An ultra-fast cooling process and coiling method for ultra-thick gauge hot-rolled coils

Abstract

An ultra-fast cooling process and coiling method for ultra-thick hot-rolled coils, which are characterized by the ultra-fast cooling process: 25.4mm thick, specification X70 strip steel is rolled out from the finishing mill and cooled to 500~ through the ultra-fast cooling section 550℃, followed by air cooling for 2 seconds, and then ordinary layer cooling to the coiling temperature of 400~450℃; the position control time of the pinch roller of the strip coiler is 0.03s, and the strip is fixed in advance; the strip head coiling is increased The number of turns is 5, and the auxiliary roller continues to be in contact with the head of the strip. When the load torque of the drum reaches 12.66KN·M, the auxiliary roller opens normally, so that the head is coiled tightly and the strip is close to the tail. When, increase the pressure of the assisting roller to 750KN to ensure stable coiling of the tail strip; the tailing time of the tail assisting roller of the ultra-thick specification strip is 8 to 12 seconds to fix the shape of the tail strip. The invention effectively improves the DWTT fracture toughness while ensuring the strength of the steel coil. The use of low-temperature coiling temperatures of 400 to 450°C has far exceeded the design capabilities of the equipment for coiling this type of steel, and is a major breakthrough in existing technology.

Description

technical field [0001] The invention belongs to the steel plate rolling technology in the field of processing, and in particular relates to an ultra-fast cooling process and a coiling method of an ultra-thick specification X70 hot-rolled coil. Background technique [0002] In order to further improve the efficiency of pipeline transportation, thick-gauge, high-grade steel, and high-pressure transmission have become a trend. From the perspective of pipeline construction and operating costs, thick-gauge welded pipes have a better market prospect. However, in the past, the coiling thickness of the hot-rolled coil production line was usually less than 22mm, and with the increase of the thickness of the steel plate, the unevenness of the surface and core of the hot-rolled coil steel plate increased. This is a technical problem in the development of thick-gauge pipeline steel. It has become a major bottleneck restricting the construction of energy pipelines. On the one hand, the p...

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Problems solved by technology

There are few reports on the production of X70 hot-rolled coils with ultra-thick specifications (25.4mm) at home and abroad

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