本文選題：鑄態(tài)球墨鑄鐵 + 碲　； 參考：《吉林大學(xué)》2017年碩士論文

【摘要】：球墨鑄鐵以其高強(qiáng)度、高韌性和低成本被廣泛應(yīng)用于機(jī)械、船舶、汽車等領(lǐng)域。隨著汽車向著輕量化、高性能和低成本的方向不斷發(fā)展,當(dāng)前的球墨鑄鐵已逐漸不能滿足行業(yè)的需求,對于像汽車曲軸這樣的結(jié)構(gòu)件不僅需要高的強(qiáng)度同時還要具備較高的韌性。目前,要想獲得高強(qiáng)度高韌性的球墨鑄鐵主要是通過熱處理實現(xiàn),而這種方式成本高、工藝復(fù)雜、成品率低,因此,在鑄態(tài)下生產(chǎn)高強(qiáng)度高韌性的球墨鑄鐵具有重大的現(xiàn)實意義。本文主要研究了微合金元素Te、B及其復(fù)合對球墨鑄鐵組織及力學(xué)性能的影響規(guī)律,優(yōu)化出合適的微合金元素Te和B的加入量,初步實現(xiàn)了鑄態(tài)球墨鑄鐵QT700-10的性能指標(biāo)要求;在此基礎(chǔ)上,進(jìn)一步研究了合金元素Mo以及納米TiC對鑄態(tài)球墨鑄鐵組織與性能的影響,為實現(xiàn)穩(wěn)定生產(chǎn)球墨鑄鐵QT700-10提供了實驗基礎(chǔ)。本文主要研究結(jié)果如下:1.研究了合金元素Te、B對球墨鑄鐵組織和性能的影響,發(fā)現(xiàn):當(dāng)Te含量不斷增加時,球墨鑄鐵組織中石墨的球化率先增高后降低,珠光體含量呈逐步降低的趨勢,相對應(yīng)的球墨鑄鐵的抗拉強(qiáng)度變化趨勢是先增加后降低,而延伸率則不斷提高。優(yōu)化出Te含量為0.0011wt.%時,球墨鑄鐵力學(xué)性能最好,抗拉強(qiáng)度為764MPa,延伸率為7.20%;在加入Te含量不變的條件下,加入不同含量的微合金元素B,隨著B含量的增加,球墨鑄鐵組織中石墨的球化率先增大后降低,珠光體含量明顯減少,球墨鑄鐵件抗拉強(qiáng)度不斷降低,而延伸率則呈上升趨勢,當(dāng)B含量為0.001wt.%時,球墨鑄鐵的抗拉強(qiáng)度為711MPa,延伸率為12.28%。2.考察了納米TiC對球墨鑄鐵組織與性能的影響。加入0.02wt.%TiC-Al中間合金時對石墨的影響不大,而使珠光體含量減少,抗拉強(qiáng)度降低,延伸率提高;加入0.02wt.%TiC-Cu中間合金時對石墨的影響不大,而珠光體含量增多,層片間距細(xì)小,抗拉強(qiáng)度及延伸率都有所提高。當(dāng)加入0.02wt.%TiC-Cu中間合金時球墨鑄鐵的抗拉強(qiáng)度為715MPa,延伸率為10.6%,達(dá)到了球墨鑄鐵QT700-10的性能指標(biāo)要求。3.通過研究球墨鑄鐵的拉伸性能和顯微組織之間的關(guān)系,要實現(xiàn)球墨鑄鐵QT700-10的目標(biāo),其顯微組織需滿足下面幾種情況:當(dāng)球化等級在1級時,珠光體含量35%～45%,鐵素體含量55%～65%,此時的珠光體層片間距240nm左右;當(dāng)球化等級在2～3級時,珠光體含量在45%～55%,鐵素體含量45%～55%,此時層片間距要220nm;當(dāng)球化等級在4～5級時,珠光體含量在50%～65%,鐵素體含量35%～50%,此時不僅珠光體的層片間距220nm,而且要結(jié)合珠光體的形態(tài)提高球墨鑄鐵的韌性。
[Abstract]:Ductile iron is widely used in machinery, ship, automobile and so on for its high strength, high toughness and low cost.As cars continue to develop in the direction of lightweight, high performance and low cost, the current nodular cast iron is no longer able to meet the needs of the industry.For a structure such as an automobile crankshaft, it needs not only high strength but also high toughness.At present, to obtain ductile iron with high strength and toughness is mainly achieved by heat treatment, which is of high cost, complex process and low yield.It is of great practical significance to produce ductile iron with high strength and toughness in the as-cast state.In this paper, the effect of microalloying element Teo B and its compound on the microstructure and mechanical properties of ductile iron was studied. The proper addition of Te and B elements was optimized, and the requirements of QT700-10 properties of as-cast ductile iron were preliminarily realized.On this basis, the effects of alloying element Mo and nanometer TiC on the microstructure and properties of as-cast ductile iron were further studied, which provided the experimental basis for the stable production of ductile iron QT700-10.The main results of this paper are as follows: 1: 1.The effect of the alloying element Teo B on the microstructure and properties of ductile cast iron was studied. It was found that with the increasing of Te content, the spheroidization of graphite in ductile cast iron first increased and then decreased, and the content of pearlite decreased gradually.The tensile strength of the corresponding ductile iron increased first and then decreased, while the elongation increased continuously.When the Te content is 0.0011wt.%, the ductile iron has the best mechanical properties, the tensile strength is 764MPa and the elongation is 7.20.The microalloying element Bwith different contents increases with the increase of the content of Te.The spheroidization of graphite in ductile iron increases first and then decreases, the content of pearlite decreases obviously, the tensile strength of ductile iron decreases continuously, and the elongation of ductile iron increases. When the content of B is 0.001wt.%,The tensile strength and elongation of ductile iron are 711 MPA and 12.28 MPA, respectively.The effect of nanometer TiC on the microstructure and properties of ductile iron was investigated.The addition of 0.02wt.%TiC-Al master alloy had little effect on graphite, but decreased the content of pearlite, decreased tensile strength and increased elongation, but the addition of 0.02wt.%TiC-Cu master alloy had little effect on graphite, but the content of pearlite increased and the interlaminar spacing was small.Tensile strength and elongation have been improved.When 0.02wt.%TiC-Cu master alloy was added, the tensile strength and elongation of ductile iron were 715 MPA and 10.6 respectively, which met the requirements of ductile iron QT700-10.By studying the relationship between tensile properties and microstructure of ductile iron, in order to achieve the goal of ductile iron QT700-10, the following conditions should be satisfied: when the spheroidization grade is in grade 1,The pearlite content is 35: 45 and the ferrite content is 5565. At this time, the distance between the pearlite layers is about 240nm; when the spheroidization grade is 2 or 3, the pearlite content is 45 / 55, the ferrite content is 45 / 55, and the lamellar spacing is 220 nm; when the spheroidization level is at 4 / 5,The content of pearlite is about 50% and the content of ferrite is 35%. At this time not only the interlaminar spacing of pearlite is 220 nm but also the toughness of nodular cast iron should be improved in combination with the morphology of pearlite.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG143.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 陳忠士;鄒澤昌;傅高升;;鑄態(tài)高強(qiáng)高韌性QT600-10合成球鐵的研制[J];福建工程學(xué)院學(xué)報;2015年04期

