Low-cost and high-performance ultrahigh-strength steel for engineering machinery and manufacturing method thereof

A technology for construction machinery and ultra-high-strength steel, which is applied to ultra-high-strength steel and its manufacturing method, which can solve the problem of insufficient yield strength and tensile strength of steel plates, high manufacturing costs, and failure to meet the ultra-high strength of 1500MPa tensile strength. Steel plate requirements and other issues, to achieve the effect of excellent weldability and fatigue impact load resistance

CN104046908AActive Publication Date: 2014-09-17BAOSTEEL ZHANJIANG IRON & STEEL CO LTD +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-09-17

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Abstract

The invention relates to low-cost and high-performance ultrahigh-strength steel for engineering machinery and a manufacturing method thereof. The low-cost and high-performance ultrahigh-strength steel comprises the following components in percentage by weight: 0.18-0.22 percent of C, less than or equal to 0.10 percent of Si, 1.30-0.60 percent of Mn, less than or equal to 0.013 percent of P, less than or equal to 0.0030 percent of S, 0.30-0.60 percent of Cr, 0.10-0.30 percent of Mo, 0.0010-0.0020 percent of B, 0.008-0.018 percent of Ti, 0.010-0.030 percent of Nb, 0.030-0.070 percent of Al, less than or equal to 0.0050 percent of N, less than or equal to 0.0030 percent of O, 0.001-0.004 percent of Mg and the balance of Fe and inevitable impurities. According to the low-cost and high-performance ultrahigh-strength steel, ultrahigh strength of a steel plate is obtained by adopting combination of controlled rolling and online DQST and on the basis of little addition of precious Mo alloy; meanwhile, the low-temperature toughness, the weldability and the fatigue impact load resistance of the steel plate are also excellent; the problems of mutual contradiction among the strength, the low-temperature toughness and the delayed crack resistance of an ultrahigh-strength steel plate as well as surface (subsurface) layer quenching are successfully solved.
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Description

technical field

[0001] The present invention relates to ultra-high-strength steel and its manufacturing method, in particular to a low-cost, high-performance ultra-high-strength steel for engineering machinery and its manufacturing method. 40°C Charpy transverse impact energy (single value) ≥ 27J, elongation at break δ 5 ≥10% and -20°C Charpy impact energy in welding heat affected zone ≥27J (average value) / 21J (single value) has excellent fatigue impact resistance. Background technique

[0002] As we all know, low-carbon (high-strength) low-alloy steel is one of the most important engineering structural materials, widely used in oil and gas pipelines, offshore platforms, shipbuilding, bridge structures, boiler containers, building structures, automobile industry, railway transportation and engineering machinery manufacturing Among them; the performance of low carbon (high strength) low alloy steel depends on its chemical composition and manufacturing process, among which st...

Examples

Embodiment Construction

[0078] The present invention will be further described below in conjunction with the embodiments and accompanying drawings.

[0079] Table 1 shows the composition of the steel example of the present invention, and the balance is Fe and unavoidable impurities. Table 2 to Table 4 respectively show the manufacturing process of the steel examples of the present invention. Table 5 is the performance of the steel of the embodiment of the present invention.

[0080] Depend on figure 1 It can be seen from the microstructure of the steel of the embodiment of the present invention that the microstructure of the steel plate is very fine and uniform, the microstructure type is tempered martensite, and the size of the martensite crystal group (packet) is small and uniform and between blocks The orientation difference is large (inferred from the strong deformation streamline), the average grain size is below 20 μm (in the longitudinal direction), and the ultra-high-strength steel plate wi...