890MPa-level high-strength steel, steel pipe and manufacturing method of steel pipe

Abstract

The invention discloses 890MPa-level high-strength steel. The 890MPa-level high-strength steel is prepared from the chemical elements including, by mass, 0.12-0.18% of C, 0.1-0.4% of Si, 0.8-1.4% of Mn, 0.5-0.9% of Cr, 0.20-0.60% of Mo, 0.01-0.08% of W, 0.50-1.30% of Ni, 0.01-0.06% of Nb, 0.03-0.12% of V, 0.01-0.05% of Al and 0.0005-0.005% of Ca, and the relational expression that 5<Ni/(C*Mo)<=50 is applicable. The invention further discloses a steel pipe which is made from the 890MPa-level high-strength steel in the scheme. The invention further discloses a manufacturing method of the steel pipe. The manufacturing method includes the steps that the steel is made and cast into a round blank; the round blank is heated; high-pressure water is used for removing scale; pipe rolling is performed; quenching-and-tempering heat treatment is performed; high-pressure water is used for removing scale; hot straightening is performed.

Description

technical field [0001] The invention relates to an alloy steel material and a manufacturing method thereof, in particular to a high-strength alloy steel material and a manufacturing method thereof. Background technique [0002] Today's construction machinery and steel structural parts are developing in the direction of large load-bearing and lightweight. The direction of lightweight is to increase the strength of the material, which can not only reduce the self-weight of the structure, save materials, but also help to improve the overall bearing capacity of the structure. However, for steel structural parts that bear high loads, in order to improve the anti-longitudinal instability ability of steel pipes, while ensuring high strength, they also need to have sufficient thickness. For example, the wall thickness of such steel structures should reach more than 16mm . However, the product performance of large-diameter thick-walled high-strength steel pipes often fluctuates gre...

AI Technical Summary

Problems solved by technology

In the high-strength steel disclosed in this Chinese patent document, W element is added, which can effectively improve the strength of the steel material, making the tensile strength of the steel material > 980MPa, and while increasing the strength, compared with other alloys Elements (such as Mo elements), the extent to which W reduces the weldability of steel is relatively low

However, due to the addition of a certain amount of W, on the one hand, it increases the difficulty of steelmaking and production, and on the other hand, the steel material after water quenching is easy to bend, and it is difficult to straighten even after tempering

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