CN114603157A - Martensite die steel and preparation method thereof - Google Patents
Martensite die steel and preparation method thereof Download PDFInfo
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- CN114603157A CN114603157A CN202210123345.0A CN202210123345A CN114603157A CN 114603157 A CN114603157 A CN 114603157A CN 202210123345 A CN202210123345 A CN 202210123345A CN 114603157 A CN114603157 A CN 114603157A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 119
- 239000010959 steel Substances 0.000 title claims abstract description 119
- 229910000734 martensite Inorganic materials 0.000 title claims abstract description 32
- 238000002360 preparation method Methods 0.000 title abstract description 27
- 238000004519 manufacturing process Methods 0.000 claims abstract description 232
- 239000000654 additive Substances 0.000 claims abstract description 228
- 230000000996 additive effect Effects 0.000 claims abstract description 228
- 238000003466 welding Methods 0.000 claims abstract description 66
- 238000000034 method Methods 0.000 claims abstract description 51
- 239000000758 substrate Substances 0.000 claims abstract description 38
- 238000010891 electric arc Methods 0.000 claims abstract description 16
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 10
- 230000000717 retained effect Effects 0.000 claims abstract description 7
- 239000002994 raw material Substances 0.000 claims abstract description 6
- 239000010410 layer Substances 0.000 claims description 349
- 239000011229 interlayer Substances 0.000 claims description 22
- 230000001681 protective effect Effects 0.000 claims description 21
- 238000000465 moulding Methods 0.000 claims description 19
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 6
- 229910052748 manganese Inorganic materials 0.000 claims description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 6
- 229910052720 vanadium Inorganic materials 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 239000000956 alloy Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 230000000977 initiatory effect Effects 0.000 claims description 2
- 239000002184 metal Substances 0.000 abstract description 4
- 229910052751 metal Inorganic materials 0.000 abstract description 4
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/20—Direct sintering or melting
- B22F10/28—Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y10/00—Processes of additive manufacturing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y70/00—Materials specially adapted for additive manufacturing
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2207/00—Aspects of the compositions, gradients
- B22F2207/01—Composition gradients
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Abstract
The application relates to the technical field of metal additive manufacturing, in particular to martensite die steel and a preparation method thereof, wherein the method comprises the following steps: obtaining a steel substrate and a welding wire; taking the welding wire as a raw material, and performing electric arc fuse wire additive manufacturing on the steel substrate layer by using a starting layer, an intermediate layer and an ending layer to obtain die steel; wherein the arc heat input of the starting layer is larger than that of the intermediate layer, and the arc heat input of the ending layer is larger than that of the intermediate layer; the unit forming volume of the starting layer is larger than that of the middle layer, and the unit forming volume of the finishing layer is smaller than that of the middle layer; the die steel includes: the steel substrate and N additive manufacturing layers covering the steel substrate are sequentially arranged from bottom to top; the metallographic structure of the die steel comprises martensite and retained austenite; by the method, the input heat and the unit forming volume of each layer are controlled, and the uniformity of the hot-working die steel structure is improved.
Description
Technical Field
The application relates to the technical field of metal additive manufacturing, in particular to martensite die steel and a preparation method thereof.
Background
The metal additive manufacturing technology is an efficient part manufacturing technology, can realize the integrated molding of a complex structure, simplifies the working procedure and greatly shortens the manufacturing period, compared with additive manufacturing technologies such as laser powder laying and laser powder feeding, the CMT electric arc additive manufacturing technology has the advantages of low raw material cost, large material adding amount in unit time and great market prospect, and the CMT electric arc additive manufacturing technology is widely concerned particularly in the aspect of mold forming of complex structures.
The H13 steel hot work die steel has higher hardenability and toughness, excellent anti-cracking ability, small heat treatment deformation and good wear resistance, and the manufacturing process of the H13 steel hot work die steel comprises the following steps: smelting, rolling, machining and heat treatment, wherein the H13 steel die formed by the additive manufacturing technology can be used for processing a complex structure cooling water channel in the die, but the existing hot work die steel metal additive manufacturing technology has the problem that the structural uniformity of the formed hot work die steel is poor because a metallographic structure has a large amount of irregular ferrite structures and residual austenite structures doped in part of martensitic steel after forming, so how to obtain the hot work die steel with good structural uniformity by additive manufacturing is a technical problem to be solved urgently at present.
Disclosure of Invention
The application provides martensite die steel and a preparation method thereof, and aims to solve the technical problem that hot work die steel obtained by additive manufacturing in the prior art is poor in structural uniformity.
