CN-117701895-B - Ultrapure smelting method of DZ125 directional superalloy return material

Abstract

The embodiment of the invention discloses an ultrapure smelting method of a DZ125 directional superalloy return material. The method carries out rapid degassing reaction on the molten liquid drops formed by high-energy beam spot bombardment at a gas-liquid interface, the total content of oxygen and nitrogen in the obtained cast ingot is not more than 10ppm, the ultralow content control of impurity elements is realized, a cooling bed refining step is not needed, a cast ingot lifting system is operated to carry out continuous smelting, the ultrapure smelting efficiency of a high-temperature alloy return material is greatly improved, the problem that the depth removing effect of the impurity elements such as oxygen and nitrogen cannot be achieved by the traditional single-link vacuum induction remelting means is solved, large-scale industrialized ultrapure smelting can be realized, the same-level recycling of the directional high-temperature alloy return material is facilitated, and the waste of strategic metal resources is avoided.

Inventors

• XUE JIANING
• HUANG DANLAN
• WU YAJING
• XU MINGZHOU
• SHI FENG
• LI ZHONGYANG
• YANG FAN
• ZHAO BIN
• LI JIAJIE

Assignees

• 北京北冶功能材料有限公司

Dates

Publication Date

20260508

Application Date

20231220

Claims (5)

1. 1. A method of ultrapure smelting of a DZ125 oriented superalloy return, comprising the steps of: s1, carrying out vacuum induction remelting on a DZ125 directional superalloy return material to obtain a raw material rod with a proper size for electron beam melting; S2, placing the raw material rod for electron beam melting in a feeding system of electron beam melting equipment, fixing a bottom ingot on an ingot lifting system, adjusting the bottom ingot to the bottom of a water-cooled copper crucible, and starting the electron beam melting equipment for preheating and vacuumizing; S3, after the vacuum degree of the smelting chamber and the electron gun chamber meets the requirement, opening the electron gun, adjusting the smelting power and the beam spot size of the electron beam, smelting, bombarding the surface of the raw material rod by using the high-energy beam spot, forming molten liquid drops after the raw material is melted, rapidly carrying out degassing reaction under the environment with high vacuum degree and large overheat degree, dripping the molten liquid drops into the water-cooled copper crucible, simultaneously operating the ingot lifting system, slowly pulling out the ingot rapidly solidified through the water-cooled copper crucible at a certain smelting speed, continuously smelting until the raw material rod is completely melted, and gradually reducing the smelting power to zero; s4, after the furnace body is cooled, taking out the ingot, and cutting off an impurity enrichment region at the top to obtain an oriented alloy return material electron beam ingot with ultra-low content control of impurity elements, wherein the total content of oxygen and nitrogen in the oriented alloy return material electron beam ingot is not more than 10 ppm; In the step S2, the inner diameter D1=50-300 mm of the water-cooled copper crucible, in the step S3, the electron beam melting power P=25-65 kW, the melting speed V=25-200 cm 3 /min of the cast ingot, and D1, P and V meet the following relational expression that 0 is less than or equal to 0.24, D1+0.16, V-P is less than or equal to 10; In the step S1, the diameter D2=20-250 mm of the raw material rod for electron beam melting, and D1 and D2 satisfy the following relation that D1 is less than or equal to 1.2 and D2 is less than or equal to 1.6.
2. 2. The ultrapure melting method of a DZ125 oriented superalloy return as in claim 1, wherein in step S3, the electron beam spot diameter ranges from 40% to 80% of the water cooled copper crucible inner diameter.
3. 3. The ultrapure melting method of a DZ125 directional superalloy return according to claim 1, wherein in step S2, the electron beam melting equipment is turned on for preheating and evacuating, the melting chamber vacuum reaches the requirement of less than 2 x 10 -2 Pa, and after the electron gun chamber vacuum reaches the requirement of less than 8 x 10 -3 Pa, the electron gun is turned on for starting melting.
4. 4. The ultrapure melting method of a DZ125 oriented superalloy return as in claim 1, wherein in step S2, the bottom ingot secured to the ingot lifting system is machined from the same grade oriented superalloy.
5. 5. The ultrapure melting method of a DZ125 oriented superalloy return as in claim 1, wherein in step S4, the thickness of the electron beam melting ingot top impurity enrichment zone is cut off to 5-20 mm.

