Continuous casting production technology for producing wide and thick-cross section pipeline steel casting blank

Abstract

The invention discloses a continuous casting production technology for producing a wide and thick-cross section pipeline steel casting blank. The continuous casting production technology comprises thefollowing steps of (1) online baking-(2) casting process-(3) employing overall-protection casting during continuous casting-(4) main components of casting powder laid on the surface of molten steel in a crystallizer-(5) steel casting process. Aiming at the technical problems of flow field bias and slag entrapment of the crystallizer, low flaw detection eligibility rate of a casting blank rolled steel plate, and the like when wide and thick-cross section pipeline steel is cast, the invention provides the continuous casting production technology for producing the wide and thick-cross section pipeline steel casting blank in order to overcome the disadvantages of the prior art; by adjusting an upper nozzle structure and a lower nozzle structure of a tundish and the viscosity of the casting powder, the 'slag entrapment' phenomenon in the crystallizer is reduced, and the cleanliness of the casting blank is increased, and then, the flaw detection eligibility rate of the rolled steel plate and rating qualification rate of inclusions are increased.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a continuous casting process, in particular to a continuous casting production process for producing steel slabs for pipelines with wide and thick sections. Background technique [0002] The China-Russia East Natural Gas Pipeline (referred to as the China-Russia East Line) is a long-distance and large-capacity natural gas pipeline jointly constructed by China and Russia. Smog has a positive and far-reaching impact on improving people’s quality of life and achieving sustainable social and economic development. Because the pipeline is laid in Northeast China, the annual minimum temperature is as low as -45°C, so the requirements for low-temperature toughness of the pipe are very high. The specification and steel grade are 25.7 / 30.8mm×OD1422mm X80M, and the steel plate 25.7×4365mm / 30.8mm×4350mm×12150mmX80M is a milestone product in the development of pipeline steel. [0003] In or...

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Problems solved by technology

[0003] In order to meet the rolling compression ratio requirements of pipeline steel plates, it is necessary to use 260 / 320mm×2770mm pipeline steel slabs for rolling. The casting slabs of this specification are difficult to produce in continuous casting production. The original continuous casting production process uses a tundish upper nozzle The structure is straight, and the lower nozzle structure is double-sided. When casting wide and thick slabs, after the molten steel enters the mold through the upper and lower nozzle channels, it is easy to form a "bias" in the flow field of the mold, resulting in the distribution of mold slag liquid slag Unevenness, slag entrainment is very easy to occur, the liquid slag is not easy to float up and remove after being involved in the molten steel, and is captured by the primary slab shell, forming inclusion defects close to the surface of the slab, resulting in passing the flaw detection of the steel plate after rolling the cast slab of wide and thick section pipeline steel The problem of low rate and low pass rate of inclusion rating

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