In a first aspect, the present application provides a method of making a martensitic die steel, the method comprising:
obtaining a steel substrate and a welding wire;
taking the welding wire as a raw material, and performing electric arc fuse wire additive manufacturing on the steel substrate layer by using a starting layer, an intermediate layer and an ending layer to obtain die steel;
wherein the arc heat input of the starting layer is greater than the arc heat input of the intermediate layer, and the arc heat input of the ending layer is greater than the arc heat input of the intermediate layer;
the unit forming volume of the starting layer is larger than that of the intermediate layer, and the unit forming volume of the finishing layer is smaller than that of the intermediate layer.
Optionally, the preparing the initial layer includes:
taking any point on the surface of the steel substrate as an arc starting point for electric arc additive manufacturing, and carrying out electric arc fuse additive manufacturing on the steel substrate to obtain a first additive manufacturing layer;
raising the welding wire by a first section of height, and performing arc fuse additive manufacturing on the first additive manufacturing layer E, wherein the additive direction is consistent with the direction of the first additive manufacturing layer, so as to obtain a second additive manufacturing layer;
repeating the step of obtaining a second additive manufacturing layer to obtain an initial layer comprising three additive manufacturing layers;
the method of making the interlayer comprises:
raising the welding wire by a second section of height, and performing arc fuse additive manufacturing on the initial layer, wherein the additive direction is consistent with the direction of the second additive manufacturing layer, so as to obtain a fourth additive manufacturing layer;
repeating the step of obtaining a fourth additive manufacturing layer M-6 times to obtain an intermediate layer comprising N-6 additive manufacturing layers;
the method for preparing the finishing layer comprises the following steps:
raising the welding wire by a third section of height, and performing arc fuse additive manufacturing on the middle layer, wherein the additive direction is consistent with the direction of the fourth additive manufacturing layer, so as to obtain an N-2 additive manufacturing layer;
repeating the obtaining of the N-2 th additive manufacturing layer twice to obtain a finishing layer comprising three additive manufacturing layers, wherein N is the total number of additive manufacturing layers, and N is greater than 7 and is an integer; m is the total number of additive manufacturing times, M > 7 and is an integer.
Optionally, the wire feeding speed for preparing the initial layer is 5m/min to 7m/min, the welding speed is 0.10m/min to 0.20m/min, the arc voltage is 21.0V to 21.5V, the current is 150A to 155A, the lap joint rate is 36 percent to 43 percent, the inter-lane residence time is 50s to 60s, the inter-layer residence time is 200s to 400s, and the protective gas flow is 10L/min to 20L/min;
the heat input for preparing the initial layer is 15750J/m-33325J/m, and the molding volume per unit time is 0.1250m3/min～0.1795m3/min。
Optionally, the wire feeding speed for preparing the middle layer is 4-6 m/min, the welding speed is 0.15-0.25 m/min, the arc voltage is 20.0-21.0V, the current is 148-154A, the lap joint rate is 36-43%, the inter-lane residence time is 55-65 s, the interlayer residence time is 200-400 s, and the protective gas flow is 10-20L/min
The heat input for preparing the intermediate layer is 11840J/m-21560J/m, and the forming volume per unit time is 0.0988m3/min～0.1519m3/min。
Optionally, the wire feeding speed for preparing the end layer is 3 m/min-5 m/min, the welding speed is 0.15 m/min-0.25 m/min, the arc voltage is 21.0V-21.5V, the current is 150A-155A, the lap joint rate is 36% -43%, the inter-lane residence time is 50 s-60 s, the inter-layer residence time is 200 s-400 s, and the protective gas flow is 10L/min-20L/min;
the heat input for preparing the finishing layer is 12600J/m-22216.67J/m, and the molding volume per unit time is 0.0741m3/min～0.1266m3/min。
Optionally, the thickness of each additive manufacturing layer of the starting layer is 10mm to 20mm, the thickness of each additive manufacturing layer of the intermediate layer is 5mm to 15mm, and the thickness of each additive manufacturing layer of the finishing layer is 5mm to 10 mm.
Optionally, the height of the first section is 5mm to 15mm, the height of the second section is 5mm to 15mm, and the height of the third section is 5mm to 15 mm.
Optionally, the steel substrate and the welding wire both comprise the following chemical components: c: 0.32-0.45%, Si: 0.80% -1.20%, Mn: 0.20-0.50%, Cr: 4.75% -5.50%, Mo: 1.10% -1.75%, V: 0.80 to 1.20 percent of the total weight of the alloy, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, and the balance of Fe and inevitable impurities.
