Bolts are some of the most commonly used fasteners out there. They are almost always made of steel, and have external threads which allow them to be fastened into materials without a pre-drilled hole. Bolts are inserted to fasten materials together with the use of a nut attached to the end to hold it securely in place.
Bolts come in several different grades, which let you know how strong they are. The higher the grade, the higher the tensile strength of the bolt. This essentially means the higher the grade number, the higher the amount of pressure or weight that a bolt can withstand before it breaks.
Here’s a simple breakdown of some of the most common bolt grades which you might come across, as well as what they should be used for.
Grade 4.6
Grade 4.6 bolts are the lowest strength bolts readily available. They have a very low carbon content, which makes their tensile strength lower. Grade 4.6 bolts, or sometimes 4.8 bolts, are best used in projects which don’t need a lot of strength and don’t come under any real stress or impact. They are a good fit for low impact DIY jobs around the house.
Grade 5.6 and 6.6
Grade 5.6 and 6.6 bolts are slightly stronger than 4.6 or 4.8 bolts, but still have a relatively low tensile strength. This low tensile strength gives 5.6 and 6.6 bolts another useful property though as it means they are more flexible and malleable than higher grade bolts. This is particularly useful in projects which might be exposed to extreme weather and temperature fluctuations, as the bolts can bend and move with changing heat without just breaking.
Grade 5.6 and 6.6 bolts are also easier to install than higher grade bolts as they can be more easily manipulated without breaking.
Grade 8.8
Grade 8.8 bolts, and all bolts which are graded higher than them, are considered high tensile bolts, also sometimes referred to as structural grade bolts.
Grade 8.8 bolts are the most commonly used of all bolts as they offer a nice middle ground of strength, suitable for lots of different purposes.
Grade 10.9
Grade 10.9 bolts are most commonly used in car manufacturing due to their strength, durability and reliability.
Grade 12.9
Grade 12.9 bolts are even stronger, made of an extremely strong steel with very high levels of carbon. Grade 12.9 bolts are often used in engines as they can withstand so much force and pressure. They are also commonly used in military vehicles and planes as they have to be so strong and reliable whilst withstanding a lot of weight.
Grade 14.9
Grade 14.9 bolts are the strongest bolts available, and are mainly used in construction.
For more information or advice on which bolt grade is right for your needs, get in touch with our team of experts at Confast.