QCAA Engineering Materials

Mild carbon steel contains a low percentage of carbon ($< 0.3\%$), making it ductile and malleable but unable to achieve the high hardness required for punches through heat treatment.

Medium carbon steel ($0.3\% - 0.6\%$ carbon) offers a balance of ductility and strength suitable for standard automotive axles, but it lacks the extreme wear resistance and hardness needed for punches.

High carbon steel is hard and used for many cutting tools, but ultra-high carbon steel is preferred when maximum hardness and wear resistance are the primary requirements for the tool.

Ultra-high carbon steel ($1.25\% - 2.0\%$ carbon) can be tempered to achieve exceptional hardness and wear resistance, making it the most suitable material for heavy-duty punches and specialized axles.

Nylon is a non-biodegradable polymer; while used in sutures, it would require a second surgery to remove if used as a screw, making it less suitable than bioabsorbable options.

Polypropylene is a non-absorbable material typically used for surgical meshes and sutures, not for temporary fixation devices that should dissolve over time.

Polylactic acid (PLA) is biodegradable and biocompatible, meaning it breaks down into harmless lactic acid in the body, eliminating the need for a second surgery to remove the screw.

Polyvinyl chloride (PVC) is generally used for external medical devices like tubing and blood bags, not implants, due to biocompatibility issues and the presence of plasticizers.