The proportion of the weld fusion line of slag produced only slightly reduce, showed that the inclusion of raw materials is not main cause of the slag to produce.
For straight seam submerged arc welding pipe defective part of the sample, by ultrasonic flaw detector manually confirm the defects in the weld seam position, use the method of machining work out defects in the weld cross section, after grinding, polishing, etching metallographic specimen.Through the analysis of the metallographic analysis, it is found that the weld slag of the welded pipe in the thick wall is located in the position of the fusion line of the inside and outside welds, as shown in figure.
Slag is the slag that remains inside the weld.From the theory analysis, automatic submerged arc weld causes of slag has the following three points: raw materials (including the parent metal, welding wire, flux) of inclusion is more.Clean up between layers of welding.The application of the welding process parameters is not good, and it is not conducive to the emergence of slag.
According to the production characteristics of the welded pipe in the direct seam, it is possible to eliminate the reason that the welding seam is not clean in the multi-layer welding layer.For more inclusions in the raw material and make the slag inclusion of weld, take inspection before welding material, replacement, new measures such as filler metals and fluxes.
As a result, the main reason for the welding process of the welded wire is the improper parameters of welding process.The welding process parameters of thick wall seam welding tube are mainly: line energy, welding current, welding voltage, welding speed, wire spacing, groove size and so on.
To do in-depth analysis from the aspects of welding metallurgy: weld fusion line causes of slag is mainly fusion line temperature is too low, make the liquid slag can not afford time to precipitate;The result is that the temperature of the fuse is too low because the peak temperature is too low or too fast.In welding under the influence of groove type, on both sides of the root of the weld the thickness of the central region is far less than the thickness of the cooling rate is smaller than on both sides of the many, therefore, easy slag, on both sides of the weld root., other conditions being the same with the groove Angle and depth of molten weld depth increases, the groove increase with the decrease of the size of the blunt edge, it increases with the decrease of the welding speed.When the line energy is constant, as the weld penetration increases, the highest temperature of the fuse line decreases, and the weld is liable to produce slag.
In the astm a53 erw steel pipe multi-wire buried arc welding, the welding speed has a large effect on weld depth and melt width, and the faster the welding speed, the lower the melting depth and the melting width.Conversely, the larger the larger.
What are the precautions for storing seamless steel pipes?
1. Choose a suitable venue and warehouse; 2. Reasonable stacking, advanced first; 3. Packaging and protective layers of protective materials; 4. Keep warehouse clean and strengthen material maintenance.
Significance of Proximity Effect on the Production of High-frequency Longitudinal Welded Pipes
In addition to the skin effect, the proximity effect is another feature of current. When alternating currents of equal magnitude and opposite directions pass through two adjacent conductors, the current will flow through the adjacent inner surface layers of the two conductors, and when the two conductors pass When alternating currents of the same size and direction, the current will flow through the outer surface layers of the two conductors. The proximity effect of the current makes the current in the conductors further uneven. It is this unevenness that makes the high-frequency welded pipe(ERW).
Summary of Advantages and Disadvantages of High-Frequency Welded Pipe Forming Methods
Advantages and disadvantages of high-frequency welded pipe forming methods
