INCREASING THE YIELD STRENGTH OF BRASS AND NICKEL ALUMINUM BRONZE MATERIALS BY COLD ROLLING AND PRECIPITATION HARDENING METHODS AS APPLICATION OF ELECTRIC KEY IGNITION SPRINGS

• Main Author: Kristika, Alia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67789
• Institution: Institut Teknologi Bandung

One of the components of the electric switch ignition is an electric key ignition spring which, according to PT KAI's standards, is made of bronze aluminum material. The electric key ignition spring is a plate that is electrified so that it can move up and down. When operating, these components often undergo plastic deformation, so that these components can not move to their original position. For this reason, the electric key ignition spring must have a high yield strength so that it is not easily plastically deformed. This research aims to increase the yield strength of the spring contact with the cold rolling method with variations in thickness reduction for brass and nickel bronze materials and precipitation hardening methods with aging temperature variations for nickel aluminum bronze materials. Before submission, chemical composition tests and tensile tests were carried out to obtain specifications for the test samples. Samples that have been enjoyed are then given several tests, including tensile testing, microstructure, and hardness testing. From the tests that have been carried out, cold rolling and precipitation hardening can increase the yield strength of both materials. For cold rolling, the yield strength of the two materials increases with the addition of the thickness reduction percentage. The optimal yield strength value for the cold rolling process of brass and nickel aluminum bronze materials is found in a 20% thickness reduction of 619,05 MPa and 716,41 MPa, respectively. As for the precipitation hardening process on nickel aluminum bronze material, the optimal yield strength value is at an aging temperature of 350 0C of 502,66 MPa.