THE EFFECT OF ALLOYING ELEMENTS ON THE MICROSTRUCTURE AND CHARACTERISTICS OF STEEL FOR CUTTING EDGE APPLICATION

• Main Author: Latif, Abdul
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/56599
• Institution: Institut Teknologi Bandung

Indonesia is a country that has abundant natural resources, including coal with total resources of 143.73 billion tons. Coal mining requires several heavy equipment, one of which is a bulldozer to displace minerals. The part of the bulldozer that is in direct contact with the mining area is called the blade, which is coated with highhardness steel at the end (cutting edge) to handle the wear phenomenon. Cutting edge materials purchased from vendors by PT Astra Otoparts – Engineering Development Center (Astra EDC) have a service life of 72 hours when hauling is carried out. Therefore, this study was conducted to examine the characteristics of the material used for cutting edges, as well as the influence of alloying elements on the microstructure and mechanical properties of steel for cutting edges. The material analyzed is the original High Strength Low Alloy (HSLA) steel which was later referred to as sample A which is currently supplied by Astra EDC, as well as carbon steel and wear plate which is then referred to as samples B and C which are also produced by other vendors and are proposed by Astra EDC to be a replacement material for original parts. All materials analyzed in this study are materials that have been heat treated by the vendor, so the analysis carried out focuses on the characteristics of each material. Prior to testing the mechanical properties, the material is characterized first. The characterizations were chemical composition analysis using Optical Emission Spectroscopy (OES) and microstructure analysis using an optical microscope (OM). After obtaining data on chemical composition and microstructure, hardness testing was carried out with the rockwell hardness test, toughness with the charpy impact test, and wear resistance with the wet sand wheel abrasion test for each material in order to obtain data, then the analysis could be carried out. Based on the result of the experiments, the material used for the cutting edge is steel with the majority of alloying elements in the form of silicon, manganese, chromium, and molybdenum. The A and B Sample materials are steel that has a bainitic and martensitic structure respectively, while C Sample has a pearlitic structure. The A, B, and C Samples have a hardness of 47.2 each; 26.8; and 49.7 HRC. From the experimental results, C Sample is a material that has the highest hardness and toughness. Wear resistance is directly proportional to the hardness of each material. The wear rates experienced by the A, B, and C Samples are 0.04; 0.08; and 0.02 gram/hour. C Sample is a material that can be used as an alternative to replace cutting edge materials, and is estimated to have a service life of up to 144 hours when hauling is carried out.