Abstract: The percentage of abnormal loss such as sticking steel and slag for 65 tconverter oxygen lance was larger in Tangshan Iron and Steel Company. The poor smelting slag and dry slag in smelt process was the main reason. Therefore, it was necessary to optimize the process parameter and oxygen nozzle life. The research results were shown as follows. For the optimized nozzle, the open blowing position of oxygen lance decreased by 100 mm and the process blowing position of oxygen lance decreased by 200 mm，the slag melting effect was good in smelting process. The variation of oxygen blowing time, smelting period and the oxygen consumption was little. The qualified rate of phosphorus content in steel increased 11.43 %. The FeO mass fraction in final slag decreased  0.25 %. The nozzle life was more than 200 heats, the steel consumption increased by 4.99 kg/t. The cold burden consumption increased 0.62 kg/t with the nozzle life increasing 50 heats. The FeO mass fraction in final slag increased 1.3  % with the nozzle life increasing 100 heats. Therefore, the economical nozzle life for 65 tconverter was 200 heats.

Key words: 65 t converter, nozzle of oxygen lance, process parameter, economical nozzle life