Rail car brake caliper - Assignment Example

Rail Car Brake Caliper Material Review for Rail Car Brake Caliper Properties of Ferrous and Non-Ferrous Metals Ferrous metals primarily contain iron. They include metals such as steel, which is a metal alloy of iron. They have high magnetic properties, high tensile strength, and durability, offer slight resistance to corrosion and are less expensive (Somaiya, Wieffering & Blaine, 2008). Non- ferrous metals are alloys not containing iron. Important non- ferrous metals include Aluminium, copper, zinc, lead, titanium, cobalt, nickel and chromium.

These metals have desirable characteristics. Copper has high conductivity, aluminum has a low weight and zinc has a non-magnetic property and is resistant to corrosion, titanium has low density and high melting point. Non-Ferrous metals are costly.Material Properties Important To the DesignstrengthIn designing the caliper the yield strength, tensile strengths and the fractured structure are significant. Yield strength refers to the minimum tension that yields plastic deformations (Somaiya, Wieffering & Blaine, 2008).

Tensile strength refers to minimum stress essential for the failure of the material. Fracture resistance is significant in measuring strain degree. Toughness and fatigueDescribes the resistance of a material to fracture and is measured using the aggregate energy contained in the material (Somaiya, Wieffering & Blaine, 2008). In the design of the brake caliper, toughness is important since strong materials absorb more energy compared to fragile ones. DuctilityDuctility is a degree of the amount of bend or strain a material can endure before breaking.

Low densityMaterials with low densities are ideal for constructing the caliper to reduce the weight of the railcar but to maintain its strength.Resistance to corrosionDesign materials of the brake caliper should possess high corrosion resistance. Melting PointsHigh melting point is significant for materials for easy welding.costMaterials used in the design should be cost effective.Mechanical Testing Methods Tension tests include; static tension tests, which define the infringement point of the material and compression tests that determine the material’s reaction to crushing (Somaiya, Wieffering & Blaine, 2008).

In general, tensile testing determines the strength and amount of stretch in the material. The failure point is the ultimate strength. Torsion test measures the relationship between stress-strain of a material. Hardness tests, which include Brinell hardness test, which uses a steel ball with enormous force. The applied weight for harder materials like iron and steel is about 3000kg while that of softer materials like aluminium alloys and copper is about 500kg (Somaiya, Wieffering & Blaine, 2008).

Vickers hardness test is obtained by dividing force by the external area. Rockwell hardness test measures the penetration depth in the material to determine the hardness. Scratch test involves scratching harder materials to rank their hardness. Harder materials scratch the softer ones. Mohs hardness scale is applicable. Rebound test utilizes changes in potential energy to determine the hardness. Indentation tests utilize the impression of force on the material to test for hardness.Recommendation for Material Aluminum oxides make calipers abrasives that boost friction because of its low density.

Steel filler recommended for boosting the strength and stiffness of the caliper. Copper improves calipers performance by providing heat and corrosion resistance. Ceramic pads reduce the overall weight and decrease noise (Somaiya, Wieffering & Blaine, 2008). Graphite increase friction and acts as a lubricant since it is cheap. Lead sulfides stabilize friction at different temperatures. Calcium hydroxide boots performance since it inhibits corrosion. Titanium used in designing calipers due to its low density and high melting points.

ReferenceSomaiya, A., Wieffering, N., & Blaine, D. (2008). Materials Technology. Cape Town: Pearson Education South Africa.