![]() ![]() Jeong, Jae-Hyun Lee, Sung-Yul Lee, Myeong-Hoon Moon, Kyung-Man [Korea Maritime University, Dong Sam-Dong,Yong Do-ku, Busan (Korea, Republic of) Baek, Tae-Sil [Pohang College, Pohang (Korea, Republic of)Ī heavy oil of low quality has been mainly used in the diesel engine of the merchant ship as the oil price has been significantly jumped for several years. Consequently, it is suggested that the mechanical and corrosion characteristics of the piston crown can be predominantly improved by repair welding method using the 1.25Cr-0.5Mo electrodeĮnergy Technology Data Exchange (ETDEWEB) Furthermore, it appeared that the corrosive products with red color and local corrosion like as a pitting corrosion were more frequently observed on the surface of the base metal zone compared to the heat affected and weld metal zones. And, the corrosion resistance of the heat affected and weld metal zones was also increased than that of the base metal zone. The weld metal and base metal zones exhibited the highest and lowest values of hardness respectively. And the corrosion properties of weld metal, heat affected and base metal zones were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. In this study, 1.25Cr-0.5Mo filler metal was welded with SMAW method in the forged steel which would be generally used with piston crown material. Therefore, an optimum repair welding for these engine parts is very important to prolong their lifetime in a economical point of view. As a result, wear and corrosion of the engine parts such as exhaust valve, piston crown and cylinder head surrounded with combustion chamber are more serious compared to the other parts of the engine. Thus, a combustion chamber of the engine has been often exposed to severely corrosive environment more and more because temperature of the exhaust gas of the combustion chamber has been getting higher and higher with increasing of using the heavy oil of low quality. ![]() Jeong, Jae-Hyun Lee, Sung-Yul Lee, Myeong-Hoon Moon, Kyung-Man Baek, Tae-SilĪ heavy oil of low quality has been mainly used in the diesel engine of the merchant ship as the oil price has been significantly jumped for several years. International Nuclear Information System (INIS) This technique does not damage the gingival/periodontal tissues or underlying tooth structure as the crown need not to be removed with jerky back-action force.Ĭorrosion Characteristics of Welding Zones Welded with 1.25Cr-0.5 Mo Filler Metal to Forged Steel for Piston Crown Material ![]() The technique described in this article consists of sectioning of a crown on facial surface followed by removal of the crown with orthodontic plier. New atraumatic easy removal technique for permanently cemented crownĭirectory of Open Access Journals (Sweden)įull Text Available Removal of a permanently cemented crown or fixed partial denture is a cumbersome procedure for a prosthodontist, especially when there is no purchase point available to remove it. Consequently, it is suggested that the corrosion resistance of the weld metal zone surely depends on the chemical components of each filler metal and welding method irrespective of the types of piston crown material. In particular, the weld metal zone welded with Inconel 718 and 0.5Mo, filler metals indicated the best and worst corrosion resistance, respectively. The weld metal zones welded with Inconel 625 and 718 filler metals exhibited higher corrosion resistance compared to 1.25Cr-0.5Mo and 0.5Mo filler metals. In this study, two types of filler metals such as 1.25Cr-0.5Mo, 0.5Mo were welded with SMAW method and the other two types of filler metals such as Inconel 625 and 718 were welded with GTAW method, respectively, and the used base metals were the cast and forged steels of the piston crown material. Moon, Kyung-Man Kim, Yun-Hae Lee, Myeong-Hoon Baek, Tae-SilĪn optimum repair welding for the piston crown which is one of the engine parts exposed to the combustion chamber is considered to be very important to prolong the engine lifetime from an economical point of view. Characteristics comparison of weld metal zones welded to cast and forged steels for piston crown material ![]()
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