Heat treatment of aluminum forgings in construction machinery is a key process, which can significantly improve the mechanical and physical properties of aluminum forgings. This paper will introduce the common heat treatment processes including aging treatment, solution treatment and quenching treatment, and explain their effects on construction machinery aluminum forgings in detail.
- Aging treatment: Aging treatment means that after solution treatment, the aluminum forgings are kept at the appropriate temperature for a period of time, so that the supersaturated solid solution in the mixture is separated out of the equal state or supersaturated crystal particles disappear, thereby improving the strength and hardness of the material. Aging treatment is divided into natural aging and artificial aging two ways.
Natural aging: The aluminum forgings after solution treatment are left at room temperature and aged by cooling themselves. This method usually takes a long time, but it can promote the uniform distribution of precipitated phase and improve the strength and hardness of aluminum forgings.
Artificial aging: Put the aluminum forgings after solution treatment into a constant temperature furnace and age treatment under certain temperature and time conditions. The artificial aging treatment time is relatively short, and high strength and hardness can be obtained. The key is to choose the appropriate time and temperature conditions to avoid the problem of over-aging or under-aging.
- Solution treatment: Solution treatment is to heat the aluminum forgings to a certain temperature, so that the alloying elements are dissolved in the aluminum matrix to form a uniform solid solution, and then quickly cooled to maintain the dissolution structure formed by it. Solid solution treatment can eliminate the phase separation in aluminum forgings and improve its plasticity and toughness.
The temperature and time of solution treatment have great influence on the result, which needs to be optimized according to the specific alloy and aluminum forgings. Higher temperature and appropriate holding time can promote the rapid dissolution of alloying elements, but too high temperature and too long holding time will lead to grain growth and precipitate aggregation, reducing the mechanical properties of the material.
- Quenching treatment: Quenching treatment is to change the structure of aluminum forgings by rapid cooling, thereby increasing its hardness and strength. The common methods of quenching treatment include water quenching, oil quenching and air cooling.
Choosing the right quenching medium and cooling rate is the key. Water quenching can achieve the fastest cooling rate, but it is easy to produce deformation and cracks. Oil quenching is a medium speed cooling method that can provide better results while taking into account hardness and deformation. Air cooling is the slowest form of cooling and is usually used for thicker aluminum forgings.
Through heat treatment process, aluminum forgings of construction machinery can obtain a series of superior properties. Solution treatment can improve the plasticity and toughness of the material, aging treatment can improve its strength and hardness, quenching treatment can further increase its hardness and strength.
It should be noted that different construction machinery aluminum forging alloys and process conditions may be different, so in actual operation should be optimized according to the specific situation. During the heat treatment process, parameters such as temperature, time and cooling speed are strictly controlled to ensure the ideal heat treatment effect.
