The elbow push system? - The main parameters of the geometric shape of the curvature radius R, and the radius of curvature of round cross section perpendicular to the roundness (the actual cross-sectional diameter of the the Ds - standard cross-sectional diameter Db) and the thickness of Delta (see Figure 1). The geometry of the process parameters affecting elbow push system: push the system with the blank material, wall thickness and outer diameter, material and shape of the mandrel head, the heating temperature and its distribution as well as the advancing speed. The following discussion of the process parameters to push the system elbow geometry. (1) push the system elbow blank material, wall thickness and outer diameter to push the system elbow geometry affect the thermal power industry is used to push the system elbow material the WB36 and A335P22. High temperature plasticity of the WB36-temperature strength is less than the high-temperature strength of the A335P22 WB36 less than A335P22 the high temperature plastic, the WB36 thermal conductivity less than the thermal conductivity of the A335P22. Therefore, in the case of the same shape and size for the billet diameter, wall thickness, and the mandrel head, WB36 and mold bonded performance to less than A335P22. Push the system elbow normalizing heat treatment, the machined port, wall thickness to be left burning and machining allowances. Usually the balance of the elbow theory 10% to 20% of the wall thickness. Elbow wall thickness delta-sectional diameter D ratio is smaller, the mold fit performance better, but the elbow arc more easily wrinkling. According to the characteristics of metal plastic deformation constant volume, made of push-shaped constant wall thickness (actually micro thinning), equal to the length of the elbow arc length of tube is derived pushing the system tube outer diameter of the formula: DP - - tube diameter; the R --- elbow radius of curvature; delta --- elbow wall thickness; --- D cross-sectional diameter of the elbow. If the actual selection of the tube diameter is small than the the Dp value calculated according to the formula, and the mold fit performance, but the elbow arc easy wrinkling. If the actual selection of the tube outer diameter than the the Dp value calculated according to the formula, the result is just the opposite. According to the above principles, the test push the system elbow tube push the system are shown in Table 1 (A left elbow segment part). (2) The material and shape of the mandrel head to push the system elbow geometry of the mandrel head material and shape is an important process parameters, by the design and manufacture of direct control. The the mandrel head material ZG1Cr18Ni9Ti, ZG3Cr20Ni14, ZG1Cr25Ni20Si2, ZG0Cr20Ni25, high-temperature strength and abrasion resistance gradually increased, the price is increased accordingly. If it is a small batch, you can select ZG1Cr18Ni9Ti, ZG3Cr20Ni14; mass production, should be selected ZG3Cr25Ni20 Si2 ZG0Cr20Ni25 but ZG0Cr20Ni25 price is too high, so this test mandrel head material selection ZG1Cr25Ni20 Fair. The mandrel head radius of curvature is divided into single, double curvature, and curvature of three. The rate of single, double curvature, the multi-curvature of the mandrel, the thrust gradually decreases gradually increased production costs. The test selected the double curvature mandrel. Divided into two kinds of circular cross-section and elliptical cross section, the cross-sectional shape of the circular cross-section create a simple, low cost, and push the system elbow ovality and thinning rate is too large; elliptical cross section production of complex, high cost, but push the system elbow ovality and thinning rate. The Experimental Method for the elliptical mandrel. According to whether the plastic segment is divided into shaping section of the mandrel head and shaping section of the mandrel head two. Shaping section mandrel production of complex, high-cost, long life time; without plastic segment mandrel making simple, low cost, fast front-end wear. The test selected shaping segment mandrel.