A thick-gauge pipeline steel hot-rolled steel strip that is easy to coil and has excellent low-temperature performance and its manufacturing method

Abstract

The invention belongs to the technical field of controlled rolling and controlled cooling production of a hot continuous rolling steel belt, and discloses a thick pipeline steel hot continuous rolling steel belt easy to coil and excellent in low-temperature performance. The steel belt comprises, by mass, 0.030-0.080% of carbon, 0.05-0.25% of Si, 1.50-1.85% of Mn, 0.014% or less of P, 0.0030% or less of S, 0.04-0.08% of Nb, 0.10-0.35% of Cr, 0.010-0.025% of Ti, 0.06% or less of V, 0.20% or less of Mo, 0.15% or less of Cu, 0.20% or less of Ni and the balance Fe and unavoidable impurities. An ultra fast cooling method is adopted for rapid cooling, and then a plate coil is re-reddened to a high temperature to be coiled by using the temperature of the plate coil. The requirements for coiling equipment are relatively low, the coiling difficulty for the thick steel belt is lowered greatly, and the difficulty of uncoiling for downstream users caused by too large internal stress is lowered. The thick steel belt which is high in strength and excellent in low-temperature impact toughness and low-temperature drop press performance and a preparation method thereof are provided by matching proper components with a rolling process.

Description

technical field [0001] The invention relates to the technical field of controlled rolling and controlled cooling of hot continuous rolling steel strips, in particular to a thick-gauge pipeline steel hot continuous rolling steel strip which is easy to coil and has excellent low-temperature performance and a manufacturing method thereof. Background technique [0002] A large number of domestic and foreign pipeline projects have put forward the demand for hot-rolled steel strip products with large thickness, strength reaching X70 and above, and excellent low-temperature performance. At present, for X70 and above-grade thick-gauge pipeline steel hot-rolled steel strips, lower coiling temperatures are often used in actual industrial production, so as to obtain medium-temperature phase-transition structures with fully completed phase transitions, such as acicular ferrite, So as to obtain good strength and toughness matching and stable batch performance. Moreover, as the thickness...

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Problems solved by technology

[0004] The invention provides a thick-gauge pipeline steel hot-rolled steel strip that is easy to coil and has good low-temperature performance and a manufacturing method thereof, and solves problems in the prior art that the thick-gauge high-strength pipeline steel strip is difficult to coil and the internal stress of the steel coil is high. At the same time, it can also avoid the technical problems of unstable yield strength, low-temperature impact toughness and low-temperature drop weight performance of thick-gauge steel strip under the condition of high-temperature coiling process

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