The surface of the lead alloy produces oxide, sulfide or other double salt compound coating during the corrosion process, which has the function of preventing oxidation, vulcanization, dissolution or volatilization, and therefore has good corrosion resistance in air, sulfuric acid, fresh water and seawater. Sex. Lead alloys containing impurities such as barium, magnesium, and zinc that do not dissolve in lead or form a second phase will reduce the corrosion resistance. The addition of antimony and selenium will eliminate the harmful effects of impurities on corrosion resistance. The addition of niobium and tantalum to niobium-containing lead alloys refines grain structure, increases strength, suppresses the harmful effects of niobium, and improves corrosion resistance.
Lead alloy has a low melting point (below 327 °C), good fluidity, low solidification shrinkage, low melting loss, small change in composition during remelting, and can cast complex shapes, clear outlines of devices, are widely used in casting and making models, etc. . Lead-tin-antimony alloy has been used in the printing industry for more than 500 years. The lead alloys used in the production of models and casts contain the effect of increasing the hardness and strength and lowering the solidification shrinkage. The contained tin plays a role in improving the flowability and contour definition. Using a lead alloy with a low melting point as a model material, the production process is simple, and has a certain service life. It is very convenient for product modification and model refurbishment. The relevant personnel in this field in China are mainly concentrated in the steel excellence network.
The deformation resistance of the lead alloy is small, and the ingot can be made into plates, strips, pipes, rods, and wires by processes such as rolling and extrusion without heating, and no intermediate annealing treatment is needed. Lead alloys have a tensile strength of 3 to 7 kgf2, much lower than most other metal alloys. Antimony is one of the important elements used to strengthen the matrix. It is only partially solid-dissolved in lead and can be used for both solution strengthening and age hardening. However, if the content is too high, the toughness and corrosion resistance of the lead alloy will change. Bad. Considering the comprehensive performance, when lead alloys are used to make corrosion resistant components such as chemical equipment and pipelines, about 6% of yttrium is appropriate. When used for making connecting members, 8% to 10% of yttrium is preferred. The lead-bismuth alloy adds a small amount of copper, arsenic, silver, calcium, barium, etc., which can increase the strength and is called hard lead.
Due to the low shear and creep strength of the lead alloy, the lead alloy is easily deformed and thinned into a foil under a certain load and rolling shear, and the lead alloy has good self-lubricating properties, wear-ability, and shock absorption. Low noise and therefore a good bearing alloy. Lead-based bearing alloys and tin-based bearing alloys are collectively referred to as babbitt alloys and can produce highly loaded locomotive bearings. Arsenic containing up to 2.5% to 3% lead alloy is suitable for heavy-duty machine bearings with high loads, high speeds, and high temperature resistance.