All position automatic welding machine for the hot

2022-07-26
  • Detail

All position automatic welding machine for steel penstock Abstract: by analyzing the difficulties of applying all position automatic welding technology in the welding construction of large diameter thick wall steel penstock, and absorbing the successful experience of similar welding machines at home and abroad, an all position automatic welding machine is developed. The welding machine has the functions of welding moment swing, adaptive groove width and automatic tracking. The overall design of the welding machine is reasonable, stable and reliable, beautiful in appearance, compact and light in mechanism. It has been successfully applied in the welding construction of diversion penstock of Gudongkou hydropower project in Xingshan County, Hubei Province and ll\14 # penstock of left plant of Three Gorges phase II project

key words: penstock; All position automatic welding machine; development; Application of

for a long time, the traditional, simple and heavy electrode arc welding technology has been used for the welding of penstocks in hydropower stations. Only a small number of longitudinal joints in the fabrication yard adopt the submerged arc automatic welding technology. The all position automatic welding technology of penstocks is still blank. With the rapid development of hydropower construction and the continuous increase of unit parameters, advanced all position automatic welding technology must be adopted for the welding of large-diameter thick wall penstock to meet the needs of construction and production

the all position automatic welding of steel penstock shall not only realize the automatic travel of the welding trolley along the weld, the automatic transportation, adjustment, swing of the welding wire and the medium-sized electromechanical control process, but also solve the droplet transfer form of the welding wire and ensure the weld forming quality of the all position welding, especially a series of automatic control technologies such as the automatic adjustment of the welding specifications at various positions; What is more important is that the on-site assembly of welds has poor quality and poor construction environment, which is difficult to meet the requirements of automatic welding construction. At present, it is still difficult to fully apply the all position automatic welding technology of penstock in the welding of large-diameter thick wall Penstock with extremely high market share. The main reasons are:

(1) the installation circumferential seam assembly of large-diameter thick wall penstock is difficult to achieve uniform and high precision, which requires that the all position automatic welding equipment can automatically adjust the relevant process parameters according to the groove size and deviation, To reduce or eliminate the influence of uneven parameters on welding quality

(2) the spatial position of the weld seam is constantly changing, which requires that the welding system can automatically and timely adjust the welding process parameters according to the position of the welding torch, so as to achieve the basic consistency of welding forming everywhere

(3) it is difficult to realize automatic control technology to match groove size, weld melt shape, and real size adjustment of welding specification parameters to ensure weld quality

therefore, how to select all position automatic welding equipment with low cost, strong adaptability, simple operation and high welding efficiency is the only way to solve the above problems. According to the welding characteristics of the penstock of the hydropower station, we have developed a set of unique all position automatic welding machines, which have been successfully applied in the welding construction of the penstock of Gudongkou hydropower station in Xingshan County, Hubei Province and the longitudinal joints of 1114

1 main development contents and implementation scheme of all position automatic welding machine

the development of all position automatic welding machine mainly includes mechanical and electrical control

1.1 mechanical design and manufacturing

the mechanical design of the whole machine includes the structural design of crawling track, crawling trolley, welding torch swing mechanism and swing adaptive groove width sensor

1.1.1 creeping track

the creeping track is composed of a rack composed of stainless steel sheet, split gear block and a hydro magnetic iron block fixed on the surface of the workpiece. The crawling trolley and the welding torch swing control Trailer clamp the rail edge with the help of four pairs of left and right rolling bearings respectively, so that they can move smoothly and flexibly along the rail. With the help of the pinion on the output shaft of the traveling motor in the crawling trolley and the rack on the rail, the crawling trolley and the welding torch swing control trailer are connected through the connecting rods on both sides, so that they can run reliably and stably on the rail, Implement all position crawling function

1.1.2 crawling trolley

crawling trolley is divided into two parts: active driving traveling trolley and passive traveling torch swing control Trailer. They are respectively provided with two pairs of bearing wheels at 60 ° to each other on both sides under the bottom plate to clamp the rail edges, which can move flexibly and reliably. One side of the bearing wheels on both sides of the clamping track can be moved laterally through the screw and slider to realize the clamping and disassembly of the trolley on the track, which makes it very convenient to load and unload the trolley on the track

1.1.3 torch swing mechanism

torch swing mechanism is a mechanism for realizing the lateral movement of welding arc by 2.2 weight measurement method. The system adopts a hollow thin-wall stainless steel square tube. A strip-shaped stainless steel plate and a rack are fixed on the swing rod, and the end of the swing rod is installed with a welding torch clamping and sensor fixing and adjusting mechanism. Relying on the chamfered edges on both sides of the strip-shaped stainless steel plate on the swing rod to mesh with the V-shaped rollers of the four bearing jackets installed on the vertical plate, a swing mechanism with flexible swing, light weight, good stiffness, small gap, stable and reliable operation and convenient disassembly is formed

