Mechanical properties of vanadium titanium gray cast iron brake drum

As shown in the figure, the hardness and tensile strength results of vanadium titanium gray cast iron with different components are compared. It can be seen that the hardness and tensile strength of 3# samples are higher than those of other samples. Compared with 1# and 2# samples, when the content of carbon and silicon increases slightly, the vanadium content increases from 0.14% to 0.22%, and the titanium content increases from 0.048% to 0.098%, the strength increases greatly from 266 MPa to 366 MPa, and the Brinell hardness increases from 205 to 263, This is because vanadium titanium element is a strong carbide forming element, which forms carbide particles as the crystallization core before Eutectic Transformation, refines graphite and strengthens the matrix structure.

At the same time, vanadium promotes the transformation of austenite to pearlite during the eutectoid transformation of castings, so that carbon exists in the form of cementite in pearlite, which eventually leads to the decrease of graphite content, the increase of pearlite content, the increase of carbide particles, and the increase of strength and hardness.

Compared with other samples, the strength and hardness of 4# samples are reduced because when the content of carbon, silicon, vanadium and titanium in 4# samples increases, thick and large graphite is formed in liquid state due to high carbon equivalent, which weakens the continuity of matrix and significantly reduces its mechanical properties.