Manufacturing method of super-thick steel plate

A manufacturing method and technology of extra-thick plate, applied in the direction of temperature control, metal rolling, etc., can solve the problems of no deformation in the central area or the deformation cannot be effectively improved, the stress state in the middle is deteriorated, and the yield of the blank is reduced, so as to reduce the core area. Porosity level, the effect of reducing center porosity and reducing the amount of trimming

Active Publication Date: 2013-05-22
UNIV OF SCI & TECH BEIJING
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  • Description
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  • Application Information

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Problems solved by technology

[0009]4) Continuous casting slab rolling-heat treatment process: Chinese patent application CN 101831526A "A processing method for extra-thick plate" and literature "High-strength low-alloy STE460 special "Thick Plate Production Test Research" ("Wide and Heavy Plate", Issue 05, 1999) introduced the method of producing high-performance extra-thick plate by normalizing after rolling and accelerated cooling after normalizing. This method can effectively improve the quality of extra-thick plate. Low-temperature toughness, but results in reduced strength and high production costs
The remaining area in the thickness direction is not deformed, resulting in a "double drum" shape on the side of the rolled billet, such as Figure 2, if this shape is maintained until the finished product, it will reduce the yield of the blank
At the same time, the uneven deformation in the thickness direction will form compressive stress in the rolling direction in the hc thickness region of the surface layer, and tensile stress in the rolling direction will be generated in the middle, which will deteriorate the stress state in the middle
In some methods, the rolling of the vertical roller mill is used to partially eliminate the "double drum" shape, but the large width-thickness ratio of the extra-thick plate cannot be effectively improved without deformation or small deformation in the central area, so that the thermal deformation can improve the structure and performance. The effect is limited, so in the undeformed or small deformed central area, the deformation recrystallization, elimination of segregation, and reduction of porosity are far worse than those of the surface layer of the billet.

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  • Manufacturing method of super-thick steel plate
  • Manufacturing method of super-thick steel plate
  • Manufacturing method of super-thick steel plate

Examples

Experimental program
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Effect test

Embodiment 1

[0037] The Q345 continuous casting slab with a thickness of 150mm is used, and the thickness of the rolled product is 60mm. After the continuous casting billet is heated to 1180°C, after descaling by high-pressure water, it enters the forced cooling zone for cooling. The forced cooling method is air mist cooling, and the cooling rate on the billet surface is 10°C / s; the continuous casting with a thickness of 150mm is cooled once. When leaving the cooling zone, the surface temperature of the billet is about 600°C, and then the billet is air-cooled and returned to the temperature to raise the surface to 780-820°C, and then it is quickly sent to the rolling mill for rolling, and the reduction in each pass is 22-30mm. After 3 passes, the surface temperature of the steel plate is still lower than 880°C, and the billet is rolled to form an extra-thick plate with a thickness of 60 mm. Afterwards, it is cooled by the accelerated cooling device after rolling, and then it is stacked for...

Embodiment 2

[0040] The continuous casting Q460 billet with a thickness of 300mm is used, and the thickness of the rolled product is 120mm. After the continuous casting slab is heated to 1200°C, after being descaled by high-pressure water, it enters the forced cooling zone for cooling. Once cooled, the surface temperature of the billet is about 570°C when it leaves the cooling zone, and then the billet is air-cooled and returned to make the surface rise to 820°C-850°C, and then it is quickly sent to the rolling mill for rolling, and the reduction in each pass is 22 ~30mm, after 4 passes of rolling, the thickness of the intermediate billet is 200mm; the surface temperature of the steel plate is slightly higher than 880°C; at this time, the intermediate billet is cooled for the second time, and the billet surface temperature is about 570°C when it exits the cooling zone, after that The intermediate billet is air-cooled and returned to 800°C-830°C, and then immediately sent to the rolling mil...

Embodiment 3

[0043] 600mm thick welded composite billet, rolled finished product thickness 200mm. After the continuous casting slab is heated to 1200°C, it is descaled by high-pressure water after it comes out of the furnace, and then rolled directly. After rolling to a thickness of 400mm, it enters the forced cooling zone for cooling. The forced cooling method is water spray cooling. The cooling rate is 80°C / s; the continuous casting with a thickness of 400mm is cooled for the first time, and the surface temperature of the billet is about 570°C when it exits the cooling zone, and then the billet is air-cooled and returned to the temperature to raise the surface to 880±15°C, and then Quickly sent to the rolling mill for rolling, the reduction of each pass is 25-35mm, after rolling for 3 passes, the thickness of the intermediate billet is 300mm; the surface temperature of the steel plate is higher than 900°C; at this time, the intermediate billet is cooled for the second time , the surface ...

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Abstract

The invention discloses a manufacturing method of a super-thick steel plate (thickness is 60 millimeters) and belongs to the steel plate production field of metallurgical industry. The manufacturing method of the super-thick steel plate comprises the following steps: firstly, sending a plate blank which is heated to a certain temperature and removed an oxide scale to cooling space to conduct forced cooling, surface temperature cooling a phase transition temperature of the super-thick plate material above Ar 1, then by short time temperature returning, the surface temperature rising to the range between 780 DEG C and 880 DEG C, and sending the plate bland to a rolling mill to roll as soon as possible; when the surface temperature of the plate blank being higher than 880 DEG C, needing to conduct the forced cooling again, and then conducting the subsequent rolling. A cooling-temperature returning-rolling process can be repeated for many times if needed till rolling to the needed thickness of the super-thick steel plate. The manufacturing method of a super-thick steel plate can increase dependent variable of the central area by increasing temperature difference between a surface layer and the central area and has the advantages of being beneficial to refining central organization and improving impact toughness, beneficial to removing center porosity of the super-thick plate, and capable of reducing double strand shape on lateral sides of the super-thick plates. The manufacturing method of a super-thick steel plate further has the advantages of being saving in investment, and flexible to operate.

Description

technical field [0001] The invention belongs to the field of steel plate production in the metallurgical industry, and relates to a method for manufacturing an extra-thick plate with a thickness ≥ 60mm, aiming at solving the problem of low mechanical properties at the center of the rolled extra-thick plate, and the double-drum shape of the side of the steel plate during the rolling process. Edge folding problem caused by further rolling with double drum type. [0002] Background technique [0003] Under the requirements of large-scale and high-efficiency construction, a large single-weight, extra-wide, and extra-thick steel plate can reduce weld seams. In the construction of offshore platforms, high-strength and large-thickness steels are widely used, especially for structures such as lifting points, which require a thickness of 80mm; the steel used for racks in jack-up platform structures requires a yield strength level of 690MPa and a thickness of 80mm. 110~150mm. High-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B1/22B21B37/74
Inventor 余伟蔡庆伍陈银莉刘涛何春雨张立杰
Owner UNIV OF SCI & TECH BEIJING
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