High-strength crankshaft of engine and preparation method thereof

Abstract

The invention discloses a high-strength crankshaft of an engine. The crankshaft is made of non-quenched and tempered steel. The non-quenched and tempered steel comprises, by weight, 0.25-0.3% of C, 1.5-2.0% of Mn, 0.15-0.25% of Si, less than or equal to 0.015% of P, less than or equal to 0.05% of S, 0.03-0.1% of Cr and the balance Fe and inevitable impurities. According to the crankshaft, the C content is low, so that a crankshaft blank is easy to straighten, and the rejection rate of the crankshaft blank is decreased; the Mn content is high, so that the strength of the crankshaft material isimproved; rare metals Mo and V are not added, so that the steel cost is reduced; and the bending strength and the torsional strength of the crankshaft are greatly improved through the strengthening mode of carbonitriding (soft nitriding) and water quenching.

Description

technical field [0001] The invention relates to the field of auto parts processing, in particular to a high-strength engine crankshaft and a preparation method thereof. Background technique [0002] On the basis of improving the protection awareness of the earth's environment, the regulations have gradually increased the displacement requirements for high-performance gasoline engines, requiring the performance of gasoline engines to be improved, the displacement to be reduced, and the cost to be reduced. 5-10%, the cost reduction of the crankshaft is an important aspect to reduce the cost of the engine. [0003] In the prior art, the ratio of the crankshaft is generally used: carbon 0.35-0.38, 42CrMo steel and other materials, and the crankshaft is formed by rounded corner rolling processing. This solution contains rare metals such as Mo and V, so its cost is relatively high. , and the C content is high, the crankshaft alignment is difficult, and the scrap rate is high. Fo...

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Problems solved by technology

[0003] In the prior art, the ratio of the crankshaft is generally used: carbon 0.35-0.38, 42CrMo steel and other materials, and the crankshaft is formed by rounded corner rolling processing. This solution contains rare metals such as Mo and V, so its cost is relatively high. , and the C content is high, the crankshaft alignment is difficult, and the scrap rate is high

For example, the content ratio of a kind of crankshaft steel disclosed in the prior art: by mass %, it contains 0.28% to 0.47% of C, 0.45% or less of Si, 0.90% to 1.50% of Mn, 0.006 % or less of S, less than 0.30% of Cu, less than 0.15% of Mo, and more than 0.06% and less than 0.32% of V, and the rest is Fe and unavoidable impurities, which contain rare elements Mo and V, making the cost higher

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