Investigation of Friction Welding Properties of Steels with Different Chemical and Mechanical Properties Used in the Oil and Gas Industry

Steels with different mechanical and chemical properties are used together in the oil and gas industry. In this case, it has brought about the necessity of joining steels with different properties by welding. Most of the time, there are problems in welding these steels with different chemical properties. Therefore, in this study, AISI 304 stainless steel, AISI 4140 tempered steel, and S235JR structural steel with different chemical and mechanical properties used in the oil and gas industry were joined by friction welding. Then, macro and microstructure studies as well as hardness measurements, tensile tests, and torsion tests were applied to the produced samples. As a result of the micro-structure studies, it was observed that the martensitic structure was formed in the full deformation region of the joint made of AISI 304 stainless and AISI 4140 tempered steel, while it was determined that the other joints were formed of recrystallized fine grains in the full deformation region with the effect of friction. When the hardness measurement results were examined, it was determined that the hardest region was the full deformation region in all welded joints produced. As a result of the tensile tests, the highest tensile strength obtained was 622.94 N/mm(2) in the joint made of AISI 304 stainless steel and AISI 4140 tempered steel. As a result of the torsion tests, the highest torsion moment was measured as 250 Nm in the sample produced from AISI 304 stainless steel and AISI 4140 tempered steel.