Among the automobile connecting rods made of various materials, the powder metallurgy automobile connecting rod has advantages in hardness, wear resistance and strength. Powder metallurgy is a material saving, energy-saving and low production cost manufacturing technology for mechanical parts, which is very suitable for mass production. Powder metallurgy automobile parts and automobile industry in developed countries are developing at the same time. At the end of 1980s, the application of PM parts in automobiles abroad has reached an average of 10-15kg per vehicle, while in China, it is only 3-5kg per vehicle. The traditional view is that powder metallurgy parts can only be used as parts with simple shape, low compactness and low strength to replace gray cast iron; With the rapid development of powder metallurgy technology, it can now be used for automotive parts with complex shape, high compactness, high strength and high precision, which can replace forged steel parts. In the past 20 years, the general hot forged steel parts have been replaced by high-strength powder metallurgy parts. Now, the use of more precise powder metallurgy parts can reduce the research and development of machining process, and significant progress has been made. Powder metallurgy hot forging connecting rod production technology is one of them.
At present, only the United States, Germany, Japan and other developed countries use powder metallurgy hot forged connecting rods. Powder metallurgy hot forged connecting rod can not only achieve the mechanical properties of machined automobile connecting rod, but also reduce the single piece cost by 50%. After hot forging, the connecting rod material has exceeded the mechanical properties of machined connecting rod material. The weight accuracy of the powder forged connecting rod can reach 1%, as shown in the table, while the weight accuracy of the forged connecting rod is 2.5%. Compared with the conventional machined connecting rod, 35% of the processing cost can be saved after reaching the economic batch. In 1992, the number of powder forged connecting rods of Ford company reached 10million. The main raw material of powder metallurgy is atomized steel powder. The production of automobile connecting rod by powder metallurgy generally goes through the following steps: powder mixing – pressing – sintering – hot forging – machining.
Basic data of car connecting rod:
| Weight | Common forged connecting rod | Powder forged connecting rod |
| Average value | 620.7g | 598.4g |
| Maximum value | 622.6g | 599.4g |
| Minimum value | 619.2g | 597.0g |
In recent years, due to the development of powder metallurgy technology, especially the emergence and application of powder metallurgy forging process, the machining allowance has been greatly reduced, which not only improves the productivity of machining, but also increases the utilization rate of raw materials. Therefore, the use of powder metallurgy for automotive connecting rods is a very promising development trend.