Insitu Crankshaft Repair of MAN B&W | In Situ Crankshaft Grinding of MAN B&W Crankshaft

by RA Power Solutions RA power solution

We were approached by a leading shipping company regarding grinding/polishing of their crankshaft of auxiliary engine no. 3 of MAN B&W 6L 28/32H.

The ship was scheduled to sail from Cape Town to Vadinar port in India. The crankshaft details of MAN B&W 6L 28/32H are as following:

S. NO	Description	Details
1	Engine Make	MAN B&W
2	Engine Model	6L 28/32H
3	Capacity of Engine	1260 kw (1710 PS) @720 RPM
4	Crankpin Diameter (in mm)	230 mm
5	Collar Length of Crankpin	120 mm
6	Bearing Working Width of Crankpin	95 mm
7	Total Length of Crankshaft	3440 mm
8	Size of Inspection Window	350 * 340 mm

Based on above information of MAN B&W 6L 28/32H. crankshaft, our two technicians along with in situ crankshaft grinding machine were deputed to Cape Town.The boarding on vessel was in short time as our technicians possess Indian CDC.

Inspection of crankshaft of MAN B&W 6L 28/32H was done and made following main observations:

All the six crankpins were subject to dimensional inspection for taper and ovality. The ovality ranging from 0.16 to 0.23 mm was observed on all the crankpins.
The crankpins were subject to MPI by high intensity magna flux torch, no crack or abnormality was observed and it was concluded that although there was surface crack like pattern on crank pin no. 3 was observed but on MPI test it was concluded that there was no crack on the crankpin.
The hardness of all the crankpins was checked by a portable hardness tester. This was done again by indexing a pattern with a gap of 15 mm vertically and horizontally.
Deflection of the crankshaft was checked and was observed within 0.04 mm . This ruled out the possibility of any loss of alignment of the crankshaft.
All crankpins were checked visually. The radius fillet and lubricating oil hole profile was observed as original with no marks or damage.
Deep bearing linemarks were observed on the crankpins.
Bearings were checked and the upper layer of the bearing was removed and had scratch marks.

Action taken by RA Power Solutions to repair crankshaft of MAN B&W 6L 28/32H

Considering the above observations, it was decided to undertake grinding of all crankpins to 0.5 mm .

The standard crankpin diameter of this crankshaft is 230 mm and bearing width of 95 mm.
The insitu grinding of all crankpins was undertaken by our technicians and size was reduced from 230 mm to 229.50 mm.
The crankshaft was again subject to final inspection and a report was prepared.

RA Power Solutions Achievement

The insitu grinding of MAN B&W 6L 28/32H crankshaft was done while sailing the vessel between Cape Town and Vadinar Port in India. The tolerance maintained of all the crankpins was within 0.03 mm.

RA Power Solutions achieved this milestone of undertaking grinding of six crankpins while sailing the vessel by using state of art, latest technological, advanced insitu crankshaft grinding machine. This machine is designed and manufactured by RA Power Solutions to have minimum or zero vibrations while in operation. The maintenance of close tolerance after grinding is possible only because of use of our latest design of insitu crankshaft grinding machine.

RA Power Solutions has the equipment ready to undertake crankshaft repair upto 700 mm diameter. Our technicians are trained in our training school and have experience ranging from 20 to 40 years in successful insitu repair of crankshaft.

For your requirement of crankshaft repair and for crankshaft grinding machine, please contact raj.shahani@rapowersolutions.com or info@rapowersolutions.com or call us at +91-9582647131

This blog is written by Mr. Raj Shahani (Managing Director of RA Power Solutions). He has more than forty years of experience in the field of engine repair and is a technical adviser to various shipping and heavy industries based all over the world.

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