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Ti microalloyed ultra-fine grain hot rolled steel at 700MPa class and production method thereof

A technology of microalloying and production methods, applied in the direction of temperature control, etc., can solve the problems of difficult implementation and high requirements for rolling equipment

Inactive Publication Date: 2009-09-09
GUANGZHOU PEARL RIVER STEEL & IRON
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this technology requires continuous low-temperature large deformation and ultra-fast cooling, which requires high rolling equipment and is difficult to implement.

Method used

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  • Ti microalloyed ultra-fine grain hot rolled steel at 700MPa class and production method thereof
  • Ti microalloyed ultra-fine grain hot rolled steel at 700MPa class and production method thereof
  • Ti microalloyed ultra-fine grain hot rolled steel at 700MPa class and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The production process of this embodiment specifically includes: electric furnace or converter smelting, refining, thin slab continuous casting (slab thickness 50-60mm), soaking, hot continuous rolling, laminar cooling, coiling and other processes.

[0036]The chemical composition weight ratio of molten steel after alloying treatment in the refining process is: C: 0.03wt.%, Si: 0.29wt.%, Mn: 2.10wt.%, P: 0.020wt.%, S: 0.008wt. %, Ti: 0.10wt.%, the rest is Fe and other unavoidable impurity elements.

[0037] Tundish molten steel adopts tundish covering agent to protect the molten steel surface. The addition scheme of the tundish covering agent is B775 for the long nozzle side, CA5 for the bottom layer on the stopper rod side, and FZ2 for the surface layer. The main components of various types of covering agents are shown in Table A.

[0038] Table A The main components of the covering agent in various models (%)

[0039]

[0040] The process is as follows:

[0041...

Embodiment 2

[0047] The production method of the present embodiment is basically the same as that of Example 1, and the different processes are as follows:

[0048] The chemical composition weight ratio of molten steel after alloying treatment in the refining process is: C: 0.07wt.%, Si: 0.10wt.%, Mn: 1.0wt.%, P: 0.008wt.%, S: 0.003wt. %, Ti: 0.14wt.%, and the rest are Fe and other unavoidable impurity elements.

[0049] The casting speed is maintained at 4.1m / min, the casting superheat is 30°C, the slab soaking temperature is 1150°C, the starting rolling temperature is 1080°C, the finishing rolling temperature is 930°C, the post-rolling cooling rate is 15°C / s, and the coiling temperature is 580°C. ℃.

[0050] See Table 2 for the mechanical properties of the 700MPa grade Ti microalloyed ultra-fine-grained hot-rolled steel sheet produced in Example 2.

[0051] The mechanical property of table 2 embodiment 2 steel plate

[0052] Steel plate thickness

[0053] The ferrite grain s...

Embodiment 3

[0055] The production method of the present embodiment is basically the same as that of Example 1, and the different processes are as follows:

[0056] The chemical composition weight ratio of molten steel after alloying treatment in the refining process is: C: 0.05wt.%, Si: 0.20wt.%, Mn: 1.5wt.%, P: 0.013wt.%, S: 0.005wt. %, Ti: 0.12wt.%, and the rest are Fe and other unavoidable impurity elements.

[0057] The casting speed is maintained at 4.5m / min, the casting superheat is 25°C, the slab soaking temperature is 1130°C, the starting rolling temperature is 1070°C, the finishing rolling temperature is 910°C, the post-rolling cooling rate is 25°C / s, and the coiling temperature is 620°C. ℃.

[0058] See Table 3 for the mechanical properties of the 700MPa grade Ti microalloyed ultrafine-grained hot-rolled steel sheet produced in Example 3.

[0059] The mechanical property of table 3 embodiment 3 steel plate

[0060] Steel plate thickness

[0061] The ferrite grain si...

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Abstract

The invention belongs to the technical field of high-strength weathering steel production, in particular discloses a Ti microalloyed ultra-fine grain hot rolled steel of 700MPa class and a production method thereof. The method utilizes the thin-slab continuous casting and rolling process to further perfect rolling and cooling control aspects by the readjustment of chemical compositions, is combined with the suitable control of grain ultrafining and TiC precipitation strengthening action, comprehensively improves the impact property and particularly improves the low-temperature impact toughness. The invention truly and reasonably matches with the strength and the toughness of the prior high-strength steel of 700MPa class, and the combination properties comprise: the yield strength is larger than or equal to 700 MPa, the tensile strength is larger than or equal to 750 MPa, the specific elongation is larger than or equal to 14 percent, and the impact absorbing energy Akv of a semi-size specimen (5*10*55mm) at 20 DEG C below zero is larger than or equal to 33 J. The production method enables the hot rolled steel to have high strength and high toughness and widens the range of practical application of the high-strength steel of 700MPa class.

Description

technical field [0001] The invention belongs to the technical field of production of hot-rolled high-strength steel plates, and in particular relates to a 700MPa Ti microalloyed ultra-fine-grained hot-rolled steel and a production method thereof. Background technique [0002] At present, 700MPa high-strength hot-rolled steel sheets have been widely used in automobiles, bridges, construction machinery and other fields. After doubling the strength of steel plates for various mechanical equipment and engineering structural parts, the thickness of the steel plates used can be greatly reduced, thereby reducing steel consumption and manufacturing costs. [0003] There are three main production methods for obtaining 700MPa grade hot-rolled steel sheets at home and abroad. The first type of precipitation strengthening based on nano-precipitates, adding alloy elements such as Ti and V that can form a large number of nanoparticles, and supplemented by elements that maintain the size ...

Claims

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Application Information

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IPC IPC(8): C22C33/00C22C38/14C21C7/00B22D11/111B22D11/16B21B37/74
Inventor 毛新平陈麒琳柴毅忠李轲新
Owner GUANGZHOU PEARL RIVER STEEL & IRON
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