Welding, separators

Joining semifinished clad products is an important step in the production of components and equipment. This presents no particular problems in roll-cladding because base material and coating can be welded separately. However, to obtain the desired properties of the system tree, respective recommendations must be observed. 

There has been some little difficulty in getting the aluminium ribbed tube but it now appears that Wolverine and maybe others will attempt to extrude, draw, or roll the tubes with integral ribs. As an alternative, it is possible to weld separate ribs inside the tube. Sciaky Brothers have expressed their assurance that this process is entirely feasible, although it is still preferable to have extruded or drawn ribs. 

Simulations of that kind result in a wide variety of A-scans and wavefront snapshots. The first screening of this material reveals, that the simulations in which the transducer is coupling partly to the V-butt weld and partly to the steel exhibit quite a number of pulses in the A-scans because the coupling at the interface of the weld results — due to the anisotropic behavior of the weld — in a complicated splitting of the transmitted wavefront. The different parts of the splitted wavefront are reflected and diffracted by the backwall, the interface, and — if present — by the notch and, therefore, many small signals are received by the transducer, which can only be separated and interpreted with great difficultie.s. 

A separate works have been carried out in order to develop AUGUR 4 2 procedure for expert ISI of primary circuit piping welds. 

This paper describes the development of a novel system for improving the quality of information provided by manual ultrasonic examination of welds, while retaining the flexibility of the human operator to apply the techniques to components of a wide range of geometries and dimensions. The system, known as CamuS (Computer Aided Manual UltraSonics) provides assistance to the manual operator in two separate areas ... 

Often repair of the found defects is extremely undesirable. Therefore, for discontinuities which are potentially hazardous, it is very important to have a onfirmation of their stability. In this case monitoring of potentially hazardous discontinuities is well supported by automated UT systems and based on the comparative analysis results, the actual data from examination of a section of the welded joint of a (hydrogen) separator are given in Figures 5,6. 

Fig.5,a. The actual data from examination of a section of the welded joint of a (hydrogen) separator. 

The reasoning behind the first change is that NDE made for Class should be a sample of the QC programme rather than a separate exercise. In this way the original purpose of the Classification checkpoints is restored and the overall quality level of welding can be monitored. 

Chisel. Chisel testing is a quick, qualitative technique that is widely used to determine the soundness of explosion-welded metal interfaces. A chisel is driven into and along the weld interface, and the abiUty of the interface to resist the separating force of the chisel provides an excellent quaUtative measure of weld ductihty and strength. 

The anode and cathode chambers are separated by a cation-permeable fluoropolymer-based membrane (see Membrane technology). Platinum-electroplated high surface area electrodes sold under the trade name of TySAR (Olin) (85,86) were used as the anode the cathode was formed from a two-layer HasteUoy (Cabot Corp.) C-22-mesh stmcture having a fine outer 60-mesh stmcture supported on a coarse inner mesh layer welded to a backplate. The cell voltage was 3.3 V at 8 kA/m, resulting ia a 40% current efficiency. The steady-state perchloric acid concentration was about 21% by weight. 

Tlie indi ddual cells are assembled into batteries after a leakage test to check for faulty welding joints in steel containers or cracks and improper seals in the plastic encased cells. Cells that are to be delivered without electroltye are emptied after the fomiation cycles. Tlie steel-cased cells hav e to be separated by mechanical means to prevent intercell shorts and are often assembled into wooden crates. Tlie cells in plastic cases can be cemented together or strapped with tape. 

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