Forecasting, production planning, and control
Ejiroghene Kelly Orhorhoro; Andrew Amagbor Erameh; Rogers Ibunemisam Tamuno
Abstract
In this study, the effects of corrosion rate on post welded annealed heat-treated medium carbon steel in seawater was investigated. The medium carbon steel samples were butt-welded by using the Shielded Metal Arc Welding (SMAW) technique and, afterwards, heat treated by annealing at different annealing ...
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In this study, the effects of corrosion rate on post welded annealed heat-treated medium carbon steel in seawater was investigated. The medium carbon steel samples were butt-welded by using the Shielded Metal Arc Welding (SMAW) technique and, afterwards, heat treated by annealing at different annealing temperature was carried out. The microstructure of the unwelded and post welded heated samples was characterised by means of optical microscopy. The as received (control), unwelded and post welded annealed medium carbon steel samples were immersed in sea water for a duration of one hundred (100) days, and this was to stimulate the effect on equipment in offshore and food processing applications. Post welded heat treatment on the microstructure, weight loss and corrosion rate were evaluated. The results obtained showed an initial increase in both the weight loss and corrosion rate of samples up to 40 days and started decreasing afterwards. It was equally observed that the post welded annealed samples showed more corrosion activities than the un-welded annealed samples. Above and beyond, corrosion activity was more prominent in samples with the highest annealing temperature. More so, the unwelded annealed medium carbon steel showed a dispersion of coalescence cementite and ferrite grain while the post welded annealed medium carbon steel samples showed a martensite (light area marked by arrows) distributed in the ferrite (dark area) matrix.
Thermal Comfort
Ubeidulla F. Al-Qawabeha
Abstract
AISI H13 tool steel is applied widely to produce many kinds of hot work dies, such as forging dies, extrusion dies, die-casting dies and so on. The successful employment of metal in engineering application relies on the ability of the metal to meet design and services requirements and to be fabricated ...
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AISI H13 tool steel is applied widely to produce many kinds of hot work dies, such as forging dies, extrusion dies, die-casting dies and so on. The successful employment of metal in engineering application relies on the ability of the metal to meet design and services requirements and to be fabricated to the proper dimensions. The capability of metal to meet these requirements is determined by mechanical and physical properties of the metal. Burnishing processes is considered as a surface plastic deformation method, which used to improve surface texture (micro hardness, average surface roughness, and maximum surface roughness). This work present the effect of isothermal annealing temperature and roller burnishing process on the surface properties of H13 alloy steel .This steel was annealed at a different temperatures to get different types of pearlite with different grains and grain size. After that, the steel was burnished with different forces, feeds, and burnishing speeds. The effect of annealing temperatures and roller burnishing on the hardness, micro hardness, average surface roughness and microstructure and metallographic analysis have been investigated. The results showed that roller burnishing could increase the surface hardness under the selected specified conditions depending on the isothermal annealing temperatures by 104%, 45% and 90% for the work parts with 3000C, 500 0C and 6200C annealing temperatures respectively. In addition, roller burnishing significantly improves the smoothness of the steel surfaces. The average roughness obtained was ranged from 0.11μm to 0.17μm. In this paper, the microstructure analysis, micrograph of the isothermal annealed H13 alloy steel have been given. It has been shown that depending on the isothermal annealing temperature there are different types of grains and grain size of treated steel in pearlite phase.
