Dual phase (DP) steels with different volume fractions of martensite and epitaxial ferrite were produced in different intercritical annealing temperatures and cooling rates. Corrosion behaviors of four different DP steels were investigated in 3.5 % NaCl solution by using potentiodynamic polarization and immersion tests. The results showed that both amounts of martensite and epitaxial ferrite have an influence on the corrosion behavior of DP steels. It was observed that corrosion resistance increased considerably with the presence of epitaxial ferrite as compared to dual phase steel containing non-epitaxial ferrite. On the other hand, the corrosion resistance of DP steels decreased with an increase in the martensite volume fraction (MVF).

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A number of studies have been conducted to reduce the use of fossil fuels and gas emissions in power generation industry (thermal and nuclear power plant) [1]. In recent years new material technology has emerged depending on this quest [2]. Cr-Mo steels are widely used at thermal power plant constructions as piping, combustion chamber, and tubing. They are known as heat resistant materials due to high creep strength, as well as their low thermal expansion and high thermal conductivity [3]. They have significantly reduced the thickness of structures thanks to its high strength; it has significantly reduced the thickness of the structures, which in turn reduces weight and the cost of production. However, the lifetimes of these steels are reduced owing to the excess oxidation that occurs when they are exposed to high temperatures for a long time [4]. Therefore, during the few decades, Cr-Mo steels have been developed by alloying with elements such as W, Ni, Nb, V, Ti as a result of extensive studies carried out in some countries with the participation of various project partners In Europe, E911 steel which includes 9% Cr, 1% Mo and 1-2% W was developed by European Creep Collaborative Committee (ECCC) [5]. E911 steel has martensitic microstructure under air cooling after

ASTM A743 CA6NM alloy is a martensitic stainless steel typically used in energy industry -runners and hydraulic turbine components- due to its superior toughness, yield and fatigue properties. In both the manufacturing, shielded metal arc welding is applied to join for this grade steels. However, weldability of the steels is limited due to formation of hard and brittle phases such as untempered martensite during welding and post weld heat treatment processes. The formation causes a reduction in toughness. In this study, influence of post-weld heat treatment procedure (single tempering and double tempering) and parameters on microstructure and hardness of AWS410NiMo all weld metal. Hardness tests were conducted from weld metal. Microstructures of the all weld metals subjected to different heat treatment process were characterized.

Purpose Paper aims to an alloy development study was carried out to increase the mechanical properties of cylinder heads. Design/methodology/approach AlSi12 alloys are used to manufacture the compressor head cylinder by high-pressure casting for easy casting and superior properties. Therefore, 1.1%, 2.4% and 3.1% Mg were added to AlSi12. The microstructures of the produced samples were characterized by optical microscope, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction methods. Hardness and tensile tests as well as Charpy impact tests were performed. Wear tests were also carried out on the pin-on disc tester, and then the wear performance was examined on the tester, which simulates the actual operating condition. Findings AlSi12 has primary Si and eutectic Si in the Al matrix. However, alloys of Mg with AlSi12 have other intermetallics such as Mg2Si and ß-Fe, as well as primary Si and eutectic Si. Hardness and tensile strength as well as improved wear performance with increased Mg content. Originality/value In this study, wear performance test to simulate the operation of the cylinder head produced by high pressure casting from AlSi12 alloy moreover tensile test, hardness test and impact test were performed. Therefore, in this study, the wear performance of the compressor head produced by high-pressure casting method by adding three different amounts of Mg to AlSi12 alloy was investigated.