Ultrahigh-strength seamless steel tube with excellent weldability and manufacturing method thereof

Abstract

The invention discloses an ultrahigh-strength seamless steel tube with excellent weldability. The ultrahigh-strength seamless steel tube comprises the following chemical elements of, by mass, 0.14% to0.18% of C, 0.1% to 0.5% of Si, 1.0% to 1.4% of Mn, 0.3% to 0.7% of Cr, 0.3% to 0.7% of Mo, 0.2% to 0.6% of W, 0.03% to 0.07% of V, 0.01% to 0.05% of Nb, 0.01% to 0.03% of Ti, 0.001% to 0.002% of B,at least one of 0.1% to 0.5% of Cu and 0.1% to 0.5% of Ni and the balance Fe and other inevitable impurities. In addition, the invention further discloses a manufacturing method of the ultrahigh-strength seamless steel tube with the excellent weldability. The ultrahigh-strength seamless steel tube is high in strength, good in toughness, excellent in welding performance and very suitable for high-strength engineering structures.

Description

technical field [0001] The invention relates to a seamless steel pipe and a manufacturing method thereof, in particular to an ultra-high-strength seamless steel pipe and a manufacturing method thereof. Background technique [0002] In today's engineering machinery and steel structure construction fields, in order to bear higher loads, reduce the self-weight of the structure, and ensure the safety of the structure, people put forward higher requirements for structural pipe materials. For steel structural components subject to high loads, the self-weight of the structure is an important factor in cost savings. Reducing the self-weight of the structure not only saves materials, but also helps to improve the bearing capacity of the structure. [0003] For the fine-grained structural steel treated by quenching + tempering process, in order to reduce the possibility of brittle fracture, it is very important to control the content of P and S in the steel and improve the high purit...

AI Technical Summary

Problems solved by technology

[0004] Achieving high toughness and weldability at the same time is the difficulty of continuous high-strengthening of seamless steel pipes. However, in the prior art, either high strength and high toughness can be achieved without weldability at the same time, and it cannot be applied to the field of engineering structures that require welding. Either with high toughness and weldability, high strength becomes a bottleneck, making high-strength and weight-reducing in the field of engineering structures difficult

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