An Analysis of Intermetallic Bonding between a Ring Carrier and an Aluminum Piston Alloy
- PDF / 2,338,686 Bytes
- 8 Pages / 593.972 x 792 pts Page_size
- 79 Downloads / 260 Views
RODUCTION
PISTONS are made mostly of aluminum alloys (Al-Si-Cu-Ni-Mg), which represent a special group of industrial alloys that are used in the automotive industry due to a combination of good casting and mechanical properties,[1–5] high strength at elevated temperatures [e.g., up to 623 K (350 C)],[1,2] and also resistance to sudden temperature changes.[1,3–5] Different types of piston alloys contain various amounts of major and minor alloying elements. The usual content of alloying elements is 11 to 23 wt pct Si, 0.5 to 3 wt pct Ni, 0.5 to 5.5 wt pct Cu, 0.6 to 1.3 wt pct Mg, up to 1.0 wt pct Fe, and up to 1 wt pct Mn.[3–5] The mechanical properties of aluminum piston alloys are defined by their micro- and macrostructures. Depending upon the engine type and operating conditions, there are different design solutions for pistons,[5] namely mono-metallic aluminum pistons, pistons with a ring carrier, pistons with a cooling channel, pistons with a cooling channel and a ring carrier, pistons with controlled expansion, pistons with controlled spreading and a ring carrier, pistons with an iron coating, forged pistons, split pistons, pistons with the first groove reinforced and pistons with an undulating mantle, etc. This paper discusses pistons for highly loaded diesel engines with a ring carrier. In order to meet the requirements for lower fuel consumption, the mean effective pressure of diesel engines for commercial vehicles is growing. These are the engines that must be SREC´KO MANASIJEVIC´, Research Associate, and RADOMIR RADISˇA, Program Manager, are with the LOLA Institute, Belgrade, Serbia. Contact e-mail: [email protected] NATALIJA DOLIC´, Assistant Professor, and ZDENKA ZOVKO BRODARAC, Assistant Professor, are with the Faculty of Metallurgy, University of Zagreb, Sisak, Croatia. MILE DJURDJEVIC´, Program Manager-R&D, is with the Nemak Europe, Linz, Austria. Manuscript submitted November 21, 2013. METALLURGICAL AND MATERIALS TRANSACTIONS A
designed to withstand high loads for long periods of work, especially in the critical areas of pistons that are thermally highly loaded. Today’s modern aluminum pistons with a ring carrier can meet these requirements. The ring carrier is specially designed for the formation of the first piston ring groove in highly loaded diesel engines. The ring carriers of standard features are made of austenitic cast iron (Ni-Resist) in order to increase the wear-resistance of the first ring groove, especially in engines with high loads.[5–10] Austenitic gray iron castings are used primarily for their resistance to heat, corrosion, and wear, as well as controlled expansion, temperature stability, castability, and machinability. The Ni-Resist ring groove inserts are manufactured into pistons to increase engine and piston life. They can also improve the air tightness of the piston in the cylinder, increase the efficiency of combustion, reduce emissions and air pollution, and contribute to the environment. These inserts are not presented to strengthen the piston. In reality, as they represent
Data Loading...
