阅读说明：本技术 一种激光选区熔化低活化铁素体/马氏体钢的组织调控方法 (Structure regulation and control method for selective laser melting of low-activation ferrite/martensite steel ) 是由 杨胶溪 杨磊 吴文亮 于 2020-04-29 设计创作，主要内容包括：一种激光选区熔化低活化铁素体/马氏体钢的组织调控方法属于激光增材制造领域。低活化铁素体/马氏体钢的含量按重量(wt％)：0.09-0.15C,0.05-0.09Si,0.5-0.9Mn,8.7-9.5Cr,0.15-0.22Ta,0.3-0.5V,1.7-2.3W,0.01-0.03Mo,0.01-0.03Cu,0.02-0.05N,0.02-0.04Al,余量Fe。本发明是采用层间重熔的方式并通过控制工艺参数、扫描策略和温度梯度对低活化铁素体/马氏体钢的组织组成进行调控。最终获得了组织稳定、致密度高、力学性能良好的低活化铁素体/马氏体钢。(A tissue regulation and control method for selective laser melting of low-activation ferrite/martensite steel belongs to the field of laser additive manufacturing. The content of the low-activation ferritic/martensitic steel is in weight percent (wt%): 0.09-0.15C, 0.05-0.09Si, 0.5-0.9Mn, 8.7-9.5Cr, 0.15-0.22Ta, 0.3-0.5V, 1.7-2.3W,0.01-0.03Mo, 0.01-0.03Cu, 0.02-0.05N, 0.02-0.04Al and the balance Fe. The invention adopts an interlayer remelting mode and regulates and controls the structure composition of the low-activation ferrite/martensite steel by controlling process parameters, a scanning strategy and a temperature gradient. Finally, the low-activation ferrite/martensite steel with stable structure, high density and good mechanical property is obtained.)

1. A selective laser melting low-activation ferrite/martensite steel is characterized in that: the low-activation ferrite/martensite steel comprises the following components in percentage by weight: 0.09-0.15C, 0.05-0.15Si, 0.5-1.3Mn, 8.7-11.5Cr, 0.15-0.22Ta, 0.3-0.9V, 1.7-3.2W,0.01-0.13Mo, 0.01-0.12Cu, 0.02-0.05N, 0.02-0.06Al and the balance of Fe; the average particle size of the prepared powder is 300-400 meshes.

2. A method of producing a laser selective melting low activation ferritic/martensitic steel as claimed in claim 1 wherein: the technological parameter regulation and control range of selective laser melting of the low-activation ferrite/martensite steel is that the laser power is 200-600W, the scanning speed is 600-2500 mm/s, the inter-layer remelting n is 1-3, the spot diameter is 80-100 mu m, the scanning interval is 50-120 mu m, the powder spreading thickness is 20-80 mu m, and the oxygen content in the cabin is 50-400 ppm; the preset temperature of the substrate is 80-120 ℃, and the supporting area ratio is 50-80%.

3. The method for regulating the structure of the low-activation ferrite/martensite steel through selective laser melting according to claim 1, wherein the structure of the low-activation ferrite/martensite steel is regulated through an interlayer remelting mode, and the method comprises the following specific steps: when the interlayer remelting n is 1, the structure consists of 44-72% of martensite and 28-56% of ferrite, and the density is 93.2-98.76%; when the interlayer remelting n is 2, the structure consists of 52 to 84 percent of martensite and 16 to 48 percent of ferrite, and the density is between 92.72 to 99.83 percent; when the interlayer remelting n is 3, the structure consists of 57-76% of martensite and 24-43% of ferrite, and the density is 93.2-99.2%.

4. A method of producing a laser selective melting low activation ferritic/martensitic steel as claimed in claim 1 wherein: and adjusting the preset temperature of the substrate to control the temperature gradient.

5. A method of producing a laser selective melting low activation ferritic/martensitic steel as claimed in claim 1 wherein: the heat conduction rate is controlled by changing the supporting area ratio.

Technical Field

The invention relates to the field of low-activation ferrite/martensite steel preparation, in particular to a structure regulation and control method for selective laser melting of low-activation ferrite/martensite steel.

Background

The nuclear fusion energy has a series of advantages of large released energy, abundant raw material reserves, low exploitation cost, high use safety and the like, is considered as the first choice of future clean energy by countries in the world, and has performed a great deal of research on the use of nuclear fusion energy.

The low-activation ferrite/martensite steel is a structural material with lower thermal expansion coefficient, high thermal conductivity, excellent swelling resistance and radiation brittleness resistance, and is widely considered as the first structural material of future fusion reactor cladding. In order to better adapt to the service environment of a fusion reactor cladding and prolong the service life of the fusion reactor cladding, the element content of low-activation ferrite/martensite steel is usually adjusted to obtain materials with different characteristics, and then the structure of the low-activation ferrite/martensite steel is regulated and controlled by combining different preparation modes and process parameters to obtain a stable-working fusion reactor cladding structure material.

The selective laser melting (S L M) technology is used as a rapid and precise metal material forming process, the thermal energy generated by a laser beam is utilized to act on metal powder, so that the metal powder is rapidly melted and rapidly solidified and formed, and parts with high precision and high complexity can be manufactured.

