Method for reducing Laves phase in nickel-based high-temperature alloy steel ingot

A technology of nickel-based superalloy and superalloy steel, which is applied in the field of metallurgical technology, can solve the problems of difficult homogenization treatment, low diffusion rate and high temperature, and achieves the advantages of reducing the difficulty of homogenization treatment, reducing smelting temperature and reducing the amount of precipitation. Effect

Active Publication Date: 2018-12-18
CHONGQING MATERIALS RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] However, the above method, especially the homogenization heat treatment to eliminate the Laves phase in the alloy, requires high temperature and long time. In a...

Method used

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  • Method for reducing Laves phase in nickel-based high-temperature alloy steel ingot
  • Method for reducing Laves phase in nickel-based high-temperature alloy steel ingot
  • Method for reducing Laves phase in nickel-based high-temperature alloy steel ingot

Examples

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Embodiment 1

[0028] Take 50Kg of the master alloy, carry out vacuum induction melting, and cast to obtain steel ingots. Take metallographic samples for microstructure observation and analysis, and then the master alloy is smelted by electroslag, and the weight percentage of CaF is about 5-7kg. 2 :CaO:Al 2 o 3 : MgO=60:15:20:5 electroslag material, crystallizer diameter is The melting current is 3±1kA, the voltage is 45±5V, and the feeding current is 1-2kA / s. Then carry out homogenization annealing at 1140°C×24h; finally, heat the ingot at 1080±15°C for 120min and start forging, start forging temperature ≥ 1080°C, final forging temperature ≥ 980°C, total forging ratio ≥ 4, then measure its mechanical properties.

[0029] see figure 1 , figure 1 (a) and (b) respectively represent the scanning electron microscope pictures of the Laves phase in the steel ingot structure of Example 1 and the elemental composition of the Laves phase. It can be seen that a large amount of Nb and Mo element...

Embodiment 2

[0031] Take 50Kg of master alloy, add vanadium-iron master alloy, make the weight percentage of vanadium element be 0.2% of master alloy weight, carry out vacuum induction melting, cast, take metallographic sample and carry out microstructure observation and analysis, and other steps are the same as the embodiment 1. Determination of its mechanical properties.

Embodiment 3

[0033] Take 50Kg of master alloy, add vanadium-iron master alloy, make the weight percentage of vanadium element be 0.5% of master alloy weight, carry out vacuum induction melting, cast, take metallographic sample and carry out microstructure observation and analysis, and other steps are the same as the embodiment 1. Determination of its mechanical properties.

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Abstract

The invention relates to a method for reducing a Laves phase in a nickel-based high-temperature alloy steel ingot. The method comprises the following steps that firstly, the nickel-based high-temperature alloy serves as a mother alloy; secondly, the mother alloy is taken out, and vacuum induction smelting is carried out, after total melting, refining is carried out, at the refining tail period, the vacuum degree is larger than or equal to 3 Pa, a valve is closed, Ar is inflated to 7 to 9 kPa, a ferrovanadium intermediate alloy is added, sufficient stirring and vibrating are carried out, afterfive minutes, the temperature is adjusted to 1470 to 1500 DEG C, slow continuous casting is carried out, discharging is carried out, and the steel ingot is obtained; thirdly, electroslag smelting is carried out, wherein electroslag with the mass percent of CaF2:CaO:Al2O3:MgO being 60:15:20:5 is used; fourthly, homogenizing annealing is 1140 DEG C*24h. The precipitation proportion of the Laves phase in the solidification process of the steel ingot obtained in the method can be obviously reduced, the steel ingot microstructure uniformity can be improved, the steel ingot subsequent homogenizationtreatment difficulty is reduced, and the mechanical property of the nickel-based high-temperature alloy is ensured.

Description

technical field [0001] The invention relates to a metallurgical process, in particular to a method for reducing Laves phase in nickel-based superalloy steel ingots. Background technique [0002] The molten steel is poured into the mold through the ladle and solidified to form a steel ingot. After the molten steel is smelted, it must be cast into an ingot or billet of a certain shape before it can be processed. The quality of steel ingots has a very important impact on subsequent production processes such as forging, hot rolling, and machining. High-quality steel ingots are an important basis for the production of alloy parts and components. [0003] Nickel-based superalloys are based on nickel element (Ni), and the Ni content is usually greater than 50%. GH4169, as a typical representative, came from the imitation of Inconel 718 alloy in my country in the 1960s. In the following decades, a lot of research work was carried out in China, which made the quality of domestic G...

Claims

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Application Information

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IPC IPC(8): C22C19/05C22C1/03C22F1/10
CPCC22C1/023C22C1/03C22C19/055C22F1/10
Inventor 莫燕刘海定王东哲吴畏刘应龙万红
Owner CHONGQING MATERIALS RES INST
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