The materials parameter i.e. microstructure as well as the processing factors i.e. aging time and temperature, the amount of plastic deformation, and residual stresses affecting the kinetic of strain ageing in the S275JRC steel were investigated in detail. For this purpose, 5 % pre-strained steel was aged at 160 o C for different intervals. The ageing behavior was determined for the as-received (AR) and homogenization & normalizing heat treated (H+N heat treated) conditions. The yield stresses before and after aging process and, the hardness values of the aged steels were considered to calculate strain aging progress. It was shown that a noticeable increase in the yield strength, tensile strength and hardness values was observed for aged AR and H+N heat treated specimens. Moreover, the repetitive increase in the yield and ultimate tensile strength was believed to be a result of strain ageing.

ÖZBu çalışmada endüstride gıda, eczacılık, kimya, petrokimya ve gemicilik alanlarında sıklıkla kullanılan östenitik ile dubleks paslanmaz çelik çiftinin birleştirilmesinde kaynak yönteminin ve ilave metal seçiminin birleştirme mekanik özelliklerine ve mikro-yapısına etkisi incelenmiştir. Bu amaçla AISI 316L östenitik ve AISI 2205 dubleks paslanmaz çelik çifti gaz metal ark kaynak yöntemi (GMAK) kullanılarak TETRA V 316L-G ve TETRA S 22 9 3L-G flaks özlü tel ile "V" kaynak ağzı açılarak birleştirilmiştir. Aynı malzeme çifti elektrik ark kaynak yöntemi kullanılarak (EAK) E308L-16 ve E2209-17 elektrot ile de uygun standartlarda birleştirilmiştir. Kaynak işlemi sonrası numunelere çekme testi uygulanmış ve test sonrası kırılma yüzeyleri incelenmiştir. Birleştirme mikro-yapıları incelenerek, mikro-sertlik ve ITAB genişlikleri ölçülmüştür. Kaynak yöntemi ve ilave metal türüne göre elde edilen sonuçlar karşılaştırılmıştır.Anahtar Kelimeler: AISI 316L-AISI 2209 paslanmaz çelik, gaz metal ark kaynağı, elektrik ark kaynağı, mekanik özellikler, mikro-yapı WELDABILITY OF DISSIMILAR AISI 316L-AISI 2205 STAINLESS STEEL COUPLE ABSTRACTIn this study, the effect of welding consumable and welding method on the mechanical properties and microstructure of weldment was investigated for joining austenitic and duplex stainless steel couple, which were used in food, pharmacy, chemistry, petro chemistry and shipping industry. According to standard, V shape welding groove was prepared for AISI 316L-AISI 2205 stainless steel couple that was welded in butt position by using gas metal arc welding (GMAW) with using TETRA V 316L-G and TETRA S 22 9 3L-G type welding wire and electric arc welding (EAW) with using E308L-16 and E2209-17 type electrodes. The mechanical properties of the weldment were determined by tensile test and fracture surface of the test samples were evaluated. In addition, hardness and HAZ width measurements and microstructure evaluation was carried out on the cross section of weldment. Results were compared according to the differences of welding method and welding consumable.

In this study, the effect of static strain aging on the fatigue behavior of a mild steel (S275JRC) was evaluated. For this purpose, the 5 % prestrained mild steel was aged at a temperature of 160 °C for different intervals. The aging behavior was determined primarily for the as-received (AR) as well as in the homogenization and normalizing heat treated (H+N heat treated) condition. The yield stresses before and after aging process as well as the hardness values of the aged steels were measured for the assessment of the strain aging progress. The dynamic mechanical behavior of strain aged samples was also determined by fatigue test under the dynamic loads. An increase in the yield strength due to strain aging and hardness induced improvement in fatigue strength of the steel were observed.