Disclosure of Invention

The invention provides a structure regulation method for selective laser melting of low-activation ferrite/martensite steel. The self-researched component proportion is adopted, and the low-activation ferrite/martensite steel with good sphericity and uniform components is prepared by a hot inert gas atomization method.

The invention regulates and controls the quality and the structure of the low-activation ferrite/martensite steel by adjusting laser parameters, remelting among layers and designing thermal gradient, and finally obtains the low-activation ferrite/martensite steel with high density and excellent mechanical property.

The technical scheme for realizing the invention is a tissue regulation and control method for melting low-activation ferrite/martensite steel by laser selective area, which is characterized by comprising the following steps:

(1) preparing a low-activation ferrite/martensite steel raw material according to the element component proportion, wherein the content of each element is as follows by weight (wt%): 0.09-0.15C, 0.05-0.15Si, 0.5-1.3Mn, 8.7-11.5Cr, 0.15-0.22Ta, 0.3-0.9V, 1.7-3.2W,0.01-0.13Mo, 0.01-0.12Cu, 0.02-0.05N, 0.02-0.06Al and the balance Fe. The method comprises the steps of firstly vacuumizing a magnesium oxide crucible and filling argon for protection by adopting a hot inert gas atomization method, then smelting the magnesium oxide crucible until the temperature of an alloy solution is 1450-1750 ℃, then pouring the magnesium oxide crucible into a tundish to start atomization, wherein an atomization medium is argon, the atomization pressure is 2.0-8.0 MPa, and then sieving powder, so that the low-activation ferrite/martensite steel powder with good sphericity and uniform components is finally prepared, and the average particle size is 300-400 meshes.

(2) And performing three-dimensional modeling on the formed part by using three-dimensional software, and adding support, slicing and repairing treatment to the formed part by adopting Magics software after the model is established. The slice thickness is 20-80 μm. The supporting area ratio is 50-80%. The supporting area ratio is changed to 50-80%, and the heat conduction rate is controlled.

(3) Laser parameters and laser scanning strategies are set according to a material system, wherein the laser power is 200-600W, the scanning speed is 600-2500 mm/s, the interlayer remelting n is 1-3, the spot diameter is 80-100 micrometers, the scanning interval is 50-120 micrometers, the powder spreading thickness is 20-80 micrometers, each layer of scanning direction rotates 0-90 degrees, each part adopts a fixed angle value until printing is completed, in order to prevent the deformation of the part caused by uneven thermal stress, the scanning direction of each layer is α degrees clockwise, namely after the first layer is completed, the scanning direction of the second layer rotates α degrees, and the like until printing is completed, the α value range is 0- α -90, if the part is not easy to deform, the rotation angle can not be changed, and in order to make the thermal stress more uniform, the value can be arbitrarily set in the value range.

(4) Preparation of a molding cabin: before the selective laser melting equipment is used for working, a forming cabin is cleaned up by using a dust collector, a scraper is adjusted until a thin layer of metal powder is spread on a substrate, then a cabin door is closed, vacuum pumping is carried out, inert gas is filled into the forming cabin to keep the oxygen content in the cabin at 50-400ppm, meanwhile, the substrate is preheated to a certain temperature (80-120 ℃), and a gas circulation system in the cabin is started. Adjusting the preset temperature of the substrate to 80-120 ℃, and controlling the temperature gradient.

(5) Selective laser melting and forming: and the selective laser melting equipment scans and forms layer by layer according to the preset laser parameters and scanning strategies, and scans the laser twice at the nth layer and the layer which is multiple of n, wherein n is 1-3, until the last layer is scanned by the laser, and the printing of the shape of the sample which is designed in advance is finished.

(6) And cutting the formed low-activation ferrite/martensite steel sample from the substrate, and regulating and controlling the structure composition of the S L M formed low-activation ferrite/martensite steel through SEM, TEM and XRD detection data feedback.

The invention has the advantages that: the method invents the low-activation ferrite/martensite steel with specific components, and the structure composition of the low-activation ferrite/martensite steel is regulated and controlled through material preparation process parameters, interlayer remelting and thermal gradient design, so that a low-activation ferrite/martensite steel product with high quality and excellent mechanical property is finally obtained. The metallurgical bonding quality of the low-activation ferrite/martensite steel can be effectively improved by utilizing an interlayer remelting mode, the cooling speed in the forming process is reduced by changing the temperature gradient, and the generation of uneven structure and thermal stress caused by too high cooling speed is effectively reduced.

Drawings

FIG. 1 is an SEM image of S L M low-activation ferrite/martensite steel in example 1

FIG. 2 is TEM image of S L M low-activation ferrite/martensite steel in example 1

FIG. 3 is an SEM image of S L M low-activation ferrite/martensite steel in example 2

FIG. 4 is TEM image of S L M low-activation ferrite/martensite steel in example 2

FIG. 5 is an SEM image of S L M low-activation ferrite/martensite steel in example 3

FIG. 6 is TEM image of S L M low-activation ferrite/martensite steel in example 3

FIG. 7 is a graph showing tensile properties of S L M low-activation ferrite/martensite steel in examples 1, 2, and 3

Detailed Description