| 摘要 |
FIELD: metallurgy.SUBSTANCE: in compliance with first version, proposed method comprises cold rolling, steel coil annealing in bell-type furnace with protective atmosphere consisting of 93% Nand 7% Hto 670°C, curing at said temperature D, its decrease to final curing temperature of 650°C and curing at said temperature Dwith duration of curing defined by formulae: D= 0.5D, D= 0.5D, where Dis total duration of annealing. Note here that tempering is performed with 2.0-2.5%-reduction. In compliance with second version, proposed method comprises cold rolling, steel coil annealing in bell-type furnace with protective atmosphere consisting of 100% Nto final curing temperature of 670°C and holding thereat for time including hours from heating start to moment when difference in temperature by stand bench thermocouple and that of core makes 30°C. Note here that tempering is performed with 2.0-2.5%-reduction.EFFECT: higher quality of cold-rolled tube 09"?"2C-grade 2,5mm-thick steel.2 cl, 1 tbl |
