Technique for manufacturing steel plate for 600MPa hydropower steel penstock

Abstract

The invention provides a technique for manufacturing a steel plate for a 600MPa hydropower steel penstock. The steel plate comprises the following chemical components in weight percentage: 0.06-0.09% of C, 0.20-0.40% of Si, 1.4-1.6% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.02-0.04% of Nb, 0.20-0.40% of Ni, 0.10-0.30% of Cr, 0.10-0.30% of Mo, 0.03-0.05% of V, 0.01-0.02% of Ti and the balance of Fe and inevitable impurities. Through a low-carbon microalloying design, a thermo-mechanical control process (TMCP) and a tempering process (T), a metallographic structure mainly based on a tempered bainite is ultimately obtained, thus achieving good matching of strength, plasticity, toughness and weldability, reducing the production cost and improving the production efficiency. The steel plate is mainly used for manufacturing the hydropower penstock.

Description

technical field [0001] The invention belongs to the field of low-alloy steels, and in particular relates to a production process of steel plates for 600MPa grade hydraulic steel pipes. Background technique [0002] Steel for hydropower is mainly used in the manufacture of auxiliary facilities such as water diversion pressure pipes, primary ribs, branch pipes, and volutes in plant dams. The steel plates are required to have sufficient strength, good plasticity, excellent toughness and welding performance. As the installed capacity and water head of hydropower stations become larger and larger, higher requirements are put forward for steel plates—the use of steel plates with higher strength, better low-temperature toughness, and better welding performance. At present, domestic hydropower stations Pressure steel pipes mainly use 600MPa-grade steel plates. Since GB19189-2011 "Quenched and Tempered High-Strength Steel Plates for Pressure Vessels" clearly stipulates that steel pla...

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Problems solved by technology

[0004] Chinese Patent Publication No. CN1932063A discloses a "High Strength Low Welding Crack Sensitivity Thick Steel Plate and Its Production Method", which is produced by online direct quenching + offline tempering process Steel plates with tensile strength ≥ 610MPa have the characteristics of simple production process and low cost. The disadvantage is that online direct quenching requires high performance of cooling equipment and cannot be widely promoted.

[0005] Chinese Patent Publication No. CN101096738A discloses "Steel Plate with Low Welding Crack Sensitivity and Its Production Method", the mass fraction of its chemical composition is: C≤0.07%, Si: 0.15 ~0.40%, Mn: 1.00~1.60%, P≤0.015%, S≤0.010%, Cr: ≤0.30%, Ni: ≤0.50%, Mo≤0.30%, Cu≤0.30%, V: ≤0.08%, Nb : ≤0.08%, Ti: 0.010~0.020%, B≤0.003%, using TMCP + tempering process to produce steel plate with tensile strength ≥610MPa, the disadvantage is that the three-stage controlled rolling process is adopted, which increases the rolling capacity The load requires the rolling mill to have a large torque and rolling force

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