A kind of low-alloy high-strength steel hot-rolled plate and its manufacturing method

Abstract

The invention relates to the technical field of iron and steel smelting and processing, in particular to a low-alloy high-strength steel hot-rolled plate and a manufacturing method thereof. The chemical composition of the hot-rolled plate contains C: 0.15-0.22%, Si: 0.25-0.65 %, Mn: 1.20-1.80%, P≤0.020%, S≤0.010%, Alt: 0.020-0.060%, Ti: 0.020-0.060%, V: 0.10-0.20%, and the rest are Fe and unavoidable impurities. The manufacturing method of the low-alloy high-strength steel hot-rolled plate is as follows: hot metal pretreatment desulfurization-converter smelting-LF furnace refining-slab continuous casting-slab heating-hot continuous rolling-normalizing treatment. The carbon content of the low-alloy high-strength steel hot-rolled plate provided by the present invention is relatively high, only relatively cheap V and Ti elements are added, and precious alloy elements such as Nb, Mo, Ni, and Cu are not added, and the microalloy elements V and Ti are used The fine-grain strengthening and precipitation strengthening effect ensure the mechanical properties of the steel plate after normalizing, and Ti can also improve the welding performance of the steel plate, so the alloy cost of the product is low.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting and processing, in particular to a low-alloy high-strength steel hot-rolled plate and a manufacturing method thereof. Background technique [0002] In the field of industrial manufacturing, it is necessary to use normalized steel plates in many occasions to manufacture welded structural parts specially used under low temperature or high temperature conditions, such as boilers, containers, bridges, ships, welding bottles, etc. serving in low temperature or high temperature environments . Therefore, for the steel plate in the normalized state, it is required to have high strength and good low-temperature impact toughness. At the same time, it is necessary to ensure that the steel plate has good welding performance. Controls have put forward higher requirements. [0003] At present, there are also low-alloy high-strength steel hot-rolled plates with a yield strength of 420MPa after ...

AI Technical Summary

Problems solved by technology

However, in the prior art, low-alloy high-strength steel plates with a yield strength of 420 MPa after normalizing are mostly made of low-carbon manganese steel. Due to the low C and Mn elements, a large amount of scarce and precious alloying elements such as Nb and Mo need to be added to the steel. , Ni, Cu, etc. to ensure that the strength of the steel plate after normalizing meets the standard requirements, so the cost of the alloy is high

At the same time, the smelting and structure control of low carbon steel (C≤0.08%) is difficult and the production cost is high

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