Precision Measuring Tools and Ferrous Metal Properties

Precision Measuring and Comparing Tools

• Metro: This may be collapsible or flexible. It is used to measure medium-sized and large objects, though sometimes inaccurately.
• Caliper (Size): A device widely used for small and medium-sized measurements, including exterior, interior, and depth.
• Goniometer: A rule that moves on a pivot, used specifically to measure angles.
• Micrometer: Ideal for small external and internal measurements requiring high precision.
• Clock Comparator: Allows for the testing of surface finishes and eccentricities through the relative comparison of two surfaces.
• Depth Micrometer: Features an axis to determine the depth of a piece with a precision estimated at one-hundredth of a millimeter.
• Diabase Marble: Used to check surfaces and serves as a reference for other measuring devices.
• Plug Gauge (Caliber Buffer): Used to verify that an internal measurement falls between two determined values.
• Thickness Gauge (Especimetro): Used to check the thickness of plates, cables, and other items in a range from 0 to 10mm.

Ferrous Metals and Carbon Structures

Ferrous metals: Iron increases its hardness when charcoal (coal vegetal) is added. Different structures exist within these metals:

• Ferrite: Pure iron or ferrite is softer and ductile.
• Cementite: This structure is fragile and hard due to the addition of carbon.
• Pearlite (Perlíca): Consisting of ferrite and cementite plates, it possesses intermediate properties.
• Austenite: This structure is deformable, slightly hard, and tough.
• Martensite: After cementite, this is the hardest structure.

Mineral Extraction and Processing

Minerals of origin: Metals are found in two forms: free (such as silver and copper) or combined (with another chemical element, such as iron). Minerals are typically found mixed with dirt and rock.

The useful portion of the mineral is called ore (mena), while the impurities are referred to as gangue (ganga). Depending on the localization, there are different ways of extracting minerals, such as quarries, open pits, and gallery mines.

The processes that determine if extraction is profitable include: geographical location, the required extraction method (quarries or mines), the nature and quality of the ore, and various economic and social factors. The ore is separated from the gangue through a process called concentration.