KmTBCr28铸铁组织和性能的研究

Study on Microstructures and Properties of KmTBCr28 High-Chromium Cast Iron

研究了铸态和不同正火加热温度和不同温度回火KmTBCr28铸铁的组织和性能。结果表明:KmTBCr28铸铁随着正火温度的提高,冲击吸收功逐渐提高,正火温度为1040℃时,材料具有较高的硬度和冲击吸收功;正火后回火,随回火温度提高,硬度有降低的趋势,冲击吸收功在100℃回火出现峰值,500℃回火出现铸铁回火脆性;KmTBCr28铸铁铸态可获得HRC54～57,AK=3.2～4.0J;奥氏体化加热温度为1040℃时,空冷100～200℃回火,铸件可获得HRC63～65,AK=4.3～4.5J。铸态及热处理态的组织为马氏体、残余奥氏体和(FeCr)7C3型碳化物组成。

Microstructures and properties of KmTBCr28 high-chromium cast iron were studied at as-cast, various normalizing temperature and tempering temperature. The results show that toughness of KmTBCr28 high-chromium cast iron is increased with the increase of normalizing temperature and higher hardness and toughness can be obtained after normalizing at 1 040℃. After normalizing and various temperature tempering, the hardness will be decreased with the increase of tempering temperature, the highest impact toughness appears as the tempering temperature is 100℃, and tempering brittleness of cast iron appears as the tempering temperature is 500℃. KmTBCr28 cast iron with the properties of HRC 54-57 and Ak=3.2-4.0 J can be obtained in as-cast. And the cast iron with the properties of HRC 63-65 and Ak=4.3-4.5 J can be obtained after normalizing at 1 040℃ and tempering at 100-200℃. The microstructure of KmTB28Cr high-chromium cast iron is martensite, retained austenite and （FeCr）7C3 type carbide at as-cast and various heat treatment status.