Steel pipe with ultrahigh strength and continuous production method of steel pipe

Abstract

The invention discloses a steel pipe with ultrahigh strength and a continuous production method of the steel pipe. The continuous production method is suitable for producing steel pipes with ultrahigh strength, pipe diameters of 20-51mm and wall thickness of 1.5-2.5mm. The steel pipe is prepared from the following components by mass percent: 0.20-0.40% of C, 0.30-1.50% of Mn, not more than 0.80% of Si, not more than 0.60% of Cr, 0.01-0.06% of Ti, 0.0008-0.0050% of B, 0.015-0.050% of Al and the balance of Fe and inevitable impurities. After adopting the above raw materials, the steel pipe can be produced by adopting a common welded pipe mill and online continuous heat treatment. The obtained welded steel pipe has ultrahigh strength and avoids the process scheme that a high strength steel plate is used as the raw material and the pipe is prepared by welding the high strength steel plate by adopting laser after roll forming of the high strength steel plate, thus greatly reducing the production cost. The mechanical properties of the obtained steel pipe with ultrahigh strength are as follows: the tensile strength is not less than 1500MPa, the yield strength is not less than 1200MPa and the elongation is not less than 6%. In the method, a heat treatment production line is installed behind a welding production line and the welding speed is matched with the heat treatment speed by adjusting the heat treatment speed, so that continuous production can be achieved, the production operability can be effectively improved and the production time and operation strength can be saved.

Description

technical field [0001] The invention belongs to the technical field of metal iron and steel, in particular to an ultra-high-strength steel pipe and a continuous production method thereof. Background technique [0002] With the implementation of the National Energy Conservation and Emission Reduction Plan, the policy of building an environment-friendly and resource-saving society has been put forward, so the development of steel materials is gradually developing towards the direction of high strength and light weight. Ultra-high-strength steel pipes will gradually be widely used in society. At present, the production processes of ultra-high-strength steel pipes are as follows: 1) High-strength steel is rolled and formed and then produced by laser welding; this method is expensive to manufacture, and the strength level is generally around 1000MPa, which belongs to the lower strength of ultra-high-strength steel pipes. part. 2) Use welding production line to weld the hot-roll...

AI Technical Summary

Problems solved by technology

At present, the production processes of ultra-high-strength steel pipes are as follows: 1) High-strength steel is rolled and formed and then produced by laser welding; this method is expensive to manufacture, and the strength level is generally around 1000MPa, which belongs to the lower strength of ultra-high-strength steel pipes. part

2) Use welding production line to weld the hot-rolled steel pipe and cut to length, then heat treatment, quenching and tempering in the heat treatment production line, so that the strength of the steel pipe can reach about 1400MPa; the disadvantage of this method is that the production of welded pipe is separated from the heat treatment process , the process is complicated, the production rate is low, and the manufacturing cost is increased

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