In a second aspect, the present application provides a martensitic die steel, the die steel including a steel substrate and N additive manufacturing layers covering the steel substrate, the N additive manufacturing layers being arranged in sequence from bottom to top, where N > 7 and is an integer;
the metallographic structure of the die steel comprises, in terms of volume fraction: the martensite is 90-97%, and the retained austenite is 3-10%.
Optionally, the Rockwell hardness of the die steel is more than or equal to 47HRC, and the tensile strength is more than or equal to 100 MPa.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:
according to the preparation method of the martensite die steel, the arc fuse additive manufacturing is carried out layer by layer through the initial layer, the intermediate layer and the finishing layer, the difference between the heat input quantity and the forming volume in unit time of preparing the initial layer, the intermediate layer and the finishing layer is limited, the initial layer adapts to the heat conduction and constraint action of a steel substrate in the preparation process, the finishing layer adapts to the heat conduction and heat convection action of an atmosphere environment in the preparation process, and the main structure of the die steel formed by the intermediate layer is matched, so that the additive manufacturing layers of different levels can be obtained, the structure of each additive manufacturing layer is uniform, and the uniform degree of the structure of the hot-working die steel obtained by additive manufacturing is improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.
FIG. 1 is a schematic flow chart of a method for preparing a martensite die steel provided in the embodiments of the present application;
FIG. 2 is a macroscopic view of a top of a martensite die steel provided in an embodiment of the present application;
FIG. 3 is a schematic view of the microstructure of a martensite die steel provided in the embodiments of the present application;
fig. 4 is a schematic diagram illustrating a phase detection result of a microstructure of a martensitic die steel provided in an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In one embodiment of the present application, as shown in fig. 1, there is provided a method of manufacturing a martensitic die steel, the method comprising:
s1, obtaining a steel substrate and a welding wire;
s2, taking the welding wire as a raw material, and performing electric arc fuse additive manufacturing on the steel substrate layer by using a starting layer, an intermediate layer and an ending layer to obtain die steel;
wherein the arc heat input of the starting layer is greater than the arc heat input of the intermediate layer, and the arc heat input of the ending layer is greater than the arc heat input of the intermediate layer;
the unit forming volume of the starting layer is larger than that of the intermediate layer, and the unit forming volume of the finishing layer is smaller than that of the intermediate layer.
As an alternative embodiment, the method of preparing the initiation layer comprises:
taking any point on the surface of the steel substrate as an arc starting point for electric arc additive manufacturing, and performing electric arc fuse additive manufacturing on the steel substrate to obtain a first additive manufacturing layer;
raising the welding wire by a first height, and performing arc fuse additive manufacturing on the first additive manufacturing layer, wherein the additive direction is consistent with the direction of the first additive manufacturing layer, so as to obtain a second additive manufacturing layer;
repeating the step of obtaining a second additive manufacturing layer to obtain an initial layer comprising three additive manufacturing layers;
the method of making the interlayer comprises:
raising the welding wire by a second section of height, and performing arc fuse additive manufacturing on the initial layer, wherein the additive manufacturing direction is consistent with the direction of the second additive manufacturing layer, so as to obtain a fourth additive manufacturing layer;
repeating the step of obtaining the fourth additive manufacturing layer for M-6 times to obtain an intermediate layer comprising N-6 additive manufacturing layers;
the method for preparing the finishing layer comprises the following steps:
raising the welding wire by a third section of height, and performing arc fuse additive manufacturing on the middle layer, wherein the additive direction is consistent with the direction of the fourth additive manufacturing layer, so as to obtain an N-2 additive manufacturing layer;
repeating the obtaining of the N-2 th additive manufacturing layer twice to obtain a finishing layer comprising three additive manufacturing layers, wherein N is the total number of additive manufacturing layers, and N is greater than 7 and is an integer; m is the total number of additive manufacturing times, M > 7 and is an integer.
In the application, a mode of gradually lifting in each step is adopted, and then an initial layer comprising three additive manufacturing layers, a middle layer comprising N-6 additive manufacturing layers and a finishing layer comprising three additive manufacturing layers are sequentially constructed through limitation of additive manufacturing directions each time, so that the forming modes of different additive manufacturing layers are controlled, and the uniform structure of the obtained die steel is ensured.
As an optional embodiment, the wire feeding speed for preparing the initial layer is 5m/min to 7m/min, the welding speed is 0.10m/min to 0.20m/min, the arc voltage is 21.0V to 21.5V, the current is 150A to 155A, the lap joint rate is 36% to 43%, the inter-track residence time is 50s to 60s, the inter-layer residence time is 200s to 400s, and the protective gas flow is 10L/min to 20L/min;
the heat input for preparing the initial layer is 15750J/m-33325J/m, and the molding volume per unit time is 0.1250m3/min～0.1795m3/min。
In the application, the positive effect that the wire feeding speed for preparing the initial layer is 5 m/min-7 m/min is that good forming and good structure control are ensured within the wire feeding speed range; when the value range of the speed is too large, the wire feeding speed is too high, the molding area in unit time is too large, and stress cracking of an additive manufacturing layer is caused.
