耐热合金球墨铸铁组织和耐热性能的试验研究
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摘要
烧结机台车工作温度在100～650℃之间,其主要的失效形式是氧化和生长造成的变形和裂纹。因此要求烧结机台车必须具有较高的高温强度、良好的高温抗变形性能及热疲劳性能。
本文通过金相组织观察、常温力学性能检测、高温抗变形性能试验和高温热疲劳试验等检测手段,研究了Mo、Cu、Cr合金元素和Si对耐热合金球墨铸铁组织、常温力学性能、高温抗变形和热疲劳性能的影响。
当Cr含量0.14%、Cu含量0.60%时,Si从2.65%增加到2.94%,金相组织中的珠光体含量从85%减少为35%,抗拉强度略有下降,高温抗变形能力显著降低,高温热疲劳性能明显提高。
当Si、Mn含量一定时,含Cr 0.26%、Cu 0.39%与含Mo 0.38%、Cu 0.3%的试样相比,珠光体含量相近,常温力学性能、高温抗变形性能、高温热疲劳性能基本相同。
为了保证烧结机台车具有良好的力学性能、高温抗变形性能和热疲劳性能,其合适的铸态组织为:基体组织40%～60%珠光体,石墨球化级别1～3级,渗碳体含量小于0.5%。化学成分为:C:3.5～3.8%,Si:2.4～2.7%,Mn:0.2～0.4%,S＜0.03%,P＜0.05%,Cr:0.15～0.2%,Cu:0.3～0.6%。
The carriage body of sintering machine worked in wretched environment. The temperature varied periodicly between 100℃and 650℃. Carriage body of sintering machine is deformed and cracked easily because of oxidation and growth in high temperature. So Carriage body of sintering machine should possess the good properties of strength in high temperature, deformation resistance and heat fatigue in high temperature.
In this paper, the effect of alloying elements Mo, Cu, Cr and Si on microstructure, mechanical properties, high temperature anti-deformation and thermal fatigue performance of ductile cast iron is researched, by the means of microstructure observation, room-temperature mechanical properties test, high-temperature deformation resistance test and high-temperature thermal fatigue experiment.
When Cr content is 0.14% and Cu is 0.60%, Si rises from 2.65% to 2.94%, the pearlite content decreased from 85% to 35%, tensile strength and elongation did not change significantly, the deformation resistance property in high temperature significantly reduced, heat fatigue has improved significantly.
The result of the experiment indicated that the properties and pearlite content in specimen containing 0.26% Cr, 0.39% Cu is similar to that of specimen containing 0.38wt%Mo. 0.30wt%Cu,when Si content is determined.
In order to reach mechanical properties, high temperature anti-deformation and thermal fatigue properties, the as-cast structure containing 40%-60%pearlite, less than 0.5 % cemenite is required. And the better spheroidization degree is between 1 and 3. Its chemical composition should be 3.5%-3.9%C, 2.4 %-2.7 %Si, 0.2% -0.4%Mn, less than 0.03%S, less than 0.05%P, 0.15%-0.2%Cr, 0.3%-0.6%Cu.
本文通过金相组织观察、常温力学性能检测、高温抗变形性能试验和高温热疲劳试验等检测手段,研究了Mo、Cu、Cr合金元素和Si对耐热合金球墨铸铁组织、常温力学性能、高温抗变形和热疲劳性能的影响。
当Cr含量0.14%、Cu含量0.60%时,Si从2.65%增加到2.94%,金相组织中的珠光体含量从85%减少为35%,抗拉强度略有下降,高温抗变形能力显著降低,高温热疲劳性能明显提高。
当Si、Mn含量一定时,含Cr 0.26%、Cu 0.39%与含Mo 0.38%、Cu 0.3%的试样相比,珠光体含量相近,常温力学性能、高温抗变形性能、高温热疲劳性能基本相同。
为了保证烧结机台车具有良好的力学性能、高温抗变形性能和热疲劳性能,其合适的铸态组织为:基体组织40%～60%珠光体,石墨球化级别1～3级,渗碳体含量小于0.5%。化学成分为:C:3.5～3.8%,Si:2.4～2.7%,Mn:0.2～0.4%,S＜0.03%,P＜0.05%,Cr:0.15～0.2%,Cu:0.3～0.6%。
The carriage body of sintering machine worked in wretched environment. The temperature varied periodicly between 100℃and 650℃. Carriage body of sintering machine is deformed and cracked easily because of oxidation and growth in high temperature. So Carriage body of sintering machine should possess the good properties of strength in high temperature, deformation resistance and heat fatigue in high temperature.
