Steel plate with 115 MPa grade yield strength and manufacturing method thereof

Abstract

The invention discloses a steel plate with the 115 MPa grade yield strength. The steel plate comprises the following chemical compositions in percentage by weight: 0.14-0.17wt% of C, 0.10-0.30wt% of Si, 0.80-1.20wt% of Mn, less than or equal to 0.015wt% of P, less than or equal to 0.003wt% of S, 0.30-0.50wt% of Cr, 0.40-0.70wt% of Mo, 1.1-2.2wt% of Ni, 0.01-0.06wt% of Nb, 0.04-0.06wt% of V, 0.003-0.02wt% of Ti, 0.03-0.07wt% of Al, 0.0006-0.0020wt% of B, the rest of Fe and other inevitable impurities. The steel plate with the 115 MPa grade yield strength also meets the following conditions: C+Mn / 2 is greater than or equal to 0.23Ni+0.32Mo+0.49Si+0.17Cr-153.21B and is less than or equal to 0.49Ni+0.64Mo+0.76Si+0.53Cr-132.61B, and Qm is greater than or equal to 2.77 and is less than or equal 4.92. The steel plate has the advantages that the yield strength is greater than or equal to 1150MPa, the tensile strength is greater than or equal to 1200MPa, the charpy impact energy (Akv) (minuse 40 DEG C) is greater than or equal to 60 J, and the carbon equivalent (CEV) is less than or equal to 0.60%, and the steel plate has excellent welding performance.

Description

technical field [0001] The invention relates to an alloy and a manufacturing method thereof, in particular to a steel plate and a manufacturing method thereof. Background technique [0002] High-strength steel plates with good low-temperature toughness are widely used in the manufacture of structural parts of large-scale machinery and equipment, such as tie rods of large-tonnage crawler cranes, push rods of coal mine hydraulic supports with high working resistance, and booms of concrete pump trucks with arm lengths exceeding 47m etc., which all use high-strength steel plates with a yield strength of 900 / 960MPa and above. Large mechanical structural parts are usually connected by welding, so there are high requirements for the strength, toughness and welding performance of the steel plate. With the increasing size of mechanical structures, high-strength steel plates with a yield strength of 1150 MPa and a lower carbon equivalent can meet the needs of large-scale mechanical e...

AI Technical Summary

Problems solved by technology

Heating quenching+tempering and controlled rolling controlled cooling+tempering process adopt the usual heat treatment furnace, the heating speed is slow, and the carbonitride grows during the tempering process, thereby reducing the impact performance of the steel plate, and the production cycle is longer, which has a relatively high production cost

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