Cast steel material for chain wheel of marine diesel engine and casting method of chain wheel

Abstract

The invention relates to a cast steel material for a chain wheel of a marine diesel engine. The cast steel material comprises the following chemical elements in percentage by mass: 0.18-0.21 percent of C, 0.85-1.00 percent of Mn, 0.35-0.55 percent of Si, less than or equal to 0.020 percent of S, less than or equal to 0.020 percent of P, less than or equal to 0.30 percent of Cr, less than or equal to 0.30 percent of Ni, less than or equal to 0.080 percent of Mo, less than or equal to 0.10 percent of V, less than or equal to 0.080 percent of Al, less than or equal to 0.060 percent of Nb, less than or equal to 0.40 percent of Cu and the balance of Fe element and other inevitable impurities. In the element proportion, the carbon equivalent that CEV is less than or equal to 0.39 percent is met, wherein CEV is calculated by a formula, namely CEV=C%+(Mn%) / 6+(Cr%+Mo%+V%) / 5+(Ni%+Cu%) / 15. In a manufacturing method, raw materials of the chain wheel are reasonably selected and unconventional normalizing thermal treatment is performed, so that the yield of the mechanical property of the chain wheel is increased, the technical problems of low tooth surface hardness and uniformity are solved, the running reliability of the marine diesel engine is enhanced, and production cost is lowered.

Description

technical field [0001] The invention relates to a marine diesel engine, in particular to a manufacturing material and a casting method for a sprocket on the marine diesel engine. Background technique [0002] On a marine diesel engine (also known as the main engine), the structure of the sprocket is as follows figure 1 and figure 2 As shown, its diameter is nearly two meters, and its weight reaches 6000kg. Because of its huge size, it is difficult to grasp during casting and prone to casting defects. The above-mentioned cast steel sprocket is used to drive the camshaft transmission of the marine low-speed diesel engine. The sprocket is an extremely important moving part of the diesel engine, which is related to the reliable operation of the diesel engine. It transmits part of the energy of the crankshaft of the diesel engine to the camshaft through the chain drive, thereby driving the cam to move. When the sprocket is working, it needs to bear periodic alternating stres...

AI Technical Summary

Problems solved by technology

[0003] In the sprocket manufacturing materials of the prior art, there are often casting defects in the sprocket teeth after the casting is completed. In practice, repairing methods are often used to remedy it. As a result, due to the difference between the repaired material and the sprocket material, the repair There will be microscopic cracks in the final part, and it will break due to fatigue during long-term use

If the sprocket teeth break during the working process of the ship's main engine, it will affect the safe operation of the main engine

There is another deficiency in the sprockets produced by the prior art, that is, the distribution of hardness is not uniform, and severe local wear often occurs, which will also affect the service life of the sprocket

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