1.1.4 swing adaptive groove width and welding automatic tracking dual-purpose sensor is designed to adapt to the on-site construction conditions of hydropower station, it is difficult to achieve uniform gap in the circumferential groove assembly of large-diameter thick wall penstock, and it is difficult to lay the track parallel to the weld during all position automatic welding. The sensor of the machine uses the probe to mechanically contact the side wall of the groove to obtain the signal, which is a signal acquisition method with reliable operation and the strongest anti-interference ability. Then, the photoelectric signal is generated through the swing rod system inside the sensor, and the rotation and stay of the welding torch swing motor are distinguished and controlled by the logic circuit to realize the function of adaptive groove width for the swing of the welding torch

1.2 development of electrical control system

the perfect design function, stable and reliable operation and good anti-interference of the electrical control system of the welding machine are very important to ensure the working quality of the welding machine. This welding machine has fully considered the basic functions required by the all position automatic welding machine and the functions of the same advanced welding machines at home and abroad, and has developed its own swing adaptive groove width and automatic tracking welding control functions. The main control functions of this machine are as follows:

1) automatic and manual selection of welding torch swing

2) torch swing setting and adaptive selection

3) adjustment of residence time on both sides of welding torch swing

4) torch swing speed adjustment

5) selection of welding arc trajectory

6) selection of welding direction

7) welding speed decreased

8) select the initial swing direction under the set swing working mode

9) arc deviation correction adjustment under setting swing mode

10) near control and remote control of welding trolley

its electrical control principle is shown in the following figure:

2 main technical parameters of the whole machine

trolley power supply: 220V 50hz

trolley creeping speed 0 ~ 450mm/min

torch swing range 0 ~ ± 40mm

torch swing speed 250 ~ 3000mm/min

torch swing mode 1) linear; 2) Serrated; 3) Trapezoid; 4) The residence time on both sides of the rectangular

welding torch is 0 ~ 5sec

automatic tracking accuracy ± 0.5sec

6 degrees of freedom for torch adjustment

the radius of curvature of welded steel pipe ≥ 1500mm

the weight of the welding machine is 18.5 kg

the welding method applicable to this welding machine is unlimited, and CQ2 gas shielded welding, flux cored wire gas shielded welding, flux cored wire self shielded welding, MAG welding, MIG welding, TIG welding and other methods can be adopted as required, Only welding power supply and welding torch with corresponding characteristics are required

3 engineering application and effect

3.1 introduction to application engineering

Gudongkou hydropower station is located in the lower reaches of Gufu River in Xingshan County, Hubei Province. The total installed capacity of the power station is 45000 kW, the average annual power generation is 124million kwh, the diameter of its penstock is 5m, the wall thickness is 16 ~ 40mm, and the total length is 6. First of all, we need to know that the main component of wood flour is cellulose + lignin + hemicellulose more than 00 M. All are made of domestic 16Mn low alloy structural steel

the Three Gorges project is a world-renowned hydropower project with a total installed capacity of 18.2 million KW and an annual power generation capacity of 84.7 billion kwh. Its penstock has a diameter of 12.4m, a wall thickness of 26 ~ 541mm, and a single pipe length of 122.5m. It is made of domestic 16MnR low-alloy structural steel and imported 600MPa low-carbon quenched and tempered high-strength steel plate

3.2 all position automatic welding process

see Table 1 for all position automatic welding process parameters. Table 1 table of process parameters of all position automatic welding

3.3 application effect

(1) comparison of various performance effects between all position automatic welding and traditional shielded metal arc welding is shown in Table 2: Table 2 Comparison of application effects of all position automatic welding

(2) through the welding application of Gudongkou penstock and 11 , The one-time qualified rate of ultrasonic flaw detection of circumferential weld is 98.1%, and the excellent rate of weld appearance quality is 100%, which is unmatched by traditional arc welding

(3) the welding trolley adopts a flexible track, which can realize stepless speed regulation and automatic wire feeding when the machine head moves and swings and stays on both sides of the weld. It is stable and reliable, and meets the basic requirements of all position automatic welding

(4) due to the realization of the new technology of mechanized and automatic welding forming characteristics, it not only reduces the labor intensity of welders, but also greatly improves the first-time qualification rate of weld nondestructive testing, and greatly reduces the influence of human factors on the welding quality

(5) by using continuous wire feeding and high current density welding, the work efficiency can be increased by more than one time compared with the electrode arc welding

(6) compared with shielded metal arc welding, this automatic welding process has deeper penetration, can adopt smaller groove angle, and can greatly reduce the width of welding heat affected zone and welding residual deformation

4 conclusion

on the basis of absorbing the successful experience of similar foreign welders, the all position automatic welding machine has been developed creatively according to the on-site construction characteristics of penstock in hydropower station; The factory's welding torch swing has important functions such as adaptive groove width and automatic tracking. The overall design of the welding machine is reasonable, the work is stable and reliable, the appearance is beautiful, and the mechanism is compact and light. It has high promotion and application value

the successful application of all position automatic welding technology in the longitudinal circumferential weld of Gudongkou penstock and the longitudinal weld construction of 11 . The application of all position automatic welding in penstock and spiral case of hydropower station is also the inevitable result of the development of welding construction technology

Copyright © 2011 JIN SHI