High-strength non-quenched and tempered steel material suitable for connection rod

Abstract

The invention relates to a high-strength non-quenched and tempered steel material suitable for a connection rod. The high-strength non-quenched and tempered steel material is characterized by comprising chemical elements of C, Si, Mn, P, S, Cr, V, N, Mo, Ni and the balance Fe and unavoidable impurities, wherein the element mass percents are as follows: C is 0.42%-0.50%, Si is 0.40%-0.70%, Mn is 0.90%-1.20%, P is 0.020% or less, S is 0.045%-0.075%, Cr is 0.20% or less, V is 0.10%-0.20%, N is 0.010%-0.020%, Ni is 0.2% or less, Mo is 0.10% or less, and the element mass percent is about 96.80%-98.10%; after the steel material is forged at the temperature of 1,250 DEG C into a test sample with the diameter phi being 30 mm and air-cooled, the mechanical performance data requirements of the non-quenched and tempered steel material are as follows: RP0.2 is larger than or equal to 700 MPa, Rm is larger than or equal to 1,000 MPa, A is larger than or equal to 10 %, and Z is larger than or equal to 25 %. After the steel material is forged, the strength level exceeds 1,000 MPa, the steel material has good toughness, swelling performance and machining performance, and the swelling connection rod manufactured and produced through the material has a relatively-high fatigue safety factor and accordingly has good application prospects.

Description

technical field [0001] The invention relates to a high-strength non-quenched and tempered steel material suitable for connecting rods, belonging to the technical field of high-strength steel materials for automobiles. Background technique [0002] Since the 1980s, non-quenched and tempered steel has developed rapidly in my country's automotive material industry. At present, the application of non-quenched and tempered steel materials represented by C70S6 series in the expansion of connecting rods in car engines has become more popular. A ferritic-pearlitic non-quenched and tempered steel with wide application worldwide. The general requirements for the material of the expansion connecting rod are high strength, certain toughness, and small plastic deformation to meet the needs of expansion and cracking. In addition, good mechanical properties and excellent fatigue properties are also required. However, according to the actual situation of mass production, it is found that th...

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Problems solved by technology

Due to the low carbon content, high ferrite content in the structure and high plasticity of this material, it is not conducive to the realization of the connecting rod expansion process to a certain extent, and the expansion process may lead to large deformation of the big end, which is difficult to process. large margin

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