23 Jul Low-temperature engineering steel with yield strength not lower than 550MPa and production method of engineering steel
Abstract
The invention discloses low-temperature engineering steel with yield strength not lower than 550MPa. The low-temperature engineering steel with yield strength not lower than 550MPa comprises the following components in percentage by weight: 0.04%-0.18% of C, 0.15%-0.50% of Si, 1.63%-2.00% of Mn, not more than 0..015% of P, not more than 0.008% of S, 0.05%-0.12% of Nb+Ti, 0.20%-0.4% of Mo+Cr, and 0.015%-0.05% of Als; the production steps are as follows: smelting and continuously casting to form blank, heating up the casting blank; rolling in a segmented manner by adopting a TMCP (Thermo-Mechanical Control Process); cooling; and straightening for the future use. The low-temperature engineering steel with yield strength not lower than 550MPa disclosed by the invention is not only capable of producing a steel plate with the thickness bigger than 80mm; the steel plate is uniform in tissue performance in the thickness direction, better in low-temperature impact toughness, i.e., impact power being not less than 100J at (-)60 DEG C, suitable for manufacturing engineering machinery that works in an extremely cold environment. The casting blank has center segregation C lower than 1.5 level and center porosity lower than 0.5 level; the low-temperature engineering steel is free of Ni and relatively low in content of Cr, Mo and other micro alloys, so that the cost is greatly lowered; the TMCP is adopted for producing without the processes including thermal treatment, PRC (Pre-stressed Reinforced Concrete), stacking slow-cooling and the like, and any other equipment is not needed to be added, so that the production process is simple and the production efficiency is high.
Year: 2013
Country: CN
Doc No: 103276301