390 MPa-grade polar hull structural steel with low-temperature toughness and preparation method of 390 MPa-grade polar hull structural steel

A low-temperature toughness, structural steel technology, applied in the field of microalloyed steel, can solve the problems of inability to meet polar ambient temperature operating conditions and high production costs, and achieve the effects of cost reduction, low-temperature toughness improvement, and simple production process

Active Publication Date: 2020-05-15
CENT IRON & STEEL RES INST
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Problems solved by technology

[0005] In view of the above analysis, the embodiment of the present invention aims to provide a 390MPa polar hull structural steel with low temperature toughness and its preparation method to solve the problem that the existing steel types cannot meet the use conditions of the polar environment temperature and the production cost is relatively high. question

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  • 390 MPa-grade polar hull structural steel with low-temperature toughness and preparation method of 390 MPa-grade polar hull structural steel
  • 390 MPa-grade polar hull structural steel with low-temperature toughness and preparation method of 390 MPa-grade polar hull structural steel
  • 390 MPa-grade polar hull structural steel with low-temperature toughness and preparation method of 390 MPa-grade polar hull structural steel

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Embodiment 1

[0035] This embodiment provides a method for preparing a 390MPa grade polar hull structural steel with low temperature toughness, comprising the following steps:

[0036] Step 1. After the molten iron is stirred and desulfurized by KR, the S content is guaranteed to be ≤0.005%, and the desulfurization time is ≤25min;

[0037] Step 2, adding high-quality scrap steel, using a converter for smelting, using Al in the ladle for deep deoxidation, and adding ferroniobium after deoxidation;

[0038] Step 3. In the LF refining stage, white slag is produced first, desulfurization and target composition adjustment are performed, and then titanium wire and calcium wire are fed in sequence. After the alloying is completed, the ladle is hoisted to the continuous casting platform;

[0039] Step 4. The continuous casting process adopts the whole process of protective pouring to ensure that the superheat of the molten steel is 10-30°C, the casting speed is controlled at 0.6-1.5m / min, and the s...

Embodiment 2

[0053] This embodiment provides a 390MPa polar hull structural steel with low temperature toughness, the chemical composition of the steel plate is C 0.08-0.12%, Si 0.10-0.20%, Mn 1.0-2.0%, S≤0.005% , P≤0.005%, Als 0.02~0.03%, Ti 0.01~0.02%, N≤0.0040%, Nb 0.015~0.030%, and the rest is Fe.

[0054] Compared with the existing technology, the 390MPa grade polar hull structural steel with low temperature toughness provided by the application does not add precious metal elements such as Ni, Cr, Mo, V and other elements to the components, which greatly saves production costs; through the rolling process The relatively fine ferrite structure is obtained, which greatly improves the toughness of the polar hull structural steel.

[0055] Exemplarily, the chemical composition of steel is C 0.08%, Si 0.1%, Mn 1.5%, S 0.004%, P0.005%, Als 0.02%, Ti: 0.015%, N 0.0030%, Nb: 0.015%, and the rest are Fe.

[0056] Exemplarily, the chemical composition of the steel is C 0.10%, Si 0.2%, Mn 1.8%...

Embodiment 3

[0067] This embodiment provides a 390MPa class polar hull structural steel with low temperature toughness. The chemical composition is C0.08%, Si 0.1%, Mn 1.5%, S 0.004%, P 0.005%, Als 0.02%, Ti: 0.015% , N0.0030%, Nb: 0.015%, and the rest is Fe.

[0068] Converter smelting is adopted, the thickness of the rolled steel plate is 40mm, the thickness of the continuous casting slab used is 360mm, the continuous casting slab is heated to 1130°C, the first stage undergoes three passes of longitudinal rolling, the final rolling temperature is 1000°C, and the cumulative deformation is 55 %, the thickness of the intermediate billet is 162mm; the temperature of the second-stage rolling is 820°C, after four passes of rolling, the final rolling temperature is 770°C, and the final rolling deformation is not less than 20%; immediately after rolling, water cooling is adopted, and the cooling rate is 10.5°C / s. The mechanical properties are shown in Table 1, and the temperature impact energy ...

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Abstract

The invention relates to 390 MPa-grade polar hull structural steel with low-temperature toughness and a preparation method of the 390 MPa-grade polar hull structural steel, and belongs to the technical field of microalloyed steel. The steel and the method are used for solving the problems that an existing steel type cannot meet the polar environment temperature use condition and the production cost is high. The method comprises the following steps that 1, molten iron pretreatment is carried out; 2, high-quality scrap steel is added, a converter is adopted for smelting, Al is adopted in a steelladle for deep deoxidation, and ferrocolumbium is added after deoxidation; 3, alloying treatment is carried out; 4, whole-process protection pouring is adopted in the continuous casting process, thesuperheat degree of molten steel is guaranteed to range from 10 DEG C to 30 DEG C, the casting speed is controlled to range from 0.6 m/min to 1.5 m/min, and the strength of secondary cooling water isadjusted so that the temperature of the molten steel can range from 920 DEG C to 970 DEG C; and 5, controlled rolling and controlled cooling are carried out, and the polar hull structural steel is prepared. According to the hull structural steel prepared through the method, the yield strength is larger than or equal to 390 MPa, the impact energy at the quarter position of -100 DEG C is larger thanor equal to 200 J, the impact fracture fiber rate is larger than or equal to 80%, and the hull structural steel can be used for building ships serving in polar regions.

Description

technical field [0001] The invention relates to the technical field of micro-alloy steel, in particular to a 390MPa polar hull structural steel with low temperature toughness and a preparation method thereof. Background technique [0002] Polar oil and gas resources are very rich, and the Arctic waterway is extremely important for my country to participate in global economic activities. However, Arctic resource exploration, development and navigation activities are facing high-risk challenges brought about by extremely harsh geological and climatic conditions, insufficient port facilities and rescue capabilities. [0003] The arctic winter is long and cold, and the lowest winter temperature in most areas can drop to -70°C, and most of the sea is covered with ice. The harsh environment of the Arctic puts forward strict technical safety requirements for equipment such as polar ships and oil drilling platforms. Therefore, the development of relevant materials is of great signi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/04B22D11/16C21C7/00C21C7/064C21D8/02C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14
CPCB22D11/16C21C7/0006C21C7/0056C21C7/064C21D8/0205C21D2211/002C21D2211/005C21D2211/009C22C33/04C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14Y02P10/20
Inventor 师仲然罗小兵柴锋柴希阳王天琪陈雪慧王瑞珍杨才福
Owner CENT IRON & STEEL RES INST
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