Generally, for elbows with different materials or wall thicknesses, different forming processes need to be selected. Commonly used seamless elbow forming processes include pushing, stamping and extrusion. Among them, the push-in of the elbow is caused by hot stamping. The elbow is a kind of pipe fitting used for pipe turning. It accounts for a large proportion of the pipe system, about 80%. The unique advantage of the elbow is that it has a more advanced manufacturing process. We should learn more about the elbow, and then the editor will introduce you to the push forming of the elbow.
Pushing is a commonly used bending method for bending stainless steel pipe fittings. The bending of elbows mainly uses the pushing method. However, according to the process characteristics, the push forming of elbows can be divided into cold push bending and hot push bending.
1. Cold push elbow forming
The so-called cold push elbow refers to the bending method of pushing the elbow under normal temperature working conditions. The steel pipe with a smaller diameter is pushed into a special mold with a slightly larger diameter, and the bending device is used for bending.The cold push elbow device is simple in structure, does not require special equipment, has high productivity, and has an elbow with a small bending radius (relative bending radius r / d≈1.3); therefore, the applicable range of cold push is: the elbow section is small (≤ 3%-5%), the outer tube wall becomes thinner (≤9%) elbows, but usually the relative thickness of the stainless steel tube is required to be t /d ≥ 0.06, otherwise, the tube blank will be caused by poor rigidity Loss of stability, resulting in bending deformation.
2. Hot push elbow forming
Compared with cold push elbow forming, hot push elbow forming is a method to push the elbow under high temperature conditions. The push during heating will cause the tube blank to produce axial expansion and axial bending deformation, thereby reducing Push the steel pipe with a smaller diameter into a special mold with a slightly larger diameter, that is, on a special pushing machine, pass through the horn mandrel under the action of axial thrust.
The hot push elbow determines the diameter of the tube blank according to the law of constant volume before and after the plastic deformation of the metal material, and the diameter of the tube blank used is smaller than the diameter of the elbow. The deformation process of the tube blank is controlled by the core mold. Even if the metal has fluidity, it will compensate for the thinning, but it cannot completely solve the problem of uneven wall thickness of the push elbow. The outer arc wall thickness will still be thinner than other places.
The above is the introduction of the forming method of the push elbow. I hope everyone can understand the forming method of the push elbow and can customize the corresponding elbow according to your needs.
