Control method of as-cast condition heavy section ferrite-based nodular iron casting graphite nodule and matrix structure

A control method, thick section technology, applied in
The present invention relates to field, can solve problems such as elongation reduction, solidification time is long, reduces casting performance, reaches the effect of excellent low-temperature impact performance, easy to grasp and operate, and reduces production cost

Active Publication Date: 2013-04-03
JIANGSU HONGDE SPECIAL PARTS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for ductile iron castings with thick and large cross-sections, due to the large modulus, slow cooling, long solidification time, a series of defects such as graphite distortion, few graphite balls and thick graphite balls are prone to appear in the center of wall thickness or hot joints. Casting properties
For the ferrite-based s

Method used

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  • Control method of as-cast condition heavy section ferrite-based nodular iron casting graphite nodule and matrix structure
  • Control method of as-cast condition heavy section ferrite-based nodular iron casting graphite nodule and matrix structure
  • Control method of as-cast condition heavy section ferrite-based nodular iron casting graphite nodule and matrix structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The casting size of this embodiment is 200×200×200mm 3 According to the shape of the bag pit of the spheroidizing treatment bag, a pressed iron plate is made, and the size of the plate just fills the bag pit; pig iron, recycled material, scrap steel and ferrosilicon are selected as ingredients, and the smelted molten iron is 1523°C for the spheroidizing treatment bag Hot ladle, hot ladle time is 4min; add Elkem 5800 nodulizer with 1.05% weight of molten iron and 4% Elkem high-calcium barium inoculant in turn in the ladle pit after ladle, and sprinkle the weight of molten iron on the inoculant For 0.2% iron filings, after compaction, put a pressed iron plate on the top of the bag pit, then add pig iron, the total weight of pig iron and pressed iron plate is 4% of the weight of the processed molten iron, and finally add 30ppm of Sb; control the mass fraction of the original molten iron For: C: 3.75-3.85%, Si: 1.10-1.40%, Mn<0.15%, P<0.050%, S<0.02%, the temperature of mol...

Embodiment 2

[0025] The casting size of this embodiment is 200×200×200mm 3 According to the shape of the pit of the spheroidizing treatment bag, a pressed iron plate is made. The size of the flat plate is just enough to fill the pit. Pig iron, recycled material, scrap steel and ferrosilicon are selected as ingredients, and the smelted molten iron is 1510°C for the spheroidizing treatment bag. Hot ladle, hot ladle time is 4min; add Elkem 5800 nodulizer with 1.05% weight of molten iron and 4% Elkem high-calcium barium inoculant in turn in the ladle pit after ladle, and sprinkle the weight of molten iron on the inoculant 0.2% of the iron filings, after compaction, put the pressed iron plate on the top of the bag pit, then add pig iron, the total weight of the pig iron and the pressed iron plate is 4% of the weight of the processed molten iron, and finally add 50ppm of Sb;; control the original molten iron Mass fraction: C: 3.75-3.85%, Si: 1.10-1.40%, Mn<0.15%, P<0.050%, S<0.02%, the temperatu...

Embodiment 3

[0029] The casting size of this embodiment is 250×250×250mm 3 According to the shape of the pit of the spheroidizing treatment bag, a pressed iron plate is made. The size of the flat plate is just enough to fill the bag pit. Pig iron, recycled material, scrap steel and ferrosilicon are selected as ingredients, and the smelted molten iron is spheroidized at 1513°C. Hot ladle, hot ladle time is 4min; add Elkem 5800 nodulizer with 1.05% weight of molten iron and 4% Elkem high-calcium barium inoculant in turn in the ladle pit after ladle, and sprinkle the weight of molten iron on the inoculant 0.2% of the iron filings, after compaction, put the pressed iron plate on the top of the bag pit, then add pig iron, the total weight of the pig iron and the pressed iron plate is 5% of the weight of the processed molten iron, and finally add 50ppm of Sb; control the quality of the original molten iron Score: C: 3.75-3.85%, Si: 1.10-1.40%, Mn<0.15%, P<0.050%, S<0.02%, the temperature of molten...

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Abstract

The invention discloses a control method of an as-cast condition heavy section ferrite-based nodular iron casting graphite nodule and a matrix structure. The control method comprises the following steps of: manufacturing a weight panel according to the shape of a spheroidizing packet; selecting pig iron, foundry returns, scrap steels and silicon irons to prepare materials; scaling the spheroidizing packet by using smelted molten iron more than or equal to 1500 DEG C; adding a spheroidizing agent, a nucleating agent, scrap iron, the weight panel, pig iron and Sb into a packet pit in sequence to carry out spheroidizing; adding an inoculation agent which accounts for 0.1-0.2% of molten iron by weight into the surface of the molten iron after the spheroidizing; stirring and scattering slag removers on the surface of the molten iron; after the spheroidizing, pouring the molten iron into a phenolic sand molded sand box which is prepared in advance so as to be cast and molded, wherein the molten iron needs to be breaded along with the flow, the breading quantity is 0.2% of the weight of a cast piece, and the box is opened after being molded and cooled to be less than 300 DEG C. The mechanical performance of the central part of a body of the material under the cast mode is as follows: the extension strength sigma b is not less than 380MPa, the surrendering strength sigma 0.2 is not less than 230Pa, and the cut-off ductility delta is not less than 20%.

Description

technical field [0001] The invention relates to a method for controlling graphite balls and matrix structure of as-cast thick-section ferrite-based ductile iron castings, in particular to a control method for spheroidization and inoculation treatment, belonging to the field of large-scale iron castings. Background technique [0002] Due to its good toughness and casting performance, ductile iron has a simple production method and its output has increased year after year. However, for ductile iron castings with thick and large cross-sections, due to the large modulus, slow cooling, long solidification time, a series of defects such as graphite distortion, few graphite balls and thick graphite balls are prone to appear in the center of wall thickness or hot joints. casting properties. For the ferrite-based structure required by the QT400-18 material in the as-cast state, due to the small number and coarseness of graphite spheres, the amount of pearlite in the casting increase...

Claims

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Application Information

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IPC IPC(8): C21C1/10C22C33/10
CPCY02P10/20
Inventor 杨金德潘冶邵建华周张松孙国雄陈立新
Owner JIANGSU HONGDE SPECIAL PARTS CO LTD
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