Method for eliminating flat coil defect of 590Mpa dual-phase steel hot coil

A dual-phase steel, grade technology, applied in the field of steel rolling, can solve problems such as flat coil defects

Active Publication Date: 2018-11-06
BEIJING SHOUGANG CO LTD
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Problems solved by technology

[0003] The present invention provides a method for eliminating the defects of 590Mpa-level dual-phase steel hot coils and flat coils, and solves the technical problem that 590Mpa-level dual-phase steel hot coils are prone to produce flat coil defects in the prior art

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  • Method for eliminating flat coil defect of 590Mpa dual-phase steel hot coil
  • Method for eliminating flat coil defect of 590Mpa dual-phase steel hot coil

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Embodiment Construction

[0022] The embodiments of the present application provide a method for eliminating defects in 590Mpa-level dual-phase steel hot coils, and solve the technical problem that 590Mpa-level dual-phase steel hot coils are prone to slab defects in the prior art.

[0023] In order to solve the above technical problems, the general idea of ​​the technical solution provided by the embodiments of the present application is as follows:

[0024] With the rolling process of hot-rolled strip steel, the temperature of the strip gradually decreases, and the austenite gradually transforms into other structures with lower transformation temperatures. Some of the structures have very low transformation temperatures, which will lead to A certain degree of phase change process is still maintained after coiling, resulting in a local uneven temperature field, resulting in uneven thermal expansion of the hot rolled coil due to uneven heating. The volume expansion of the outer ring of the hot coil is greater...

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Abstract

The invention belongs to the technical field of rolling steel, and discloses a method for eliminating a flat coil defect of a 590Mpa dual-phase steel hot coil. The method includes controlling the hotrolling finishing temperature according to the ferritiszation phase transition starting temperature of austenite to promote transformation of the austenite into ferrite; dividing a hot rolling coolingsection into a fast cooling section and a slow cooling section and cooling a hot rolled plate to the cold intermediate temperature in the fast cooling section to promote transformation of the austenite to the ferrite and promote transformation of the austenite to pearlite in the slow cooling section. According to the method, high proportion transformation of the austenite to the ferrite and the perarlite with higher stability in the rolling process is achieved by finishing temperature control and subsection cooling and cooling target temperature control, the ratio of the residual austenite isreduced, so that phase change expansion caused by transformation of the austenite to bainite in the hot coil cooling process and the corresponding flat coil defect are greatly reduced.

Description

Technical field [0001] The present invention relates to the technical field of steel rolling, in particular to a method for eliminating defects of 590Mpa-level dual-phase steel hot coil flat coils. Background technique [0002] As a kind of high-strength steel, 590Mpa grade dual-phase steel is characterized by the coexistence of ferrite and martensite, consisting of a soft ferrite phase and a hard phase of more than 20% martensite. After the rolled plate and coil are unloaded from the coiler, the hot coil shape is good at this time, but after a few days of storage, flat coils often appear, also known as the phenomenon of coil collapse. The steel coil changes from the round shape at the end of the coiling Oval shape, resulting in the subsequent cold rolling process unable to smoothly roll up production. Summary of the invention [0003] The invention provides a method for eliminating the defects of 590Mpa-level dual-phase steel hot coil flat coils, and solves the technical problem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/02C22C38/02C22C38/04
CPCC21D8/0226C21D2211/005C21D2211/009C22C38/02C22C38/04
Inventor 陈瑾焦会立商光鹏王明哲张誉公杨华辛艳辉刘丰
Owner BEIJING SHOUGANG CO LTD
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