Analysis of mechanical properties connecting rod bolts outboard. motor FT50CEHD

Transcription

1 Int. Journal of Applied Sciences and Engineering Research, Vol. 4, Issue 5, by the authors Licensee IJASER- Under Creative Commons License 3.0 Research article ISSN Analysis of mechanical properties connecting rod bolts outboard motor FT50CEHD Ery Diniardi 1, Syawaluddin 1, Anwar Ilmar Ramadhan 1 Rifatul Mubarok 1, Hasan Basri 2 1-Mechanical Engineering Department, Faculty of Engineering, University of Muhammadiyah Jakarta, Jakarta 10510, Indonesia 2- Automotive and Heavy Equipment Department, Faculty of Engineering, University of Muhammadiyah Jakarta, Jakarta 10510, Indonesia DOI: /ijaser Abstract: Damage to the outboard motor FT50CEHD occurs when the boat was used for 10 hours. Damage includes to the outbreak of cylinder block, curved connecting rod which caused fracture of the bolt connecting rod, and its occurs just in cylinder number one. The purpose of this research is to determine the main cause of damage to the connecting rod bolts FT50CEHD outboard motor. The method used was a visual inspection / non-destructive test, chemical analysis, Mechanical Properties Analysis and Metallography Examination by SEM (Scanning Electron Microscope) on the bolt fracture surface. Results of laboratory testing bolt material in good condition in terms of chemical composition and mechanical properties as in accordance with the standard material. Typography broken bolt shows the type of ductile fracture and the fracture surface showed dimple fracture in the middle and on the edge was the shear fracture. This type of fracture was caused due to the excessive tensile and torsional force. Conclusion of this research was the connecting rod bolt damage occurred because of excessive tightening torque. Keywords: Outboard engine, connecting rod bolts, scanning electron microscope, mechanical properties 1. Introduction Indonesia as an archipelagic country where most of Indonesia is water and consists of islands as well as maritime policy a priority of the current government, the marine transportation modes that ship is still a marine transportation mode that works well and continues to grow (ASM team, 1993). In the development of engine technology ships are quite efficient in supporting the activities of inter-island transactions reviewed in the use of fuel and power are great, the safety factor of the ship's engine itself becomes the most important factor (Dagel John F 2011). This encourages industry-competitive automotive industry to produce a product quality machine. The reliability of a ship's engine must be assured either directly or indirectly. This meant that when ships used to operate in carrying out activities not experience disruption caused by the ship's engine died suddenly in the middle of the ocean, so it will be very detrimental to the vessel and also threaten the safety of the ship (Dieter, G.E 1996). Outboard engine is the engine of the boat, or small boats which consists of driving the engine, transmission, propeller or water jet. Machine attached to the stern of the boat. Aside from being a mover outboard engines are also used to drive the boat / ship and its engine by turning the propeller on an axis ( Compared to the engine in a ship, outboard motors can be easily removed from the vessel for storage or repair. Because of the ease of this that many ship owners who used to wear in the engine switch to the outboard engine ( Especially now outboard engines are *Corresponding author ( anwar.ilmar@ftumj.ac.id) 665 Received on August 2015; Published on October, 2015

2 already available that is powered up to 350 HP (Misumi corporation 2007). Damage occurs when the outboard engine FT50CEHD new vessel reached about 10 hours in total use of new events such damage first occurs. Problems that occur on these machines is quite serious because at the time the ship operates the engine suddenly died suddenly in the middle of the sea (Ramachandran V et al., 2005). Through the process of dismantling visible damage include rupture of the cylinder block, curved due to broken connecting rod connecting rod bolts, all of which occur in cylinder No. 1 (one). See Figure 1. Figure 1: Damage of Engine FT50CEHD 2 Research methodology The method implemented in this study is testing labs to test the metallurgical and materials. Covering visual examination, examination of the chemical composition, mechanical properties examination, and examination of bolt fracture surface using SEM (Scanning Electron Microscope). Flowchart of this research can be see Figure 2. Figure 2: Flowchart of research 666

3 3. Results and discussion 3.1 Visual inspection Through demolition (overhaul) cylinder block of machine FT50CEHD discovered damage to materials crank pin and bearing in the form of surface scorched / black indicating the existence of friction excess and found the crooked connecting rod is then followed by the discovery of damage to the lining cylinders and rupture of the crankcase / chamber cover shaft crank of which are indicated as a result of colliding with the material connecting rod cylinder. 3.2 Micro inspection In the connecting rod bolt fracture shows the type of broken clay due to the tensile load is seen by the reduced diameter or cone shape and the fracture surface looks stringy. See Figure 3. Figure 3: Connecting rod bolt fracture surface 4. Chemical composition analysis Testing the chemical composition of material connecting rod bolts using optical emission spectrometer. Methods of testing done by ASTM standard A751; ASTM E415. Results of chemical composition analysis can be see Table 1. Table 1: Comparison of the chemical composition of the material standard with a broken bolt sample Chemical Material No Composition ( %) JIS G4105 SCM435 sample of bolt 1 C Si Mn P S Cu Ni Cr Mo

