Silver based solders are usually alloys based on silver or silver based solid solution. This kind of filler metal has excellent technological properties, low melting point, good wetting and sealing properties, excellent strength, plasticity, conductivity and corrosion resistance. It can be used to braze almost all ferrous and non-ferrous metals except aluminum, magnesium and other low melting point metals. And Xiaobian to further understand the following:
There are many kinds of silver based solders, but almost all of them contain copper. In order to reduce the melting point and silver content, alloying elements such as zinc, nickel and cadmium are usually added to form ternary or multicomponent alloys.
B-ag72cu is the most widely used eutectic solder in vacuum devices. Its melting point is low, there is no temperature interval when crystallizing. It has good brazing performance, good wettability and fluidity on copper and nickel, and good conductivity. However, the solder has high brittleness, low strength and poor wettability to stainless steel, alloy steel and superalloy. Therefore, in order to improve the wettability and spreading property of solder, copper or nickel should be plated on the brazed surface in advance. This filler metal can also be used for the pre brazing of titanium and titanium alloy.
The properties of b-ag50cu are similar to that of b-ag72cu, but the plasticity of b-ag50cu is improved due to its low silver content. However, with the increase of melting temperature range, it is suitable for brazing wide gap joints and can be used for the pre stage brazing of multi-stage brazing.
B-ag92cu has good fluidity, higher strength and corrosion resistance than the former two. It is mainly used for brazing titanium and titanium alloy, titanium and stainless steel. Because of its high melting point, it can be used in the first stage of stage brazing.
B-agmn has high melting point and good high temperature strength. It can be used for brazing stainless steel and titanium alloy working below 400 ℃. B-ag80au is a kind of heat-resistant solder with excellent properties, but it is seldom used because of its high cost.
B-ag90pd has high strength at medium temperature, excellent corrosion resistance, oxidation resistance, wettability and good plasticity of joint. The strength and wettability of b-ag80pd for low alloy steel, stainless steel and superalloy were further improved. However, because the price of PD is more expensive than AG, the content of PD should be reduced as much as possible on the premise of meeting the use requirements. B-ag95pd was developed for this purpose. Due to the very low vapor pressure of PD, Ag PD solder is especially suitable for brazing important parts of vacuum or nonmetal.
B-ag95al is a kind of filler metal with high strength, excellent corrosion resistance and heat resistance. It is mainly used to braze stress components used below 400 ℃. When ti-11cr-13v-3al alloy is brazed, the shear strength at room temperature is τ≥ 150MPa, and that at 400 ℃ is τ ≥ 100MPa. The melting point of b-ag87al is lower than that of b-ag95al, and its properties are similar to that of b-ag95al. It is mainly used for brazing α - titanium alloy and α + β dual phase titanium alloy.
B-ag94al (MN) is based on b-ag95al with less than 1% Mn (mass fraction). The corrosion resistance of the joint can be improved by brazing titanium alloy with this filler metal.
On 2018-08-08 11:45:46
