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Bone is a basic part of the human skeletal system which serves as the main foundation of the human skeletal system. and millions of people suffer from bone damage caused by natural diseases or accidents. Bone implants are used to replace, assist or augment diseased or injured biological tissue. One of the medical implants in use today is bone implants. bone implants that are currently commonly used are bone implants with a type of metal material because they have high strength, stiffness, and stiffness. In addition, metal-type bone implants can withstand higher loads than other types of implants. SS 316 L material is often used as a bone implant because it has good mechanical properties and a low corrosion rate. But with a low corrosion rate and good biocompatibility properties, SS 316 L is limited in its use in clinical application. This study aims to find substitute material as bone implants. testing using specimens in the form of ST-41 steel plates coated with Titanium Nitride (TiN) instead of bone implants. Immersion of specimens was carried out with corrosive media in the form of Simulated Body Fluid (SBF) as corrosive media. Testing uses a Scanning Electron Microscope (SEM) to analyze the surface characteristics of the specimen. The results of this study were no damage or apatite coating that protected the surface of the specimen with immersion for 12 hours. While at 336 hours immersion, there is a corrosion point on each specimen. However, the ST-41 steel specimen contained apatite grains on its surface.

Corrosion is a change in the properties of a material, mainly metal, due to a reaction with the surrounding environment. One of The ways to inhibit corrosion is by adding inhibitors. Organic inhibitors are inhibitors that are considered environmentally friendly. In this study, the guava leaf extract of Psidium guajava was used as an organic inhibitor. Materials used are API 5L Grade B steel in 1M HCl solution as corrosive media with the concentration of the extract used in this study 1188ppm with a temperature variation of 30, 35, 40, 45, and 50 Celcius degrees. The types of tests carried out in this study were Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization. The results of the potentiodynamic polarization test of organic inhibitors obtained an efficiency of 96.7550% with a corrosion rate of 1,04460 mm/year at a temperature of 30 degrees Celsius. In the electrochemical impedance spectroscopy test, the efficiency was 96,8546%, at a temperature of 30 degrees Celsius. The results of this study showed that the inhibitor of organic Psidium Guajava extract was The higher the temperature given to the inhibitor, it does not significantly affect the efficiency of the inhibitor, which acts the corrosion rate.

Biomaterials are materials used to replace parts of living systems. 316 L stainless steel has long been used as a substitute material for bone dislocation victims. This research aims to substitute 316 L stainless steel bone implant material with Cr-Ni coated ST 41 carbon steel which has been immersed with varying time-intensity with Simulated Body Fluid. Material testing uses the method of potentiodynamic polarization, electrochemical impedance spectroscopy, and Scanning Electron Microscope. The results of this study are in the form of a comparison of corrosion rate and surface characteristics between 316 L stainless steel and Cr-Ni coated ST 41 Carbon Steel. The immersion time of the material for 12 hours and 366 shows a low corrosion rate with a corrosion rate of 0.0051714 mm year−1 with and 0.001557 mm year−1 for ST41 carbon steel material with Cr-Ni coating, whereas in Stainless Steel 316 L has a corrosion rate value of 0.0029546 mm year−1 and 0.0013166 mm year−1. Surface characteristics show insignificant differences between ST41 steel with Cr-Ni coating and 316 L stainless steel. The results of the study show that Cr-Ni coated ST41 carbon steel material can substitute 316 L stainless steel as a biomaterial in bone implants because it has a low corrosion rate and different insignificant surface characteristics.

The process of metal spinning is the process of forming sheet metal with a combination of rotary motion and compression force to produce the products according shape mandril. This spinning process has the potential to be applied to small industries producing pan. Because it is necessary for application of the spinning process to form a pan products. Pans that will be realized based carbon steel plate with a shape like a teflon pan. Circular steel plate was placed in front of the mandrill and was gripped by the clamping components assisted by clamping the magnet system. Combination of rotary motion and compression force of the roll will cause the deformation of carbon steel to produce a product. Experiments performed with materials of carbon steel with a thickness of 0.8 mm and 1mm. In conclusion, the calculation of forces on the formation of carbon steel plate with a thickness of 0.8 mm is 14.722 kgf or 144, 277 N, with a thickness of 1 mm of 18.402 kgf or 180, 339 N. The existence of magnetic components will greatly assist the process of clamping plate material so the process of formation by the method of spinning operations become easier in operation. Keywords : pan, spinning process, mandrill, magnetic. ABSTRAK Proses metal spinning adalah proses pembentukan lembaran logam dengan kombinasi gerak putar dan gaya tekan sehingga menghasilkan produk sesuai bentuk mandril. Proses spinning ini sangat berpotensi untuk dapat diterapkan pada industri kecil yang memproduksi produk wajan. Karena itu perlu dilakukan penerapan proses spinning untuk membentuk produk wajan. Wajan yang akan diwujudkan berbahan plat baja karbon dengan bentuk seperti wajan teflon. Plat baja berbentuk lingkaran ditempatkan di depan mandrill dan dicekam dengan komponen clamping dibantu dengan pencekaman dengan system magnit. Kombinasi gerak putar dan gaya tekan dari roll akan menyebabkan deformasi baja karbon sehingga dihasilkan produk. Percobaan dilakukan dengan bahan baja karbon dengan ketebalan 0,8 mm dan 1mm. Kesimpulannya, perhitungan gaya pembentukan pada plat baja karbon dengan tebal 0,8 mm adalah 14,722 Kgf atau 144, 277 N, dengan tebal 1 mm sebesar 18,402 kgf atau 180, 339 N. Adanya komponen magnet akan sangat membantu proses pencekaman bahan plat sehingga proses operasional pembentukan dengan metode spinning menjadi lebih mudah dalam operasional. Kata kunci: wajan, proses spinning, mandill, magnet.