Titanium's role in steel includes deoxidizing, reducing grain growth, and stabilizing austenitic stainless steels.

• A. Deoxidizes steel and helps limit grain growth
• B. Increases carbon content to form cementite
• C. Increases manganese content
• D. Has no effect on grain structure

Answer: (A)

Titanium is valued in steelmaking both for removing oxygen and for controlling grain size. As a deoxidizer, titanium scavenges oxygen to form stable Ti oxides, which are removed with the slag, leaving cleaner steel. That same titanium, dissolved in the iron, forms stable precipitates (carbides or nitrides) during heating, and these particles pin grain boundaries. By hindering grain boundary movement, they slow grain growth, especially during high-temperature processing and welding.

In austenitic stainless steels, titanium also helps stabilize the structure by binding with carbon and nitrogen as TiC or TiN, which prevents chromium carbide from precipitating at grain boundaries. This maintains chromium in solution and preserves corrosion resistance.

So the statement that titanium deoxidizes steel and helps limit grain growth best describes its practical role. It does not act by increasing carbon content to form cementite, nor by increasing manganese, and it does affect grain structure through precipitation that halts grain growth.