High-temperature resistant seamless steel pipe and production method thereof

Abstract

The invention relates to a high-temperature resistant seamless steel pipe and a production method thereof. The seamless steel pipe is characterized by consisting of the following chemical components in percentage by mass: 0.08 to 0.12 percent of C, 0.20 to 0.45 percent of Si, 0.40 to 0.60 percent of Mn, 8.50 to 9.50 percent of Cr, 0.85 to 1.10 percent of Mo, less than or equal to 0.40 percent of Ni, 0.06 to 0.10 percent of Nb, 0.18 to 0.25 percent of V, 0.03 to 0.07 percent of N, less than or equal to 0.018 percent of P, less than or equal to 0.008 percent of S, less than or equal to 0.01 percent of total Al, less than or equal to 0.003 percent of O, and the balance of Fe and inevitable impurities. The heating temperature of a pipe blank in an annular furnace is 1,230 to 1,260 DEG C, and the temperature difference of the pipe blank in the cross section and the length direction is + / -15 DEG C. A normalizing and tempering technology is adopted in heat treatment, the normalizing temperature is 1,040 to 1,080 DEG C, and the heat preservation time is not less than 1.5 minutes per 1 milliliter of wall thickness and is not less than 30 minutes; and the tempering temperature is 750 to 780 DEG C, the heat preservation time is not less than 1 hour, and cooling is performed in still air. The microstructure of the seamless pipe is martensite. The method is high in production efficiency, can be used for producing pipes with multiple diameters, is high in economic benefits and suitable for large-scale production, and has high popularization value.

Description

technical field [0001] The invention relates to a high-temperature-resistant seamless steel pipe and a production method thereof, belonging to the field of metallurgical materials. Background technique [0002] In recent years, my country's electric power industry has developed rapidly, and power plant boilers have developed to large capacity and high parameters. According to the national development strategy, small and medium-sized coal-fired units will be gradually restricted and eliminated, and units above 300MW will become the main units of major power grids. The maximum actual wall temperature of the main steam pipeline of the large-capacity, high-parameter unit, the hot end of the reheat steam pipeline and other high-temperature pressure-bearing equipment has exceeded 600 °C. Generally, high temperature resistant steel should have high creep rupture strength, limited hardness and good toughness. The high-temperature strength and oxidation resistance of 12Cr1MoV steel...

AI Technical Summary

Problems solved by technology

The high-temperature strength and oxidation resistance of 12Cr1MoV steel, which was widely used in these high-temperature parts, could not meet the requirements.

At present, the high-temperature-resistant seamless steel pipes required by domestic enterprises are mainly supplied from abroad, and the supply period is long and the price is expensive, which seriously restricts the development of my country's electric power industry, thus affecting the speed of my country's economic development

At present, only a few manufacturers in China have manufactured high-temperature-resistant seamless steel pipes that meet the standards by forging and extrusion methods, but this method has low production efficiency, low yield, and serious waste of resources, and can only produce large-diameter thick-walled pipes.