2 柳建國;曾大新;;鑄態(tài)QT700-10技術(shù)初探[J];鑄造;2014年05期

3 李永真;張立平;王守河;張東;;QT850-5球墨鑄鐵的熱處理工藝[J];金屬加工(熱加工);2014年07期

4 朱華明;辛國忠;胡茍生;張樹林;彭紅軍;;鑄態(tài)低溫高韌性球墨鑄鐵QT400-18L缸體的研究及應(yīng)用[J];鑄造技術(shù);2014年01期

5 張伯明;王繼祥;;高Si球墨鑄鐵的新發(fā)展[J];現(xiàn)代鑄鐵;2013年05期

6 陳忠士;傅高升;藍(lán)敏俐;;鑄態(tài)高強(qiáng)度高韌性合成球鐵QT750-5的研制[J];鑄造技術(shù);2013年05期

7 張景超;王彥華;趙靖宇;吳越;呂燁哲;孫玉福;;硼對等溫淬火球墨鑄鐵組織及性能的影響[J];鑄造;2013年02期

8 王峰;嚴(yán)增男;;球墨鑄鐵的球化與孕育處理工藝[J];現(xiàn)代鑄鐵;2012年04期

9 胡勇;饒麗;陳國香;;Mn、Cu對球墨鑄鐵組織性能的影響[J];兵器材料科學(xué)與工程;2012年04期

10 楊思一;叢建臣;孫海濤;于海明;慈惟紅;;高強(qiáng)度高韌性球墨鑄鐵曲軸鑄造技術(shù)[J];現(xiàn)代鑄鐵;2011年06期

相關(guān)會議論文 前1條

1 賀聞豪;葉升平;韓曉紅;唐鎖云;;中國球墨鑄鐵消失模鑄造技術(shù)進(jìn)展與生產(chǎn)應(yīng)用[A];2010年中國鑄造活動周論文集[C];2010年

，

本文編號：1747593