{"id":4392,"date":"2020-11-19T13:13:10","date_gmt":"2020-11-19T13:13:10","guid":{"rendered":"https:\/\/www.aluminiumceramicfiber.com\/?p=4392"},"modified":"2020-11-19T13:13:10","modified_gmt":"2020-11-19T13:13:10","slug":"impurities-in-aluminum-alloy","status":"publish","type":"post","link":"https:\/\/www.aluminiumceramicfiber.com\/id\/impurities-in-aluminum-alloy\/","title":{"rendered":"Pengotor dalam Paduan Aluminium"},"content":{"rendered":"

Pengotor cair dalam cairan paduan aluminium terutama berupa garam klorida yang terbentuk di tempat. Garam klorida tersebut dapat berada dalam bentuk padat atau cair. Setelah terbentuk, garam ini sangat sulit dihilangkan dari aluminium cair. Klorin dan aluminium dapat bereaksi membentuk AlCl\u2083 pada suhu sekitar 178\u00b0C. Jika tidak ada magnesium dalam aluminium cair, AlCl\u2083 akan dengan cepat menguap dan keluar dari aluminium cair. Jika aluminium cair mengandung lebih dari 0,2 wt% magnesium, AlCl\u2083 akan bereaksi dengan magnesium untuk membentuk MgCl\u2082. Jika MgCl\u2082 masuk ke dalam coran, zat ini merupakan pengotor yang sangat berbahaya. Demikian pula, natrium, kalsium, litium, dan strontium yang terdapat dalam aluminium cair juga akan bereaksi dengan AlCl\u2083 untuk membentuk garam klorida yang sesuai. Zat murni dari garam klorida ini umumnya berbentuk padat pada suhu lelehnya, dan membentuk campuran cair setelah membentuk sistem eutektik dengan magnesium klorida. Menghilangkan campuran garam klorida cair ini dari aluminium cair merupakan tantangan yang sangat sulit. Pasalnya, bahkan dengan menggunakan saringan logam, kedua cairan yang tidak dapat bercampur tersebut tidak dapat dipisahkan. Karena kepadatan yang rendah dan ukuran partikel yang kecil dari garam klorida cair ini, garam tersebut tidak akan mengendap dalam aluminium cair. Ketika fluks garam berbasis natrium klorida digunakan dalam proses pembentukan terak, hal ini menyebabkan reaksi gabungan antara fluks dan pembentukan fragmen yang mengandung terak dalam fase cair. Sangat sulit untuk mengikis zat-zat ini. Zat-zat tersebut mudah bercampur dengan oksida dan terak. Kepadatan agregat yang terbentuk sangat mirip dengan kepadatan aluminium cair.<\/p>\n

\"Pengotor<\/p>\n

Pengotor dalam paduan aluminium dan produk cetakan injeksi yang dihasilkan memiliki banyak dampak merugikan:<\/strong><\/p>\n

Adanya inklusi terak menghambat aliran logam. Hal ini bahkan dapat menyebabkan pengisian tidak sempurna, terutama pada bagian yang tipis.<\/p>\n

Kehadiran inklusi terak berdampak negatif terhadap sifat-sifat mekanis, yang menyebabkan penurunan kekuatan leleh, kekuatan tarik, perpanjangan, dan ketangguhan benturan.<\/p>\n

Banyak inklusi terak yang bersifat keras dan mengganggu kinerja pemesinan. Inklusi terak pada permukaan memengaruhi proses penyelesaian akhir seperti pelapisan elektro, pengecatan, anodisasi, dan sebagainya.<\/p>\n

Inklusi terak merupakan lokasi yang paling disukai untuk terjadinya nukleasi pori hidrogen. Inklusi tersebut berikatan dengan atom hidrogen pada permukaan bagian dalam untuk membentuk molekul hidrogen. Kemudian, inklusi tersebut berubah menjadi terak padat di dalam logam cair.<\/p>\n

\"Proses<\/p>\n

Metode pengendalian pengotor dalam logam cair<\/strong><\/p>\n

1) Jangan gunakan pemecah terak, bahan pemurnian<\/a>, bahan penghilang gas, dan bahan penutup yang mengandung natrium klorida dalam jumlah besar untuk mencegah polusi sekunder pada aluminium cair. Baik penelitian teoretis maupun penerapan praktis menunjukkan bahwa komposisi bahan bantu peleburan aluminium yang ideal harus hanya mengandung sedikit natrium klorida, yang dapat mendorong pengapungan dan akumulasi kotoran, serta rake terak berupa bubuk kering dengan kandungan aluminium yang sangat rendah.<\/p>\n

2) Jaga agar suhu panas berlebih aluminium cair tetap serendah mungkin. Hindari suhu reaksi klorida cair. Suhu reaksi klorida cair mencapai 718\u00baC\u2013732\u00baC, yang dapat menekan dampak negatifnya.<\/p>\n

3) Mengontrol komposisi kimia bahan baku. Jika sejumlah besar ingot aluminium daur ulang dan limbah daur ulang digunakan dalam bahan baku tungku, serta bahan kimia yang mengandung klorin digunakan untuk memurnikan aluminium cair, maka perlu dipastikan bahwa konsentrasi sisa natrium, kalsium, kalium, dan litium berada dalam batas tingkat ekonomi minimum. Pada saat yang sama, proporsi bahan pengendap dan bahan pemurnian harus ditingkatkan secara tepat.<\/p>\n

4) Memasang saringan pada jembatan yang melintasi tungku, memasang nosel berputar dalam unit pengolahan khusus untuk meniup bubuk guna pemurnian, atau menggunakan sumbat ventilasi di bagian bawah untuk meniup guna pemurnian, semuanya merupakan proses canggih yang efektif untuk memurnikan aluminium cair.<\/p>","protected":false},"excerpt":{"rendered":"

The liquid impurities in the aluminum alloy liquid are mainly chloride salts generated in situ. The chloride salt can be in a solid state or in a molten state. Once formed, it is very difficult to remove from molten aluminum. Chlorine and aluminum can combine to form AlCl3 at about 178\u00baC. If there is no […]<\/p>\n","protected":false},"author":1,"featured_media":4394,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[86],"tags":[],"class_list":["post-4392","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"yoast_head":"\nImpurities in Aluminum Alloy | Method of Controlling Molten Impurities<\/title>\n<meta name=\"description\" content=\"Impurities in Aluminum Alloy have a negative impact on mechanical properties, reducing yield strength and tensile strength.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.aluminiumceramicfiber.com\/id\/impurities-in-aluminum-alloy\/\" \/>\n<meta property=\"og:locale\" content=\"id_ID\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" 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