A high-elongation hot-rolled structure control steel with tensile strength ≥ 800mpa and production method

Abstract

A high-elongation hot-rolled structure control steel with a tensile strength ≥ 800MPa, the composition and weight percentage of which are: C: 0.07-0.09%, Mn: 1.95-2.10%, Si: 0.70-0.80%, P≤0.008 %, S≤0.002%, Als: 0.02~0.04%; production method: RH vacuum furnace treatment after converter smelting; heating of cast slab; segmental rolling; segmental variable speed cooling: coiling; Under the premise of ensuring the tensile strength above 800MPa, the present invention makes the yield strength ≥ 500MPa, the elongation ≥ 25%, the strength-plastic product ≥ 20GPa%, and the yield-strength ratio < 0.65, which can meet the forming requirements of thick-gauge high-strength steel. Moreover, the alloying elements are simple, and precious alloys such as Nb, V, and Mo are not added, and the cost of the alloy can be reduced by at least 10%.

Description

technical field [0001] The invention relates to a hot-rolled steel for automobiles and a production method thereof, in particular to a high-elongation hot-rolled structure control steel with a tensile strength greater than 800MPa and a production method thereof; and is suitable for steel plates with a thickness of 2-12mm. Background technique [0002] In recent years, the automotive industry, especially commercial vehicles, semi-trailers, passenger cars and other market segments, has become more and more urgent to reduce weight. Related manufacturers have put forward clear requirements for vehicle weight reduction to meet the mandatory national standard GB1589-2016, etc. regulatory requirements. On the one hand, the wheels, axles, saddles and other structural parts of commercial vehicles and other models need to be drawn, reamed and other forming processes in the manufacturing process. There are clear requirements for edge forming performance. On the other hand, the thickne...

AI Technical Summary

Problems solved by technology

The lower limit of the elongation in this document is only 15%, which cannot meet the forming requirements of deformed and complex parts. At the same time, the thickness of the finished product is only 1.2-4.0mm, which cannot meet the needs of thicker specification steel, and there are many alloy elements, and the relative cost is high.

Images