Leaded bronze is a copper alloys containing more lead material. In the metal structure of the alloy, lead is almost insoluble in bronze, and mostly exists between the grains.
What is leaded bronze used for?
The main function of leaded copper alloys is to improve machinability. They are known for their corrosions resistance and long service life.
Common applications include wire and cable connectors, electrical plug connectors, door handles, screws and nuts, bushings, rolling mill bearings, and more.
Effect of Heat Treatment on Corrosion Resistance of Leaded Bronze
USTC has papers: Cu-Sn-Pb copper alloys containing calculated 15%-20% Sn were cast by traditional casting techniques. Corrosion tests were carried out on the samples heat-treated and not heat-treated at different temperatures in an acidic Cl–containing environment, and their corrosion resistance was analyzed by metallographic and XRD.
The results show that after heat treatment, the internal intergranular structure is changed, the δ phase is decomposed or reduced, and the α phase is recrystallized. Selecting the appropriate heat treatment temperature can enhance the corrosion resistance of nickel bronze and achieve the effect of controlling “powder rust”.
Mechanical properties & physical properties of Leaded Bronze
Lead material element has high specific gravity and low melting point, making them very difficult to cast. The values in the performance tables represent reasonable values for general use.
There is also an industry norm that they should not be used for actual normative purposes due to commercial differences in ingredients and manufacturing limitations. Please refer to the applicable normative standard reference.
Advantages and disadvantages of leaded bronze
| GB/T | ZCuPb15Sn8 | ZCuPb20Sn5 |
| ASTM | C93800 | C94100 |
| BSEN | CC496K | CC497K |
| HARDNESS | ≥55HB | ≥45HB |
| FRICTION COEFFICIENT | ＜0.15 | ＜0.13 |
| MAXIMUM LOAD | 100N/㎜² | 100N/㎜² |
The advantages of leaded bronze material
Small friction coefficient, high toughness, and high temperature and high-pressure resistance.
The disadvantages of leaded bronze
Because the melting points of copper alloys and lead are very different, and they are not mutually soluble, the casting performance (continuous cast, centrifugal cast, san cast) is not good, and it is easy to produce reverse segregation, which increases the lead content on the surface of the casting.
At the same time, the lead particles are coarse and the distribution is extremely uneven, so it cannot be achieved. Expected anti-wear effect.
Leaded bronze performance test results
Some experiments show that the addition of trace rare earth to the cast high leaded tin bronzes ZQPb25 can eliminate the reverse segregation of the casting, refine the lead particles, and make them evenly distributed, thereby improving the anti-wear performance.
After adding different types of trace rare earth to ZQPb25, the experimenter also obtained the same test results, among which the effect of adding mixed-light rare earth was the best. On the basis of the test, it was further applied to production.
Several leaded tin bronze bearing copper sleeves with 0.3% mixed-light rare earth added to copper slloys (ZQPb25) were trial-produced to replace the high leaded tin bronze ZQSn6-6-3 bearing bronze on several tugboat diesel engines. Sleeve (spindle copper sleeve and clip blue copper sleeve).
After more than a year of actual operation and use, the thermal expansion results show that ZQPb25 with rare earth has better anti-wear performance than ZQSn6-6-3 bearing copper sleeve, the wear amount is reduced by about 5 times, and the wear on the main shaft is also reduced. , protect the spindle.
Due to the serious wear and tear of the ZQSn6-6-3 high leaded tin bronzes bearing copper sleeve, it was originally stipulated that it should be replaced once a year, but after using the ZQPb25 bearing copper sleeve with rare earth, some of them continue to be used because of the small amount of wear.
Why is lead added to bronze?
Good corrosion resistance and strength properties. Wear-resistant, good weldability.
Good cold formability. Various springs, especially for the electrical industry. Used in the paper, pulp, and chemical industries, shipbuilding, and mechanical engineering. Leaded tin bronzes has better resistance than tin copper alloys, lower tin content, higher strength, very good sliding properties. Good cold formability, weldability, machinability rating and hardness.
Sliding parts, plain bearings (especially thin-walled bearings), and sliding guides. High-stress worm gears and gears, screws, and bolts.
Can you use leaded bronze?
Lead is added to many copper alloyS to make all types of free machining alloys. Lead does not affect the structure and mechanical properties and physical properties of copper alloys because it is practically insoluble in solid bronzes. Lead coppers are categorized as low lead copper alloys, or free-machining alloy and high lead alloys.
Chemical composition show because copper is harder than lead, a lightweight non-lead bullet does not accelerate as fast as a traditional bullet without boosting pressure. We will research the coated metal arc welding and gas shielded arc welding impact on product.
What bushing products are available in leaded bronze?
We specialize in the production and processing of copper parts, which can be processed such as turning, milling, planing, grinding, gear hobbing, stamping, etc., and can provide one-stop service from raw materials to finished products. Welcome new and old customers to map and customize all kinds of copper parts.
- Cone crusher: bowl-shaped bearing bush, straight sleeve, tapered copper sleeve, eccentric shaft sleeve, drive shaft sleeve, thrust bearing, grinding disc,pump impellers, washers.
- Copper worm gear/worm/sliding plate/special-shaped/continuous cast tubes/plate/rod.
Leaded bronze bushing industry project
The domestic market is mainly mining machinery industry equipment and industrial gearboxes.
- Mining machinery: Requires bearings with high surface pressure and side pressure, such as spindle bushings.
- Industrial gear wheels: Require bearings that can withstand the high frequency of sliding speeds
Because copper is harder than lead, a lightweight non-lead bullet does not accelerate as fast as a traditional bullet without boosting pressure.
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