本文關(guān)鍵詞：風(fēng)電球墨鑄鐵件鑄造工藝及組織數(shù)值模擬的優(yōu)化　出處：《山東大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 數(shù)值模擬分析 鑄造工藝 石墨球 珠光體

【摘要】：由于化石能源數(shù)量有限,環(huán)保意識(shí)逐漸增強(qiáng),風(fēng)能作為一種取之不盡的清潔能源越來越受到人們的重視。風(fēng)力發(fā)電設(shè)備,例如風(fēng)電輪轂、底座、轉(zhuǎn)軸等,體積都比較龐大,重量一般都在10t以上,在鑄造生產(chǎn)過程中出現(xiàn)廢品將會(huì)造成巨大的損失;風(fēng)力發(fā)電設(shè)備工作環(huán)境也比較惡劣,一般都運(yùn)行在室外寒冷的環(huán)境中,因此對其各方面的力學(xué)性能有較高的要求。對此,我國國家標(biāo)準(zhǔn)對該類球墨鑄鐵件的組織及力學(xué)性能都進(jìn)行了嚴(yán)格的要求。在實(shí)際生產(chǎn)過程中,風(fēng)電球墨鑄鐵件經(jīng)常會(huì)產(chǎn)生一些缺陷,鑄造工藝對其有著重要的影響,因此鑄造工藝的設(shè)計(jì)是否合理就顯得尤為重要。本文探究了鑄造模擬仿真軟件在該類鑄件中的應(yīng)用,確定出了模擬各階段的參數(shù)設(shè)置,為鑄造工藝設(shè)計(jì)的合理性提供了重要的參考依據(jù);并且利用該軟件對風(fēng)電輪z@件當(dāng)前的鑄造工藝進(jìn)行了模擬仿真,發(fā)現(xiàn)在鑄件的頂部位置存有縮孔、縮松缺陷,這與實(shí)際生產(chǎn)過程中經(jīng)常出現(xiàn)缺陷的位置比較吻合;經(jīng)過分析,鑄件頂部產(chǎn)生缺陷的主要原因?yàn)槊翱陬i的過早封死造成鐵液補(bǔ)縮不足及冷鐵排放的不合理所造成的;通過對冷鐵的重新布置及冒口形式的改變可以完全消除鑄件頂部產(chǎn)生的缺陷。風(fēng)電設(shè)備器材屬于典型的厚大斷面球墨鑄鐵件,為了研究不同的壁厚對其組織性能的影響,在風(fēng)電輪轂件上設(shè)計(jì)了附鑄楔形試塊。實(shí)驗(yàn)結(jié)果表明,在當(dāng)前工藝條件下,整個(gè)附鑄楔形試塊的基體組織全部為鐵素體基體;隨壁厚的增大,組織中的石墨球的密度逐漸降低,石墨球尺寸逐漸變大,石墨球圓整度逐漸變差;壁厚達(dá)到一定程度(高溫階段的冷卻速度為5.5℃/min,共晶反應(yīng)平臺(tái)時(shí)間51.7min),組織中會(huì)出現(xiàn)碎塊狀石墨,碎塊狀石墨的出現(xiàn)會(huì)極大地降低鑄件的性能;在厚大斷面處,由于冷卻速度比較慢,有些Si元素會(huì)在石墨球周圍富集,當(dāng)石墨球周圍Si元素的含量大于2.25%時(shí),石墨球發(fā)生破裂的幾率就會(huì)大大增加,出現(xiàn)碎塊狀等畸變石墨球。為了研究風(fēng)電球墨鑄鐵件組織中珠光體與冷卻速度的關(guān)系,利用DSC熱分析儀對若干個(gè)試樣分別以恒定的冷卻速度對其進(jìn)行冷卻處理。結(jié)果表明,隨著冷卻速度的增大,珠光體的含量近似呈線性增加,根據(jù)此關(guān)系可以推出當(dāng)冷卻速度大于4.1℃/min時(shí),組織中珠光體的量將大于10%;當(dāng)冷卻速度小于1.4℃/min時(shí),組織中將全部為鐵素體基體。并且以該實(shí)驗(yàn)數(shù)據(jù)為基礎(chǔ),建立了珠光體分解速率模型,經(jīng)過實(shí)驗(yàn)驗(yàn)證,所建立的模型具有很高的準(zhǔn)確性,這為風(fēng)電球墨鑄鐵件生產(chǎn)過程中組織的判斷提供重要的參考作用。
[Abstract]:Due to the limited amount of fossil energy and the increasing awareness of environmental protection wind energy as an inexhaustible clean energy has been paid more and more attention. Wind power generation equipment such as wind wheel hub base rotating shaft and so on. The volume is relatively large, the weight is generally more than 10 tons, in the foundry production process, the waste will cause huge losses; Wind power equipment working environment is also relatively bad, generally operating in the cold outdoor environment, so the mechanical properties of its various aspects of higher requirements. The structure and mechanical properties of this kind of ductile iron are strictly required by the national standard of our country. In the actual production process, some defects often occur in the wind power ductile iron. Casting technology has an important impact on it, so whether the casting process design is reasonable or not is particularly important. This paper explores the application of casting simulation software in this kind of castings. The parameter setting of each stage of simulation is determined, which provides an important reference for the rationality of casting process design. The software is used to simulate the current casting process of the wind turbine z. it is found that there are shrinkage holes and shrinkage defects at the top of the castings. This is consistent with the position where defects often occur in the actual production process. After analysis, the main reasons for the defects at the top of the castings are caused by the premature sealing of the riser neck and the unreasonable discharge of cold iron. The defects in the top of the castings can be completely eliminated by the rearrangement of the cold iron and the change of the riser form. The wind power equipment and equipment belong to the typical thick and large section ductile iron castings. In order to study the effect of different wall thickness on the microstructure and properties of the wheel, the tapered specimen was designed on the wind wheel hub. The experimental results show that under the current technological conditions. The matrix structure of the attached wedge-shaped specimen is all ferrite matrix. With the increase of wall thickness, the density of graphite nodule decreases gradually, the size of graphite sphere becomes larger, and the roundness of graphite ductile becomes worse. The wall thickness reaches a certain degree (the cooling rate at high temperature is 5.5 鈩，

本文編號(hào)：1394995