錬 (tempering, refine, drill, train, polish)

しかし、『百錬抄』および『玉葉』がその要旨を今日に伝えている。

However, the Hyakuren-sho and Gyokuyo have transmitted its essentials to the present day.

精錬用転炉の炉内に羽口から酸素富化した空気を吹き込む操業において、羽口煉瓦に与える機械的衝撃頻度を最小限に抑制して、羽口煉瓦の寿命を確保延命しながら、全羽口について打開作業を進める。

To progress a punching/opening work for all tuyeres, while ensuring and prolonging the service life of tuyere bricks, by minimizing frequency of mechanical impact shock applied to the tuyere bricks, in the operation for supplying oxygen-enriched air into a converter for refining from the tuyeres.