Screw and Bolt

The most widely used fastener in the world is undoubtedly screws and bolts. First, let's talk about the difference between screw and bolt.

If a nut is used in a connection, the cylindrical element with external threads is called a bolt.

Bolts (nut connection) are generally used to connect structural steels and mechanical parts. When the bolts are tightened, the connection is provided by the tensile tension they take on.

Bolts and screws are defined under many standards in the world according to their shape and strength. Before giving information about the most widely used standards in Turkey, let's briefly give information about the tensile strength of bolts.

In the DIN norm, bolt qualities are shown as 4.6, 8.8 (See Table 1) In this display, the first number gives approximately 1/10 of the breaking stress, and the product of the second number and the first number gives the yield stress.

Example: For 6.8 quality bolt

Tensile at break = 6X10=60 Kg/mm²

Yield stress = 8X6=48 Kg/mm²