Heat treatment technology has a crucial impact on the intrinsic quality of chain parts, especially motorcycle chains. Therefore, in order to produce high-quality motorcycle chains, advanced heat treatment technology and equipment are necessary.
Due to the gap between domestic and foreign manufacturers in terms of understanding, on-site control and technical requirements of motorcycle chain quality, there are differences in the formulation, improvement and manufacturing process of heat treatment technology for chain parts.
(1) Heat treatment technology and equipment used by domestic manufacturers. The heat treatment equipment in my country’s chain industry lags behind that of industrially developed countries. In particular, domestic mesh belt furnaces have a series of problems such as structure, reliability and stability.
The inner and outer chain plates are made of 40Mn and 45Mn steel plates, and the materials mainly have defects such as decarburization and cracks. Quenching and tempering adopts ordinary mesh belt furnace without recarburization treatment, resulting in excessive decarburization layer. The pins, sleeves and rollers are carburized and quenched, the effective hardening depth of quenching is 0.3-0.6mm, and the surface hardness is ≥82HRA. Although the roller furnace is used for flexible production and high equipment utilization, the setting of process parameters The settings and changes need to be made by technicians, and in the production process, these manually set parameter values cannot be automatically corrected with the instantaneous change of the atmosphere, and the quality of heat treatment still depends to a large extent on the on-site technicians (technical workers) The technical level is low and the quality reproducibility is poor. Taking into account the output, specifications and production costs, etc., this situation is difficult to change for a while.
(2) Heat treatment technology and equipment adopted by foreign manufacturers. Continuous mesh belt furnaces or cast chain heat treatment production lines are widely used abroad. The atmosphere control technology is quite mature. There is no need for technicians to formulate the process, and the relevant parameter values can be corrected at any time according to the instantaneous changes in the atmosphere in the furnace; for the concentration of the carburized layer , the distribution status of hardness, atmosphere and temperature can be automatically controlled without manual adjustment. The fluctuation value of carbon concentration can be controlled within the range of ≤0.05%, the fluctuation of hardness value can be controlled within the range of 1HRA, and the temperature can be strictly controlled within ± Within the range of 0.5 to ±1℃.
In addition to the stable quality of inner and outer chain plate quenching and tempering, it also has high production efficiency. During carburizing and quenching of the pin shaft, sleeve and roller, the change of the concentration distribution curve is continuously calculated according to the actual sampling value of the furnace temperature and carbon potential, and the set value of the process parameters is corrected and optimized at any time to ensure the carburized layer Intrinsic quality is under control.
In a word, there is a big gap between my country’s motorcycle chain parts heat treatment technology level and foreign companies, mainly because the quality control and guarantee system is not strict enough, and it still lags behind developed countries, especially the difference in surface treatment technology after heat treatment. Simple, practical and non-polluting coloring techniques at different temperatures or keeping the original color can be used as the first choice.
Post time: Sep-08-2023