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"Retak dingin merupakan salah satu kendala yang sering terjadi pada pengelasan baja tahan aus. Skripsi ini berisi tentang penelitian pengaruh preheat dan perbedaan kawat las terhadap ketahanan retak dan sifat mekanis dari baja tahan aus CREUSABRO® 8000 dengan menggunakan pengelasan Shielded Metal Arc Welding (SMAW). Elektroda yang digunakan adalah elektroda E 7018 dan MG NOX 35. Sampel terdiri dari 6 buah plat CREUSABRO® 8000 yang dilas dengan elektroda E 7018 dan MG NOX 35. Proses preheat dilakukan dengan menggunakan burner pada hasil sambungan dengan varibel tanpa preheat, preheat 150°C, preheat 250°C. Berdasarkan hasil analisa data, penerapan perlakuan preheat pada temperatur 150°C dan 250°C tidak mengakibatkan adanya retak dingin pada hasil lasan. Selain itu, perlakuan preheat dan penggunaan elektroda MG NOX 35 mampu meningkatkan sifat mekanis pada hasil lasan. Perlakuan preheat dan pemilihan elektroda memberikan pengaruh signifikan terhadap terjadinya retak dingin dan sifat mekanis serta dapat dijadikan salah satu metode pengendalian retak dingin pada pengelasan baja tahan aus CREUSABRO® 8000.

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Cold cracking is the one of problem on wear resistance plate welding. On this project consist of reseach on influence preheating treatment and welding electrode in crack resistance and mechanical properties of CREUSABRO® 8000 wear resistance steel with SMAW process. Welding electrodes that be used are E 7018 and MG NOX 35. All of sample consisted of 6 CREUSABRO® 8000 wear resistance steel plates that be joined with E 7018 and MG NOX 35 electrode. The process of preheat is done by using burner with 3 joining for each variable consisting of without preheat, preheat 150°C, dan preheat 250°C.

Based on the results of data analysis, cold cracking is not consist to the application of preheat at 150°C and 250°C. Application of preheat and MG NOX 35 electrode also can improve mechanical properties of weld area. Application preheating and selection of welding electrode provides a significant influence on cold cracking and mechanical properties as well as can be used as a method of controlling cold cracking in welding of CREUSABRO® 8000 wear resistance steel."

"[ABSTRAKKomposit nano Al A356 berpenguat partikel Al2O 3 berpotensi untuk meningkatkan kekuatan sifat mekanis tanpa mengorbankan keuletan pada matriks. Pada penelitian ini dilakukan variasi penambahan fraksi volume dari partikel nano Al2O 3 sebesar yaitu 0.1%, 0.2%, 0.5%, 1%, dan 1,2%. Untuk meningkatkan kemampubasahan dari Al2O 3 pada Al A356 ditambahakn Mg sebesar 10%. Hasil penelitian menunjukkan bahwa komposit Al A356/Al2O 3 dengan 0.5% Vf memiliki sifat mekanis yang lebih baik daripada yang lain. Nilai kekuatan tariknya mencapai 140,3 MPa lalu elongasinya sebesar 9,563% dan kekerasannya mencapai 46,2 HRB. Akan tetapi nilai mekanis dari kekuatan tarik masih dibawah dari Al A356 As cast maupun Al 356. Fenomena ini disebabkan karena adanya porositas dan persebaran partikel nano yang tidak merata.ABSTRACTAluminium A356 nano composite reinforced with Al2O 3 particle have a potential to increase mechanical properties while maintaining good ductility. In this study, the addition %Vt variation of Al2O 3. Variation used is 0.1%, 0.2%, 0.5%, 1%, dan 1,2%. To improve wettability of Al2O 3 in Al A356 addes 10% Mg. The results showed that the composite Al A356 / SiC 0,5% Vf have better mechanical properties than others. The ultimate tensile strength reach 140.3 MPa with 9.56% elongation. Hardness value reach 46,2.1 HRB. However, the value of ultimate tensile strength is still below the mechanical Al A356 As cast and Al 356. This phenomenon is due to the porosity and bad particle dispersion.;Aluminium A356 nano composite reinforced with Al2O 3 particle have a potential to increase mechanical properties while maintaining good ductility. In this study, the addition %Vt variation of Al2O 3. Variation used is 0.1%, 0.2%, 0.5%, 1%, dan 1,2%. To improve wettability of Al2O 3 in Al A356 addes 10% Mg. The results showed that the composite Al A356 / SiC 0,5% Vf have better mechanical properties than others. The ultimate tensile strength reach 140.3 MPa with 9.56% elongation. Hardness value reach 46,2.1 HRB. However, the value of ultimate tensile strength is still below the mechanical Al A356 As cast and Al 356. This phenomenon is due to the porosity and bad particle dispersion.;Aluminium A356 nano composite reinforced with Al2O 3 particle have a potential to increase mechanical properties while maintaining good ductility. In this study, the addition %Vt variation of Al2O 3. Variation used is 0.1%, 0.2%, 0.5%, 1%, dan 1,2%. To improve wettability of Al2O 3 in Al A356 addes 10% Mg. The results showed that the composite Al A356 / SiC 0,5% Vf have better mechanical properties than others. The ultimate tensile strength reach 140.3 MPa with 9.56% elongation. Hardness value reach 46,2.1 HRB. However, the value of ultimate tensile strength is still below the mechanical Al A356 As cast and Al 356. This phenomenon is due to the porosity and bad particle dispersion., Aluminium A356 nano composite reinforced with Al2O 3 particle have a potential to increase mechanical properties while maintaining good ductility. In this study, the addition %Vt variation of Al2O 3. Variation used is 0.1%, 0.2%, 0.5%, 1%, dan 1,2%. To improve wettability of Al2O 3 in Al A356 addes 10% Mg. The results showed that the composite Al A356 / SiC 0,5% Vf have better mechanical properties than others. The ultimate tensile strength reach 140.3 MPa with 9.56% elongation. Hardness value reach 46,2.1 HRB. However, the value of ultimate tensile strength is still below the mechanical Al A356 As cast and Al 356. This phenomenon is due to the porosity and bad particle dispersion.]"

