Pipeline steel Charpy specimen fracture separation degree grading method

Abstract

The invention relates to a pipeline steel Charpy specimen fracture separation degree grading method, which comprises the following steps of: (1) for a specimen having fracture separation in a Charpy test, measuring the lengths of separation cracks on specimen fractures, and endowing the cracks with different scores m according to the lengths of the separation cracks; (2) sorting according to the lengths of cracks on the fractures, and endowing the differently sorted fracture separation cracks with different weight coefficients k; (3) adding each product of a scores mi of each fracture separation crack on the specimen fracture and a weight coefficient ki to obtain a total sore M of the fracture separation of the specimen; and (4) dividing the fracture separation degree into four grades, namely I grade, II grade, III grade and IV grade according to the total score M. If the specimen fracture separation coefficient exceeds a certain grade, a series temperature impact toughness test is carried out, a rise platform parameter is calculated, factors such as a pipeline transportation parameter, material toughness property and the like are comprehensively considered according to a calculation result, and a control measure is taken for the fracture separation of the material.

Description

technical field [0001] The invention relates to a grading method for evaluating the fracture separation degree of high-strength pipeline steel Charpy impact toughness test specimens, in particular to a pipeline steel Charpy impact specimen fracture separation of L555 / X80 strength level produced by a controlled rolling process degree of evaluation method. Background technique [0002] The phenomenon of fracture separation (also called fracture delamination) is a secondary phenomenon found at the fracture of the controlled-rolled plate during the mechanical performance test (including tensile test, impact test, drop weight test, CTOD test, etc.) and hydraulic blasting test. Cracks or delaminations, which are perpendicular to the fracture surface and parallel to the surface of the steel plate (coil). Separation generally occurs in the direction parallel to the principal stress, which is caused by the stress perpendicular to the principal stress and appears as a secondary crack...

AI Technical Summary

Problems solved by technology

Due to various factors such as tests and materials, some parameters are sometimes difficult to determine, even if they can be determined, sometimes several parameters vary greatly

In addition, a series of temperature shock tests must be carried out to obtain these parameters, which is not feasible for daily product inspections, so an engineering-feasible fracture separation evaluation method must be proposed

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