<p><em>The development and progress of science and technology in the metal plating industry has become a field of work that is experiencing rapid advances ranging from the type of coating, a coating material that is used, and the results of a layer. The metal plating industry needs not only demand resistance to corrosion, but also the strength of the material, has a beautiful appearance, and has a high economic value. one of them, namely by means of electroplating coating.</em><em> </em><em>The purpose of this research is to know the influence of variations in the strength of an electric current and time of electroplating nickel-chrome against the thickness of the surface layer of low carbon steel. The benefits of this research are expected to add to the knowledge about the coating on the process of electroplating nickel-chrome and can apply it. In the activities of this research material used is low carbon steel plates with a size 40 mm x 25 mm x 1 mm with the number 27 specimens are coated using electroplating method with the variation of strength of electric current of 0.5 A, 1 A, 1.5 A and time electroplating 10 minutes, 15 minutes, 20 minutes. </em><em>T</em><em>esting done next the thickness of the layer.</em><em> </em><em>Results of the study showed that the highest hardness of nickel-chrome electroplating process occurs on a variation of value the highest layer thickness variation in the strength of the current 1.5 A long coating 20 minutes 1.97 µm.</em></p>

The research aims to investigate the effect of the cooling medium on the hardness characteristic and microstructure of the 42CrMo4 steel due to hardening treatment at a temperature of 830°C and holding time of 30 minutes. Various oil such as SAE-10W40, SAE-20W50, SAE-40, and used oil was used in the cooling medium. The changes in product size, hardness, and microstructure have been carefully assessed. The results indicated that the viscosity of the coolant medium strongly influenced the cooling rate of the cooling medium, hardness, and microstructure. SAE-10W40 oil and SAE-20W50 oil only needed 2 hours to return within room temperatures before quenching, whereas SAE-40 oil and used oil took 3 hours. The sample size did not change after hardening-quenching. However, there was a residual carbon layer on the sample surfaces. Quenching caused the changes of microstructure from pearlite and ferrite to ultrafine double phase, consisting of martensite and austenite, which were unable to transform during rapid cooling. The highest hardness value was achieved by the treated product, which was quenched in SAE-10W40, which had 54.59 HRC. The high hardness was attributed to the content of 95% martensite. However, used-oil caused in similar hardness as SAE-20W50.

<em>The level of fuels’ consumption as an energy source in the world is currently experiencing huge increase. When the use of the oil as fuels is not managed properly, it can be sure that the oil will run out and triggered the world’s energy crisis. Currently, plastik waste become a serious problem that can lead into the environment contamination if not properly managed. One of the solution to overcome the energy crisis and environmental polution is to find and create a renewable energy such as biofuel. The research was conducted in order to know the effect of combustion temperature on pyrolisis process based on the Low Density Polythylene (LPDE) plastic material to produce biofuel. The eraly stages of the research was start with pyrolisis process of the LDPE plastic which comes from the bottle and glass logo waste with the reactor temperature of 250 ºC and 300 ºC. The weight of each material was 2 kg. After getting the crude oil, the researcher examined the crude oil characteristic from pyrolisis process using viscosity test, density test, caloric value test, and flash point test. From the test results, the test results that the gigher the temperature in the pyrolisis reactor, the production of the biofuel oil from pyrolisis were more and have a better quality. The result of the experiment pointed out that the higher the pirolysis reactor temperature , the greater the yield and the better quality. The pyrolisis result was crude oil with each of the weight was 240 ml on the 250 ºC reactor temperature and 260 ml on the 300 ºC reactor temperature. The viscosity test showed the results 3.128 mm²/s on the 250 ºC reactor temperature and 2.698 mm²/s on the 300 ºC reactor temperature. The density on the 250 ºC reactor temperature was 0.9984 and 0.9085 on the 300 ºC reactor temperature. The caloric value test on the 250 ºC reactor temperature showed the results 9084.101 kal/g on the first test and 8765.253 kal/g on the second test. Whereas the caloric value test on the 300 ºC reactor temperature were 9588.312 kal/g on the first test and 9507.779 on the second test. The results of the crude oil flash point test on 250 ºC and 300 ºC showed the same temperature result at 28.5 ºC. From the characteristic test results it can be concluded that the crude oil from the pyrolisis process has approaching the kerosene characteristic and entered into the fuel category.</em>

<em>Macaroni Tubing P110 1.900″ x 4.19 lbs/ft which applicated at Snubbing and Oil and Gas industry, exposed to Corrosive fluids such as NH4Cl, KCl and Sea Water. Macaroni Tubing P110 1.900″ x 4.19 lbs/ft also has mechanical treatment especially Tensile force. That’s why effects of NH4Cl, KCl and Sea Water fluid to Corrosion Rate and Tensile strength Macaroni Tubing P110 1.900″ x 4.19 lbs/ft shall be known. Starting from those issue, Immersion corrosion testing using NH4Cl, KCL and sea wáter instruments is conducted, and Tension testing is performed to the material after exposed to those corrosive fluids. Immersion corrosion testing method is used to analyze corrosion rate and Tension testing is used to analyze the tensile strength. The result shown that the fastest Corrosion rate is material which immersed to 6% NH4Cl with average corrosion rate value 0,210 mm/year. In second position is material which immersed to 3% KCl with average corrosion rate value 0.132 mm/year and the latest is material which immersed to sea water with average corrosion rate value 0.095 mm/year. Meanwhile, tensile strength test shown 676.53 Mpa for Raw Material specimens, 664.19 Mpa for specimens which immersed to 3% KCl, 653.51 Mpa for specimens which immersed to 6% NH4Cl and 669.55 Mpa for specimens which immersed to sea water. From those three specimens which immersed to corrosive fluid shown tensile strength decreased than Raw Material tensile strength and Specimen which immersed to 6% NH4Cl shown the biggest value.</em>