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Method for feeding silico-calcium core-spun yarn

A cored wire, silicon calcium technology, applied in the field of silicon calcium cored wire feeding, can solve the problems of steel flow interruption, deterioration of steel mechanical properties, etc.

Active Publication Date: 2012-05-30
SHANXI TAIGANG STAINLESS STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The current feeding method of silicon-calcium cored wire is to feed after the RH vacuum treatment is completed. For aluminum-containing steel, if the mixing effect of ladle bottom blowing is not good, this method cannot make the high melting point Al in molten steel 2 o 3 Inclusions change from clusters to low melting point 12CaO·7Al 2 o 3 Spherical inclusions are fully buoyed
Sampling from the slab and observed under the electron microscope, clustered Al larger than 20 μm in each field of view 2 o 3 Inclusions account for Al 2 o 3 More than 50% of the total number of inclusions, so that in the continuous casting process, Al 2 o 3 The inclusions will quickly adhere to the nozzle wall to block the nozzle, causing the steel flow to be interrupted; during the rolling process, the large particles of Al in the steel 2 o 3 The inclusions will be broken and distributed continuously along the rolling direction, which will deteriorate the mechanical properties of the steel

Method used

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  • Method for feeding silico-calcium core-spun yarn

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] This example is carried out on a 200-ton double-station RH refining furnace. Two bottom blowing gas supply devices are installed at the bottom of the ladle used. The normal gas supply flow rate of single bottom blowing and weak stirring is 50-100 L / min. The smelted steel grade is 9% Ni, and the mass percentage of its finished product composition is shown in Table 1.

[0035] Table 1

[0036] C

[0037] See Table 2 for the mass percentage of molten steel components before feeding the calcium-silicon cored wire.

[0038] Table 2

[0039] C

[0040] See Table 3 for the mass percentage distribution of calcium-silicon cored wire with a diameter of 13 mm.

[0041] table 3

[0042] Ca

[0043] Note: The quality of the core powder is 230g / m, the ratio of powder to iron is 1:1.05, the water content of the core powder is 0.22%, and the particle size of the core powder is 20 mesh.

[0044] 201 tons of 9% N molten steel, the temperature of molt...

Embodiment 2

[0049] This embodiment is carried out on an 85-ton single-station RH refining furnace. Two bottom blowing gas supply devices are installed at the bottom of the ladle used. The normal gas supply flow rate of single bottom blowing and weak stirring is 30-80 L / min. See Table 5 for the mass percentage of the finished product composition of the smelted steel P20HL.

[0050] table 5

[0051] C

Si

mn

P

S

Cr

Ni

Mo

Al

0.28

-0.40

0.20

-0.80

0.60

-1.00

≤

0.030

≤

0.020

1.40

-2.00

≤

0.20

0.30

-0.55

≥0.02

[0052] See Table 6 for the mass percentage of molten steel components before feeding the calcium-silicon cored wire.

[0053] Table 6

[0054] C

Si

mn

P

S

Cr

Al

Ni

Mo

0.39

0.63

0.94

0.008

0.005

1.84

0.04

0.03

0.41

[...

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Abstract

The invention relates to a method for feeding a silico-calcium core-spun yarn. The method comprises the following steps of in sequence: I, before the RH (Relative Humidity) vacuum treatment of aluminiferous steels, pre-calculating the Ca content needed in molten steels according to the ratio of the Ca content in the molten steel after feeding the silico-calcium core-spun yarn to the Al content in the molten steel before feeding the silico-calcium core-spun yarn being 0.10-0.15, and calculating a feeding amount of the silico-calcium core-spun yarn according to a Ca recovery rate of 15-23 percents and the quality of core powder per meter of the silico-calcium core-spun yarn; II, feeding the silico-calcium core-spun yarn into the molten steel of a ladle at a feeding speed of 150-300 m / min by using a double-tube; III, then slightly stirring for 6-15 min; and IV, carrying out RH vacuum refining treatment. The silico-calcium core-spun yarn preferably comprises the following components in percentages by weight: 28-31 percent of Ca, 55-65 percent of Si, 0.2-1.0 percent of C, 0.04S being not more than 0.05 percent and not less than P and 1.0-2.4 percent of Al. The method for feeding the silico-calcium core-spun yarn can obviously reduce an Al2O3 cluster-shaped impurity with a diameter more than 20 mu m and improve fluidness of the molten steel and enhance inherent quality of the steel.

Description

technical field [0001] The invention relates to a method for feeding silicon-calcium cored wire. Background technique [0002] The current feeding method of silicon-calcium cored wire is to feed after the RH vacuum treatment is completed. For aluminum-containing steel, if the mixing effect of ladle bottom blowing is not good, this method cannot make the high melting point Al in molten steel 2 o 3 Inclusions change from clusters to low melting point 12CaO·7Al 2 o 3 Spherical inclusions are fully buoyed. Sampling from the slab and observed under the electron microscope, clustered Al larger than 20 μm in each field of view 2 o 3 Inclusions account for Al 2 o 3 More than 50% of the total number of inclusions, so that in the continuous casting process, Al 2 o 3 The inclusions will quickly adhere to the nozzle wall to block the nozzle, causing the steel flow to be interrupted; during the rolling process, the large particles of Al in the steel 2 o 3 The inclusions will b...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/00C21C7/10
Inventor 张增武
Owner SHANXI TAIGANG STAINLESS STEEL CO LTD