Briefly introduce the characteristics and methods of thinning and stretching

Thinning and stretching is a kind of stamping and stretching process, which aims to realize the forming process of extremely thin-walled cup-shaped parts, and it can also realize the forming of extremely thin-walled pipe parts, such as high-pressure containers and bullet shells. So what are the characteristics of thinning and stretching, what methods are there, and what kind of materials are suitable for thinning and stretching? The author will ask you to give a brief introduction below. 1. The characteristics of thinning and stretching: (1) The gap between the concave and convex molds is smaller than the thickness of the blank, and the straight wall part of the blank is compressed when passing through the gap, resulting in obvious thinning phenomenon, which makes the side wall height Increase, so it is called thinning and stretching. (2) The thinned stretched parts are of high quality, the wall thickness is relatively uniform, the wall thickness deviation is within ±0.01mm, and the surface roughness Ra value is below 0.2um. And because of the two-way compression, the grains are fine and the strength is improved. (3) The residual stress of the thinned tensile parts is relatively large, and some even crack during storage. This phenomenon can be eliminated by low-temperature tempering. (4) There is no wrinkle problem (compared with non-thinning stretch), and no edge holding device is needed. 2. There are two methods for thinning and stretching: (1) The wall thickness becomes thinner and the inner diameter is also reduced --- The deformation and stress are more complicated, and the workpiece is easy to crack, so it is usually not used. (2) The wall thickness becomes thinner, and the inner diameter is not significantly reduced-it is a more commonly used method. 3. The materials commonly used for thinning and stretching are: copper, oxygen-free copper, phosphor bronze, aluminum, aluminum alloy, low carbon steel, stainless steel, etc. The above is a brief introduction of thinning and stretching, I hope it will be helpful to you. Precision, 12 years dedicated to the processing and customization of precision drawing parts, providing various stamping drawing parts, special-shaped drawing parts, thinning and drawing, welcome to customize with drawings and samples. [Related Recommendations] Learn more: How to select molds for drawing parts