Production method of ultra-high strength toughness ductile iron crankshaft with pearlite matrix

Abstract

The production method of the pearlite matrix ultra-high strength ductile ductile iron crankshaft provided by the present invention selects low-sulfur and low-titanium pig iron, ordinary carbon steel and self-produced recycled iron as the main charge, and adds specific proportions of 75% ferrosilicon and 65% high-carbon manganese Iron, electrolytic copper and graphite-type recarburizers; smelted at a specific frequency in an intermediate frequency furnace, adding nodulizers, inoculants, silicon-calcium-manganese deoxidizers, and then tapped for nodularization. The nodularization process requires a specific tapping position, speed, and tapping The first step is to select a specific inoculant flow rate and total amount during the pouring process, and adopt a specific normalizing process for the crankshaft casting to prepare an ultra-high-strength ductile ductile iron material with a strength exceeding 1000 MPa, an elongation ≥ 5%, and a matrix material of pearlite type. Its comprehensive performance far exceeds that of ordinary ductile iron and ADI materials with the same tensile strength. The preparation method is applied to J4200 crankshaft, JX400 crankshaft and other parts to realize the preparation of ultra-high strength and toughness material with pearlite matrix, reduce the cost and obtain remarkable benefits.

Description

technical field

[0001] The invention belongs to the field of ductile iron casting technology, and in particular relates to a production method of a pearlite matrix ultra-high-strength ductile ductile iron crankshaft with a tensile strength exceeding 1000 MPa and an elongation exceeding 5%. Background technique

[0002] When designing engine crankshaft parts, designers usually select materials that can meet the yield strength from the national standard materials according to indicators such as strength and elongation. Currently, among ductile metal materials with a strength exceeding 1000MPa and an elongation of not less than 5%, usually only 40Cr, 42CrMo, engineering high-strength cast steel or ADI materials can meet the design requirements of the crankshaft structure.

[0003] 1. According to the standard of GB / T1348-2009: the maximum strength of ordinary ductile iron can reach 900MPa, and the elongation rate is 2%. There are a few domestic manufacturers who can make QT800-...

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