Liquid iron inoculation process for ductile iron pipes

A technology for ductile iron pipes and molten iron, which is applied in the field of inoculation of molten iron for ductile iron pipes, can solve the problems that it is difficult to achieve mechanical properties such as strength and toughness of ductile iron pipes, and achieve the goals of reducing the quantity, increasing the tensile strength, and reducing the scrap rate Effect

Active Publication Date: 2010-12-22
河北新兴铸管有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the pipe wall specified in the new industry standard for ductile iron pipes is thinner than that in the current industry standard, it is difficult to incubate molte

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] Embodiment 1: molten iron inoculation process for ductile iron pipes, comprising the following steps: (1) inoculation in the spheroidizing bag, adding 0.4% inoculant of molten iron weight in the spheroidizing bag, adding an appropriate amount of inoculant in the spheroidizing process, After the inoculant is completely melted, enter the next procedure; (2) Incubate with the flow, add 0.2% inoculant of the molten iron weight in the pouring ladle, and after the molten iron is transferred into the pouring ladle, it can be 0.2% of the mass of the molten iron in the ladle % inoculant, pouring can only be done after the inoculant is completely melted; (3) pipe mold powder inoculation, spray pipe mold powder 20g / m on the inner surface of the pipe mold before pouring and when pulling out the pipe 2 ; Its key improvement is: increase tundish inoculation between described step (1) and step (2), add the inoculant of 0.15% of molten iron weight in tundish, after molten iron is transf...

Embodiment 2

[0009] Embodiment 2: molten iron inoculation process for ductile iron pipes, comprising the following steps: (1) inoculation in the spheroidizing bag, adding 0.5% inoculant of molten iron weight in the spheroidizing bag, adding an appropriate amount of inoculant in the spheroidizing process, After the inoculant is completely melted, enter the next process; (2) inoculate with the flow, add 0.15% inoculant of molten iron weight in the pouring ladle, after the molten iron is transferred into the pouring ladle, it can be inoculated according to 0.15% of the mass of molten iron in the pouring ladle % inoculant, pouring can only be done after the inoculant is completely melted; (3) pipe mold powder inoculation, spray pipe mold powder 25g / m on the inner surface of the pipe mold before pouring and when pulling out the pipe 2 ; Its key improvement is: increase tundish inoculation between described step (1) and step (2), add the inoculant of 0.2% of molten iron weight in tundish, after m...

Embodiment 3

[0010] Embodiment 3: molten iron inoculation process for ductile iron pipes, comprising the following steps: (1) inoculation in the spheroidizing bag, adding 0.6% inoculant of molten iron weight in the spheroidizing bag, adding an appropriate amount of inoculant in the spheroidizing process, After the inoculant is completely melted, enter the next process; (2) Incubate with the flow, add 0.25% of the inoculant of the molten iron weight in the pouring ladle, and after the molten iron is transferred into the pouring ladle, it can % inoculant, pouring can only be done after the inoculant is completely melted; (3) pipe mold powder inoculation, spray pipe mold powder on the inner surface of the pipe mold before pouring and when pulling out the pipe 30g / m 2 ; Its key improvement is: increase tundish inoculation between described step (1) and step (2), add the inoculant of 0.25% of molten iron weight in tundish, after molten iron is transferred into tundish, can according to middle 0...

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PUM

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Abstract

The invention discloses a liquid iron inoculation process for ductile iron pipes, which comprises the following steps of: (1) inoculating in a spheroidizing ladle, and adding an inoculator accounts for 0.4 to 0.6 weight percent of the liquid iron into the spheroidizing ladle; (2) performing stream inoculation, adding an inoculator in an amount which is 0.1 to 0.25 weight percent of the liquid iron into a pouring ladle; and (3) performing pipe powder inoculation, spraying pipe powder on the inner surface of a pipe die before pouring and during pipe drawing in a ratio of 20-30g/m<2>. The key improvement is that: a tundish inoculation step is added between the step (1) and the step (2), wherein an inoculator in an amount which is 0.15 to 0.25 weight percent of the liquid iron is added into the tudish, and after the inoculator is completely melted, the liquid iron is transferred into the pouring ladle for stream inoculation. The liquid iron inoculation process has the advantages that: a tundish inoculation process is added between the spheroidizing ladle inoculation and the stream inoculation to realize long-acting inoculation of the liquid iron; the residual magnesium in the spheroidizing liquid iron can be effectively reduced; the tensile strength and the yield strength are improved; and meanwhile, conditions are created for reducing high-temperature annealing temperature and stabilizing the size of the ductile iron pipe finished products.

Description

technical field [0001] The invention relates to a production process of molten iron for ductile iron pipes, in particular to an inoculation process of molten iron for ductile iron pipes. Background technique [0002] Centrifugal ductile iron pipes are widely used in construction projects such as water and gas transmission due to their high strength and good toughness. Therefore, improving and stabilizing the quality of centrifugal ductile iron pipes to achieve higher standards is an urgent problem that ductile iron pipe manufacturers need to solve. The main factors affecting the quality of ductile iron pipes are as follows. The first point The chemical composition of blast furnace molten iron, such as sulfur, titanium, silicon, etc.; the second point is the control of the carbon equivalent of molten iron after spheroidizing; the third point is the control of magnesium content in molten iron after spheroidizing. The present invention is mainly aimed at the improvement of the...

Claims

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Application Information

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IPC IPC(8): C22C33/08C21C1/10
Inventor 葛华光田建军朱传斌
Owner 河北新兴铸管有限公司
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