"Kitosan diketahui memiliki sifat yang keras dan ketahanan termal yang tinggi. Pemanfaatan kitosan sebagai material insulasi digunakan dengan menggunakan metode coating pada busa poliuretan dengan densitas 16’4 kg/m3 . Pelapisan kitosan pada busa poliuretan diawali dengan pelarutan kitosan dalam larutan asam. Jenis asam berpengaruh terhadap kualitas lapisan yang dihasilkan. Jenis asam yang digunakan yaitu asam asetat (CH3COOH) dan asam format (CH2O­2). Kualitas yang dihasilkan dari produk busa poliuretan dengan jenis asam tersebut menunjukkan hasil yang berbeda. Produk jenis asam asetat memiliki sifat mekanis yang lebih baik dibandingkan produk jenis asam format di mana nilai UTS pada produk dengan konsentrasi asam 1% v/v yaitu 3,05 kg/cm2 (produk asam asetat) dan 5,53 kg/cm2 (produk asam format). Konsentrasi asam yang digunakan memiliki pengaruh terhadap sifat mekanis dan termal yang berhubungan dengan banyaknya ikatan hidrogen yang dihasilkan. Dari produk busa poliuretan yang diperoleh, kemudian dibandingkan antara PU-Virgin (busa poliuretan tanpa perlakuan), PU-Kitosan (produk busa poliuretan terbaik), dan PU-Headliner (produk headliner densitas 45 kg/m3)

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Chitosan is known to have hard properties and high thermal resistance. The use of chitosan as an insulation material is used by using a coating method on polyurethane foam with a density of 16.4 kg / m3. Coating of chitosan in polyurethane foam begins with the dissolution of chitosan in an acid solution. The type of acid affects the quality of the coating produced. The types of acids used are acetic acid (CH3COOH) and formic acid (CH2O2). The quality produced from polyurethane foam products with this type of acid shows different results. Acetate acid products have better mechanical properties than form acid products where UTS values ​​in products with an acid concentration of 1% v / v are 3.05 kg / cm2 (acetic acid product) and 5.53 kg / cm2 (product formic acid). The acid concentration used has an influence on the mechanical and thermal properties associated with the number of hydrogen bonds produced. From polyurethane foam products obtained, then compared between Virgin PU (untreated polyurethane foam), PU-Chitosan (the best polyurethane foam product), and PU-Headliner (headliner product density of 45 kg / m3."