Preparation And Study On Cold Spraying Coating Based On Shaft Parts Repair

Shaft parts repair is particularly important in view of shaft parts wear can degrade the mechanical equipment’s performance leading to safe trouble. Due to shaft parts wear usually occurs on the surface, we can create wear-resisting coating by surface engineering technologies to extend the life of shaft parts. There is a variety of surface repair methods, they have their own advantages and disadvantages, in order to overcome the shortcomings of existing technology, we propose to repair the shaft parts by cold spraying method. Cold spraying technology has many advantages: low working temperature, high density, simple equipment and small thermal impact on the substrate.In this paper, 316 L stainless steel powder and Ni Cr alloy powder were chosen as the coating materials. Based on the characteristics of these two kinds of powder, 316 L stainless steel coating and Ni Cr alloy coating were prepared by cold spray process.The microstructures and properties of the coating were studied by metallographic microstructure observation and microhardness testing. The results show that the two kinds of cold spraying coating were not found obvious flaws, they have low porosity and their thickness can reach the need of shaft parts repair in actual working condition. Two kinds of cold spraying coating‘s surface microhardness are significantly higher than that of the 45# steel substrate surface. They improved the substrate surface hardness, and then enhance the substrate wear resistance.The wear test show that in the dry condition, the total weight loss of 316 L stainless steel coating is slightly smaller than that of the 45# steel substrate, and the Ni Cr alloy coating’s total weight loss is far less than that of the 45# steel substrate. The 45# steel substrate show of abrasive wear, adhesive wear and oxidation wear characteristics. The two kinds of cold spray coating show of the abrasive wear and adhesive wear characteristics. In lubrication condition, the total weight loss of 316 L stainless steel coating is bigger than that of the 45# steel substrate. The total weight loss of Ni Cr alloy coating is far less than that of the 45# steel substrate. The 45# steel substrate and cold spraying Ni Cr alloy coating show of abrasive wear and adhesive wear characteristics. Cold spray 316 L stainless steel coating show of abrasive wear, adhesive wear and fatigue wear characteristics. Cold spraying Ni Cr alloy coating can greatly improve the wear resistance of substrate after repair, but cold spray 316 L stainless steel coating couldn’t meet the requirement of repair.