MATERIALS SELECTION TO EXCAVATOR TEETH IN MINING INDUSTRY

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MATERIALS SELECTION TO EXCAVATOR TEETH IN MINING
INDUSTRY

• J.E. Fernández a, R. Vijande a, R. Tucho a, J.
  Rodriguez b, A. Martin
• Presentation by
• Mohammed A. Najid

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OUTLINE

• Introduction
• Objective
• Materials
• Laboratory tests
• Experimental tests
• Experimental Results
• Field tests in open cast mine
• Field Test
• Field Test Results
• Comparison between experimental results and field
  test results
• Conclusion

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INTRODUCTION

• Hard alloys are normally used as materials for
  excavators teeth in mining industry.
• The alloys contain cast iron alloyed with
  different elements.
• In most cases these alloys do not have enough
  anti-wear properties and coatings are employed as
  a good alternative.
• Regarding the coating materials, two types are
  basically employed for these applications steel
  alloys of chromium, vanadium, niobium and
  materials formed from a weldable ferrite matrix
  containing tungsten carbide of varying shapes and
  sizes.

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INTRODUCTION

• To select the most appropriate materials for
  using as protective coatings, a two stage
  research plan was carried out.
• Firstly, to carry out an abrasion test program in
  the laboratory by using a standard testing
  machine. The standard testing method for abrasion
  ASTM G105-89 (standard test method for conducting
  wet sand/rubber wheel abrasion tests) was
  selected, using as main elements wet sand (Table
  1) and a rubber wheel.
• Secondly, when the laboratory tests had been
  finished, a further test program was carried out
  in an opencast mine. The materials were tested in
  real working conditions and the results of both
  experimental programs were compared.

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OBJECTIVE

• The main objective is comparing laboratory tests
  of abrasive resistance and real field tests to
  select the most appropriate materials for using
  as protective coatings in the excavator teeth. If
  the result is positive, the laboratory tests
  could be used as a less expensive method to
  determine the wear performance of the coating
  under real working conditions.

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MATERIALS

• As it has been mentioned, several types of cast
  iron were selected to study their wear properties
  and performance under real field conditions.
• The different materials tested and some
  characteristics are included in Table below

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LABORATORY TESTS

• Experiment details
• As a laboratory abrasion test, the standard ASTM
  G105-89 was used.
• Laboratory Results
• From the laboratory tests, the weight lost by
  each material was determined and is indicated in
  the following figure.

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Experimental Results
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Field tests in open cast mine

• Field Test
• Initially, the analysis was carried out on 126
  teeth (18 of each material) that were mounted
  onto the first seven buckets of a bucket wheel
  with 20 units. The teeth are mounted on the bun,
  with 11.7m cutting diameter, which rotates to 4.3
  rpm.
• The bucket with excavator teeth mounted on it is
  shown in the figure-1 below

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Fig. 1 - Bucket wheel of excavator.
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Field Test Results

• Value that the company will assign to each
  material, taking in to account duration and
  wire characteristics.
• Note Here material MR5 is taken as reference.

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Comparison between experimental results and field
tests

• MR1 0.85 X
• MR3 4.2 X
• MR4 3 X
• MR5 X
• MR8 1.09 X
• MR9 2.1 X
• MR14 0.9 X

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CONCLUSION

• A comparison between experimental results and
  field test results shows that material MR3 is the
  best choice among the given set of materials.
• The comparison also shows that there is an
  acceptable relation (coefficient of correlation
  0.85) between the laboratory tests and the real
  life behavior (field tests). That is to say, the
  material that shows a good field wear
  performance, also shows it in the laboratory.