Stress Releaving

After the casting process, it’s essential to mitigate residual stresses that can compromise the integrity and performance of the final product. Our stress relieving process is meticulously designed to enhance the durability and reliability of your castings. Here’s a detailed look at how we ensure optimal outcomes.

Understanding Residual Stresses: When metal is cast, it cools unevenly, leading to internal stresses that can cause warping, cracking, or reduced mechanical properties. These stresses can arise from temperature gradients, phase transformations, and the solidification of the metal. To counter these challenges, we employ a comprehensive stress relieving methodology.

Pre-Treatment Inspection: Before initiating the stress relieving process, we conduct a thorough inspection of the castings. This includes visual assessments and non-destructive testing (NDT) techniques like ultrasonic testing or dye penetrant inspections to identify any existing flaws or irregularities. Understanding the specific characteristics of each piece allows us to tailor our approach.

Heat Treatment: The cornerstone of our stress relieving process is heat treatment. We carefully heat the castings to a pre-determined temperature, typically between 300°F and 1200°F (150°C to 650°C), depending on the material specifications. This controlled heating process allows the internal stresses to relax without altering the material’s structure.

Uniform Heating: We utilize precision heating equipment to ensure uniform temperature distribution throughout the casting. This prevents the introduction of new stresses that can occur with uneven heating.

Soaking Period: Once the desired temperature is reached, we maintain it for a specific soaking period. This duration, usually ranging from 1 to several hours, depends on the material thickness and type. The soaking phase is crucial as it allows enough time for the metal atoms to rearrange and relieve stresses.

Controlled Cooling: After the soaking period, controlled cooling is paramount. We gradually reduce the temperature of the castings to avoid thermal shock, which could introduce new stresses. Depending on the specifications, we may use air cooling or controlled furnace cooling to achieve a gentle and steady temperature drop.

Final Inspection: Once the castings have returned to room temperature, we conduct a final inspection to ensure that the stress relieving process was effective. This may involve additional NDT methods and dimensional checks to confirm that the castings meet stringent quality standards.