Method for preventing Q345B directly-loaded slabs from having cold-bending cracks

A Q345B and slab technology, applied in the field of preventing cold bending cracks of Q345B direct-loading slabs, can solve the problems of the specific morphology, inclusion type and distribution of modified MnS without specific research and lack of research, so as to reduce production costs and processes. And the operating conditions are simple and easy to achieve

Active Publication Date: 2013-12-25
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Although the modification technology of MnS is mentioned in the prior art, there is no specific study on the specific morphology, inclusion type and distribution of modified MnS
At the same time, there is also a lack of research on how to modify MnS to meet the needs of the direct packaging process.
Especially for the precipitation process and control method of NdC, the existing literature lacks relevant research

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] LF moves out molten steel [S]: 0.005%, rare earth addition amount: 140kg.

[0021] Argon blowing flow of argon station: 30Nm 3 / min, time: 5min.

[0022] Table 1 Example 1 contains chemical components

[0023] Re% Nb% C % Ti% 0.002 0.025 0.16 0.01

[0024] No gray large-sized sulfide inclusions can be seen under the metallographic examination, and no simple MnS inclusions can be seen under the scanning electron microscope.

[0025] No cracks were found after cold bending of the slab after rolling.

Embodiment 2

[0027] LF moves out molten steel [S]: 0.0035%, rare earth addition amount: 120kg.

[0028] Argon blowing flow of argon station: 40Nm 3 / min, time 4min.

[0029]

[0030] Table 2 Example 2 contains chemical components

[0031] Re% Nb% [ C % [ Ti % 0.0015 0.026 0.17 0.012

[0032] No gray large-size sulfide inclusions can be seen under the metallographic examination, and no simple MnS inclusions can be seen under the scanning electron microscope; no cracks can be seen after the slab is cold-bent after rolling.

Embodiment 3

[0034] LF moves out molten steel [S]: 0.0026%, and the amount of rare earth added is 100kg.

[0035] Argon blowing flow of argon station: 50Nm 3 / min, time 3min.

[0036] Table 3 Example 3 contains chemical components

[0037] Re% Nb% C % Ti% 0.0012 0.03 0.18 0.015

[0038] No gray large-size sulfide inclusions can be seen under the metallographic examination, and no simple MnS inclusions can be seen under the scanning electron microscope; no cracks can be seen after the slab is cold-bent after rolling.

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PUM

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Abstract

The invention provides a method for preventing Q345B directly-loaded slabs from having cold-bending cracks, and the method comprises the following steps: after LF (Ladle Furnace) refining and complete deoxidation alloying are performed, adding a rare earth alloy at an adding amount of 0.38-0.54 kg / t; controlling that in an LF evacuated liquid steel, the content of S is less than and equal to 0.005%, the content of Ti is greater than or equal to 0.01%, and [Nb]*[C] is greater than or equal to 0.004%; under the conditions that the argon-blowing flow of an argon station is 30-50 nm<3> / min and the argon blowing time is 3-5 min, carrying out argon-blowing and killing on the obtained object, and then placing the obtained product into a casting machine. The method disclosed by the invention is simple in process and operating conditions, and easy to implement; cold-bending cracks of Q345B directly-loaded slabs caused by slag inclusion defects can be effectively prevented, thereby improving the internal quality of slabs; problems existing in a direct loading process for micro alloyed steel are solved, and the production cost can be reduced.

Description

technical field [0001] The invention belongs to the technical field of smelting technology, and in particular relates to a method for preventing cold-bending cracks of Q345B direct-loading slabs. Background technique [0002] The continuous casting slab direct loading process refers to the hot slab of the casting machine at a higher temperature (A 1 ~A 3 ) directly into the heating furnace, and rolled after heating. During the direct assembly process, it was found that the cold bending performance of the Q345B steel rolled plate was not satisfactory after direct assembly, and cracks appeared. How to solve the cold bending cracks of the direct assembly rolled material has become the key to the realization of the direct assembly process. [0003] In the literature "Analysis of Causes of Cold Bending Cracking of Q345B Hot Rolled Strip Steel", the factors affecting the cold bending performance are analyzed. The paper believes that more inclusions and severe band structure are ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/04C21C7/06C21C7/072
Inventor 康伟廖相巍于赋志李超方恩俊康磊
Owner ANGANG STEEL CO LTD
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