Description

Ultrapure smelting method of DZ125 directional superalloy return material Technical Field The embodiment of the invention relates to the technical field of alloy smelting, in particular to an ultrapure smelting method of a DZ125 directional superalloy return material. Background The directional solidification casting superalloy has good medium and high temperature comprehensive performance and excellent fatigue resistance, has good casting performance, is mainly used for manufacturing gas turbine engine rotor blades and guide blades for aerospace, and has larger and larger demand for directional superalloy along with the rapid development of aerospace technology. The directional superalloy generally contains Ni, co, cr, W, mo, ta, hf and other strategic metals, but because of the complex design of a pouring system, the blade has a certain rejection rate, so that the material utilization rate of alloy parts is generally only 10-20%, and a large amount of return materials are generated. As the high-temperature remelting casting process is carried out in the production process of casting high-temperature alloy parts, the alloy melt reacts with a crucible, a shell and the like to form nonmetallic impurities, and the nonmetallic impurities mainly exist in the returned materials in the form of oxygen-nitrogen compound, so that the oxygen and nitrogen contents in the alloy are greatly increased, the high-temperature plasticity and the fatigue service life of the alloy are obviously reduced, and the alloy must be subjected to strict purification process treatment to be considered for recycling. At present, a return material purifying and recycling technology meeting the same level of use requirements is not formed at home, so that the domestic directional high-temperature alloy return material is not formally applied, and serious waste of strategic metal resources is caused. The DZ125 directional casting superalloy contains element hafnium, and has strong interaction with impurity elements in the smelting and casting process, so that the content of gas impurities such as oxygen, nitrogen and the like in the returned material is high, the occurrence state of the impurity elements can be changed, and the deep removal effect cannot be achieved by adopting the traditional single-unit vacuum induction remelting process. The electron beam smelting technology is mainly applied to smelting refractory metals and alloys with high vacuum degree, high energy density and other characteristics, and the purification rate is obviously higher than that of other vacuum smelting equipment. At present, the technology for purifying the multi-element alloy by adopting an electron beam smelting technology mainly comprises cold bed furnace refining, the problem of main element burning loss exists in the electron beam refining alloy, the refining temperature and the refining time are improved at one time, the aim of high-energy beam spot irradiation melt is to generate large superheat degree to promote impurity volatilization, the main element volatilization in return materials is also serious, the smelting efficiency is lower, and the recycling cost of the return materials is obviously improved. Therefore, how to efficiently and rapidly realize the purification of the directional solidification casting superalloy return material, so that the impurity elements such as oxygen, nitrogen and the like in the return material alloy can be controlled to be ultra-low in content, and the purification is still a challenge for the same-level reuse of the directional alloy return material. Disclosure of Invention In order to solve the technical problems that the content of oxygen, nitrogen and other gas impurities in the return material of the directional casting superalloy is high, the occurrence state of impurity elements is changed, the deep removal effect cannot be achieved by adopting the traditional single vacuum induction remelting process, the smelting efficiency of refining by adopting an electron beam cooling bed is low, the recycling cost of the return material is obviously improved and the like, the invention provides an ultrapure smelting method of the return material of the DZ125 directional superalloy. The invention adopts electron beam drop melting technology, and carries out rapid degassing reaction on molten liquid drops formed by high-energy beam spot bombardment at a gas-liquid interface, so that the total content of oxygen and nitrogen in the obtained cast ingot is not more than 10ppm, the ultra-low content control of impurity elements is realized, a cold bed refining step is not needed, and an ingot lifting system is operated to carry out continuous melting, so that the ultra-pure melting efficiency of the directional high-temperature alloy return material is greatly improved. The ultra-pure smelting method of the DZ125 directional superalloy return material has the advantages of solving the problem that the traditional single va