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Rotary austenite toughening-based low-temperature steel and method for preparing same

A low-temperature steel and austenite technology, applied in the field of low-temperature steel rolling and heat treatment process, can solve the problems of low product qualification rate and unstable heat treatment process.

Inactive Publication Date: 2010-06-02
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, Taiyuan Iron and Steel Co., Ltd. began to develop 9Ni steel in the late 1990s, and passed the national appraisal in 2007, and has now begun to supply; Anshan Iron and Steel has also developed 9Ni steel, and passed the certification in 2008; etc. have also actively carried out relevant research work, but there are generally problems such as low product qualification rate and unstable heat treatment process.

Method used

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  • Rotary austenite toughening-based low-temperature steel and method for preparing same
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  • Rotary austenite toughening-based low-temperature steel and method for preparing same

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preparation example Construction

[0035] The invention relates to a method for preparing a low-temperature steel based on rotary austenite toughening, the process comprising:

[0036] The mass percentage of the chemical composition of steel is selected as C: 0.02% ~ 0.04%, Si: 0.05% ~ 0.15%, Mn: 0.5% ~ 0.8%, Mo: 0.07 ~ 0.1%, Ni: 8.5 ~ 9.5%, P: ≤0.01%, S: ≤0.005%, the balance is Fe and unavoidable impurities; steelmaking is carried out by smelting in a vacuum induction furnace, slowly cooled to room temperature after pouring, and sent to a heating furnace. The heating temperature is 1200 ~ 1220 ℃, after 1 hour of heat preservation, it is taken out for rolling. The rolling adopts two-stage controlled rolling, and a total of 9 passes, the first 4 passes are rough rolling, and the last 5 passes are finish rolling. Rough rolling is rolled in the austenite complete recrystallization zone, the starting rolling temperature is 1150°C, and the finishing rolling temperature is controlled at 980°C; the finish rolling is r...

Embodiment 1

[0038] The chemical composition of the selected steel is: C 0.036%, Si 0.10%, Mn0.70%, Ni 9.02%, Mo 0.096%, P 0.0068%, S 0.005%, and the balance is Fe and unavoidable impurities. The steel is smelted in a vacuum induction furnace. After pouring, it is slowly cooled to room temperature and sent to the heating furnace. The heating temperature is 1200 ~ 1220 ℃, after 1 hour of heat preservation, it is taken out for rolling. The rolling adopts two-stage controlled rolling, and a total of 9 passes, the first 4 passes are rough rolling, and the last 5 passes are finish rolling. Rough rolling is rolled in the austenite complete recrystallization zone, the starting rolling temperature is 1150°C, and the finishing rolling temperature is controlled at 980°C; the finish rolling is rolling in the austenite non-recrystallizing zone, the starting rolling temperature is 900°C, and the finishing rolling temperature is 900°C. Control at 800°C, control the cooling rate and final cooling tempera...

Embodiment 2

[0041] The selection of raw materials, steelmaking, rolling and testing steps are the same as those in Example 1. The difference from Example 1 is that the heat treatment process adopts a double quenching process, and the solution quenching process is 800 ° C for 1 hour, water cooling; two-phase zone quenching The process is 650°C for 1h, water cooling, and the tempering process is 570°C for 1h, water cooling.

[0042] Such as figure 2 , Figure 8 Shown: After testing, when the above double quenching process is adopted: the yield strength is 645MPa, the tensile strength is 700MPa, the elongation after fracture is 25%, the impact energy at -196°C is 177J, and the structure is lath martensite and ferrite. body and 10.15% swivel austenite.

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Abstract

The invention discloses rotary austenite toughening-based low-temperature steel and a method for preparing the same. The low-temperature steel is refined from C, Si, Mn, Mo and Ni which are taken as main chemical components. The method for preparing the low-temperature steel of the invention comprises the following steps: firstly, selecting raw materials, smelting the raw materials with a vacuum induction furnace, pouring a smelting product, slowly cooling the product until temperature reaches the room temperature, transferring the product to a heating furnace for heating and heat preservation for 1 hour, and taking the product out for rolling, wherein the rolling is controlled through two stages of a recrystallization type and a non-recrystallization type for 9 times; and after the rolling, controlling a cooling speed and a final cooling temperature, finally rolling the product into a 15 mm thick steel plate and then performing quenching and tempering heat treatment or dual-quenching heat treatment. The low-temperature steel prepared by the method comprises rotary austenite with different contents and different distributions, so the products with different strengths and low-temperature toughness can be obtained; and the low-temperature steel is 550-710 MPa and 680-750 MPa in yield strength and tensile strength respectively, is 150-220 J in transverse impact energy under the experiment condition of -196 DEG C, and can meet the performance requirements required by LNG building.

Description

technical field [0001] The invention relates to a rolling and heat treatment process of low-temperature steel for LNG based on rotary austenite toughening. Background technique [0002] Natural gas is a high-quality energy source, which has the advantages of high combustion calorific value and less pollution. With the continuous improvement of environmental protection requirements, people pay more and more attention to it, and it is widely used in power generation, automobile fuel, residents' life and industry. Natural gas generally needs to be liquefied, and the storage and transportation of liquefied natural gas (LNG) has incomparable advantages over other transportation methods: First, it can reduce the risk of pipeline construction and make ocean-going natural gas trade possible. An effective method of recovery; secondly, the cost of storage and transportation is low, and the cost of ground transportation of LNG per unit weight is only 1 / 6 to 1 / 7 of the cost of pipeline...

Claims

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Application Information

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IPC IPC(8): C22C38/12C21C5/56C21D1/18B21B37/74B21B37/56
Inventor 唐荻蔡庆伍武会宾杨跃辉张坤
Owner UNIV OF SCI & TECH BEIJING
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