap screw has a specified minimum tensile strength of 120,000 psi. Therefore, for design purposes, its shear strength could be reasonably assumed to be 70,000 psi.”

What is M in bolt size?

The letter ‘M’ indicates that this bolt uses a metric thread. The number ‘8’ refers to the nominal diameter of the bolt shaft in millimeters. The number 1.0 is the thread pitch of the bolt, which is the distance between threads, in millimeters. And the final figure, 20, is the length in millimeters.

What is the difference between grade 2 and grade 5 titanium?

Grade 2 is “commercially pure” titanium and provides light weight and corrosion resistance but isn’t quite as strong as alloys like Grade 5. Grade 5, or Ti 6Al-4V, is titanium alloyed with 6% aluminum and 4% vanadium. The resultant alloy increases strength, as well as heat and corrosion resistance.

What is the strongest metal bolt?

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.

Are stainless steel bolts stronger than Grade 5?

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.

Which bolt is stronger Grade 8 or Grade 5?

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.

Are Grade 5 bolts rust proof?

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.

Will a Grade 5 bolt shear?

For example, an SAE grade 5 hex cap screw has a specified minimum tensile strength of 120,000 psi. Therefore, for design purposes, its shear strength could be reasonably assumed to be 70,000 psi.” Quick Tip: For instructions on how to calculate the strength for your bolt, see Calculating Yield and Tensile Strength.

What is the hardest grade of bolt?

Grade 8

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.

How do you tell what grade a bolt is?

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.

What grade are engine bolts?

Grade 5

Most automotive hardware is Grade 5 rated and is identified by three radial lines on the head of the bolt. They are made from a medium carbon steel that is quenched and tempered.

What does 4.8 mean on a bolt head?

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.

What does a 7 on a bolt mean?

The marks approximately correspond to the following property classes: Head Mark “4”: 4.6, 4.8, 5.6, 5.8, 6.8. Head Mark “7”: 8.8. Head Mark “8”: 9.8. #2.

How do you tell if a bolt is SAE or metric?

That the manufacturer puts on there so you can ignore all that the numbers you're looking for is what's important okay the first number is going to be the tensile strength of the bolt.

What does 8.8 mean on a bolt?

So, in English, a Property Class 8.8 bolt is a bolt with a nominal tensile strength of 800 MPa and a nominal yield strength that is 80% of that nominal tensile strength, so 640 MPa.

What does 3 lines on a bolt 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 is M in bolt size?

The letter ‘M’ indicates that this bolt uses a metric thread. The number ‘8’ refers to the nominal diameter of the bolt shaft in millimeters. The number 1.0 is the thread pitch of the bolt, which is the distance between threads, in millimeters. And the final figure, 20, is the length in millimeters.

Is Grade 8 or 8.8 Stronger?

Table 1.

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.

What is a Grade 5 nut?

Grade 5 Hex Nut, Plated. SAE J995 Grade 5 hex nuts are medium strength nuts manufactured from quenched and tempered medium carbon steel. Grade 5 hex nuts are available in diameters from 1/4″ through 1 1/2″ inclusive. Dimensional specifications are governed by ASME B18.