PIPELINE SHEET STEEL OF CLASS X80 WITH HIGH EQUIVALENT CONTENT OF CARBON AND HIGH IMPACT STRENGTH AT LOW TEMPERATURES FOR USE IN BENT PIPES AND METHOD OF PRODUCTION THEREOF

摘要

FIELD: metallurgy.;SUBSTANCE: invention relates to metallurgy, particularly, to production of pipe sheet steel of strength class X80 used for production of bent pipes. Steel has the following chemical composition, wt. %: C: ≤ 0.10; Mn: 1.55–1.90; Si: ≤ 0.45; S: ≤ 0.001; P: ≤ 0.010; Nb: 0.045–0.08; Ti: ≤ 0.015; V: ≤ 0.008; Al_t: ≤ 0.06; N: ≤ 0.0040; O: ≤0.004; Mo: ≤ 0.40; Cu: ≤ 0.30; Ni: 0.20–1.5; Cr: ≤ 0.35; Mo+Cu+Ni+Cr ≤ 1.5; Ceq: 0.35–0.53 %; Pcm: 0.17–0.27 %; balance are Fe and constant impurity elements.;EFFECT: steel has high mechanical properties and high impact viscosity at low temperatures.;4 cl, 2 dwg, 3 tbl