Low-alloy steel hot-rolling coil plate of which yield strength is more than 345Mpa, and preparation method of low-alloy steel hot-rolling coil plate

A low-alloy steel and yield strength technology, which is applied in the field of hot-rolled low-alloy steel coils with a yield strength of 345Mpa or more and its preparation, can solve the problems of uneven performance of steel strips and difficulty in precise control of hot-rolling temperature, and achieve Reduce smelting costs, improve center segregation, and prevent the tube from being out of round

Active Publication Date: 2015-01-07
LAIWU STEEL YINSHAN SECTION CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The higher the content of Mn element, the greater the impact on the segregation of the continuous casting slab, and the Mn element is still a harden

Method used

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  • Low-alloy steel hot-rolling coil plate of which yield strength is more than 345Mpa, and preparation method of low-alloy steel hot-rolling coil plate
  • Low-alloy steel hot-rolling coil plate of which yield strength is more than 345Mpa, and preparation method of low-alloy steel hot-rolling coil plate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1. The chemical composition percentage of steel is as follows:

[0026] C: 0.16%, Si: 0.14%, Mn: 0.49%, P: ≤0.021%, S: ≤0.011%, Ti: 0.043%, and the rest is Fe element and unavoidable impurities.

[0027] 2. The production process of Q345B low-alloy hot-rolled coil, taking the specification of 5.75mm×1150mm as an example:

[0028] (1) Production process

[0029] KR hot metal pretreatment-BOF-LF-CC-slab heating-rough rolling-finish rolling-coiling;

[0030] (2) Preparation process

[0031] KR molten iron pretreatment controls the sulfur content of the molten iron below 0.010%, and the temperature of the molten iron is 1230°C. The basicity of converter slag is controlled at 3.0-3.5, and the temperature of steel discharge is based on the carbon drawing temperature. When the carbon drawing temperature is equal to the temperature of steel discharge, the steel discharge operation can be carried out. The slag blocking method of tapping adopts a sliding plate to block slag, a...

Embodiment 2

[0036] 1. The chemical composition percentage of steel is as follows:

[0037] C: 0.17%, Si: 0.18%, Mn: 0.52%, P: ≤0.017%, S: ≤0.006%, Ti: 0.036%, and the rest is Fe element and unavoidable impurities.

[0038] 2. The production process of Q345B low-alloy hot-rolled coil, taking the specification of 9.75mm×1350mm as an example:

[0039] (1) Production process

[0040] KR hot metal pretreatment-BOF-LF-CC-slab heating-rough rolling-finish rolling-coiling;

[0041] (2) Preparation process

[0042] KR molten iron pretreatment controls the sulfur content of the molten iron below 0.010%, and the temperature of the molten iron is 1239°C. The basicity of converter slag is controlled at 3.0-3.5, and the temperature of steel discharge is based on the carbon drawing temperature. When the carbon drawing temperature is equal to the temperature of steel discharge, the steel discharge operation can be carried out. The slag blocking method of tapping adopts a sliding plate to block slag, a...

Embodiment 3

[0047] 1. The chemical composition percentage of steel is as follows:

[0048]C: 0.19%, Si: 0.14%, Mn: 0.54%, P: ≤0.015%, S: ≤0.005%, Ti: 0.033%, and the rest is Fe element and unavoidable impurities.

[0049] 2. The production process of Q345B low-alloy hot-rolled coil, taking the specification of 11.5mm×1350mm as an example:

[0050] (1) Production process

[0051] KR hot metal pretreatment-BOF-LF-CC-slab heating-rough rolling-finish rolling-coiling;

[0052] (2) Preparation process

[0053] KR molten iron pretreatment controls the sulfur content of molten iron below 0.010%, and the temperature of molten iron is 1245°C. The basicity of converter slag is controlled at 3.0-3.5, and the temperature of steel discharge is based on the carbon drawing temperature. When the carbon drawing temperature is equal to the temperature of steel discharge, the steel discharge operation can be carried out. The slag blocking method of tapping adopts a sliding plate to block slag, and the ta...

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PUM

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Abstract

The invention belongs to the technical field of iron and steel, and particularly relates to a low-alloy steel hot-rolling coil plate of which the yield strength is more than 345Mpa, and a preparation method of the low-alloy steel hot-rolling coil plate. The low-alloy steel hot-rolling coil plate of which the yield strength is more than 345Mpa comprises the following chemical components in percentage by weight: 0.14%-0.20% of C (carbon), 0.10%-0.40% of Si (silicon), 0.20%-0.90% of Mn (manganese), S (sulphur) which is smaller than or equal to 0.030%, P (phosphorus) which is smaller than or equal to 0.030%, 0.015%-0.060% of Ti, and the balance of iron and inevitable impurities. The coil plate disclosed by the invention has the advantages that compared with an ingredient system in which the manganese content is more than 1.0%, the cost of producing Q345B hot-rolling coil plates by using the production technology is reduced, the center segregation of Q345B continuous casting billets is improved, the internal organization of steel bands is improved, and the performance of steel band pass is stabilized.

Description

technical field [0001] The invention belongs to the technical field of iron and steel. Specifically, the invention relates to a low-alloy steel hot-rolled coil with a yield strength of 345Mpa or more and a preparation method thereof. Background technique [0002] The main components of Q345B low-alloy hot-rolled coils in most manufacturers are C, Si, Mn, P, and S, and the content of Mn is higher than 1.0%. Since 2008, most iron and steel enterprises have experienced losses, and the pressure on smelting costs is huge, among which the cost of Mn alloys accounts for a large part of Q345B production. Cost reduction has become the first goal of iron and steel enterprises. [0003] Element segregation refers to the uneven distribution of trace elements in steel, some enriched and some very few, resulting in uneven material of steel, which in turn produces defects and affects its mechanical properties, such as bearing capacity and plastic properties. The higher the content of Mn ...

Claims

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Application Information

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IPC IPC(8): C22C38/14C22C33/04C21D8/02
CPCC21D8/0205C21D8/0226C22C33/04C22C38/02C22C38/04C22C38/14
Inventor 郝帅李四军孙建卫张桂南刘曌娲杨旭赵培林
Owner LAIWU STEEL YINSHAN SECTION CO LTD
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