The automotive manufacturing industry has different requirements for coating hardness in different parts, as follows:
Exterior coating of vehicle body
Daily use protection requirements: The coating on the surface of the car body has the main functions of aesthetics, corrosion resistance, and a certain degree of scratch resistance to cope with various situations in daily use, such as contact with cleaning tools during car washing, slight scratches from tree branches, etc. It is usually required that the pencil hardness reach between 2H-4H. At this hardness level, the car paint can maintain the surface integrity well, avoid scratches that may affect the appearance of the car, and meet the overall requirements for texture and glossiness of the car appearance.
Process and cost considerations: From the perspective of coating technology, this hardness range is also easy to achieve through common automotive painting, baking paint and other processes, and will not significantly increase costs due to excessive pursuit of high hardness. On the basis of ensuring the effectiveness of use, it achieves good economy.
Automotive interior coating
Balancing aesthetics and durability: The coating on the interior of a car should not only meet aesthetic requirements and create a comfortable interior environment, but also withstand a certain degree of friction, scraping, and other situations, such as seat adjustment buttons, door handles, and other frequently touched parts. Its hardness generally requires a Shore hardness (HA) of around 70-90, which can maintain a good appearance of the coating in daily use, prevent wear and discoloration, and provide a comfortable feel that matches the overall quality of the interior.
Special material adaptation: At the same time, for different interior materials such as plastic, leather, etc., the coating hardness also needs to be adjusted appropriately. For example, in the coating of leather interior, the flexibility of the leather should be fully considered, and the texture of the leather itself should not be damaged due to the coating being too hard. It is also necessary to ensure sufficient hardness to extend its durability.
Coating of internal engine components
Dealing with harsh working conditions: Many internal components of the engine, such as valves, lifters, piston rings, etc., are subjected to high temperature, high pressure, high mechanical stress, and frequent friction under harsh working conditions. In order to reduce the wear of parts, extend their service life, and ensure the reliable operation of the engine, the coating hardness requirements for these parts are relatively high, usually with a Rockwell hardness (HRC) of around 55-70.
Stable performance guarantee: The high hardness enables these parts to better resist friction, impact, and other effects during repeated engine starts and long-term continuous operation, maintaining their good shape and dimensional accuracy, ensuring the precision of the fit between engine components, and thus ensuring stable power output and overall good performance of the engine.
Chassis and suspension system coating
Anti stone impact and corrosion resistance: Car chassis and suspension systems often face impacts from stones on the road, erosion from mud and water, and wear caused by various complex road conditions. The coating needs to have sufficient hardness to resist stone impact and prevent rusting and corrosion of chassis components. Generally, the Rockwell hardness (HRC) is required to be between 40-60, which can ensure a certain wear resistance while coordinating with the strength, toughness, and other properties of chassis components, making the chassis and suspension system durable in complex driving environments.
Collaboration with protective materials: In addition, this part of the coating sometimes works together with protective materials such as chassis armor. The hardness of the coating should be adapted to the characteristics of these protective materials to form an effective protective system, ensuring the structural integrity and functional stability of the chassis and suspension system.
Automotive wheel hub coating
Balancing aesthetics and durability: Car wheels are not only important components that bear the weight of the vehicle, but their appearance also affects the overall aesthetics of the car. On the one hand, the wheel hub coating should have high hardness to resist wear caused by brake dust, road foreign objects, etc. during daily driving, and on the other hand, it should meet the aesthetic requirements of different styles of wheel hub designs. It is usually required that the Rockwell hardness (HRC) be between 50-70, so that the wheel hub maintains a good appearance during frequent braking and rotation, reduces scratches and wear, and exhibits a good texture.
Different materials are treated differently: For wheels made of different materials, such as aluminum alloy wheels and steel wheels, the coating hardness requirements may also vary slightly. Aluminum alloy wheels have a relatively soft texture and may require a slightly harder coating to enhance protection; The steel wheel hub itself has high strength, and the selection of coating hardness will take into account its cost and compatibility with other protective measures.
In short, the automotive manufacturing industry has detailed and differentiated requirements for coating hardness based on factors such as functional requirements, usage environment, and material characteristics of different parts, in order to ensure the overall performance, appearance, and service life of automobiles.
 
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