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A production method for improving the surface quality of low-carbon boron-added steel wire rod

A technology of surface quality and production method, which is applied in the production field of improving the surface quality of low carbon and boron-added steel wire rods, can solve the problems of crystallizer liquid level fluctuation, nozzle nodules, and increase production costs, so as to eliminate influence and prevent cracks. Defect formation, thermal stress reduction effect

Active Publication Date: 2019-01-11
INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, AlN formed after adding Al elements is also easy to gather and precipitate along the grain boundary, and will also have a great impact on the high-temperature shaping of steel, but its precipitation temperature range is different from that of BN, so the surface temperature control range in the continuous casting process is different. ; After adding Ti element, TiN will precipitate at the grain boundary and within the grain during the solidification process, gather less at the grain boundary, and have less influence on high-temperature plasticity, but the chemical activity of Ti element is relatively large, and it is easy to combine with O, N The combination of elements to form TiOx and TiN causes nozzle nodulation, which affects the pourability of the continuous casting process, and also causes large fluctuations in the liquid level of the mold, thereby affecting the surface quality of the continuous casting slab
Therefore, the method of adding Al or Ti elements to the steel cannot improve and solve the problem of the surface quality of the low-carbon boron-added steel, and also increases the production cost.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The steel type in this example is SAE1006B. Through molten steel smelting, the mass percentage of the chemical composition of the finished product is controlled as follows: 0.05%≤C≤0.10%, 12ppm≤B≤20ppm, 0.08%≤Si≤0.20%, Mn≤0.80%, Al≤0.005 %, the rest is Fe and unavoidable impurity elements;

[0017] This type of steel is produced on a billet continuous casting machine. The section of the continuous casting slab is 140mm*140mm. During the continuous casting process, the superheat is controlled within the range of 25-35°C, and the casting speed is stable at 2.7±0.05m / min. The cooling water volume of the crystallizer is 1700±20L / min, the vibration frequency of the crystallizer is controlled at 180Hz, and the amplitude is controlled at 7.0mm;

[0018] The specific water volume of the secondary cooling in continuous casting is controlled at 0.90L / kg, of which the secondary cooling zone 1 and 2 adopts the full water cooling mode, the secondary cooling zone 3 and 4 adopts the a...

Embodiment 2

[0022] The steel type in this example is SAE1015B. Through molten steel smelting, the mass percentage of the chemical composition of the finished product is controlled as follows: 0.12%≤C≤0.18%, 12ppm≤B≤18ppm, 0.10%≤Si≤0.16%, Mn≤0.80%, Al≤0.005 %, the rest is Fe and unavoidable impurity elements;

[0023] This type of steel is produced on a billet continuous casting machine. The cross-section of the continuous casting billet is 140mm*140mm. During the continuous casting process, the superheat is controlled within the range of 22-40°C, and the casting speed is stable at 2.75±0.05m / min. The cooling water volume of the crystallizer is 1700±20L / min, the vibration frequency of the crystallizer is controlled at 200Hz, and the amplitude is controlled at 6.5mm;

[0024] The specific water volume of the secondary cooling in continuous casting is controlled at 0.98L / kg, of which the secondary cooling zone 1 and zone 2 adopt the full water cooling mode, the secondary cooling zone 3 and 4...

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Abstract

The invention discloses a production method capable of improving surface quality of a low-carbon boration steel wire rod. Through optimized adjustment of process parameters of a continuous casting crystallizer and secondary cooling process parameters, continuous casting blank surface temperature primary ladder cooling is achieved, heat stress in the continuous casting process is reduced, meanwhile, the high-temperature brittle area caused by adding of boron in the low-carbon boration steel is avoided, forming of low-carbon boration steel continuous casting blank surface crack defects can be effectively prevented, and the surface quality control of subsequent low-carbon boration steel wire rod finished products is facilitated; through the effect of BN on the high-temperature plasticity in the heating and initial rolling process of the low-carbon boration steel blank, the effect of the improper control of rolling temperature on the wire rod finished product surface quality of the low-carbon boration steel can be reduced or removed.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a production method for improving the surface quality of low-carbon boron-added steel wire rods. Background technique [0002] Boron-containing steel refers to steel with boron as the main alloying element. A very small amount (5-30ppm) of boron can significantly improve the hardenability of steel, and can improve the overall performance of steel while reducing production costs. However, the addition of B also greatly increases the crack sensitivity of the steel. Therefore, by adding Al or Ti to the steel, the influence of B on the surface quality of the low-carbon boron-containing steel can be reduced. Both methods are based on different thermodynamic conditions, by adding elements that are easier to combine with [N] elements to reduce or avoid the formation of BN, thereby reducing the accumulation of BN at grain boundaries. However, the AlN formed after the a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06B22D11/18B22D11/22
CPCB22D11/18B22D11/225C22C38/02C22C38/04C22C38/06
Inventor 周青峰邹长东徐松苏笃星
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE