A low-cost high-strength pipe material and its preparation method

Abstract

The invention discloses a low-cost and high-strength pipe material and a preparation method thereof. Alloy components meet the following range requirement including, by mass percent, 0.03%-0.06% of C,5%-8% of Ni, 17%-22% of Cr, 1.8%-3.0% of Al, not larger than 0.3% of Ti, not larger than 3% of Co, not larger than 0.6% of Nb, not larger than 1.5% of W, not larger than 1.0% of Mo, not larger than 3% of Cu, not larger than 0.25% of N, not larger than 0.1% of Zr, not larger than 0.05% of Mg, not larger than 0.006% of B and the balance Fe. A prepared alloy is smelted into alloy mother liquor, andthe alloy mother liquor is prepared into an alloy ingot through a negative pressure casting process; and then after the alloy ingot is rolled to form a plate within the range of 850 DEG C-1,100 DEG C,solution treatment and aging treatment are carried out. The alloy has excellent strength performance and meanwhile has good oxidization resistance. The room-temperature tensile strength of the alloyis not lower than 750 MPa, and the yield strength of the alloy exceeds 650 MPa.

Description

technical field [0001] The invention belongs to the field of metal materials, and in particular relates to a low-cost, high-strength pipe material and a preparation method thereof. Background technique [0002] High chromium martensitic heat-resistant steel has been widely used because of its low cost and excellent performance. The high chromium content ensures that the alloy has good oxidation resistance and corrosion resistance, which further ensures the performance of the alloy under severe working conditions. Among them, the most representative is 9-12Cr martensitic heat-resistant steel, which has been widely used in supercritical and ultra-supercritical thermal power units. However, with the gradual increase of steam parameters of thermal power units, the performance requirements of materials are becoming more and more stringent. Traditional materials have been difficult to meet the impact of steam temperature rise on materials. Among them, insufficient oxidation res...

AI Technical Summary

Problems solved by technology

However, as the degree of alloying increases, high-temperature ferrite is often formed, and at the same time, the ductile-brittle transition temperature of the alloy is increased, resulting in a sharp decrease in the plasticity of the alloy, which has a serious impact on the performance of the alloy.

According to the current research results, the addition of Ni and Al elements can significantly improve the strength of the alloy, but at the same time have a significant impact on the plasticity. The addition of a small amount of Al element will cause the ductile-brittle transition temperature of the alloy to increase rapidly and seriously reduce the plasticity.

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