4 Based on Table 1 shows the chemical composition in accordance with standard specifications bolt material is JIS G 4105 SCM435, so this is a good bolt material. 4.1 Analysis of mechanical properties Tensile testing The standard test used by Test Laboratory Department of Metallurgy and Materials Engineering refers to the standard JIS Z 2241; ISO while testing machine used is Gotech AI-7000 LA 10 with tensile speed of 25 mm / min. Code Table 2: Results of tensile testing standard connecting bolt Sample Dimension [mm] Area [mm 2 ] Length [mm] Tensile Strength [Kg/mm 2 ] Yield Strength [Kg/mm 2 ] Elongation [%] Connecting rod bolt Hardness testing Hardness testing cylinder connecting rod bolt conducted to determine changes in the nature of violence. From the test results on samples of material hardness connecting rod bolt cylinder indicates that the material hardness values between to HRC. Table 3: Hardness value broken connecting rod bolt Positions Value of Hardness (HRC) Table 3 above can see that the bolt sample hardness value of 41.8 HRC. If the converted value of sample hardness approaching bolt with tensile strength of the material in the tensile bolt (bolt standard) of 135 kg / mm2. It can be concluded good mechanical properties bolt. 4.3 Metallography analysis with SEM SEM testing conducted on connecting rod bolt fracture to see typography fracture and cracking mechanisms. See Figure 3 and

5 Hill Fracture Cracks Amid The Figure 3: Fracture surface SEM magnification of 100X and 200X Figure 4: Fracture surface SEM magnification of 500x Figure 3 and 4 visible features of the basin indicating that the area is experiencing a core void before the break. Fractures that occurred showed a collection basin bowl basin as a result of the incorporation of micro void. Hollows have been called a dimple. 669

6 The fracture process starting from the incorporation of micro void material. Micro void core in areas of discontinuity strain caused by second-phase particles, inclusions, and the grain boundary. with increasing strain on the material, then micro void will grow together and form a continuous fracture surface. Judging from its size, the dimple is formed there are small and large while the size of the basin that is formed on the fracture surface is also affected by the number of particles and the distance between the particles which micro void if the number of particles slightly and the distance between the particles apart so micro void will grow bigger before joining with other micro void. Thus forming a large basin. While a small basin formed if the number of particles to each other more and so micro void could not grow bigger when joining micro void others. At the edge of the fracture surface is visible grains shift from a hill leads into fault. Analysis of the two-part fracture is a fracture dimple proficiency level resulting from the imposition of excessive tensile and shear fractures were caused by shear force or in this case a large torsional force. Analysis origin fusion of two styles that excessive tightening torque that is out of specification. 4. Conclusion Based on the research results obtained the following conclusions: 1. Material broken connecting rod bolts in good condition in terms of chemical composition and mechanical properties as standard material in accordance with the connecting rod bolt is JIS SCM Typography connecting rod bolt fracture surface using the SEM shows the type of broken clay and fault fracture surface shows dimple in the middle and on the edge is the shear fracture. This type of fracture was caused due to the imposition of excessive tensile and torsional force large. 3. The main cause damage to the connecting rod bolts for tightening torque excess so that the bolt is deformed in the form of necking or narrowing of the diameter of the screw approach the plastic limit bolt material so that when exposed to the additional burden resulting in a broken bolt and engine failure. 5. References 1. ASM team, ASM Metal Handbook Volume 12 Fractography, American for Metals, The United States of America 2. Dagel John F Piston, Piston Rings, and Connecting Rod Assembly, Diesel Engine Repair, The United States of America 3. Dieter G.E Mechanical and Metallurgy, Third Edition, Jakarta Misumi corporation, 2007, Misumi part cataloque. Tokyo, Japan. 7. Ramachandran V, Raghuram. A.C., Krishnan. R.V., Bhaumik. S.K Failure Analysis of Engineering Structures, ASM International, Ohio, United States 8. Yamaha Motor Company, Ltd Stroke. Hammamatsu : Yamaha Motor Company, Ltd. 9. Yamaha Motor Company, Ltd Service manual FT50C, FT50D. Hammamatsu : Yamaha Motor Company, Ltd. 670