A study of microstructure and tensile property with casting S45C welding

For energy saving and longer life time of a large casting iron may use of weld repairs or make up to more save manufacture time and energy than re-casting. Such as breakage, crack and wear in large casting iron castings used weld to repair casting for eco-energy. The purpose of this study is to investigate the dissimilar joint property of S45C carbon steel with the multi-layer method and the multi-pass welding method. Four weld rods, experimentally examined the influence on microstructures, which were marked as A, B, C and D, respectively. The microstructures of joint bead were observed by the optical microscope. The specimens of tensile test were made according to ASTM E8M. The experimental results were shown as following: 1. The pearlite structures and the bainite structures were formed in welded zone by the weld rod of middle carbon steels. The yield strength and ultimate strength of the specimens were 360MPa and 460MPa. 2. The feature of welded specimen was close to stainless steel due to the stainless steel rod included some Cr and Ni. In addition, a ferritic-austenitic two-phase stainless steel was observed in optical microscope.

Process Parameters Research of Vibratory Stress Relief for Large Casting

Taking the generator as research object, this paper was trying to determinate the parameters of vibration stress relief with a new method by the aid of finite element software with powerful function. Firstly, size and distribution of remnant stress were determined. Then the modality analysis and harmonic response analysis were carried on the workpiece by using the kinetics analysis function of finite element method. Finally, some crucial parameters of vibration stress relief were obtained.The research method and conclusion would provide the important reference values for casting enterprise to determine technological parameters of vibration stress relief.

Study of Large Castings Lost Foam Online Non-Contact Detection

This paper aimed at traditional large casting with lost foam detection which has slown speed and low efficiency problems, developed a new non-contact detection method which combined digital close range photogrammetry measurement techniques and grating projection measurement techniques, fulfilled a car wind screen board lost foam 3272mm x 1205mm x 555mm online detection, has produced non-contacted online detection method. The results showed that method with fast detection speed、high efficiency, and can satisfy the large castings lost foam online non-contact detection requirements.

The Effect of Microstructural Differences on NA2SO4-Induced Corrosion of Superalloy CMSX-4 at High Temperatures

Single crystal (SC) nickel based superalloys have been used in aero engine applications for a long time. The SC casting techniques are not yet widely used in the land based engine components because of their much larger size which makes casting and the subsequent heat treatment more difficult. In large casting, microporosity and elemental segregation are more severe. The γ/γ′ eutectic structure and dendritic arm spacing are also larger due to large casting size. All these defects will affect the heat treatment process and the subsequent service properties, including the resistance to oxidation and hot corrosion. In this work, as-cast and heat treated CMSX-4 specimens from small and large blades were used to study the effects of cast defects and heat treatment on Na2SO4 -induced hot corrosion resistance of the single crystal superalloy. The tests were carried out between 900 to 1000°C, for times ranging than 10 to 600 hours in the presence of a Na2SO4 deposit. The specimens from as-cast large blade underwent catastrophic attack after a short exposure time. But the initiation time for catastrophic attack approximately doubled in the case of wholly solution heat treated specimens. It is thus likely that although the hot corrosion resistance of this single crystal material is not as good as that of IN738, proper heat treatment can improve its hot corrosion resistance.