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Автор: N.Bailey, F.R.Coe, T.G.Gooch, P.H.M.Hart, N.Jenkins, R.J.Pargeter
Издательство: Woodhead Publishing
Год издания: 1993
isbn: 1855730146
Количество страниц: 160
Язык: english
Формат: PDF
Размер: 7 Мб
Каталожный номер: 56910
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This book details the graphical system developed by the Welding Institute to prevent hydrogen cracking. The system is based upon the determination of the carbon equivalent (CE) via equations that are provided. This CE is then used with the hydrogen content introduced during welding to set the horizontal axis of a nomograph. One then draws a line upwards from the appropriate CE value (determined by the CE and H content) until it intersects a line defining preheat level being used. A horizontal line is then drawn from the intersection point of the CE line and preheat line until it hits a line defining the combined plate thickness (which is determined by the part geometry). A vertical line is then down from this intersection point until it hits another horizontal axis at a point which identifies the proper heat input. This system thus allows one to determine the appropriate heat input based upon the CE of the steel, the H level introduced in welding (which is determined by the welding process and variables such as the proper handling of electrodes), the amount of preheat and the part geometry. Data on the Martensite start temperature is provided, as this is required to set some preheat temperatures. Data on hydrogen diffusion is also provided, which is needed to set bake out requirements to eliminate any hydrogen that may be present. British standards are used for the specific steels that are mentioned, so conversion is necessary to apply this data to steels defined by other standards.
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