Converter pretreatment and cold charging and heating method for high-carbon and high-alloy continuous casting slab

A heating method and continuous casting slab technology, applied in the field of metallurgy, can solve problems such as unreasonable connection of continuous casting slab hot delivery and hot charging process, casting slab fracture, oxidative decarburization of corners, etc., to achieve the suppression of brittle structure and oxidative decarburization The formation of the carbon layer, the change of the organizational form, and the effect of ensuring smooth production

Active Publication Date: 2022-05-03
PANGANG GRP XICHANG STEEL & VANADIUM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, due to the unreasonable connection of the continuous casting slab hot delivery and hot charging process, some high-carbon and high-alloy slabs cannot be hot-sent and hot-charged, and fractures often occur in the conventional stacking and furnace charging process
At the same time, the hardenability of high-carbon and high-alloy steel is better. During the conventional stacking cooling process of cast slabs, the cooling rate at the corners is higher than that at the center. High cooling rates are prone to produce brittle structures, and the internal stress of these brittle structures is relatively high. Large, it is easy to produce microcracks when subjected to external influences; once microcracks occur, the internal stress is more likely to concentrate at the microcracks; at this time, the microcracks expand rapidly and eventually lead to the breakage of the slab
[0004] In addition, during the heating process of hot rolling, the temperature rise rate of the corners is faster than that of the center, and serious oxidation and decarburization occurs at the corners.

Method used

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  • Converter pretreatment and cold charging and heating method for high-carbon and high-alloy continuous casting slab
  • Converter pretreatment and cold charging and heating method for high-carbon and high-alloy continuous casting slab

Examples

Experimental program
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Effect test

Embodiment 1

[0051] The billet material is hot-formed steel, and its chemical composition is C: 0.34%, Si: 0.61%, Mn: 1.74%, P: 0.011%, S: 0.002%, Cr: 0.24%, V: 0.155%, Nb : 0.035%, Als: 0.56%; it belongs to the steel type with high carbon content, high manganese content and high vanadium content.

[0052] The thickness of the slab is 230mm. After the continuous casting production, the two slabs off the assembly line are slowly cooled for 75 hours according to the following continuous casting slab stacking and slow cooling method; before hot rolling production, the following continuous casting slab preheating method is preheated for 12 hours , the temperature measured by the temperature measuring gun is 433°C; the hot rolling is heated by a walking beam heating furnace, the temperature in the preheating section of the hot rolling heating furnace is 715°C, and the preheating time is 68 minutes. The time is 63 minutes, the second heating temperature is 1106°C, the soaking temperature is 1244...

example 1

[0056] The billet material is chrome-molybdenum steel for high-pressure gas cylinders, and the chemical composition is C: 0.32%, Si: 0.44%, Mn: 1.54%, P: 0.010%, S: 0.002%, Cr: 1.14%, Mo: 0.260 %, Nb: 0.005%, Als: 0.06%; it belongs to the steel type with high carbon content, high manganese content, high chromium content and high molybdenum content;

[0057] The thickness of the slab is 230mm, 8 slabs are produced by continuous casting, 4 slabs are hot sent and hot loaded and rolled, and the remaining 4 slabs are rolled off the assembly line, and they are conventionally stacked until they are completely cooled. After the remaining slabs were placed for several days, they were ready to be produced again. When the quality of the slabs was checked before furnace loading, it was found that there were a large number of cracks at the corners of the slabs that could not be removed, and production could not continue. The remaining slabs could only be scrapped.

example 2

[0059] The billet material is reinforced plastic high-strength steel, and its chemical composition is C: 0.26%, Si: 0.45%, Mn: 2.03%, P: 0.010%, S: 0.002%, Cr: 0.03%, V: 0.005%, Nb: 0.005%, Als: 0.76%; it belongs to the steel type with high carbon content, high manganese content and high aluminum content;

[0060] The thickness of the slab is 230mm, and the continuous casting produces 8 slabs, which are conventionally stacked until completely cooled. When checking the quality of the slab before charging, no cracks were found, and then the furnace was heated in a conventional way. The temperature requirement of the preheating section is ≤1100°C, the actual temperature of the preheating section is 1053°C, and the preheating time is 32 minutes; the temperature requirement of the first heating section is 1100-1250°C, the actual temperature of the first heating section is 1186°C, and the time is 34 minutes; the second heating section The temperature of the section is 1200-1320°C, ...

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PUM

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Abstract

The invention provides a pretreatment of high-carbon and high-alloy continuous casting slabs, which comprises the following steps: A) stacking and slowly cooling the high-carbon and high-alloy continuous casting slabs; B) stacking and slowly cooling the high-carbon The high-alloy continuous casting slab is preheated; the application also provides a method for cold charging and heating of the high-carbon and high-alloy continuous casting slab, that is, the high-carbon and high-alloy continuous casting slab that has undergone the above-mentioned pre-treatment for furnace charging is subjected to cold charging and heating. In this application, by optimizing the slow cooling and cold charging heating process system of the billet off-line, the microstructure of the corners of the billet has been changed, the formation of brittle structures and oxidized decarburization layers at the corners has been suppressed, and the problem of high carbon and high alloy steel has been effectively solved. The difficult problem of cold-loading and fracture of cast slabs ensures the smooth production of high-carbon and high-alloy steels and reduces the rejection rate.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a method for pre-charging and cold-charging heating of high-carbon and high-alloy continuous casting slabs. Background technique [0002] In order to save energy and raw materials, realize the lightweight of automobiles, and reduce carbon emissions, advanced ultra-high-strength automotive steel plates are increasingly valued by the automotive industry. With the continuous improvement of steel strength, the carbon content and alloy content gradually increase. Due to the increase in strength, there is a risk of casting slab fracture. Continuous casting slabs generally adopt hot delivery and hot charging process. [0003] However, due to the unreasonable connection of the continuous casting slab hot delivery and hot charging process, some high-carbon and high-alloy slabs cannot be hot-sent and hot-charged, and fractures often occur during conventional stacking and furnace chargin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D11/124B22D11/12
CPCB22D11/124B22D11/1213B22D11/001
Inventor 王宏伟张劲超周伟陈培友龚慧
Owner PANGANG GRP XICHANG STEEL & VANADIUM CO LTD
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