COMPARISON STUDY BETWEEN NiHARD4 CAST IRON AND HIGH CHROMIUM CAST IRON FOR SHOT BLASTING BLADE APPLICATION

• Main Author: RUSKANDI (NIM : 23709005); Dosen Pembimbing : Dr.Ir. Budi Hartono Setiamarga, CECEP
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/15219
• Institution: Institut Teknologi Bandung

Blade is a Shot Blasting machine component that serves as a thrower steel shots. Blade undergoes rubbing action or friction with steel shots made of hardened carbon steel in carrying its function. Therefore, Blade must have good abrasive or wear resistance. Material for the Blade in general is a NiHard4 white cast iron. However, data from previous research showed that the rate of the depletion Blade with this material is still quite high at 0.01 mm/h and the average lifespan is only 30 – 40 hours. In additon the use of this NiHard4 is considered expensive because it contains element of Ni in considerable numbers. Based on these issues the abrasive resistance of the Blade need to be improved that is characterized by a lower depletion rate and simultaneously has more economic value through proper material selection. <br /> <br /> <br /> <br /> <br /> The research began with the study on the characteristics of some abrasive resistant cast iron materials. This sequence has resulted in high chromium cast iron as a selected material for the Blade and then proceed with designing the chemical composition that refers to two aspects to be achieved that are better quality and lower prices. After that, Blade is made by sandcasting process. Service test is carried out during the 10.35 hours in both as cast condition and after a heat treatment process to determine its wear rate. Some testing were also performed such as chemical composition and metallography examination, hardness testing, XRD and impact testing in order to examine the relationship of these data with the depletion rate of the resulting Blade. <br /> <br /> <br /> <br /> <br /> The research has resulted in some conclusions that are the use of high chromium white cast iron (2.76%C, 30% Cr) for Blade was proven to have a lower depletion rate or wear rate rather than NiHard4. Its wear rate is 0.003 mm/hr and 0.002 mm/hr in as cast condition and after heat treatment respectively. Hence the lifespan of the Blade is 3 times and 5 times longer than Nihard4 one in as cast condition and after heat treatment respectively. Its manufacturing cost is also cheaper to Rp 11.200,- till Rp 11.500,- compared to NiHard4. Cost saving obtained from the use of this high Cr cast iron is Rp 1.678.400,- and Rp 3.168.000,- in as cast condition and after heat treatment respectively.