LPG boat storage tank steel plate and production method thereof

Abstract

The invention discloses an LPG boat storage tank steel plate and a production method thereof. The steel plate comprises 0.05-0.12wt% of C, 0.30wt% or less of Si, 0.50-1.30wt% of Mn, 0.015wt% or less of P, 0.008wt% or less of S, 0.020-0.060wt% of Al, 0.15-1.20wt% of Cu, 0.20-1.50wt% of Ni, 0.35-1.00wt% of Cr, 0.20-0.60wt% of Mo, 0.008-0.020wt% of Ti, one or more of 0.0020-0.10wt% of Nb, 0.030-0.060wt% of V and 0.0005-0.0020wt% of B, and the balance Fe and inevitable impurities. The method comprises the steps of molten iron advanced desulphurization, converter top and bottom blowing, vacuum treatment, continuous casting, casting blank heating, rolling and heat treatment, the heating temperature of a casting blank is 1170-1250DEG C, and the heating rate of the casting blank is not less than 8min / cm; the blooming temperature is 1050-1150DEG C, the finishing temperature is 850-940DEG C, and the accumulated reduction rate of last three passes is not less than 16%; and heat treatment adopts online quenching and tempering treatment, or adopts offline quenching and tempering treatment. The steel plate obtained in the invention has the advantages of excellent mechanical properties, good hot and cold processing performance, excellent weldability and low sensitivity of weld cracks.

Description

technical field [0001] The invention relates to metallurgical technology, in particular to a steel plate for an LPG ship storage tank and a production method thereof. Background technique [0002] Liquefied Petroleum Gas (LPG for short) is one of the main energy varieties in my country. It is widely used in industrial production and residential life because of its cleanliness, safe and convenient storage and transportation, and high thermal efficiency. LPG is a complex mixture, the main components are hydrocarbons containing three carbon atoms and four carbon atoms, which are called carbon three and carbon four in the industry, mainly propane and butane, and also contain a small amount of propylene, butene and other components. LPG is in a gaseous state at normal temperature and pressure, and can be turned into a liquid state by pressurization, cooling or a combination of both. Because LPG has a high critical temperature, it can be compressed into a liquid at room temperat...

AI Technical Summary

Problems solved by technology

It is difficult for existing steel plates to take into account the various performance requirements of steel plates for LPG ship storage tanks

[0004] The Chinese invention patent application with the application number CN201210121739.9 discloses a steel plate for storage tanks of LPG ships and its production method. ~0.40%, Mn: 1.05~1.10%, P≤0.012%, S≤0.005%, Cr: 0.30~0.35%, Ni: 0.40~0.45%, Mo: 0.25~0.30%, Nb: 0.02~0.03%, V : 0.035~0.040%, Ti: 0.01~0.02%, B: 0.0015~0.0020%, N≤0.010%, Cu≤0.20%, total Al: 0.02~0.05%, the balance is Fe and unavoidable impurities; the steel plate The production method includes the following steps: smelting-LF / VD refining-casting-heating-rolling-cooling-quenching and tempering-finished product; the thickness of the steel plate for LPG ship storage tank is 8-50mm, the steel plate has high compactness, strength High, good low-temperature impact toughness and good lamellar tear resistance, but the welding crack sensitivity coefficient Pcm value of the steel plate is high (Pcm(%)=C+Si / 30+Mn / 20+Cu / 20+ Ni / 60+Cr / 20+Mo / 15+V / 10+5B)), the welding performance cannot be guaranteed; and the low temperature toughness of the base metal has certain advantages only above -20°C, and the temperature is below -20°C When the low temperature toughness of the steel plate cannot be guaranteed

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