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Method for controlling morphologies of inclusions in cast structure of steel

A technology of as-cast structure and inclusions, which is applied in the field of spherical composite inclusions, and can solve problems such as differences in steel properties

Active Publication Date: 2012-12-12
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For ductile manganese sulfide, it is also a very common inclusion in steel. When MnS is elongated by rolling, the toughness in the rolling direction is significantly higher than that in the transverse direction, resulting in a difference in the properties of the steel in the rolling direction and transverse direction.

Method used

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  • Method for controlling morphologies of inclusions in cast structure of steel
  • Method for controlling morphologies of inclusions in cast structure of steel
  • Method for controlling morphologies of inclusions in cast structure of steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] After the molten iron with sulfur content of 0.0015wt% is smelted in a 300-ton converter, the steel is tapped to the ladle. During the tapping process, slag is added to the ladle to adjust the top slag composition of the ladle. After tapping, the molten steel composition: C 0.06wt%, Si 0.14wt% , Mn 0.09wt%, P 0.008wt%, S 0.0023wt%, temperature 1614°C. Subsequently, the ladle enters the RH station for refining outside the furnace. After the molten steel is vacuum degassed, aluminum is used to deoxidize the oxygen content to 0.0050wt%, and then titanium-iron alloy is used to deoxidize to 0.0012wt%.

[0051] According to the composition requirements of the steel grade, adjust the composition of alloying elements such as C, Si, Mn, Nb, Mo in the steel to the target composition, and finally, add ferro-titanium alloy according to the upper limit of the composition of the steel grade for final deoxidation and alloying of titanium, and at the same time in the ladle slag layer ...

Embodiment 2

[0057] The molten iron containing 0.0010wt% sulfur was smelted in a 300-ton converter, followed by RH refining and continuous casting according to the same steps as described in the examples, and the process is omitted. The main parameters are as follows:

[0058] The composition of the molten steel after the converter is tapped: C 0.04wt%, Si 0.15wt%, Mn 0.10wt%, P0.005wt%, S 0.0025wt%, temperature 1622°C.

[0059] RH refining treatment. The oxygen content is deoxidized to 0.0120wt% by silicon-manganese, and then deoxidized to 0.0060wt% by titanium-iron alloy.

[0060] The main active ingredients of the cored wire alloy are: calcium 22wt%, silicon 54wt%, magnesium 6wt%, TiO 2 9 wt%. The amount of material added was 0.30 kg / ton of steel.

[0061] The cooling intensity of the secondary cooling section of continuous casting is 1.6 tons (cooling) water / ton steel.

[0062] The analysis results of the main components of the ladle slag samples are as follows:

[0063]CaO 45wt%...

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Abstract

The invention discloses a method for controlling the morphologies of inclusions in the cast structure of steel, which comprises the following steps that: 1) sulfur content control on molten steel in the process of smelting: the sulfur content of a steel billet is reduced to be below 0.0030 wt %; 2) fractional deoxidization: the fractional deoxidization is implemented through oxygen isotopic control and the utilization of titanium deoxidization; 3) top slag control: through refining slag composition control, MnO-Ti2O3 compound inclusions are finally formed in the molten steel; 4) calcium treatment and inclusion miniaturization; 5) cooling control; and 6) the obtained inclusion is in an internal-external layer compound structure, the inclusion in the internal layer takes MnO and Ti2O3 as main ingredients, and the inclusion in the external layer is a MnS film compound inclusion for coating, the particle size of the inclusion is 0.5-5.0 microns, the number of particles in the inclusion is100-2000 / mm2, and the particles are distributed in the steel in a dispersion mode. The method disclosed by the invention is a method for forming a dispersed fine spherical compound inclusion taking Ti2O3 as main ingredients in the cast structure of steel, the special inclusion is mainly used for controlling the structure of steel in a welding heat influence area, and thus obviously improving the toughness of steel in the welding heat influence area.

Description

technical field [0001] The invention relates to a smelting process, in particular to a method for forming a fine dispersion in the as-cast structure of steel, containing Ti 2 o 3 method for spherical composite inclusions as principal components. Background technique [0002] Toughness refers to the ability of a material to resist cracking and crack propagation under external loads, that is, the ability of a material to absorb energy during the elastic-plastic deformation process experienced before fracture, and it is a comprehensive manifestation of strength and plasticity. For iron and steel materials, excess strength and insufficient toughness are relatively common problems. Around the strengthening and toughening of materials, domestic and foreign scholars have carried out a lot of research work and proposed many strengthening and toughening methods, basically through alloying and precipitation. , grain refinement and other comprehensive effects to achieve. [0003] Ho...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D27/00C21C7/00C21C7/06C21C7/064
CPCY02P10/20
Inventor 郑庆胡会军
Owner BAOSHAN IRON & STEEL CO LTD