本发明的一种屈服强度555MPa级高韧性管线钢及其生产方法，管线钢化学成分按质量百分数为：C：0.04～0.08％，Si：0.05～0.15％，Mn：1.0～1.2％，S：0.001～0.003％，P：≤0.008％，Als：0.02～0.05％，Nb：0.05～0.07％，Ti：0.015～0.025％，余量为Fe和不可避免杂质。制备时，将相应成分钢坯加热保温后，控制开轧温度和总累计压下，进行3道次粗轧，粗轧后对中间坯进行快速降温，再进行4道次精轧，控制开轧、终轧温度与总累计压下，获得7～15mm厚钢板，结合快冷与空冷降温，制得屈服强度555MPa级高韧性管线钢。本发明通过成分与工艺整体调配，制备出具有高强度，高低温韧性，低屈强比，易于成形，‑40℃下冲击吸收功可达380J的高韧性管线钢。

The invention relates to a 555MPa grade high toughness pipeline steel and its production method. The toughening chemical composition of the pipeline is C: 0.04 ~ 0.08%, Si: 0.05 ~ 0.15%, Mn: 1.0 ~ 1.2%, S: 0.001 ~ 0.003%, P: ≤ 0.008%, Als: 0.02 ~ 0.05%, Nb: 0.05 ~ 0.07%, Ti: 0.015 ~ 0.025%, residual Fe and inevitable impurities. Preparation, the corresponding components of billet heating, heat preservation, after open rolling temperature and the total cumulative pressure under control, 3 a roughing of roughing to rapid cooling of intermediate billet, after finishing to 4 passes, controlled rolling, finishing temperature and under the pressure of the total accumulated, get 7 ~ 15 mm thick steel plate, combined with the fast cooling and air cooling and cooling, produce yield strength 555 mpa grade and high toughness pipeline steel. The invention through the composition and process of the overall deployment, preparation of high strength, high and low temperature toughness, low flexure strength ratio, easy to form, 40℃ impact absorption power can reach 380J high toughness pipeline steel.