The production and processing methods about beveling machine for pressure pipe making

Date:2016-10-13

1 Project Overview             

Second seat Jinping Hydropower Station in Sichuan Liangshan Yi Autonomous Prefecture Muli, Yanyuan on the Yalong River, at the junction of three counties mianning Jinping Great Bend, karaoke system to the Yalong River estuary five development Step Power station. Jinping hydropower utilization Yalong Bay 150km Jinping large natural gap, straighter tunnel excavation of diversion and power generation. Jinping dam located downstream of 7.5km at a plant located in the eastern end of a large bay big ditch. Normally, the reservoir 1646m, backwater length of 7.5km, corresponding storage capacity is 14.01 million m3, reservoirs dead water level 1640m, fixed capacity of 9.05 million m3, regulating capacity of only 4.96 million m3. Wan power plant total installed capacity of 8x60 kW, for many years the average annual generating capacity of 24.23 billion kW · h. Header set low gate, gate access to the basin area of 103 000 km2, gate site at annual average flow 1220m3 / s. Reservoir has daily regulation function, and JinpingI synchronous operation with annual regulation characteristics.

Jinping Hydropower Station were arranged eight penstocks, penstock pipe sections each average about 175. Pipe maximum diameter 6.5m, the minimum diameter of 6.05m, the maximum length of a single axis of 3m, a single minimum axial length of 1.296m. 8 penstock in the direction toward the upstream segment 28.8m from the plant upstream side wall at 2.38m (penstock end), the use of 600MPa high-strength steel. The inner diameter of the pipe section is 6.05m, 6.5m and 6.05m ~ 6.5m gradient of the cone, its thickness, respectively 56ram, 52mm, 48mm, 44mm, 40mm. The remaining segments are used 16MnR 500MPa grade pressure vessel steel, the main part of the high-pressure pipeline including flat section, the curved section, the shaft section, recurved segment and a lower flat section, the inner diameter of the steel pipe are 6.5m, steel plate thickness of 20mm, respectively, 22ram, 24mm, 28ram, 36ram, 38mm, single pipe length of 447m ~ 490m. 8 are set to the full length of penstock stiffener ring materials are 16MnR of 500MPa grade pressure vessel steel.

My unit construction of most of the pressure pipe manufacture, wherein the sheet 38ram below, all using the slope machining automatic beveling machine performed. In penstock peak production, groove preparation step is very compact, and met head off sheet in the sheet metal processing,beveling machine does not walk on the sheet, the sheet processing blunt edge sample sizes and other issues affecting the penstock production efficiency, delay the construction period. How safe, efficient, and shelf life of the penstock plate processing, it is particularly important.

2. Preparation prior to processing           

Manshuiwan steel from the transfer station to the factory ship, there should be full-time personnel hoisting steel, industrial pipe portion, Ann prime rings, maintenance personnel should be the Ministry of plate thickness, type, size, weight, arrival time, make a record and acceptance. Lifting operations should pay attention to the signal, commanding officers and the driver to concentrate on operating, accurate, 10cm ~ 30cm, smooth and rope force to check whether an object even after lifting the load off the ground, the brake mechanism is safe and reliable; lifting member when the angle between the wire rope should be less than 60. And to ensure that the choice of wire rope safety factor of more than 8 times; according to the type of material, the thickness of the stacked classification and woods support pad, the pad off the ground, the upper awning material should be added to prevent corrosion, contamination and deformation. Press the assembly sequence, the sheet transport by truck to the CNC cutting machine platform, records indicate good plate number NC increases the drawing sheet model corresponding (Technical Department prepared after the copy to the CNC cutting machine), according to the drawing on the plate rehearse, cutting. Groove preparation is an important step and it requires penstock longitudinal seam, girth were "X" slope processing, in order to step slope butt welding, the joint can occur without penetration process defects.

Preparation groove construction: 1 device performance CHP-21 G Series Spain Greece SA automatic Walking groove machine, there are positive and negative, positive beveling machine (CHP a 21G) groove machining positive, anti-beveling machine (CHP a 21GVI) machining the back groove (no need to flip the sheet metal processing). Slope angle of 200 to 45. Stepless adjustable bevel per minute length 1.7m, an automatic processing line down the slope width of 9mm, motor power 2.94kW, voltage 380V, can process sheet metal thickness in the range of 9mm ~ 50mm. Special cutter for common carbon steel, alloy steel, high strength steel, stainless steel and other materials. 2 processing methods. Workpiece plate should be placed on a height of 80cm from the ground around the platform, smooth floors, a special steel plate, adjust the height of the machine travels, the machine travels in the processing of car spring in a relaxed state, easy to walk smoothly. A process according to card processing sheet sentinel loft numbered labels, grinder grind repair plasma flame cutting left horn projecting defect. Projecting sheet edge defects easy to make beveling machine stops working the way travel. Sheet metal processing (such as sheet material for the Q345, a thickness of 24mm, both positive and negative slope angle 30., in the form of a groove 14ram, outside 8mm, blunt edge of 2ram). Loosen the eight screws on both sides of the beveling machine, adjust the angle pointer 300 and tighten the bolts. The first adjustment processing tugboat aligned side tick signs indicating 22 (first processing sheet thickness smaller than ticks 2mm), the first machining depth 8ram; second processing on the basis of the first processing on at least 3 scale, the scale indicates 19 standard cards, processing depth is 3mm; the third time in the first machining process on the basis of less then 2 mark, indicated as 16 standard cards, processing depth of 3mm. Three times the total depth of processing within the groove 14mm. After the front groove processing is completed, the processing method of the same anti-bevel, angle adjustment 300, adjust the side tugs side tick signs indicating the alignment of 22, the amount of processing time traveling depth 8ram. When beveling machine downtime, first turn off the power switch, unplug it, pushed off the work area, clear the iron, after wiping the machine with a normalized provisioning. Then, wearing protective glasses on Slope polished, polished smooth, no slag, cracks, corrosion and then hair brush on zinc-rich primer to prevent rusting.

Use automatic Walking groove machine pressure vessels slope, no vibration, no heat, no fumes, no dust; using standard carbide inserts clean burr free edge; adjustable cutting depth, variable angle of 150 to 45. More efficient than gas cutting groove, does not change the structure of the metal phase, can improve production efficiency. It is a large-scale production of pressure vessels better approach. Beveling machine penstock slope for processing, can better ensure the quality of the welding process, it can be used in more large-scale production and processing of the pressure vessel.