| 摘要 |
FIELD: metallurgy.SUBSTANCE: steel slab is heated, its composition including in wt %: Si - 0.8-7, acid-soluble Al - 0.01-0.065, C - 0.085 or less, N - 0.012 or less, Mn - 1.0 or less, S - equivalent to Seq. defined by equation "Seq.=[S]+0.406·[Se]", where [S] is S content, [Se] is Se content of 0.015 or less, Fe and unavoidable impurities making the rest. Slab is subjected to hot rolling, annealing, cold rolling, decarburising annealing for primary recrystallisation, coat application for secondary recrystallisation. Between decarburising annealing and secondary recrystallisation, nitriding processing (step S7) is performed at final annealing. Final temperature of hot rolling (step S7) makes 950°C or lower. Note here that sheet cooling is started 2 seconds after final rolling while coiling is made at 700°C or lower. Rate of hot-rolled sheet strip heating to 800°°C-1000°C in annealing (Step S3) makes 5°C/s. Cooling rate in period from termination of final rolling to start of coiling makes 10°C/s or higher.EFFECT: higher density of magnetic flux.9 cl, 3 dwg, 4 tbl |
