Silver hard solder

In another study on hard solder compounds, it was found that the silver hard solder L-Ag 40 Cd proved to be resistant in association with the steel 1.4301 in hot water containing up to 50 mg/1 chloride [32]. 

Silver solder is a common form of hard solder it is an alloy of silver and copper, usually with zinc and sometimes tin or cadmium added. Silver solders melt in the range 600 to 700°C and have high mechanical strength. 

There are two types of solders soft and hard. Soft solders usually consist of a mixture of lead and tin and the heat required to melt them is supplied by a soldering iron. Hard solders include brass (copper-zinc alloys) solders, silver solders, copper solders, nickel-silver solders, and solders for light alloys the heat to melt them is usually supplied by a blow torch. 

Hard Soldering.— To Solder Brass. in Chapter XQ, which about covers the w hole l ing, varying only in the composition of the solder for different metals. Tho biiiss solder there described acts equally well for soldering copper, hut for silver a solder is made oompoeed of tw o parts silver and one part brass. 

Hard soldering is applicable in most cases. Spelter solder, silver solder (m.p. about 700°C) and pure silver (m.p. 960°C) are used. The cleaned junctions are sprinkled with a generous amount of borax, and when they are sufficiently hot the solder (as powder or as wire) is added. With a large amount of borax and pure silver, even Mo and W can be hard soldered. 

A soft solder melts at a temperature in the range 200-300°C and consists of a Un-lead alloy. The tin content varies between 80% for the lower end of the melting range and 31% for the higher end. Hard solders contain substantial quanUUes of silver in the alloy. Brazing solders are usually alloys of copper and zinc, which melt at over 800°C. 

Solders are typically classified as either soft or hard. Some confusion often results from this convention because some hard solders are really braze materials if the melting temperature criterion is applied. Soft solders typically consist of alloys containing lead and tin, but also often contain indium (In), bismuth (Bi), antimony (Sb), or silver (Ag). In practice, most soft alloys melt at temperatures lower than 450°C, usually between 180°C and 300°C. High-tin solders, typical of lead-free solders, tend to be stiffer, harder, and less ductile compared to high-lead solders. Hard solders often contain metals such as Au, Zn, Al, and Si. 

Joints in copper components may be a source of trouble. Copper/zinc brazing alloys may dezincify and consequently give rise to leaks . In some waters, soft solders are preferentially attacked unless in a proper capillary joint. Copper/phosphorus, copper/silver/phosphorus, and silver brazing alloys are normally satisfactory jointing materials. Excessive corrosion of copper is sometimes produced by condensates containing dissolved oxygen and carbon dioxide. Rather severe corrosion sometimes occurs on the fire side of fire-back boilers and on electric heater element sheaths under scales deposited from hard waters . 

Two types of silver solder are available. The soft-silver solders are generally alloys of silver with lead, which, like the common tin-lead soft solders, melt below 400°C. The soft-silver solders have the advantage over the Sn-Pb variety of greater resistance to creep under load. The hard-silver solders generally contain copper as the primary alloying constituent. These solders generally melt above 600°C. One common type of silver solder, AWP 355, is resistant to fluorine and many fluorides. 

Gold solder is a liquid found in the shafts we spoke of, flowing down along a vein of gold, with a slime that is solidified by the cold of winter even to the hardness of pumice stone. A more highly spoken of variety of the same metal has been ascertained to be formed in copper mines, and the next best in silver mines. 

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