Inoculation method of nodular cast iron

A ductile iron and flow inoculation technology is applied in the inoculation of ductile iron and the preparation of ductile iron alloys.

Inactive Publication Date: 2014-05-21
CHONGQING JIDING METAL CASTING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The ductile iron castings produced by conventional technology can meet the product requirements after testing, but the number of graphite balls can only reach about 50-70% of the standard requirements, so that it cannot meet the preparation requirements of special castings. For example: large castings due to size It is too large, limited by the capacity of the heat treatment furnace, it can only be produced in the cast state, and the wall thickness is generally more than 100mm. Graphite distortion occurs, the number of balls decreases, graphite balls increase, grains become coarser, the spheroidization rate decreases, component segregation, intergranular carbides increase, and graphite floats, resulting in spheroidization recession and greatly reducing the mechanical properties of castings

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  • Inoculation method of nodular cast iron

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Experimental program
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Effect test

Embodiment 1

[0021] 1. Inoculation in the molten iron ladle, the first inoculation in the molten iron ladle when it is released from the furnace is smelted in an intermediate frequency furnace at 1550°C, and the BaCaSi high-efficiency composite inoculant of the type J-3 is added at 0.45% of the total weight of the casting when it is released from the furnace, and placed in the molten iron ladle carry out the first pregnancy;

[0022] 2. Ladle inoculation, after step (1) the molten iron is allowed to stand to remove slag, then cool down to a pouring temperature of 1385°C, and add BaCaSi high-efficiency composite inoculant of model J-3 to 0.25% of the total weight of the casting during pouring. second pregnancy

[0023] 3. Flowing inoculation, when pouring, use 0.05% of the total weight of the casting to add SiZrSr special inoculant model P-1T for conventional instantaneous flow inoculation.

Embodiment 2

[0025] 1. Inoculation in the ladle, the first inoculation in the ladle when it is released from the furnace. The intermediate frequency furnace is smelted at 1550 ° C. When it is released from the furnace, 0.65% of the total weight of the casting is added to the BaCaSi high-efficiency composite inoculant of type J-3, and it is placed in the ladle. carry out the first pregnancy;

[0026] 2. Ladle inoculation, after step (1) the molten iron is allowed to stand still to remove slag, then cool down to a pouring temperature of 1390°C, and add BaCaSi high-efficiency composite inoculant of model J-3 to 0.35% of the total weight of the casting during pouring. second pregnancy

[0027] 3. Flowing inoculation, when pouring, use 0.1% of the total weight of the casting to add SiZrSr special inoculant model P-1T for conventional instantaneous flow inoculation.

Embodiment 3

[0029] 1. Inoculation in the molten iron ladle, the first inoculation in the molten iron ladle when it is released from the furnace is smelted in an intermediate frequency furnace at 1550°C, and the BaCaSi high-efficiency composite inoculant of the type J-3 is added at 0.55% of the total weight of the casting when it is released from the furnace, and it is placed in the molten iron ladle carry out the first pregnancy;

[0030] 2. Ladle inoculation, after step (1) the molten iron is allowed to stand to remove slag, then cool down to a pouring temperature of 1380°C, and add BaCaSi high-efficiency composite inoculant of type J-3 to 0.3% of the total weight of the casting during pouring. second pregnancy

[0031] 3. Flowing inoculation, when pouring, use 0.15% of the total weight of the casting to add SiZrSr special inoculant model P-1T for conventional instantaneous flow inoculation.

[0032] Tested by Shanghai Materials Research Institute as follows:

[0033]

[0034] It ca...

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Abstract

The invention discloses an inoculation method of nodular cast iron, relates to a preparation method of nodular cast iron alloy, and belongs to the technical field of nodular cast iron alloy production. The inoculation method comprises the steps of in-ladle inoculation, ladle-to-ladle inoculation and metal-stream inoculation. The inoculation method has the beneficial effects that the ladle-to-ladle inoculation process is added between the in-ladle inoculation step and the metal-stream inoculation step, an instantaneous multi-inoculation special technology is realized, the long-acting inoculation of molten iron is achieved, the residual magnesium content in nodulizing molten iron can be effectively reduced, the number of cementite in a casting-state structure is reduced, as for the mechanical performances of the nodular cast iron, the tensile strength of the nodular cast iron can reach 453 Mpa, the yield strength of the nodular cast iron can reach 287 Mpa, the ductility of the nodular cast iron can reach 21-25%, and the number of graphite nodules in the nodular cast iron reaches 150 / mm<2>.

Description

technical field [0001] The invention relates to a method for preparing a nodular cast iron alloy, which belongs to the technical field of nodular cast iron production, in particular to a nodular cast iron inoculation method. Background technique [0002] Ductile cast iron is spheroidized graphite obtained through spheroidization and inoculation treatment, which effectively improves the mechanical properties of cast iron, especially improves plasticity and toughness, thereby obtaining higher strength than carbon steel. Ductile cast iron is a high-strength cast iron material developed in the 1950s. Its comprehensive performance is close to that of steel. It is based on its excellent performance that it has been successfully used to cast some complex stress, strength, toughness, and wear resistance. Parts with high performance requirements. Spheroidization refers to the process in which graphite in cast iron becomes graphite crystallization under the influence of added nodular...

Claims

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Application Information

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IPC IPC(8): C21C1/10C22C33/08B22D1/00
Inventor 古正炳杨明川
Owner CHONGQING JIDING METAL CASTING
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