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The key process of cylinder liner-less technology for automobile engines | Surface roughening method
2023/7/21
With the increasingly strict standards of automobile emission and fuel consumption, the whole automobile industry is facing the challenge of energy saving and environmental protection. In order to reduce fuel consumption and exhaust emissions, the traditional method is to reduce the weight of the automobile, so it is a development trend for aluminum alloy engine block to replace cast iron block. In addition, the combustion efficiency of the engine can be significantly improved by reducing the friction inside the engine. A new automobile engine technology-cylinder liner-free technology has attracted the attention of many automobile manufacturers.
The cylinder liner-free technology of automobile engine refers to the introduction of thermal spraying technology to spray a layer of wear-resistant low-carbon alloy coating on the surface of pretreated aluminum engine cylinder hole to replace the traditional cast iron cylinder liner, and the sprayed cylinder block is still an integrated cylinder block. The technology of cylinder body without cylinder liner mainly includes: casting, rough machining, surface roughening of cylinder hole, preheating, spraying, finishing and honing. The following is a brief description of one of the key processes of cylinder liner-less technology, namely, the surface roughening method of cylinder bore:
The purpose of surface roughening is to increase the surface area, form a surface structure that enables the coating to mechanically adhere to the surface of the substrate, increase the mechanical bite force between the coating and the substrate, make the surface more activated, and then improve the bonding strength between the coating and the substrate. There are many ways of surface roughening, such as sandblasting, machining roughening, high-pressure water jet roughening, etc. Among them, sandblasting is a commonly used roughening method, which is suitable for roughening the metal surface. After sandblasting, the base metal can obtain a clean, rough and highly active surface, and the roughened surface needs to be cleaned by oil-free high-pressure dry air before spraying. Machining coarsening is to process the surface of aluminum cylinder into a certain profile by machining, using single-axis machining center and Mapa cutter, which has the characteristics of low machining cost and complete machining, but when coarsening cast iron cylinder, the cutter has great wear and poor economic applicability. High-pressure water jet roughening is only suitable for aluminum cylinder, not for cast iron cylinder. It uses liquid jet to scour the surface of substrate without abrasive, and only needs to be dried after roughening, but the surface roughness value is relatively low.
Surface roughening, as a key process in cylinder liner-less technology, directly affects the bonding strength and coating performance. Therefore, it is necessary to pay attention to the surface roughening process in the processing of cylinder liner-less cylinder block and choose the appropriate roughening method to activate the surface and achieve production efficiency.
The cylinder liner-free technology of automobile engine refers to the introduction of thermal spraying technology to spray a layer of wear-resistant low-carbon alloy coating on the surface of pretreated aluminum engine cylinder hole to replace the traditional cast iron cylinder liner, and the sprayed cylinder block is still an integrated cylinder block. The technology of cylinder body without cylinder liner mainly includes: casting, rough machining, surface roughening of cylinder hole, preheating, spraying, finishing and honing. The following is a brief description of one of the key processes of cylinder liner-less technology, namely, the surface roughening method of cylinder bore:
The purpose of surface roughening is to increase the surface area, form a surface structure that enables the coating to mechanically adhere to the surface of the substrate, increase the mechanical bite force between the coating and the substrate, make the surface more activated, and then improve the bonding strength between the coating and the substrate. There are many ways of surface roughening, such as sandblasting, machining roughening, high-pressure water jet roughening, etc. Among them, sandblasting is a commonly used roughening method, which is suitable for roughening the metal surface. After sandblasting, the base metal can obtain a clean, rough and highly active surface, and the roughened surface needs to be cleaned by oil-free high-pressure dry air before spraying. Machining coarsening is to process the surface of aluminum cylinder into a certain profile by machining, using single-axis machining center and Mapa cutter, which has the characteristics of low machining cost and complete machining, but when coarsening cast iron cylinder, the cutter has great wear and poor economic applicability. High-pressure water jet roughening is only suitable for aluminum cylinder, not for cast iron cylinder. It uses liquid jet to scour the surface of substrate without abrasive, and only needs to be dried after roughening, but the surface roughness value is relatively low.
Surface roughening, as a key process in cylinder liner-less technology, directly affects the bonding strength and coating performance. Therefore, it is necessary to pay attention to the surface roughening process in the processing of cylinder liner-less cylinder block and choose the appropriate roughening method to activate the surface and achieve production efficiency.
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