Production method of hot continuous rolling plate with low residual stress for bridge U rib

Abstract

The invention relates to the field of production processes of hot continuous rolling plates, in particular to a production method of a hot continuous rolling plate with low residual stress for a bridge U rib. The method comprises the following steps of 1) smelting; 2) heating a casting blank; 3) conducting rough rolling; 4) conducting finish rolling; 5) cooling; 6) coiling; 7) conducting slow cooling; 8) flattening; 9) flattening and crosscutting a hot continuous rolling coil; 10) conducting heat treatment, namely packaging each bundle of steel coils into a continuous hot discharge furnace oneby one for stress relief heat treatment; and (11) longitudinally slitting. The residual stress of the hot continuous rolling plate for the 345-370 MPa grade bridge U rib obtained by adopting the scheme is within -15 to +15 MPa.

Description

technical field [0001] The invention relates to the field of production technology of hot continuous rolling plates, in particular to a production method of hot continuous rolling plates for bridge U ribs with low residual stress. Background technique [0002] The hot continuous rolling plate is produced by the hot continuous rolling mill, and the flat plate is opened by the shearing line, and delivered in the state of bundled steel plate. The ultra-thin gauge (6-8mm) steel plates for bridges have been produced by hot continuous rolling process. The steel billets are rough-rolled by a four-roll reversible rough-rolling mill, then finish-rolled by a 7-stand continuous unit, and then coiled after laminar flow cooling. Then it is flattened and cut to length for the bridge manufacturer to make U-ribs. The steel plate produced according to this technological process has the advantages of low cost and high dimensional accuracy of the steel plate. [0003] But at present, the big...

AI Technical Summary

Problems solved by technology

However, the release and elimination of residual stress such as structural stress, thermal stress, and processing stress in the steel are incomplete. In the process of casting slab heating, finishing rolling, subsequent heat treatment and processing application, there is a lack of sufficient means of stress relief. The elimination of internal stress in rolling, cooling and other processes cannot fully eliminate the internal stress of the steel coil. After the steel coil is flattened, side bending and flatness problems will exist to varying degrees

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