Weld, description

This paper deals with the control of weld depth penetration for cylinders in gold-nickel alloy and tantalum. After introducing the experimental set-up and the samples description, the study and the optimization of the testing are presented for single-sided measurements either in a pulse-echo configuration or when the pump and the probe laser beams are shifted (influence of a thermal phenomenon), and for different kind of laser impact (a line or a circular spot). First, the ultrasonic system is used to detect and to size a flat bottom hole in an aluminium plate. Indeed, when the width of the hole is reduced, its shape is nearly similar to the one of a slot. Then, the optimization is accomplished for... 

Fig. 2 Description of the weld depths penetration for gold-nickel alloy and tantalum cylinders.

General description. Burnthrough as discussed here specifically refers to the melting of tube metal in the vicinity of the weld such that a cavity is formed. If burnthrough is severe, a continuous channel may be produced that can cause leakage. 

General description. In incomplete fusion, complete melting and fusion between the base metal and the weld metal or between individual weld beads does not occur (Fig. 15.8). Incomplete fusion that produces crevices or notches at surfaces can combine with environmental factors to induce corrosion fatigue (Chap. 10), stress-corrosion cracking (Chap. 9), or crevice corrosion (Chap. 2). See Fig. 15.9. 

General description. Porosity refers to cavities formed within the weld metal during the solidification process. Such cavities may form due to decreased solubility of a gas as the molten weld metal cools or due to gas-producing chemical reactions within the weld metal itself. At times, cavities can form a continuous channel through the weld metal (worm holes, piping), resulting in leaks (Case History 15.3). 

General description. Slag inclusions are various nonmetallic substances that become entrapped in the weld during the welding process. Typically, the inclusions are located near the surface and along the sides of the weld (Fig. 15.15). The inclusions may form from reactions occurring in the weld metal or may be metal oxides present on the metal prior to welding. They may be isolated particles or may form relatively continuous bands. 

General description. In weld-root cracking, cracks originate at the root of the weld (Fig. 15.17). Such cracks may propagate into the weld, through the weld, into adjacent components, or through a relatively brittle heat-affected-zone base metal. 

BEOs are most often used for point sources or small line or surface sources. See Chapter 7 for descriptions of sources. BEOs are sometimes used for lines or surfaces when the source is moving along the line or on the surface. This naturally demands the exhaust to move with (or be moved with) the source movements (e.g., during painting or seam welding). They have also been used for side suction from baths and tanks-- and these exhausts are usually called rim exhausts see Rim Exhausts. However, for these sources push-pull systems (Section 10.4.3) are often more efficient. Side hoods can also be used, e.g., when molten metal is poured however, in these cases an enclosed exhaust is more efficient. 

Description Conventional wet fluorescent AC yoke magnetic particle inspection used for detection of cracks at a surface. Blending the welds and sanding smooth increases sensitivity. Polish and etch as in a creep evaluation looking for microscopic damage. Replicas can be taken for laboratory analysis. Conventional radiography used to inspect welds for cracks. Internal visual inspection of pressure vessels for surface blistering. Monitors the sound that cracks emit when they are stressed. 

For a detailed description of thermocouple materials, their maintenance, insulation, welding, etc., see also Wang (1990). 

JM Mine was moored, pear-shaped, contact mine which had no horns. The jolt received by the pendulum firing mechanism, when a ship struck the mine, closed an electrical contact and fired the detonator. - The mine was filled with ca 110 lbs of a HE ( ) (pp 44-45, Fig 18) Pomegranate Mine was a Vickers antenna mine purchased before WWII. It was spherical, 41 inches in diam, with six chemical horns on the upper hemisphere and two addnl ones welded to the lower hemisphere. An upper antenna and float and/or lower antenna were secured to the mine. No data for HE filler (pp 44 45, Fig 19) Type 3 Mine was the first Japanese attempt to use influence mines, copied from German S Mine. Their cylindrical A1 cases were either 7 or 11 feet long and 21 inches in diam. No data for HE used and the description of the mine given in Ref 1, p 46 is hard to understand Mark 2 Mod 1 Explosive Hook was actually a device for mine sweeping rather than a mine. 

In the recently introduced continuous methods of nitroglycerine manufacture nitrators made from acid resistant steel are used since the art of welding stainless steel had progressed remarkably by the 1930 s. The design and construction of nitrators for nitrating glycerine are included in the descriptions of individual methods of nitration. 

When welding polyethylene and polypropylene, clean, freshly cul surfaces should be prepared, and nitrogen should be used in the torch because a thin film of oxide prevents a satisfactory bond. sNeil Bartlett kindly supplied a description of this technique. 

We now come to another important part of the specification—namely, recitation of the objects of the invention. They are all stated as relating to a method of welding in which the itemized drawbacks are overcome. And then we find the usual stereotyped expression Other objects of the invention will become apparent as the description of our invention proceeds. ... 

Many of the design and fabrication details for equipment are governed by various codes, such as the ASME Codes. These codes can be used to indicate definite specifications or tolerance limits without including a large amount of descriptive restrictions. For example, fastening requirements can often be indicated satisfactorily by merely stating that all welding should be in accordance with the ASME Code. 

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