Metals welding

In this figure one can clearly see an image of a weld defective area with a superimposed groove defectometer Fe2 4 mm thick. The depth of a minimum groove was 0,5 mm. One can clearly see a groove 0,2 mm deep, which corresponds to sensitivity less than 2% Both incomplete root penetration and metal weld beads can be clearly seen in the image. 

BE-7301 Life optimization of dissimilar metal welds for high temperature components Mr. V. Bicego CISE SpA... 

FlOiei Evaluation of techniques for assessing corrosion cracking In dissimilar metal welds Dr D.R. Tice AEA Technology... 

Ultrasonic Testing of Austenitic and Dissimilar Metal Welds,... 

Acetylene is used primarily as a raw material for the synthesis of a variety of organic chemicals (see AcETYLENE-DERiVED CHEMICALS). In the United States, this accounts for about 80% of acetylene usage and most of the remainder is used for metal welding or cutting. The chemical markets for acetylene are shrinking as ways are found to substitute lower cost olefins and paraffins for the acetylene, with some products now completely derived from olefinic starting materials. Metalworking appHcations, however, have held up better than chemical uses. 

Transition Joints. Use of explosion-clad transition joints avoids the limitations involved in joining two incompatible materials by bolting or riveting. Many transition joints can be cut from a single large-area flat-plate clad and deflvered to limit the temperature at the bond interface so as to avoid undesirable diffusion. Conventional welding practices may be used for both similar metal welds. 

Elimination. The sensitization that leads to weld decay is a reversible process, and elimination can be achieved by appropriate heat treatment of the affected metal. Weld decay may also be avoided by specifying proper materials and welding techniques. 

Level-Float 3.2.1.5.2 Piping Systems-Metal-Welds Suppression Systems-Water... 

Estimate air leakage into the system based on possible weld cracks, metal weld, or metal porosity ... 

Plate evaporators (Figure 7.8) are formed by cladding a tubular coil with sheet metal, welding together two embossed plates, or from aluminium extrusions. 

These recent tests were conducted at applied stress levels similar to those that might be experienced by ASME Section Vm, Division 2 vessels. Test exposure times exceeded 50,000 hours depending on applied stress and temperature. The test specimens were from weldments of thick section plates and represented base metal, weld metal, and heat-affected zone. Detrimental effects of hydrogen were found down to the Figure 1 limit of 850°F (454°C) at 2000 pounds per square inch absolute (14 megapascals) and 3000 pounds per square inch absolute (21 megapascals) hydrogen partial pressure. 

Rowe, M.D., Nelson, T.W., and Lippold, J.C., Hydrogen-induced cracking along the fusion boundary of dissimilar metal welds, Welding Res., February, 1999, p. 31. 

A listed material may be used at any temperature not lower than the minimum shown in the tables in Appendix IX, provided that the base metal, weld deposits, and heat affected zone (HAZ) are qualified as required by the applicable entry in Column A of Table GR-2.1.2(b)(2). 

B-l Except as provided in Notes (2) and (3), heat treat base metal per applicable ASTM specification listed in para. GR-2.1.3(b) then impact test base metal, weld deposits, and HAZ per para. GR-2.1.3 [see Note (1)1. When materials are used at design min. temp, below the assigned curve as permitted by Notes (1) and (2) of Fig. GR-2.1.2(b)A, weld deposits and HAZ shall be impact tested [see Note (1)1. 

B-3 Engineering design shall be assured by suitable tests [see Note (5)] that base metal, weld deposits, and HAZ are suitable at the design min. temp. 

The recommended materials of construction can be welded using standard methods and matched filler metal weld wire. 

Aluminum, copper, nickel, and their alloys unalloyed titanium A-6 (a) No additional requirements A-6 (b) No additional requirements unless filler metal composition is outside the range for base metal composition then test per column B-6 B-6 Designer shall be assured by suitable tests [see Note (4)] that base metal, weld deposits, and HAZ are suitable at the design min. temp. 

Hjollund NHI, Bonde JPE, Jensen TK, et al. 1998. Semen quality and sex hormones with reference to metal welding. Reprod Toxicol 12(2) 91-95. 

---