In this paper, the effect of alloying elements Mo, Cu, Cr and Si on microstructure, mechanical properties, high temperature anti-deformation and thermal fatigue performance of ductile cast iron is researched, by the means of microstructure observation, room-temperature mechanical properties test, high-temperature deformation resistance test and high-temperature thermal fatigue experiment.
When Cr content is 0.14% and Cu is 0.60%, Si rises from 2.65% to 2.94%, the pearlite content decreased from 85% to 35%, tensile strength and elongation did not change significantly, the deformation resistance property in high temperature significantly reduced, heat fatigue has improved significantly.
The result of the experiment indicated that the properties and pearlite content in specimen containing 0.26% Cr, 0.39% Cu is similar to that of specimen containing 0.38wt%Mo. 0.30wt%Cu,when Si content is determined.
In order to reach mechanical properties, high temperature anti-deformation and thermal fatigue properties, the as-cast structure containing 40%-60%pearlite, less than 0.5 % cemenite is required. And the better spheroidization degree is between 1 and 3. Its chemical composition should be 3.5%-3.9%C, 2.4 %-2.7 %Si, 0.2% -0.4%Mn, less than 0.03%S, less than 0.05%P, 0.15%-0.2%Cr, 0.3%-0.6%Cu.
引文
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[15]石德珂,金志浩.材料力学性能[M].西安:西安交通大学出版社,1998年5月.148
[2]中国机械工程学会铸造分会编.铸造手册[M].第1卷,铸铁,北京:机械工业出版社,2002年1月.3、345、347、623.
[3]郝石坚.现代铸铁学[M].北京:冶金工业出版社,2004年6月.214、61
[4]姜志超主编.球墨铸铁铸造新工艺新技术与产品质量缺陷控制实用手册北方工业出版社2006年9月.881-882.
[5]陆文华等.铸造合金及其熔炼[M].北京:机械工业出版社,1997年10月.52-54、55.
[6]Heine H.J..Foundry Management and Technology[M].1986,114(8),18.
[7]戴国团,龙金福.提高烧结机台车栏板及炉篦条使用寿命的材质研究[J].湖南冶金,第1期,1995年1月.6-8.
[8]符寒光等.第九届中国铸造学术会议论文集[C].沈阳:东北大学出版社,1997.114-117.
[9]张进鹏.360M2烧结机台车的铸造生产[J].安阳工学院报,第3期(总第15期),2005年6月.17-19.
[10]许利军.提高烧结机台车炉篦条使用寿命的材质研究[J].湖南冶金,第1期,2002年1月.12-14.
[11]郭拔常.改进烧结机台车材质的研究[J].烧结球团,第2期,2001年3月.15-17.
[12]周继阳编著.冲天炉问答[M].北京:机械工业出版社,1995.34
[13]许峰,于泉珠,范希营,王丽萍.450M2烧结机球墨铸铁侧壁的制作及其抗热疲劳的性能[J].铸造,1997(9).20-23.
[14]郝石坚.现代球墨铸铁[M].北京:煤炭工业出版社,1989年5月.63-67.
[15]石德珂,金志浩.材料力学性能[M].西安:西安交通大学出版社,1998年5月.148