Tin-containing alloys, including tin-based
tin alloys (except tin-lead solder), and alloys with tin as the main additive element, are an important outlet for tin consumption, accounting for about 23% of the total tin consumption. Mainly used in automobile, locomotive, tractor bearing and heavy machine bearing, among which tin-based babbitt is the most widely used.
(1) Copper-tin alloy
Copper-tin alloy refers to a copper alloy containing 5-15% Sn and a small amount of Zn. It is the oldest alloy (also known as "bronze"), with high mechanical strength and hardness, good casting performance and processing performance, and corrosion resistance. , good load-carrying properties, proper electrical conductivity and ease of welding. At present, the traditional use of bronze bells and bronze sculptures is still prosperous, but its main use is still in engineering. In engineering, copper-tin alloys are mainly used in three forms: castings, forgings (rods, strips, tubes and wires) and sintered powder metallurgy components.
Among them, the cast bronze alloy contains Sn-5-13% and phosphorus. In addition, Zn can be used to replace part of Sn (without P), resulting in a series of alloys called gunmetal. As-cast bronze and gunmetal combine good corrosion resistance, wear resistance, moderate strength and good castability. Widely used as valves and fittings in contact with seawater, boiler feed water and inorganic acids; used as gears and sliding bearings.
The wrought alloy contains up to 8% tin and has high strength and corrosion resistance. It can be processed into sheets, strips, tubes, rods and wires, and its uses include making springs and instrument parts, condenser tube sheets and tubes, containers, and bearings, springs, plugs and wire wrap connections for electronic equipment.
Powder metallurgy bronze parts, typically containing 10% tin, for partially lubricated or non-lubricated bearings. Powder metallurgy is also used to produce a special alloy that is otherwise difficult to produce.
(2) Babbitt alloy
Babbitt is the most widely known bearing material, with applications dating back to the era of the Industrial Revolution. Babbitt is the only material suitable for rotation relative to low hardness shafts. Compared with other bearing materials, it has better adaptability and press-fit, and is widely used in large marine engines, turbines, alternators, and other large rotating mechanical.
Babbitt alloys can be simply divided into three types: high-tin alloys, high-lead alloys and master alloys (in alloys, both tin and lead occupy an important proportion). In all these alloy systems, antimony and copper serve as important alloying and hardening elements, and their structures are composed of hard, intermetallic compounds dispersed in a soft matrix.
(3) Aluminum-tin alloy
Compared with babbitt alloys, aluminum-tin alloys can meet stronger and stricter operating conditions of machinery and equipment. Commonly used aluminum-tin alloys are:
1) Alloys containing 6% tin for heavy duty working environments with the limitation that they need to work with specially hardened shafts.
2) Alloy bearings containing 20% tin have a compromise between high fatigue strength and good surface properties. Applications include high-load crankshaft bearings for high-speed gasoline and engines, vibrators, camshafts, gear transmissions, tie rod bushings and thrust washers.
3) The alloy containing 30% tin is used in the occasions where the dust is particularly serious and the embedment is important, and the alloy containing 40% tin is used in the cross bearing of the marine engine