Braze welding

Hermetically Sealed. A hermetically sealed device shall be sealed against the entrance of an external atmosphere and the seal shall be made by fusion, e.g., soldering, brazing, welding, or the fusion of glass to metal. 

Filler Metal metal added during welding, braze welding, brazing or surfacing. 

Flux material used during welding, brazing or braze welding to clean the surfaces of the joint, prevent atmospheric oxidation and to reduce impurities. 

Zhadkevich, A. M. (2004) History of origination, technological features and technical capabilities of the first methods of soldering and brazing, Welding J. 11, 39-44. 

Molybdenum boride (Mo B) is used to braze (weld) special metals and for noncorrosive electrical connectors and switches. It is also used to manufacture high-speed cutting tools and noncorrosive, abrasion-resistant parts for machinery. 

Inside the shell sits the tube bundle, in which the tubes are either brazed, welded, or rolled to a circular single or double tube sheet. Typical tube flow patterns are either one, two, four, or six passes. 

In the electrical and electronic equipment market, adhesives compete with other joining methods such as mechanical fasteners, brazing, welding, soldering, and thermocompression bonding. Major uses of adhesives in the electrical and electronic equipment market are shown in Table 1.5. Adhesives are generally the preferred method of joining whenever... 

Type Materials Lower melting Silver brazing Welding Flux Gas Arc Resistance welding Plasma arc or tungsten inert gas Butt welding ... 

Other areas of corrosion concern are the membrane seals. If the seals are composed of flexible graphite, a preferred sealing material as discussed above, then corrosion by the common feed stream constituents is not a problem. However, with any metal seal - whether it be a brazed, welded, or soft-metal gasket seal - it is prudent to evaluate the potential for corrosion specifically at the seal. This evaluation is complicated by the fact that with brazed and welded seals, the metallurgy of the seal is influenced by the addition of the membrane alloy to the liquid braze alloy or weld pool. Experience has shown that welded seals to Pd—40Cu membranes, in which the membrane is welded to either Monel or 304L stainless steel, rapidly fail when subjected to 50 ppm hydrogen sulfide at 400 °C. 

Brazing— Welding with coalescence by heating, using nonferrous filler metal welding, i.e. joining by heat, is the generic term. 

Effectiveness, pressure drop and differential pressure between two sides for the recuperator used in an existing gas-turbine plant are approximately 88%, 6% of GT plant total pressure drop and 1.4MPa, respectively, in addition, components with the brazing welding have never been used in primary components. The CHX with diffusion welding is one of the best candidates to solve above problems. 

Plate heat exchangers (PHEs) are the most common form of compact heat exchanger, but their area densities are inferior to other types discussed in this chapter. There are several forms of construction, mainly associated with the methods used to seal the edges of the plates - gaskets, braze, welding or laser welding. The PHE is widely used in the liquid food processing industry, where the use of... 

Diamond is grown in air with a simple unmodified oxy-acetylene brazing/welding torch.l l Substrates such as silicon can be rapidly coated when exposed to the reducing portion of the flame but uniformity in structure and composition is not readily achieved. 

Braze welding (see Fig. 2.35) uses filler metals such as brass or bronze, which are not distributed in the joint by capillary action. The benefits of the flexible oxy-acetylene process make this a frequent choice here. Braze welding produces very strong joints in steel and copper. It is widely used to repair cast parts. 

Unqualified employees and mechanical equipment must be at least 10 feet away from overhead power lines. If the voltage exceeds 50,000 volts, the clearance distance should be increased 4 inches for each 10,000 volts. OSHA requires portable ladders to have nonconductive side rails if used by employees who would be working where they might contact exposed energized circuit parts. Also, conductors are to be spliced or joined either with devices identified for such use, or by brazing, welding, or soldering with a fusible alloy or metal. All splices, joints, and free ends of conductors shall be covered with an insulation equivalentto that of the... 

Depositing filler metal on a smface by welding, spraying, or braze welding to increase resistance to abrasion, erosion, wear, galling, impact, or cavitation damage. 

Braze welding base metal is pre-heated with an oxyacetylene or oxypropane gas torch at the joint area. Brazing filler metal, usually supplied in rod form, and a flux is applied to joint area, where the filler becomes molten and fills the joint gap through capillary action. Although no fusion takes place, very high temperatures are required, typically 700 °C. Some finishing may be necessary to clean flux residue and excess braze. 

Brazing. Welded and back-brazed tube-to-tube sheet joints are normally used in the fabrication of heat exchangers for molten salt service. The back-brazing operation serves to remove the notch inherent in conventional tube-to-tube sheet joints, and the braze material minimizes the possibility of leakage through a weld failure that might be created by thermal stresses in service. 

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