There is a common misconception that all corrosion-resistant bearings are suitable for underwater use, but this is not the case. Underwater robots, drones, propeller shafts, and submerged conveyors all require application-specific design considerations and specialist bearings. Here Chris Johnson, managing director at underwater bearing supplier SMB Bearings, investigates which bearing materials are suitable for underwater use.
一些耐腐蚀轴承可以操作exposed to freshwater, saltwater, steam, or other chemicals, but not all are suitable for continuous underwater use. Fully submerging a bearing can impact its lifespan, depending on the material it is made from. One example is 440-grade stainless steel bearings. They are highly resistant to fresh water and weak chemicals, but if placed in saltwater or fully submerged, they will quickly corrode.
轴承通常由于腐蚀，润滑剂衰竭或污染而过早失效。如果轴承不适合长期水下使用，水可以进入该组件并夸大这些常见问题。如果外壳密封破裂，液体可以进入系统并稀释润滑，从而产生额外的摩擦，从而损坏更宽的部分。咸水或化学物质也会腐蚀轴承，从而导致零件的寿命缩短。因此，设计工程师应考虑轴承的应用和环境，以确保其设备不会出乎意料地恶化并导致昂贵的停机时间。
Choosing an appropriate bearing
有很多适合沉浸的轴承，但是为应用程序选择正确的轴承是关键。陶瓷轴承不受盐水的影响，因此适用于在海上能源站点的水下无人机使用。二氧化锆或氮化硅材料高度耐用，可以承受在螺旋桨或水下输送机中可能需要的高负荷。
Plastic bearings are also highly corrosion resistant to fresh and saltwater and can operate effectively when fully submerged. Plastic alternatives are a less costly solution and have low levels of friction, although load capacity is lower than steel or ceramic bearings.
316不锈钢轴承可有效地在不腐蚀和高温下完全浸入淡水中，因此可用于海洋工业的低负载和速度应用，例如螺旋桨轴。如果在轴承上有规则的水流以提供防止腐蚀所需的氧气，则轴承还将承受浸入盐水中。
投资适当的润滑将确保轴承的效率保持较高。还可以添加防水油脂，因此不会通过任何水接触稀释润滑。
并非所有耐腐蚀轴承都适合在水下长时间使用，因此投资合适的轴承，例如陶瓷，塑料或某些钢，将使制造商能够确保其产品的寿命很长，而无需不断替代受损或腐蚀轴承。研究轴承可以承受的不同条件有助于提高效率并降低替换零件的总体成本。
SMB轴承
www.smbbearings.com
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