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A kind of ultra-high-strength high-toughness low-carbon martensitic cast steel and its preparation method

A low-carbon martensite, ultra-high-strength technology, applied in the field of low-carbon alloy cast steel heat treatment process, can solve the contradiction between strength, toughness, weldability, etc., and achieve good energy saving effect, low notch sensitivity, and energy saving. Effect

Active Publication Date: 2017-03-08
XI AN JIAOTONG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the above three cast steels generally have contradictions between strength, toughness and weldability.

Method used

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  • A kind of ultra-high-strength high-toughness low-carbon martensitic cast steel and its preparation method
  • A kind of ultra-high-strength high-toughness low-carbon martensitic cast steel and its preparation method
  • A kind of ultra-high-strength high-toughness low-carbon martensitic cast steel and its preparation method

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preparation example Construction

[0026] The invention discloses a method for preparing ultra-high-strength, high-toughness, low-carbon martensitic cast steel. The manufacturing process steps are:

[0027] (1) First put the raw material steel, ferrochrome, ferrosilicon, and pig iron into the intermediate frequency induction furnace in a certain proportion, and then heat up until the raw material is melted into molten steel;

[0028] (2) Add a certain proportion of ferromolybdenum, ferrovanadium, electrolytic nickel, pure copper and ferromanganese to the molten steel in order to make the content of alloy elements the same as that of the above-mentioned ultra-high-strength, high-toughness, low-carbon martensitic cast steel. The liquid is kept warm until its composition is homogenized;

[0029] (3) Raise the temperature to 1600°C to 1650°C, add 0.10% to 0.20% of the weight of the molten steel for deoxidation of aluminum, feed silicon-calcium wire into the molten steel before it is released from the furnace, and t...

Embodiment 1

[0040] The chemical composition by weight percentage is: C: 0.19%, Cr: 1.0%, Mn: 1.5%, Si: 0.8%, Mo: 0.2%, V: 0.1%, Ni: 0.2%, Cu: 0.3%, P ≤0.02%, S: ≤0.02%, Ca: 0.08%, and the balance is smelted and cast with iron raw materials, and then the obtained castings are heated to 940°C for 4 hours, then quickly released from the furnace for quenching, and then tempered at 220°C 4 hours will do.

[0041] The main metallographic structure of the obtained material is a low-carbon tempered martensite structure, which has excellent strength, ductility and toughness, and good wear performance and welding performance. The yield strength is 1195MPa, the tensile strength is 1425MPa, the elongation is 14%, the reduction of area is 42%, the low temperature impact energy Akv (-40°C) is 36J, the Brinell hardness is 400HBW, and the fracture toughness is K 1c 110MPa·m 1 / 2 , The low-temperature ductile-brittle transition temperature (FATT) is -60°C.

Embodiment 2

[0043] The chemical composition by weight percentage is: C: 0.17%, Cr: 1.1%, Mn: 1.2%, Si: 1.8%, Mo: 0.2%, V: 0.1%, Ni: 0.4%, Cu: 0.2%, P ≤0.02%, S: ≤0.02%, Ca: 0.09%, and the balance is iron raw materials for smelting and casting, and then the obtained castings are heated to 920°C for 3 hours, then quickly quenched, and then tempered at 200°C 4 hours will do.

[0044] see figure 1 The metallographic structure diagram of the ultra-high-strength, high-toughness, low-carbon martensitic cast steel after casting. It can be seen from the figure that the structure after casting is pearlite and ferrite; see figure 2, is the metallographic structure diagram of the ultra-high-strength, high-toughness, low-carbon martensitic cast steel. It can be seen from the figure that its structure is all lath martensite; see image 3 , is the scanning electron microscope image of the sample fracture of the super-high strength and high toughness martensitic cast steel at -56°C for the Charpy impa...

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Abstract

The invention discloses ultra-high strength and high tenacity low-carbon martensite cast steel. The ultra-high strength and high tenacity low-carbon martensite cast steel comprises the chemical components including, by mass, 0.10%-0.25% of C, 0.5%-1.5% of Cr, 0.5%-2.5% of Mn, 0.5%-2% of Si, 0.1%-0.5% of Mo, 0.1%-0.5% of V, 0.1%-0.4% of Ni, 0.1%-0.3% of Cu, 0.05%-0.1% of Ca, not larger than 0.02% of P, not larger than 0.02% of S and the balance Fe. A preparation method of the ultra-high strength and high tenacity low-carbon martensite cast steel comprises the steps that 1, firstly, raw steel, ferrochromium, silicon iron and pig iron are heated proportionally till the raw materials are molten to form molten steel, ferromolybdenum, ferrovanadium, electrolytic nickel, pure copper and ferromanganese are sequentially added to the molten steel, the temperature is kept before the added components are homogenized, and then liquidsteel is obtained; 2, aluminum is added to the heated liquidsteel for deoxidation, and then a silicon-calcium wire is added to the liquidsteel for casting; 3, the temperature of castings obtained after casting is performed is kept, then water quenching treatment is performed on the castings, and then tempering treatment is performed to obtain the ultra-high strength and high tenacity low-carbon martensite cast steel. The ultra-high strength and high tenacity low-carbon martensite cast steel is excellent in comprehensive mechanical performance, and the preparation method is easy to implement, saves energy and is environmentally friendly and the method is suitable for industrial mass production.

Description

technical field [0001] The invention belongs to the technical field of heat treatment technology of low-carbon alloy cast steel, and in particular relates to an ultra-high-strength, high-toughness low-carbon martensitic cast steel and a preparation method thereof. Background technique [0002] Steel has always been an important pillar of national economic construction and social development. With the rapid development of my country's economy, the demand for steel has increased sharply year after year, and the output has also increased sharply. From 1996, my country's crude steel output exceeded 100 million tons, ranking first in the world. By 2012, my country's crude steel output was 716 million tons, accounting for 46.3% of global steel production. In a few years, my country's steel output has doubled. It has provided a strong boost for my country's highway, railway transportation, urban construction, and national defense construction. However, it is unavoidable that the i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/58C22C38/46
Inventor 柳永宁江涛孙俊杰刘宏基
Owner XI AN JIAOTONG UNIV