Cylinder Covers

Reconditioning of Cylinder Covers

Although local/partial repairs can be carried out on request, our standaard procedure is to remove the lower combustion bowl of the covers and replace it by a new one.
This is the only reliable way to make sure that all cracks, which always originate on the cooling water side, are eliminated. At the same time, taking advantage of the fact that the inner surface is exposed, the latter is machined in order to remove the rough "as cast" finish, thereby reducing the chance of future cracking.

This is a typical B&W bore cooled Cylinder Cover as received at our works. Inner and Outer Coolingwater Shields or if applicable as with other Engine makes, the Coolingwater Plugs are allways removed for Pre-Inspection of cracks, lime deposit and casting holes.

After the cylinder cover is grit blasted and cleaned the combustion side is removed using an automatic flame cutter. The upper part is machined and fully inspected it will then undergo a reconditioning as per outcome of the Pre-Inspection report according to the Summary Workshop Procedures iniated by Ing. Mr Johan M. van West.

The combustion side of this Sulzer cylinder cover is machined away, to open the cooling water bores to open and to weld the cracks in the cooling area.

The new combustion bowl, made by a foundry accepted by the classification societies, is machined on the cooling water side and welded to the finished upper part.

Heattreatment (PWHT) in Electric controlled furnace
Capacity up to 5000 Kgs. All process stress relieving temperatures controlled and registrated with pen recorder.

When the welding is completed, the whole assembly is stress relieved at a temperature appropriate to the materials used.

Machining of welded area at the combustion side

The final machining of the combustion bowl is done in accordance with the manufacturer's specifications. The exact profile of the combustion bowl is guaranteed by the employment of CNC machine tools.

The unit is then thoroughly inspected, water pressure tested and certified by the relevant class society.

Finished cover MC-type painted and corrossion protected.
Water pressure tested and brought under Classification