Introduction:
The wire drawing process is a metalworking operation used to reduce the diameter of a wire by pulling it through a series of dies. During this process, lubricants are used to reduce friction and heat generation, which helps in achieving a smooth and defect-free surface on the wire. The choice of lubricant plays a crucial role in determining the final surface finish of the wire.

Explanation:
The bright shining surface on the wire is obtained when a thin fluid lubricant is used in the wire drawing process. This choice of lubricant is preferred over other options because of the following reasons:

1. Reduced Friction:
A thin fluid lubricant has low viscosity, which means it can flow easily between the wire and the die surfaces. This reduces the frictional forces acting on the wire during the drawing process. Lower friction leads to less heat generation and prevents damage to the wire's surface, resulting in a bright and shiny finish.

2. Effective Cooling:
Thin fluid lubricants have good heat transfer properties. They can absorb and carry away heat generated during the wire drawing process. Effective cooling helps in preventing excessive heating of the wire, which can lead to surface defects and discoloration. By maintaining an optimal temperature, the thin fluid lubricant contributes to the production of a bright and shiny surface.

3. Uniform Lubrication:
The low viscosity of a thin fluid lubricant allows for uniform and consistent lubrication across the wire's surface. It ensures that the lubricant spreads evenly, forming a thin film between the wire and the die. This uniform lubrication minimizes the chances of surface irregularities and ensures a smooth, polished finish on the wire.

4. Easy Cleaning:
Thin fluid lubricants are easily washable and can be removed from the wire's surface with relative ease. After the wire drawing process, the lubricant can be cleaned off using appropriate cleaning agents or through subsequent washing steps. The easy removal of the lubricant ensures that the wire's bright and shining surface is not masked by any residue.

Conclusion:
In the wire drawing process, the use of a thin fluid lubricant is essential to achieve a bright and shining surface on the wire. The low viscosity, effective cooling, uniform lubrication, and easy cleaning properties of a thin fluid lubricant contribute to the production of a defect-free and visually appealing wire surface.