SU494426A1 - Cast iron - Google Patents

Description

one

The invention relates to the field of metallurgy, in particular to the search for wear-resistant cast irons used for parts operating under conditions of friction at elevated temperatures and limited lubrication, for example, for valve guides of internal combustion engines.

Known cast iron of the following chemical composition, wt.%:

2.02-4.04 0.5-8.3 0.3-1.27 0.03-1.15, 0.02-2.5 0.04-2.0 0.05-0.4 0.09-1.0 Else

Cast iron has the following properties:

Tensile strength at break, kg / mm

32.5

 Strength limit - at a bend, to g / mm53,0

Deflection boom, mm3,2

Hardness HB, kg / mm 241

Wear, mm 0,018-0,023

Bushes of Chukhun of known composition do not have sufficient wear resistance.

To increase the wear resistance under conditions of elevated temperatures, boron is introduced into the proposed cast iron at the following ratio between the components, weight. Carbon3,2-4,2

Silicon1.0-2.0

Manganese 0.6-1.2

Chrome 0.25-0.8

Copper0,4-1,3

Vanadium 0.2-0.6 phosphorus 0.4-1.0 Bor0.005-0.03 Iron The remaining cast iron in the cast state has the following properties: Tensile strength at break, kg / m 33.0-35.0 Strength at bending, kg / mig 53.5-57.0 3.0-3.4 Strength deflection, HB hardness, kg / mg 248-269 0.01 I Wear mm Insertion of boron in phosphorous cast iron ensures obtaining a fine mesh of phosphide eutetics, as well as significantly reduces the waste of vanadium present in cast iron. The high vanadium content creates solid (H 750–1280 kg / mm) complex inclusions consisting of phosphide eutetics and complex carbides with high heat resistance. The proposed cast iron has a high stability of the structure at elevated temperatures. For 6 hours of testing at 670 ° C, the hardness does not change and is 240-280 HB. Claims: Cast iron containing carbon, silicon, manganese, chromium, copper, vanadium, phosphorus and iron, characterized in that, in order to increase wear resistance under conditions of temperatures, boron is introduced into it in the following ratio between components, in%: 3.2-4.3 Carbon 1.0-2.0 Silicon 0.6-1.2 Manganese 0.25-0.8 0.4-1.2 Copper 0.2-0.6 Vanadium 0.4 -1.0 phosphorus 0,005-0,03 Bor Rest Iron.