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Production method of hot-rolled no-fold low carbon steel

A production method and technology of low-carbon steel, which is applied in the production field of hot-rolled non-wrinkle low-carbon steel, can solve the problems of easy wrinkling, high elongation, and low yield strength, etc., so as to improve the qualified rate of products, and the measures are simple and easy Effect

Inactive Publication Date: 2012-07-18
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Within the scope of meeting the national standard, a narrow range of carbon ≤ 0.07% is used. Although the product performance meets the national standard and the internal control delivery standard (yield strength ≥ 235Mpa, tensile strength 370-500Mpa, elongation ≥ 26%), the yield Low strength (minimum 255Mp, ≤295Mp ratio 20-25%), high elongation, resulting in "mild steel" that is actually prone to wrinkling

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] The present embodiment produces the steel grade that brand name is Q235B, and the weight percentage content of its original C is 0.032%, and the weight percentage content of its original Mn is 0.33%, and its original crimping temperature of setting is 560 ℃, and product thickness is 1.75 mm.

[0019] Its steps:

[0020] 1) Smelting:

[0021] Since the production of non-cold rolled steel with a thickness of ≤2 mm, there is no need to adjust the content of C and Mn;

[0022] 2) Continuous casting and rolling;

[0023] 3) Perform coiling:

[0024] Due to the production of non-cold-rolled steel with a thickness of 1.75 mm, there is no need to increase its coiling temperature;

[0025] 4) Leveling.

[0026] The steel produced by it has been inspected after uncoiling, and no wrinkle defects have been found.

Embodiment 2

[0028] The present embodiment produces the steel grade that brand name is Q235B, and the weight percentage content of its original C is 0.032%, and the weight percentage content of its original Mn is 0.33%, and its original setting crimping temperature is 660 ℃, and product thickness is 2.75% mm, the steel standard stipulates that the upper limit of the weight percentage of C is 0.20%, the upper limit of the weight percentage of Mn is 0.55%, and the lower limit of the weight percentage of Mn is 0.10%.

[0029] Its steps:

[0030] 1) Smelting:

[0031] Due to the Q235B non-cold-rolled steel with a product thickness of 2.75 mm: the weight percentage content of the original C is 0.032%, so the weight percentage content of 0.15% C is increased on this basis, and the weight percentage content of C is 0.182%; the original steel The weight percent content of Mn in water is 0.33%, on this basis, reduce 0.05% by weight to 0.28%, which does not exceed the lower limit value specified in...

Embodiment 3

[0038] The present embodiment produces the steel grade that brand name is Q235B, and the weight percentage content of its original C is 0.052%, and the weight percentage content of its original Mn is 0.33%, and its original setting crimping temperature is 660 ℃, and product thickness is 2.30 mm, the steel standard stipulates that the upper limit of the weight percentage of C is 0.20%, the upper limit of the weight percentage of Mn is 0.55%, and the lower limit of the weight percentage of Mn is 0.10%.

[0039] Its steps:

[0040] 1) Smelting:

[0041] Because the product thickness produced is Q235A non-cold-rolled steel of 3.75 millimeters: the weight percentage content of original C is 0.052%, so increase the weight percentage of 0.10% C on this basis, make the weight percentage content of C be 0.152%; The weight percent content of Mn in molten steel is 0.33%, on this basis, increase 0.20% by weight to 0.53%, which does not exceed the upper limit specified in the steel standa...

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Abstract

The invention provides a production method of hot-rolled no-fold low carbon steel, comprising the following steps of: smelting, wherein for non-cold-rolled steel with thickness more than 2mm, increasing the content of C in molten steel is increased by 0.01-0.17% by weight on the basis of the C content of a produced steel ball, and for cold rolled steel and non-cold-rolled steel with thickness less than or equal to 2mm, the contents of C and Mn are not needed to be adjusted; performing continuous casting and rolling; and coiling, wherein for the non-cold-rolled steel with thickness more than 2mm, the coiling temperature is increased by 1-3% on the basis of the existing set coiling temperature of the produced steel ball, and for the non-cold-rolled steel with thickness less than or equal to2mm, flattening is performed. Compared with the prior art, the contents of C and Mn in the molten steel, and the coiling temperature of rolled steel are adjusted for the non-cold-rolled steel with thickness more than 2mm provided by the invention, so that the defect that the coiled steel is easy to fold when being uncoiled is eliminated, user requirements are met, the product yield is improved and the measures are simple and easy to implement.

Description

technical field [0001] The invention relates to a production method of low-carbon steel, in particular to a production method of hot-rolled non-wrinkle low-carbon steel. Background technique [0002] In the low-carbon steel plate produced by CSP hot rolling at present, during the quality inspection in the factory, its appearance, performance, composition and other indicators meet the national standards through quality inspection, but after the user uncoils, it is found that there are regular creases on the surface of the steel coil , which is called wrinkle defect, for which users often raise quality objections, and the wrinkle quality objection rate is as high as 10.24%. At present, the methods for controlling the wrinkle defects in CSP hot rolling all adopt the method of adjusting carbon and manganese in steel and increasing the coiling temperature of hot rolling. [0003] During production, it was found that the hot-rolled coils with lower yield strength and thinner thic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/04B21C47/02
Inventor 刘小鸥何金平谭佳梅张永锟刘先同
Owner 武汉钢铁有限公司