Yazar "Najafigharehtapeh, Asghar" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    An effect of environment temperature and pre-heat treatment on the electrofusion welding of polyethylene natural gas pipes
    (Gazi Univ, Fac Engineering Architecture, 2018) Najafigharehtapeh, Asghar; Kacar, Ramazan
    The standard recommends for electrofusion welding of polyethylene pipes, used for natural gas and water transportation network to be carried out at the temperature from -5 degrees C up to +30 degrees C. In this study, an effect of the environment temperature on the properties of weldment is investigated. For this purpose, high density polyethylene (PE100) pipes were joined with electrofusion welding method at the various environment temperatures (room temperature, 0, -10, -20 and -30 degrees C) as received condition and by using preheat treatment (60 degrees C). According to standard, leaking and crushing test has been carried out and the double decohesion peeling test has been also applied for determining the strength of weldment. Thus, decohesion toughness, K, and nominal energy E-n, for decohesion of weldment calculated. Conclusively, the strength of the weldment increased meanwhile the ductility decreased by increasing crystalline amount in weld region associate to increasing environment temperature. It was determined that the pre-heat treatment process affected positively features of weldment which was joined in low environment temperature meanwhile; the strength of weldment joined at room temperature is affected negatively.
  • Küçük Resim Yok
    Öğe
    Effects of welding methods on the mechanical properties of joining dissimilar steel couple
    (Gazi Univ, Fac Engineering Architecture, 2018) Kacar, Ramazan; Emre, Hayriye Ertek; Isineri, Ali Umit; Najafigharehtapeh, Asghar
    In this study, the weldability of wear resistant hardox steel to austenitic stainless steel with shielded metal arc welding (SMAW) and gas metal arc welding (GMAW) methods was investigated and an effect of welding method on the mechanical properties and microstructure of weldment was examined. According to standard, welding groove was prepared for Hardox 400-AISI 304 steel couple that was multi pass welded in butt position by using GMAW and SMAW methods. The mechanical properties of the weldments were determined by tensile, three point bending and V-notch impact tests. In addition, hardness measurement and microstructure evaluation was carried out on the cross section of weldment. According to findings; the tensile strength, weld metal notch impact toughness and ductility of the samples joined with the GMAW method were determined higher than those joined with SMAW.