CONTROL MATERIAL, AND METHOD FOR PRODUCING SAME

Abstract

The invention has for its object to provide a control material that is used with a wire injection process for graphite spheroidization in ductile cast iron production for the purpose of gaining control of the reaction of magnesium and achieving weight reductions. In the wire injection process for graphite spheroidization, the control material characterized by comprising a porous, volcanic silicate mineral containing 70 to 75% by weight of SiO.sub.2 is filled together with a magnesium alloy in the wire.

Claims

1. A control material that is filled together with a magnesium alloy in a wire in a wire injection process for graphite spheroidization, characterized by being a porous, volcanic silicate mineral containing 70 to 75% by weight of SiO.sub.2.

2. The control material according to claim 1, characterized by having a porosity of 60 to 80%.

3. The control material according to claim 1, characterized by having an Ig. loss of 0.5% or less.

4. The control material according to claim 2, characterized by having an Ig. loss of 0.5% or less.

5. The control material according to claim 1, characterized by having a specific gravity of 0.5 to 1.0 g/cm.sup.3.

6. The control material according to claim 2, characterized by having a specific gravity of 0.5 to 1.0 g/cm.sup.3.

7. The control material according to claim 3, characterized by having a specific gravity of 0.5 to 1.0 g/cm.sup.3.

8. The control material according to claim 4, characterized by having a specific gravity of 0.5 to 1.0 g/cm.sup.3.

9. The control material according to claim 1, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

10. The control material according to claim 2, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

11. The control material according to claim 3, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

12. The control material according to claim 4, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

13. The control material according to claim 5, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

14. The control material according to claim 6, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

15. The control material according to claim 7, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

16. The control material according to claim 8, characterized by being a fired spherical member having a diameter of less than 5 mm or a fired rod member having a length of less than 5 mm.

17. A method for producing a control material that is used with a wire injection process for graphite spheroidization, characterized in that said control material comprises a porous, volcanic silicate mineral containing 70 to 75% by weight of SiO.sub.2.

18. The method for producing a control material according to claim 17, characterized in that the control material is produced by processing a porous, volcanic silicate mineral having a particle diameter of 3 mm or less into a spherical member having a diameter of less than 5 mm or a rod member having a length of less than 5 mm while using a powdery, volcanic silicate mineral having a particle diameter of 0.1 mm or less and a water content of 15 to 35% by weight.

19. The method for producing a control material according to claim 17, characterized in that the control material is fired at 900 to 1000 C.

20. The method for producing a control material according to claim 18, characterized in that the control material is fired at 900 to 1000 C.

Description

MODES FOR CARRYING OUT THE INVENTION

[0038] A wire used with the wire injection process has a diameter of 6 to 16 mm, and is obtained by covering a magnesium alloy, a control material and additives with a metallic thin sheet.

[0039] The control material production method that is one embodiment of the invention is now explained.

[0040] In the first step, a porous, volcanic silicate mineral containing SiO.sub.2 is sieved into a powdery, volcanic silicate mineral having a particle diameter of 0.1 mm or less and a water content of 15 to 35% weight and a porous, volcanic silicate mineral having a particle diameter of 3 mm or less.

[0041] The process then goes to the second step in which the powdery, volcanic silicate mineral having a particle diameter of 0.1 mm or less is used as a binder and mixed with the porous, volcanic silicate mineral having a particle diameter of 3 mm or less, and the mixture is granulated with a diameter of less than 5 mm.

[0042] The process then goes to the third step in which the granulated spheres having a diameter of less than 5 mm are dried.

[0043] The process then goes to the fourth step in which the granulated spheres having a diameter of less than 5 mm are fired at 900 to 1000 C.

[0044] Through the steps as mentioned above, the control material that is one embodiment of the invention is produced.

[0045] By analysis, the thus produced control material is found to have the following features.

[0046] The control material is a porous, volcanic silicate mineral containing 73.0% by weight of SiO.sub.2, and has a porosity of 60 to 80%, an Ig. loss of 0.33% and a specific gravity of 0.5 to 1.0 g/cm.sup.3. The spherical control material has a diameter of less than 5 mm.

[0047] To ascertain the water absorption of the control material according to the embodiment here, the following experimentation is done. Fifty (50) grams of the control material were placed in an aluminum dish having a diameter of 120 mm and a depth of 30 mm, and dried in a drying furnace having a temperature of 105 C. for a time period of 24 hours. The mass (mass upon drying) of the dried control material was measured.

[0048] The dried control material was then placed in an environmental tank having a temperature of 20 C. and a humidity of 90% RH in which the mass of the control material (mass upon water feeding) was measured while water was periodically absorbed in the control material for 120 hours.

[0049] As calculated in accordance with water absorption (%)=(mass upon water feedingmass upon drying/mass upon drying100, the control material according to this embodiment was found to have a water absorption of less than 1% from the start of water feeding up to the lapse of 120 hours.

[0050] In other words, the control material according to the embodiment here is less likely to absorb water from the atmosphere over time so much so that its storage over an extended period is facilitated. In addition, the control material after storage over an extended period remains stabilized in terms of the amount of foaming in a molten metal as is the case with a control material not subject to storage over an extended period.

[0051] In the aforesaid embodiment of the control material production method, a mixture of the binder powdery, volcanic silicate mineral having a particle diameter of 0.1 mm or less with the porous, volcanic silicate mineral having a particle diameter of 3 mm or less is spherically granulated with a diameter of less than 5 mm; however, the present invention is in no sense limited to it. For instance, a mixture of the binder powdery, volcanic silicate mineral having a particle diameter of 0.1 mm or less with the porous, volcanic silicate mineral having a particle diameter of 3 mm or less may be formed into a rod member having a length of less than 5 mm.

[0052] In the aforesaid control material embodiment, the control material is a porous, volcanic silicate mineral containing 73.0% by weight of SiO.sub.2; however, the present invention is by no means limited to it. For instance, depending on the casting conditions used, the control material may comprise a porous, volcanic silicate mineral containing 70 to 75% by weight of SiO.sub.2.

[0053] In the aforesaid control material embodiment, the control material has an Ig. loss of 0.33%; however, the present invention is not limited to it whatsoever. For instance, depending on the casting conditions used, the control material may have an Ig. loss of 0.5% or less.