Alloy steel for high-strength gas cylinder, gas cylinder and manufacturing method thereof

Abstract

The invention relates to alloy steel for a high-strength gas cylinder. The alloy steel consists of the following chemical components in percentage by weight: 0.30-0.38 percent of C, 0.15-0.37 percent of Si, 0.60-0.90 percent of Mn, 0.80-1.20 percent of Cr, 0.15-0.30 percent of Mo, 0.01-0.05 percent of Al, 0.00-0.25 percent of Ti, 0.02-0.25 percent of Nb, 0.03-0.20 percent of W, less than or equal to 0.010 percent of P, less than or equal to 0.010 percent of S, 0.002-0.004 percent of Ca, less than or equal to 0.0035 percent of N and the balance of Fe and inevitable impurities, wherein Ti+Nb is more than or equal to 0.07 percent; and the total quantity of impurity elements is less than 0.05 percent. A manufacturing method of the high-strength gas cylinder comprises the following steps of: smelting, refining, performing VD (Vacuum Distillation) treatment, controlling the content of elements P and S in the steel, and adjusting the content of N simultaneously; before tapping, feeding Si-Ca wires in an amount of 2-3 meters into every ton of steel for denaturalizing inclusions; pouring a square billet with a large square billet continuous casting machine under the protection of argon gas, blooming at the temperature 1,050-1,090 DEG C, and cogging to obtain a square billet material; manufacturing a seamless gas cylinder; preserving the heat of the seamless gas cylinder at the temperature 800-940 DEG C for 30-60 minutes, and performing water quenching treatment; and tempering at the temperature 500-650 DEG C, and preserving heat for 30-120 minutes. The obtained gas cylinder steel has a tempered sorbite structure, the tensile strength is over 1,100 MPa, and the low-temperature impact toughness at the temperature 50 DEG C below zero is over 45 J / cm<2>.

Description

technical field [0001] The invention relates to low-alloy steel for gas cylinders, in particular to a high-strength low-alloy steel for producing high-pressure seamless gas cylinders and a preparation method thereof. Background technique [0002] Gas cylinders refer to mobile pressure containers that can be re-inflated and used to hold permanent gas, liquefied gas or dissolved gas under normal circumstances. As a gas storage container, steel gas cylinders have been widely used in industry, mining, military, medicine, diving, automobiles and other fields. According to different manufacturing processes, steel gas cylinders can be divided into welded gas cylinders and seamless gas cylinders. The welded gas cylinder is a steel cylinder made of steel plate as raw material, stamped and welded. Seamless gas cylinders are made of steel billets, which are stamped and stretched, or seamless steel pipes, which are hot-spun to close the mouth and bottom. The seamless gas cylinder fun...

AI Technical Summary

Problems solved by technology

[0008] Most of the low-alloy steel types involved in the above-mentioned patents or applications adopt the method of adding Ni element and increasing Mo content at the same time to achieve the purpose of improving material strength, toughness and tempering stability, but the addition of Ni and Mo elements will increase the cost of the material alloy , so that the final gas cylinder price increases

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