Group 4Stapler Material Analysis

Sample 2a - Stapler Housing

7 - Spring

8 - Anvil

9 - Pin

Experimental Issues

• During SEM experiments, organic oils are used. This evaporates, causing a background ‘noise’ of carbon during SEM analysis.

• Contamination from Bakelite could also occur.

• Calculation of Carbon content in materials is difficult.

Nickel Plating

• Nickel coating may have a carbon content in it as part of the manufacturing process. Plating solutions can contain carbon to prolong life

• Could contain organic compounds to eliminate the mechanical polishing process

C % wt Fe % wt Ni % wtSample 2a - Staple Housing 3.81 3.75 91.73Sample 7 - Spring 6.41 5.88 87.05Sample 8 - Anvil 2.2 2.52 95.28

Sample 2a – Staple Housing

• Low quality steel

• Ferrite structure with low carbon content (1.9 C %wt, 97.1 Fe %wt)

• 94.6 HV

Sample 7 – Spring

• Nickel plating • Forming occurs

via cold drawing process.

• 655 HV due to high volume of dislocations

Sample 8 - Anvil

• Nickel plated

• Martensite at edges

• Cementite present

• Quenching process

• Carburisation (6 C %wt, 94 Fe %wt)

• 135 HV in bulk of material

Sample 9 - Pin

• Ferrite structure with some inclusions (4.5 C % wt, 95 Fe %wt)

• Forming can be seen in pin cross section.

• 221 HV

• Low quality steel

Potential Alternatives

• Recyclable materials

• Alternative design

• Multifunctional

Bibliography

• R.E.Smallman, R.J.Bishop, (1995), Metals and Materials, Butterworth-Heinemann, USA

• P.E.J. Flewitt, R.K.Wild, (2003),Physical Methods for Material Characterisation, 2nd ed, IoP, UK

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Thank you!

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