Din933 Grade 8.8

Class 8.8 FULL THREAD Bolts

Description

A cap screw with metric thread pitch, threaded to the head, made from medium carbon steel and heat-treated. Grade-A bolts are the

preferred style for most applications. Grade-B bolts have looser tolerances and can be manufactured in a cold or hot-forging process

Applications/Advantages

Has greater tensile strength than Class 4.6, 4.8 and 5.8 cap screws. Being threaded to the head makes the part useful for mounting

motors to machinery. They are also used in automotive and truck repair.

Material

Class 8.8 cap screws can be made from a carbon steel with additives (such as Boron, Manganese or Chromium) which conforms to the following chemical composition-- Carbon: 0.15-0.40%; Phosphorus: 0.035% maximum; Sulfur: 0.035% maximum. In case of plain carbon boron alloyed steel with a carbon content of less than 0.25% (ladle analysis), the minimum Manganese content shall be 0.6%

Class 8.8 cap screws can be made from a carbon steel which conforms to the following chemical composition-- Carbon: 0.25-0.55%; Phosphorus: 0.035% maximum; Sulfur: 0.035% maximum

Heat Treatment

Core Hardness For dia less or equal to 16mm

Rockwell C22 - 32 (Vickers HV 250 - 320)

For diameters greater than 16mm

Rockwell C23 - 34 (Vickers HV 255 - 335)

Surface Hardness

Shall not be more than 30 Vickers points above the measured core hardness on the product

Proof Load For dia less or equal to 16mm

640 N/mm2 minimum

For diameters greater than 16mm

660 N/mm2 minimum

Tensile Strength For dia less or equal to 16mm

800 N/mm2 minimum

For diameters greater than 16mm

830 N/mm2 minimum

Elongation

12% minimum

Plating

Zinc,HDG,Plain,Dacrotized,Teflon,Colorful Dye