How to Repair the Severely Worn Crankshaft?

Here is the Crankshaft Supplier to share with you about repairing problems after crankshaft wear.If the engine crankshaft is severely worn and the grinding method cannot be repaired or the effect is poor, plasma spraying can be used to repair it.

(1) Surface treatment of the journal before spraying

① According to the wear of the journal, round it on a crankshaft grinder, and the diameter is generally reduced by 0.5-1mm.

②Use copper to shield and protect the adjacent journal of the journal to be sprayed.

③Use a napping machine for napping the surface to be coated. Using nickel strips as electrodes, the nickel is melted on the surface of the journal under 6-9V, 200-300A alternating current.



(2) Spraying

Clamp the Crankshaft on the rotatable worktable and adjust the distance between the spray gun and the workpiece. Choose nickel-clad aluminum as the base material, and the mixture of wear-resistant alloy cast iron and nickel-clad aluminum as the material of the working layer; the thickness of the bottom layer is generally about 0.2mm, and the thickness of the working layer is determined according to needs.

During the spraying process, the temperature of the sprayed journal should generally be controlled at 150~170℃. After spraying, the crankshaft shall be kept in an oven at 150-180℃ for 2 hours, and then cooled with the oven to reduce the stress between the sprayed layer and the journal.

(3) Treatment after spraying

After spraying, check whether the sprayed layer and the journal base are tightly bonded, if not tight enough, remove the respray. If the inspection is qualified, the crankshaft can be ground. Due to the high hardness of the plasma sprayed coating, a softer tin carbide grinding wheel is generally used for grinding, and the feed rate during grinding should be smaller to avoid cracking the coating. In addition, after grinding, be sure to grind the oil passage holes with sand bars to prevent burrs from scratching the tiles. After cleaning, the crankshaft is immersed in 80-100℃ lubricating oil and boiled for 8-10 hours. After the lubricating oil fully penetrates into the coating, it can be loaded into the car for use.

I hope the above sharing is helpful to everyone. In addition, the company also provides Wind Power Shafts and drive shafts. Please feel free to contact if necessary