Abstract
Keywords
Aluminum Casting Alloys, Aluminum Forging Alloys, Friction Welding, Bonding Boundary, Tensile strength
Abstract
Heat-resistance improvement of aluminum castings is the most important target for increasing diesel engine performance in areas such as decreasing diesel engine emission and increasing engine performance. Improving the heat-resistance of piston and cylinder head is one of the effective methods. In commercial aluminum castings, developing the additional elements on base metal and adjusting heat treatment conditions are always used as the general solutions for improving heat-resistance performance.
This paper deals with the partial reinforce method to improve the heat resistance performance; especially the cylinder combustion area. Due to high cost of mass production, friction-welding process has been selected as a partial reinforce method for this research. Under many test results, aluminum forging metal was used for friction-welding material based on their high mechanical and physical performances.
Friction Welding Process
First, cylinder head was fixed on friction welding equipment; whereby the aluminum forging material was used as rotary material to joint to cylinder head. In friction welding process, the water-cooling process was used for decreasing the input heat and decreasing cylinder head construction deformation. In addition, the friction welding shape was designed to increase the joint force to avoid any defect on joint boundary. As a result, it is very important to control the friction revolution, upset force and friction time for controlling the friction welding performance. Water-cooling process was also used as an effective method to avoid the deformation on friction welding area.
The Main Results Obtained are as Follows:
1. Aluminum forging metal was successfully jointed to aluminum castings without any defect.
2. The boundary strength of friction-welded zone is bigger than base metal.
3. Aluminum forging metal shows superior heat-resistance performance during test pieces testing.
4. Production cost is still a subject that needs to be fixed.