High-strength high-toughness X80 hot rolling coiled sheet for spiral buried arc welding and production method thereof

Abstract

The invention provides an X80 hot rolling steel plate used for a high-obdurability spiral hidden arc welded tube and a production method thereof, which belong to the technical field of steel rolling. The X80 hot rolling steel plate comprises the following compositions in weight percentage: 0.03 to 0.08 weight percent of carbon, 0.10 to 0.25 weight percent of silicon, 1.60 to 1.95 weight percent of manganese, 0.09 to 0.11 weight percent of niobium, 0.020 to 0.030 weight percent of vanadium, 0.010 to 0.020 weight percent of titanium, 0.10 to 0.30 weight percent of molybdenum, 0.10 to 0.30 weight percent of copper, 0.10 to 0.30 weight percent of nickel, 0 to 0.30 weight percent of Cr, less than or equal to 0.018 weight percent of phosphor, less than or equal to 0.003 weight percent of sulfur, less than or equal to 0.006 weight percent of nitrogen, 0 to 0.0005 weight percent of boron, less than or equal to 0.0003 weight percent of hydrogen, and the balance being ferrum and unavoidable trace impurities. The production method comprises the following steps: heating the compositions at a temperature of between 1,150 and 1220 DEG C; stopping rough rolling at a temperature of between 1,020 and 1,080 DEG C; stopping fine rolling at a temperature of between 800 and 840 DEG C; coiling the rolled steel sheet at a temperature of between 400 and 480 DEG C; and performing fine rolling according to the compression ratio, that is the thickness of an intermediate billet to that of finishing outlet is more than or equal to 3. The X80 hot rolling steel plate is particularly suitable to be used in a gas pipeline with high pressure, long distance and large aperture.

Description

technical field [0001] The invention belongs to the technical field of steel rolling, and in particular provides a production method of X80 hot-rolled coils for high-strength and toughness spiral submerged arc welded pipes, which are used in high-pressure, large-diameter and long-distance natural gas and oil pipeline projects. Background technique [0002] High-pressure, large-diameter and long-distance pipeline transportation of natural gas and oil is the current development trend of pipeline transportation. According to the national "Eleventh Five-Year" energy development plan, the pipeline laying length of the second line of the West-East Gas Pipeline Project is more than 7,000 kilometers, and the annual gas transmission volume is 300. 100 million cubic meters, the pipe diameter is 1219mm, and the rated delivery pressure is 12MPa. In order to meet the pipeline design indicators of the "Second West-East Gas Pipeline" and reduce pipeline procurement and construction costs, ...

AI Technical Summary

Problems solved by technology

For example, application number 200410025584.4, titled "High-strength and high-toughness X80 pipeline steel and its hot-rolled plate manufacturing method", shortcomings: 1) It is clearly stated that the production specification is ≤15mm, and the scope of use is limited (such as "the second west-east gas transmission line" 18.4mm specification X80 hot-rolled coil); 2) High Nb composition design is not adopted, even if the waterfall specification X80 still needs to add a large amount of expensive Mo alloy, the production cost pressure is high; 3) In addition, Baosteel adds V (0.045%) microalloy content High, production cost pressure

The patent name of the Institute of Metals is "a method for preparing high-clean, high-strength and tough gas pipeline steel", and the patent application number is 00123128.6. Not only the strength level is X70, but there is still no design method with high Nb content

[0003] In addition, European steel pipes once produced X80 flat plates, because the C content is 0.07-0.11%, there is a defect of low low temperature impact toughness

South Korea’s Puxiang has tried to produce X80 hot-rolled coils, but the product thickness and performance requirements are obviously not up to the application conditions

Images