Filler Metal Alloys

Commercial filler metals are aluminium silicon alloys containing from 6.8 % to 13 % silicon. 

The solidus (or the point at which melting begins) is 577 °C for all Al/Si filler metal alloys. However, melting occurs in a range. Before the filler metal becomes fully liquid 

Alloy AA Si [85] Start Melting Fully Molten Braze Range 

Special developments for filler metal alloys are focused on the control of fluidity and flow pattern [86, 87]. By adding specific trace quantities of alloying elements (e.g., Li, Na), brazing characteristics improve. These effects appear to be relating to reduced surface tension. Under certain conditions, brazing can be accomplished with reduced flux loads or with no flux at all [88]. 

The concept of a brazing sheet that is supplied with a flux coating is very plausible. Such material would significantly change the way heat exchangers are currently manufactured in that the flux application step would be eliminated. 

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Representative set of weldments was examined site welds (with pearlitic type weld metal) and two types of site weld repair zones with different welding technologies using Cr-Ni filler metals and Ni-based alloy. Results of AUGUR 4.2 inspection were compared with manual ultrasonic inspection ones in terms of defect detection, characterization, positioning and sizing in order to estimate correlation between these data. 

There is hardly a metal that cannot, or has not, been joined by some welding process. From a practical standpoint, however, the range of alloy systems that may be welded is more restricted. The term weldability specifies the capacity of a metal, or combination of metals, to be welded under fabrication conditions into a suitable stmcture that provides satisfactory service. It is not a precisely defined concept, but encompasses a range of conditions, eg, base- and filler-metal combinations, type of process, procedures, surface conditions, and joint geometries of the base metals (12). A number of tests have been developed to measure weldabiHty. These tests generally are intended to determine the susceptibiHty of welds to cracking. 

The enhanced strength and corrosion properties of duplex stainless steels depend on maintaining equal amounts of the austenite and ferrite phases. The welding thermal cycle can dismpt this balance therefore, proper weld-parameter and filler metal selection is essential. Precipitation-hardened stainless steels derive their additional strength from alloy precipitates in an austenitic or martensitic stainless steel matrix. To obtain weld properties neat those of the base metal, these steels are heat treated after welding. 

AWS) has issued specifications covering the various filler-metal systems and processes (2), eg, AWS A5.28 which appHes to low alloy steel filler metals for gas-shielded arc welding. A typical specification covers classification of relevant filler metals, chemical composition, mechanical properties, testing procedures, and matters related to manufacture, eg, packaging, identification, and dimensional tolerances. New specifications are issued occasionally, in addition to ca 30 estabUshed specifications. Filler-metal specifications are also issued by the ASME and the Department of Defense (DOD). These specifications are usually similar to the AWS specification, but should be specifically consulted where they apply. 

Solders and Fluxes. Dental solders, like all dental alloys, must be biologically tolerated in the oral environment. They are specifically designed or employed for the purpose of fusing two pieces of dental alloy through the use of an intermediate low temperature filler metal. 

Brazing Alloy filler metal used in brazing. 

Consumable inserts may be used, provided they are of the same nominal composition as the filler metal and will not cause detrimental alloying of the subsequent weld deposit. The welding procedure using consumable inserts shall be qualified as required by para. GR-3.2.4. The consumable insert shall be used for welding the root pass of butt welded pipe components requiring complete weld joint penetration (CWJP) utilizing the GTAW or PAW processes. 

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. 

Orthodontics - [DENTAL MATERIALS] (Vol 7) -brazing filler metals for [SOLDERS AND BRAZING FILLER METALS] (Vol 22) -shape-memory alloys for [SITAPE-MEMORY ALLOYS] (Vol 21)... 

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