A method for reducing the laves phase in nickel-based superalloy steel ingots

A nickel-based high-temperature alloy and high-temperature alloy steel technology, applied in the field of metallurgical technology, can solve the problems of low diffusion rate, high temperature, and difficult homogenization treatment

Active Publication Date: 2020-07-07
CHONGQING MATERIALS RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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 addition, the diffusion rate of Nb and Mo elements in the GH4169 alloy is small, and the microscopic segregation is serious, so the homogenization treatment is very difficult.

Method used

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  • A method for reducing the laves phase in nickel-based superalloy steel ingots
  • A method for reducing the laves phase in nickel-based superalloy steel ingots
  • A method for reducing the laves phase in nickel-based superalloy steel ingots

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Experimental program
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Effect test

Embodiment 1

[0028] Take 50Kg of master alloy, carry out vacuum induction melting, and cast to obtain a steel ingot. Take metallographic samples for microstructure observation and analysis, and then the master alloy is electroslag smelted, using a mass percentage of about 5-7kg CaF 2 : CaO: Al 2 O 3 : MgO=60:15:20:5 electroslag slag, the crystallizer diameter is Melting current 3±1kA, voltage 45±5V, feeding current 1-2kA / s. Then, 1140℃×24h homogenization annealing was carried out; finally, the ingot was kept at 1080±15℃ for 120min before forging, the forging temperature was ≥1080℃, the final forging temperature was ≥980℃, and the total forging ratio was ≥4, and its mechanical properties were measured.

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

Embodiment 2

[0031] Get 50Kg of master alloy, add ferrovanadium master alloy, make vanadium element weight percentage content be 0.2% of the master alloy weight, carry out vacuum induction melting, cast, take metallographic sample to carry out microstructure observation and analysis, the remaining steps are the same as the embodiment 1. Determine its mechanical properties.

Embodiment 3

[0033] Get 50Kg of master alloy, add ferrovanadium master alloy, make the weight percentage of vanadium element be 0.5% of the master alloy weight, carry out vacuum induction melting, cast, take metallographic sample and carry out microstructure observation and analysis, the remaining steps are the same as the embodiment 1. Determine 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 injected into the mold through the ladle and solidified to form a steel ingot. After the molten steel is smelted, it must be cast into ingots or billets of a certain shape before processing. The quality of the ingot has a very important impact on the subsequent production processes such as forging, hot rolling, and machining. High-quality steel ingots are an important basis for the production of alloy parts. [0003] Nickel-based superalloys use nickel element (Ni) as the matrix, and the Ni content is usually greater than 50%. As a typical representative, GH4169 originated from the imitation of Inconel 718 alloy in my country in the 1960s. In the following decades, a lot of research work has been carried out in China, which has continuously improved the quality...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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