| 摘要 |
FIELD: processes. ^ SUBSTANCE: invention relates to field of thermo mechanical treatment. Steel blank, containing of, wt %: C - 0.15-0.20, Si 0.01- 0.15, inclusively, Mn - 0.05-1.0, Cr - 0.05-1.5, Mo - 0.05-1.0, Al ëñ0.10, V - 0.01-0.2, Ti - 0.002-0.03, B - 0.0003-0.005 and N - 0.002-0.01, one or more components selected from group: Ca, Mg and rare earth elements in specified amount, P ëñ 0.025%, S ëñ 0.010% and Nb ëñ 0.005%, at fulfillment of conditions: C+(Mn/6)+(Cr/5)+(Mo/3) ëÑ 0.43 and Ti ù N < 0.0002-0.0006 ù Si, the rest is Fe and admixtures, it is heated up to temperature 1000-1250C, it is rolled with finite temperature of rolling 900-1050C, it is tempered received steel pipe directly from the temperature not lower than transformation temperature Ar3, it is tempered in the range of temperatures from 600C up to transformation temperature Ac1 or after rolling received steel pipe is additionally heated in the range of temperatures from transformation temperature Ac3 up to 1000C in flow line, it is tempered up to temperature not lower than transformation temperature Ar3 and subject to abatement in the range of temperatures from 600C up to transformation temperature Ac1. ^ EFFECT: obtained pipe allows high strength and distinct, and also allows high ratio of yield limit to tensile strength and distinct resistance against PCC. ^ 2 cl, 1 ex, 4 tbl |
