| 摘要 |
The invention relates to the metallurgy, in particular to the method for strengthening sheet roll products, and can be used for making high pressure welded pipes for main gas- and oil pipelines. A method for strengthening sheet roll products consists in heating all sheet and cooling its selective separate areas which have the appearance of inclined bars, the angle of inclination of which relative to the length of sheet is determined according to given formula taking into account the modules of elasticity of fixed and non-fixed bars, and according to the calculated direction the crack movement is concentrated, being braked in the presence of alternate boundaries of division of two environments. Moreover, in the case of subsequent making welded pipes from the strengthened steel sheet, geometrical parameters of inclined bars are in addition determined: width thereof and distance between them, i.e. strengthening chosen bars is carried out by cooling thereof providing their location on length of welded pipe in the form of a spiral bar. The invention provides braking the crack length and movement distribution during a possible destruction of sheet and thereby increase in operating properties of sheet rolled products and welded pipes made from them.
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