Isothermal hardening bainite thin wall cylinder cover

Abstract

The invention relates to an isothermal quenching bainite thin wall cylinder liner. The isothermal quenching bainite technology comprises the following steps: the temperature of a high bainite transformation region is 350 to 450 DEG C, and the isothermal quenching is operated at 350 to 380 DEG C. A cylinder liner after being roughly machined is arranged in a vertical pit furnace, the temperature of the cylinder liner is elevated to 900 to 930 DEG C, the cylinder liner is insulated for two hours, then cooled to 350 to 380 DEG C, and delivered to a salt bath furnace to be insulated for two hours. The isothermal quenching bainite cylinder liner material comprises the following elements according to the content percentage: 2.8 to 3.0 percent of C, 1.7 to 2.1 percent of Si, 0.6 to 0.9 percent of Mn, 0 to 0.15 percent of P, 0.35 to 0.5 percent of Mo, 0.6 to 1.2 percent of Cu, 0.2 to 0.4 percent of Ni, 0.25 to 0.45 percent of Cr, and 91 to 92.5 percent of Fe.

Description

Technical field [0001] The invention relates to a cylinder liner, in particular to an austempering bainite thin-walled cylinder liner, which is suitable for high wear resistance and low emission requirements of engines such as large and medium-sized passenger cars, small cars, trucks, ships, locomotives, and generator sets. Background technique [0002] At present, the domestic engine cylinder liner materials mainly include: high-phosphorus cast iron, boron cast iron, vanadium-titanium cast iron, alloy cast iron, etc. After the engine has been used for a period of time, due to the relative wear of the inner wall of the cylinder liner and the piston ring, the matching gap increases, resulting in cylinder Medium and high-pressure gas leaks to the crankcase, which reduces the power, deteriorates the oil, reduces the lubricating effect, and causes early wear; at the same time, due to the increased clearance between the inner wall of the cylinder liner and the piston ring, the eng...

AI Technical Summary

Problems solved by technology

[0002] At present, the domestic engine cylinder liner materials mainly include: high-phosphorus cast iron, boron cast iron, vanadium-titanium cast iron, alloy cast iron, etc. After the engine has been used for a period of time, due to the relative wear of the inner wall of the cylinder liner and the piston ring, the matching gap increases, resulting in cylinder Medium and high-pressure gas leaks to the crankcase, which reduces the power, deteriorates the oil, reduces the lubricating effect, and causes early wear; at the same time, due to the increased clearance between the inner wall of the cylinder liner and the piston ring, the engine oil escapes and increases the discharge. pollution; moreover, the price of alloy materials is very expensive, and the manufacturing cost of alloy cylinder liners has risen sharply; more importantly, limited resources are not fully utilized

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