how does aluminum alloy processing stress eliminate credit
aluhm > 02-25-2018, 06:08 AM
Aluminum alloy is the most widely used in industry of non-ferrous metal structural materials, aluminum alloy density is low, but the intensity is high, close to or more than high-quality steel, plastic, can be processed into various profiles, with excellent electrical conductivity, thermal conductivity and corrosion resistance, in aviation, aerospace, automotive, machinery manufacturing, shipping and widely used in chemical industry.
Aluminum alloy in the process especially machining process prone to large deformation and stress lead to size out-of-tolerance scrap, some no deformation at the time the poor tend to produce deformation cause greater system after installed. The existing methods of stress, such as thermal aging stress, vibration aging stress, mechanical drawing, model correction and deep cold composite stress, etc.
Heat ageing to stress generally for small parts, is a traditional method to stress, because a lot of aluminum alloy material is very sensitive to temperature, so limits the aging temperature can't is too high, otherwise will reduce the strength of the material. So usually thermal aging in temperature is not higher than 200 ℃, so the stress effect is only about 10-35%.
Vibration aging to stress is the use of a controlled vibration energy by holding the vibrator on the surface of the products processed on the processed products, at a specific frequency vibration under processing, so as to achieve the aim of release, to reduce the residual stress in workpiece. This kind of processing method is common in large structural parts, welding and casting parts to stress treatment, the removal effect is about 50-60%.
Mechanical stretching method is the principle of eliminating stress after quenching of aluminum alloy plate, add a certain amount of permanent tensile plastic deformation along the rolling direction, make the tensile stress with the original plastic deformation occurred after quenching residual stress superposition, to ease and release residual stress. The results show that the mechanical drawing method can eliminate more than 90% residual stress. However, this method is only suitable for simple parts with simple shape, and it has a high requirement for the homogeneity of the aluminum alloy sheet before stretching, and is mainly used in aluminum processing factories.
Loading module and the correction method of cold pressing is in a special finishing the mould, through strict control of set limit to cold plastic to eliminate the residual stress of aluminium alloy forging complex shape, the method is to adjust, not eliminate the overall stress level of the parts, it makes some parts of the residual stress on aluminum alloy products was released at the same time, has the potential to other parts of the residual stress increased. In addition, due to the large residual stress of the workpiece, the deformation of the mould can cause the cold to harden, crack and fracture. While too little deformation causes the stress relieving effect, and the cost of production of plastic mold is high, the difficulty of the orthopedic operation is bigger also, so the limitations of such a method is in practice application.