10B21 is a cold heading steel, which belongs to the American standard material and is a carbon steel material, also known as boron steel. It has good plasticity and is not too strong, but it can withstand huge tensile forces and resist frequent impacts, meeting general performance requirements; at the same time, the heat treatment effect of 10B21 wire is obvious, and its performance is better than 20 steel. Its good plasticity makes it suitable for cold heading forming process, and it can manufacture mechanical parts with complex shapes and small and exquisite precision screws.

It is not allowed to produce 10.9-grade bolts, but it is allowed to produce bolts below 9.8-grade bolts

Chemical element content (%)

Specification：2.00~42.00mm

Application: Commonly used to manufacture fasteners such as bolts, nuts, screws or other structural parts, widely used in machinery manufacturing, automobile manufacturing, electrical and other fields.

10B21 What effect does the boron content of wire have on its performance?

Boron is an important alloying element in 10B21 wire.
-Boron can significantly improve the hardenability of steel, allowing the steel to obtain a deeper hardened layer during quenching. This can replace some of the rarer and noble metals such as nickel (Ni), chromium (Cr), molybdenum (Mo), etc. to a certain extent, thereby saving costs. By adding a trace amount of boron, the strength of 10B21 wire can be increased and the hardenability can be improved after heat treatment.

-Boron dissolving in solid solution can make the crystal lattice larger, thereby improving the strength. Boron in the grain boundaries can prevent the diffusion of recrystallization and can increase the thermal strength of steel.

It should be noted that the effect of boron will weaken or even disappear as the carbon content in the steel increases. When selecting boron-containing carburizing steel, it must be considered that after the part is carburized, the hardenability of the carburized layer will be lower than the hardenability of the core.