Analisis Pengaruh Kadar Water Glass dan Waktu Injeksi CO2 terhadap Sifat Pasir Cetakan dan Stabilitas Geometri Hasil Cor Aluminium 6061

Santoso, Wijaya (2026) Analisis Pengaruh Kadar Water Glass dan Waktu Injeksi CO2 terhadap Sifat Pasir Cetakan dan Stabilitas Geometri Hasil Cor Aluminium 6061. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Sand casting merupakan salah satu metode pengecoran yang banyak digunakan karena memiliki fleksibilitas proses, biaya relatif rendah, dan mampu menghasilkan komponen dengan bentuk sederhana hingga kompleks. Kualitas hasil cor sangat dipengaruhi oleh sifat cetakan pasir, khususnya kekuatan mekanik, ikatan antarbutir, dan kualitas permukaan rongga cetakan. Pada sistem pasir silika dengan bahan pengikat water glass, proses pengerasan dapat dilakukan melalui injeksi gas CO₂ yang membentuk gel silika sebagai pengikat antarbutir pasir. Penelitian ini bertujuan untuk menganalisis pengaruh kadar water glass terhadap struktur, sifat mekanik pasir cetakan, dan kualitas permukaan hasil cor Aluminium 6061, serta mengevaluasi penggunaan injeksi CO₂ selama 3 menit pada sistem pasir silika/water glass. Variasi cetakan yang digunakan adalah PS-WG 6%, PS-WG 9%, PS-WG 12%, dan bentonit sebagai pembanding. Pengujian yang dilakukan meliputi X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), uji kompresi, uji geser, observasi visual hasil cor, dan pengujian surface roughness. Hasil XRD menunjukkan bahwa seluruh variasi didominasi oleh fasa SiO₂, sedangkan pada PS-WG 12% teridentifikasi fasa minor Na₂CO₃ dan Na₂Si₂O₅ yang berkaitan dengan reaksi water glass dan CO₂. Hasil SEM menunjukkan bahwa peningkatan kadar water glass menyebabkan material pengikat antarbutir semakin banyak, sehingga struktur pasir cetakan tampak lebih rapat. Hasil uji mekanik menunjukkan bahwa PS-WG 12% memiliki kuat tekan, Modulus Young, kuat geser, dan modulus geser tertinggi, masing-masing sebesar 0,3577 MPa, 14,56 MPa, 0,02865 MPa, dan 0,07074 MPa. Namun, hasil surface roughness menunjukkan bahwa PS-WG 6% menghasilkan permukaan cor paling halus dengan nilai Ra 5,56 µm dan Rz 32,57 µm, sedangkan PS-WG 12% menghasilkan nilai kekasaran tertinggi. Dengan demikian, peningkatan kadar water glass dapat meningkatkan kekuatan mekanik dan kestabilan bentuk cetakan, tetapi juga berpotensi meningkatkan kekasaran permukaan hasil cor. Pemilihan kadar water glass perlu mempertimbangkan keseimbangan antara kekuatan cetakan dan kualitas permukaan cor Aluminium 6061.
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Sand casting is one of the most widely used casting methods due to its process flexibility, relatively low cost, and ability to produce components with simple to complex geometries. The quality of the casting is strongly influenced by the properties of the sand mold, particularly its mechanical strength, intergranular bonding, and mold cavity surface quality. In silica sand molds using water glass as a binder, hardening can be carried out by CO₂ gas injection, which forms silica gel as a bonding phase between sand particles. This study aims to analyze the effect of water glass content on the structure, mechanical properties of molding sand, and surface quality of Aluminum 6061 castings, as well as to evaluate the use of 3-minute CO₂ injection in the silica sand/water glass system. The mold variations used were PS-WG 6%, PS-WG 9%, PS-WG 12%, and bentonite as a comparison. The tests included X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), compression testing, shear testing, visual observation of castings, and surface roughness testing. The XRD results showed that all variations were dominated by SiO₂, while minor phases of Na₂CO₃ and Na₂Si₂O₅ were identified in PS-WG 12%, indicating the reaction between water glass and CO₂. SEM observations showed that increasing the water glass content increased the amount of binder material between sand particles, resulting in a denser mold structure. Mechanical testing showed that PS-WG 12% had the highest compressive strength, Young’s modulus, shear strength, and shear modulus, with values of 0.3577 MPa, 14.56 MPa, 0.02865 MPa, and 0.07074 MPa, respectively. However, surface roughness testing showed that PS-WG 6% produced the smoothest casting surface, with Ra and Rz values of 5.56 µm and 32.57 µm, while PS-WG 12% produced the highest surface roughness. Therefore, increasing the water glass content can improve the mechanical strength and shape stability of the mold, but may also increase the surface roughness of the casting. The selection of water glass content should consider the balance between mold strength and the surface quality of Aluminum 6061 castings.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Aluminium 6061, Injeksi CO2, Sand casting, Water glass, Aluminium 6061, Injection CO2, Sand casting, Water glass
Subjects:	T Technology > TN Mining engineering. Metallurgy T Technology > TN Mining engineering. Metallurgy > TN687 Electric furnaces. T Technology > TS Manufactures > TS233 Sand casting. Metal castings--Thermal properties.
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User:	Wijaya Santoso
Date Deposited:	21 Jul 2026 07:23
Last Modified:	21 Jul 2026 07:26
URI:	http://repository.its.ac.id/id/eprint/136002

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