Effect of Pulsed Magnetic Field on Solidification Structures of Metals

1
Effect of Pulsed Magnetic Field on
Solidification Structures of Metals

• Metal Solidification Research Group, Shanghai
  University

Zhai Qi-Jie , Gao Yu-Lai, Li Qiu-Shu
Corresponding author, email qjzhai_at_staff.shu.edu
.cn Personal website http//www.foundrymate.com
October 11, 2004
2
Four Parts

• Metal Solidification Research Group, Shanghai
  University

• Background
• Experimental procedure
• Results and discussion
• Conclusions

3
Background

• Metal Solidification Research Group, Shanghai
  University

• Can obviously refine the solidification
  structure
• No research on pure metal, e.g. Al
• No consensus is acquired about the effect of
• magnetic field
• Little information is available about the
• refinement mechanism

4
Experimental procedure

• Metal Solidification Research Group, Shanghai
  University

• High-voltage pulsed power source
• and the solidification equipment
• Materials choose pure Al, gray iron and
• stainless steel
• Analysis methods OM, TA

5
Results and Discussions Effect on Al

• Metal Solidification Research Group, Shanghai
  University

• B0T
• (b) B0.3T
• (c) B0.38T
• (d) B0.51T

Macrostructure of the solidified samples under
the pulsed magnetic field with different
intensities
6
Results and Discussions Effect on Al

• Metal Solidification Research Group, Shanghai
  University

Relation between the intensity of the pulsed
magnetic field and the average grain size
7
Results and Discussions Effect on Al

• Metal Solidification Research Group, Shanghai
  University

Distribution of the magnetic induction intensity
in the intense magnetic generator
8
Results and Discussions Effect on Al

• Metal Solidification Research Group, Shanghai
  University

Relationship between the intensity of pulsed
magnetic field and solidification temperature
9
Results and Discussions Effect on gray iron

• Metal Solidification Research Group, Shanghai
  University

Chemical composition of experimental gray iron
10
Results and Discussions Effect on gray iron

• Metal Solidification Research Group, Shanghai
  University

(a) B0T (b) B1.2T (c) B3.1T (d) B6.4T
Graphite morphology of hypoeutectic gray iron
under different pulsed magnetic field parameters

11
Results and Discussions Effect on gray iron

• Metal Solidification Research Group, Shanghai
  University

(a) B0T (b) B0.3T (c) B1.2T (d) B2.6T
Graphite morphology of hypereutectic gray iron
under different pulsed magnetic field parameters

12
Results and Discussions Effect on gray iron

• Metal Solidification Research Group, Shanghai
  University

Effect of the magnetic intensity on the length
of the graphite
Effect of the magnetic intensity on the
thickness of the graphite

13
Results and Discussions Effect on gray iron

• Metal Solidification Research Group, Shanghai
  University

B3.1T
B0T
Relation between the temperature and time for
solidification of gray iron
14
Results and Discussions Effect on stainless
steel

• Metal Solidification Research Group, Shanghai
  University

(a)B0T (b)B0.78T (c)B1.10T (d)
B1.35T (e)B1.8T (f)B3.00T (g) B3.24T (h)
B3.84T

15
Conclusions

• Metal Solidification Research Group, Shanghai
  University

1. The solidified structure of pure aluminum evolved
   from columnar grains to equi-axed ones, and the
   grain size becomes smaller as the augment of the
   intensity of pulsed magnetic field. The effect of
   the pulsed magnetic field on the solidification
   temperature of Al can be neglected.
2. The pulsed magnetic field can refine and improve
   the graphite morphology of the gray iron. Also,
   the pulsed magnetic field can decrease its
   undercooling of the eutectic transformation.

16
Conclusions

• Metal Solidification Research Group, Shanghai
  University

• The solidification structures of austenitic
  stainless steel are changed from coarse columnar
  crystals to narrow and thin ones after adding
  pulsed magnetic field. However, equi-axed grains
  cant be obtained.

17
Acknowledgement

• Metal Solidification Research Group, Shanghai
  University

Financially supported by (1) National Natural
Science Foundation of China, (2) Science and
Technology Committee of Shanghai Municipality
18
The end. Thank you!
19
Experimental equipments

• Metal Solidification Research Group, Shanghai
  University

20
Schematic of the solidification equipment

• Metal Solidification Research Group, Shanghai
  University

1-Magnetic field generator 2- Pouring cup
3-Liquid metal 4-Mould 5-Cooling System
6-Computer-controlled thermometric system
7-Pad 8-Mobile platform 9-Thermal couples
10-Pulse power source