75-mm Z15 series steel plate prepared by rolling 250-mm casting blank and production method of 75-mm Z15 series steel plate

Abstract

The invention discloses a 75-mm Z15 series steel plate prepared by rolling 250-mm casting blank which comprises the following chemical components in percentage by mass: 0.08-0.16 wt% of C, 0.20-0.50 wt% of Si, 1.15-1.60 wt% of Mn, at most 0.020 wt% of P, at most 0.010 wt% of S, at most 0.20 wt% of microalloying elements (Nb+Ti), at most 0.050 wt% of Als, and the balance of Fe and residual elements. The production method comprises the following steps: converter smelting, LF (ladle furnace) refining, vacuum refining, casting, heating, rolling, controlled cooling, slow cooling and heat treatment. The chemical components of low-carbon low-manganese multi-element compound microalloying elements are reasonably designed, and LF and VD (vacuum degasser) techniques are used for ensuring the cleanliness of the steel, so that the total grade of various inclusions does not exceed 3.0; and by effectively taking the measures above, thickness-property Z15 steel plate by rolling 250mm continuous casting blank which is at least 60mm thick can be successfully produced. The quality of the real object of the product satisfies the level of Q345C-Z15, the property tolerance is high, the continuous casting blank is directly substituted for the steel ingot, and the TMCP (Thermomechanical Control Process) is substituted for normalizing, thereby greatly lowering the production cost.

Description

technical field [0001] The invention relates to steel products, in particular to a 250mm billet TMCP rolled 75mm Z15 series steel plate and a production method thereof. Background technique [0002] In the past 20 years, the steel structure of high-rise buildings, offshore oil production platforms and similar important buildings (structures) in my country have developed vigorously. In this kind of buildings (structures), due to the need of structural bearing capacity, thick plate welded structures are often used. During the manufacturing and welding of thick plate structures, due to steel quality and welded structures, thick plates are prone to lamellar tearing. This is very unfavorable for joints under tension in the thickness direction. Steel plates with good performance in the thickness direction were not fully produced in my country in the 1980s and 1990s, and a batch of thick plates were needed to meet the growing needs of the domestic construction market. In recent ye...

AI Technical Summary

Problems solved by technology

However, due to the difficulty in production and the special requirements for process equipment, the steel plate with a thickness of more than 60mm (including 60mm) in the thickness direction cannot be fully produced.

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