Stop wasting Energy on Heat Treatments

Are you tired of dealing with skyrocketing energy bills due to inefficient heat treatment processes for your HPDC parts? Let’s discuss how optimizing your heat treatment can lead to massive energy savings and improved part quality.

If you check the specifications for crash-relevant alloys, like AlSi10MnMg, you’ll notice that every OEM requires a two-step heat treatment. The first step of that heat treatment is the solutionizing step. Dissolving primary phases and distributing solute elements homogeneously across the aluminum matrix is necessary. This is achieved within minutes for elements like Magnesium or Zinc, while elements like Copper require hours for the same outcome. The eutectic silicon needles, which are sharp and often a starting point for cracks, become round during the solution heat treatment. A sphere has the lowest surface area in relation to its volume, making it the most surface-energy-efficient form.

Subsequently, the quenching process takes place. The castings are rapidly cooled to solidify the homogeneous condition of the matrix. However, this state isn’t stable and tends to form dispersoids again. While water-quenching cools the fastest, it results in the most significant distortion of the casting. On the other hand, air-quenching is slower but reduces distortion considerably.

The second step of the heat treatment process is aging. The quenched matrix is in a supersaturated state and thermodynamically unstable. All the elements are dissolved within the Al-matrix, causing a lot of stress. These elements aim to form precipitates, and the aging process dictates how they form. The precipitates need to be small to increase strength without significantly affecting the material’s elongation.

Just from reading, you can already see that multiple factors impact each other. The temperature level affects the diffusion of solute elements. The chemical composition fluctuates throughout the production. A higher temperature enables faster diffusion, but it also decreases the strength of aluminum. This, in turn, affects the distortion of the part. The quenching rate also impacts properties after annealing and distortion. Moreover, castings with higher wall thicknesses require more time in the furnace, and higher temperatures demand more gas or electricity to heat up the furnace. Changes in the casting process additionally result in different residual stresses, which further influence distortion after heat treatment.

Conducting heat treatment trials is time-consuming and resource-intensive. Numerous factors (product, chemical composition, temperatures, times, quenching rates) must be considered. Even with DOE experiments, the process remains lengthy, and achieving the optimal point for production is uncertain.

If you’re interested in cutting your energy costs while increasing the quality of your castings, schedule a free Consultation Call down below.