What role does ferrosilicon play in casting?

Ferrosilicon is used as an inoculant and a nodularizing agent in the cast iron industry. Cast iron is an important metal material in modern industry. Ferrosilicon is cheaper than steel, easy to melt and smelt, and has excellent casting properties and much better shock resistance than steel. In particular, ductile iron, its mechanical properties are at or close to those of steel. Adding a certain amount of ferrosilicon to cast iron can prevent the formation of carbides in iron and promote the precipitation and spheroidization of graphite. Therefore, in the production of ductile iron, ferrosilicon is an important inoculant (helping to precipitate graphite) and spheroidizing agent. .

Titanium has the strongest affinity with nitrogen, oxygen and carbon, and has a stronger affinity with sulfur than iron. It is a good deoxidizer and degasser and an effective element for fixing nitrogen and carbon. Although titanium is a strong carbide-forming element, it does not combine with other elements to form complex compounds. Titanium carbide has strong binding force, stability, and is not easy to decompose. Only when it is heated to above 1000 °C in steel can it slowly dissolve into solid solution. Before being dissolved, the titanium carbide particles have the effect of preventing grain growth. Since the affinity between titanium and carbon is much greater than that between chromium and carbon, titanium is often used to fix carbon in stainless steel to eliminate the depletion of chromium at the grain boundary, thereby eliminating or reducing intergranular corrosion of steel.

Titanium is also one of the strong ferrite forming elements, which strongly increases the A1 and A3 temperatures of the steel. Titanium can improve plasticity and toughness in ordinary low alloy steel. Increased strength as titanium fixes nitrogen and sulfur and forms titanium carbide. After normalizing, the grains are refined, and the precipitation to form carbides can significantly improve the plasticity and impact toughness of the steel. Titanium-containing alloy structural steels have good mechanical properties and process properties. The main disadvantage is that the hardenability is slightly poor. Titanium with a content of about 5 times carbon is usually added to high-chromium stainless steel, which can not only improve the corrosion resistance (mainly anti-intergranular corrosion) and toughness of the steel, but also organize the grain growth tendency of the steel at high temperature and improve the steel. welding performance.