Abstract: In view of steel production capacity improvement and the transformation of big scrap steel ratio production mode, the requirement for ladle volume expansion was put forward. Through modeling and numerical calculation after ladle volume expansion，the temperature field and stress field were analyzed. After the expansion ladle reached the steady-state cycle, the ladle wall surface temperature reached the maximum value of 280 ℃,and the slag line position reached the maximum value of 310 ℃, which was in the safe range. The thickness of the working layer of ladle wall was reduced by 30 mm, the effective capacity of the ladle was increased from 277 t to 286 t, and the monthly production capacity was increased by 18 000 t. While promoting the improvement of steelmaking capacity, the power cost, refractory cost and labor cost were reduced, and the annual economic benefit was about 14 million yuan. 

Key words: ladle, expansion, effective volume, surface temperature, refractory