Development of braze repair technology for Ni-Al-Bronze (NAB) propellers

大型船舶的螺旋桨多由镍铝青铜(NAB)制成。在使用过程中，由于腐蚀、异物撞击和冲刷/磨损造成损坏。这些螺旋桨的更换成本在几美元到数万美元之间。因此，需要修复/恢复这些昂贵的部件。多米尼斯工程公司目前正在使用熔焊工艺修复NAB螺旋桨。这一过程是劳动密集型的，而且交货期很长，因为每个缺陷都必须手动焊接。此外，焊接过程经常会导致裂纹和变形，这将需要反复焊接、矫直、重新倾斜和热处理。为了向客户提供大规模、快速周转的螺旋桨维修服务，Dominis Engineering正在寻求一种更高效的工艺，使他们能够在批量工艺中修复多个部件上的所有缺陷。

A large number of propellers for large ships are made of Ni-Al-Bronze (NAB). During service, damages occur due to corrosion, foreign object impact and erosion/wear. Replacement cost of these propellers is in the range of several to tens of thousands of dollars. As such there is a demand to repair/restore these costly parts. Dominis Engineering is currently using a fusion welding process to repair NAB propellers. This process is labour intensive and has a long lead time as every defect has to be welded manually. Furthermore, the welding process often results in cracking and distortion which will require repeated welding, straightening, re-pitching and heat treatment. In order to provide a large scale, fast turnaround propeller repair service to its customers, Dominis Engineering is seeking a more efficient process which allows them to repair all defects on multiple parts in a batch process.