Easy-welding low-carbon bainitic steel and manufacturing method thereof

A carbon bainite steel, easy to weld technology, applied in the direction of temperature control, metal rolling, etc., can solve the problems of insufficient low temperature toughness, inability to suppress local embrittlement of M-A island, low ratio of boron to nitrogen, etc., to achieve production The effect of simple process
CN101787489BInactive Publication Date: 2012-07-25YANSHAN UNIV
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Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Patents(China)
Current Assignee / Owner
YANSHAN UNIV
Publication Date
2012-07-25
Estimated Expiration
Not applicable Β· inactive patent

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Abstract

The invention discloses an easy-welding low-carbon bainitic steel and a manufacturing method thereof, belonging to the technical field of microalloy steel. The steel comprises the chemical components by weight percent: 0.02-0.08% of C, 1.20-1.80% of Mn, 0.10-0.50% of Si, less than or equal to 0.010% of S, less than or equal to 0.015% of P, 0.10-0.30% of Mo, 0.020-0.050% of Nb, 0.03-0.10% of V, 0.005-0.030% of Ti, 0.0050-0.010% of N, 0.0005-0.0020% of B, less than or equal to 0.035% of Al and balance of Fe and inevitable impurities. The proportion between the boron content and the nitrogen content in the steel simultaneously meets the conditions that 3N-10B is more than or equal to 0.005 and less than or equal to 0.015, and Ti+V+10B is more than or equal to 8.525N. The production process of smelting by an electric furnace or a converter, external refining, continuous casting and controlled rolling and cooling is adopted. The invention has the advantages that the yield strength of the steel is more than or equal to 550MPa, the tensile strength is more than or equal to 670MPa, the elongation is more than or equal to 20%, and the charpy impact energy under -40 DEG C is more than or equal to 200J; the charpy impact energy under -40 DEG C in a near weld zone is more than or equal to 100J when the weld heat input is 20-100Kj / cm; and the production process is simple and convenient.
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Description

technical field

[0001] The invention belongs to the technical field of micro-alloy steel, and in particular provides an easy-to-weld low-carbon bainite steel and a manufacturing method. Background technique

[0002] When 5-30ppm boron is added to the steel and segregated at the austenite grain boundary in the form of solid solution boron, the Ξ³β†’Ξ± transformation can be delayed. Compared with delaying the transformation of bainite, the effect of boron on the formation of proeutectoid ferrite is much greater, which is beneficial to the formation of bainite. When boron in the steel interacts with alloying elements such as manganese, molybdenum, chromium, and copper, the effect of promoting bainite transformation is more significant. In a wide range of cooling rates, the continuous cooling transformation of austenite will produce A large number or even all bainite structures. In addition, the joint effect of trace amounts of boron and niobium can significantly inhibit the recry...

Claims

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