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What are the repair methods for 200KW diesel generator set crankshaft wear?

June 29, 2022
The crankshaft is a very important part within the engine, the crankshaft and connecting rod are the components that convert the up and down motion of the piston into rotary motion, the small end of the connecting rod is connected to the piston and the large end of the connecting rod is connected to the crankshaft. Crankshaft wear is a relatively common problem for 200KW diesel generators. The main reason for engine crankshaft wear is poor lubrication, and it may also be caused by the engine running in high speed area for a long time. Therefore, 200KW diesel generator must be inspected during the overhaul of the crankshaft to identify the situation and choose the correct repair or restoration method to ensure the fatigue strength and wear resistance required by the crankshaft. In this article, top Bo power for you to introduce the 200KW diesel generator crankshaft wear after the conventional repair methods.
A, crankshaft arc spraying repair method
Thermal spraying technology is a surface engineering technology that has been widely used in diesel generator set repair in recent years. It is the molten state of the spraying material through high-speed airflow to make it atomized spray on the surface of the parts, forming a spray layer of a metal surface processing method.
At present, it has been widely used in the manufacture of various functional coatings and the repair of diesel generator parts.
In order to make the spray layer and the substrate to obtain a good combination, to repair the journal to sand roughening treatment, sandblasting process parameters are: sandblasting pressure of 0.65MPa, sandblasting angle of 85 °, sandblasting distance of 180 ~ 200mm. then block the oil hole and copper skin to spray the journal of the neighboring journals for masking protection.
CMD-AS-1620 electric arc spraying equipment is selected. First, spray the primer layer with nickel-aluminum composite wire. Then choose φ2mm 3Cr13 spraying wire for arc spraying, spraying process parameters are: voltage 38~40V, current 110~130A, compressed air pressure
0.65MPa. In order to obtain a dense coating, in the spraying to continuous spraying, there should not be a long pause in the middle, otherwise it will affect the bonding strength. Spraying thickness is generally appropriate to leave a processing margin of 0.8~1mm.
After spraying to check whether the spraying layer and the journal substrate combined closely, such as not close enough, then remove the re-spray. If the inspection is qualified, the crankshaft can be ground. The grinding feed should be 0.05~0.10mm. After grinding, grind the oil channel hole with an abrasive strip, and after cleaning, immerse it in 80~100°C lubricating oil and cook it for 8~10h, after the lubricating oil fully penetrates into the coating, it can be loaded and used.
Second, the crankshaft manual electric arc welding repair method
When the 200KW diesel generator crankshaft main journal wear serious, can use the symmetric welding repair method. The process is: first the journal surface oil and dirt, and then bur bur around the journal pockmarked; choose 3 ~ 4mm diameter mild steel welding rod for symmetric welding, welding current of 145 ~ 155A, after welding the journal size than the standard journal to 2 ~ 3mm, and then grinding processing to the standard size.
When cracks occur, first open the bevel with burin, open U-shaped bevel along the cracked surface, the depth of the bevel should be invisible to the crack, the width is 13~14mm, preheat the welding part to 400°C with oxy-acetylene flame before welding, and then carry out symmetric welding. After welding, the oil channel should be drilled through, chiseled and repaired smoothly, and then ground and processed to the standard size.
Third, the crankshaft of other parts of the damage
200KW diesel generator starter thread damage can be repaired by increasing the threaded hole, should be careful not to damage the chamfer of the threaded hole; if the rear end of the crankshaft flange end face or outer cylindrical face of the main journal centerline circular runout, available turning end face or column surface method to eliminate; flange disk connected to the flywheel bolt hole wear, available to enlarge the fixed bolt repair method after reaming. If the bearing hole of the front bearing of the first shaft of the transmission is installed on the flange disk, the radial circular runout of the main axis line is overrun, and the repair method is used to fix the set.