Thermal roll-forming process of unequal-thickness U-ribs

Abstract

The invention belongs to the technical field of thermal roll-forming and relates to a thermal roll-forming process of unequal-thickness U-ribs. The process includes the steps of 1, feeding a pre-formed U-rib formed by the traditional cold-bending process into an induction heater through a feed rack, selecting a proper heating area through an adjusting mechanism, and feeding the pre-formed U-rib into a roll-forming unit after a temperature required temperature is reached; 2, acquiring a formed U-rib in unequal thickness, formed by the roll-forming unit having two passes, for rough forming and finish forming, respectively, with great residual stress in corners and ends caused by cold bending and thermal roll-forming deformation; 3, feeding the formed U-rib into a continuous destressing annealer which is used mainly for destressing and annealing the bent parts and ends of the U-rib in the unequal thickness, with higher thermal efficiency; and 4, allowing cooling and performing cutting to length. The process has the advantages that forming speed is high, thermal efficiency is high, the formed U-rib has low residual stress, welding area of the U-rib and a bridge deck is enlarged, and connection strength of the U-rib and the bridge deck and fatigue resistance of a weld are improved.

Description

Technical field [0001] The invention relates to a U-rib forming technology for bridges, in particular to a local hot roll forming technology of U-ribs with unequal thickness at the end. Background technique [0002] At present, in the field of bridge construction, orthotropic bridge decks have been widely used in bridge engineering. Orthotropic bridge decks are mainly composed of steel decks and beams and longitudinal ribs welded to them. The beams are mainly diaphragms and longitudinal ribs. Mainly closed stiffeners, namely U ribs. Because U-shaped ribs can provide greater torsional rigidity and bending rigidity, and can improve the stress state of the entire bridge deck, it has become the most commonly used cross-sectional form of modern orthotropic bridge decks. [0003] However, in recent years, reports on the fatigue hazards of the U-shaped ribs have continuously appeared at home and abroad, causing the fatigue life of the bridge deck to be lower than the design service life ...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem that the welding area between the existing U-rib and the bridge deck is small and the weld seam is prone to fatigue and cracking, the present invention proposes a U-rib hot roll forming process with non-equal thickness at the end

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