The welding speed for preparing the initial layer is 0.10 m/min-0.20 m/min, so that the forming structure of the additive manufacturing layer can be well controlled within the welding speed range; when the value range of the speed is too large or too small, the adverse effect is that the welding speed is too fast or too slow, the thickness of the additive manufacturing layer is not uniform, and the surface flatness is poor.
The positive effect that the arc voltage of the initial layer is 21.0-21.5V is ensured to be in the arc voltage range, the welding wire can be well formed, and the structure of the additive manufacturing layer is well controlled; when the value range of the voltage is too large, the adverse effect is that the voltage is too high, which indicates that the formability of the welding wire is deteriorated due to too high heat input, and the additive manufacturing layer has defects such as hole cracks.
The positive effect that the current for preparing the initial layer is 150-155A is that in the current range, the welding wire can be well formed, and the structure of the additive manufacturing layer is well controlled; when the value range of the current is too large, the adverse effect is that the current is too large, which indicates that the heat input is too high, the formability of the welding wire is deteriorated, and the additive manufacturing layer has defects of hole cracks and the like.
The positive effect that the lap joint rate of the prepared initial layer is 36-43% is to ensure that the additive manufacturing layer is well formed; when the value range of the overlapping ratio is too large or too small, the adverse effect is that the thickness of the additive manufacturing layer is not uniform and the surface flatness is poor.
The method has the advantages that the inter-channel residence time for preparing the initial layer is 50-60 s, and the deformation of the additive manufacturing layer caused by thermal stress can be avoided within the residence time range; when the value range of the time is too large, the time is too long, the temperature of a plurality of previous working procedures of additive manufacturing is too low, the cooling speed is too high, the additive manufacturing layer is deformed and cracked, when the value range of the time is too small, the retention time is too short, the heat dissipation is insufficient, the thermal stress is too large, and the additive manufacturing layer is deformed and cracked.
The positive effect that the interlayer residence time for preparing the initial layer is 200-400 s is that the thermal stress can be effectively avoided in the time range, so that the deformation of the additive manufacturing layer caused by the change of the thermal stress is avoided; when the value range of the time is too large, the time is too long, the temperature of a previous layer of working procedure of multiple additive manufacturing is too low, the cooling speed is too high, the additive manufacturing layer is deformed and cracked, when the value range of the time is too small, the retention time is too short, the heat dissipation is insufficient, the thermal stress is too large, and the additive manufacturing layer is deformed and cracked.
The positive effect that the flow of the protective gas for preparing the initial layer is 10L/min-20L/min is that in the flow range, the defects of holes, cracks and the like caused by oxidation of materials in the melting and solidifying process in the additive manufacturing process can be avoided; when the value range of the gas flow is too large, the gas flow is too fast, and the gas flow affects the melting and solidifying process of the material, and when the value range of the gas flow is too small, so that the additive manufacturing layer is oxidized in the melting and solidifying process of the material in the additive manufacturing process, and defects such as holes and cracks are caused.
As an optional embodiment, the wire feeding speed for preparing the middle layer is 4-6 m/min, the welding speed is 0.15-0.25 m/min, the arc voltage is 20.0-21.0V, the current is 148-154A, the lap joint rate is 36-43%, the inter-lane residence time is 55-65 s, the inter-layer residence time is 200-400 s, and the protective gas flow is 10-20L/min
The heat input amount for preparing the intermediate layer is 11840-21560J/m, and the molding volume per unit time is 0.0988-0.1519 m3/min。
In the application, the positive effect that the wire feeding speed for preparing the middle layer is 4-6 m/min is that in the wire feeding speed range, the additive manufacturing layer can be well formed, and the structure of the additive manufacturing layer is well controlled; when the value range of the speed is too large, the wire feeding speed is too high, the molding volume in unit time is too large, and stress cracking of an additive manufacturing layer is caused.
The welding speed for preparing the middle layer is 0.15-0.25 m/min, so that the additive manufacturing layer can be well formed and the structure of the additive manufacturing layer can be well controlled within the welding speed range; when the value range of the speed is too large or too small, the adverse effect is that the welding speed is too fast or too slow, the thickness of the additive manufacturing layer is not uniform, and the surface flatness is poor.
The positive effect that the arc voltage for preparing the middle layer is 20.0-21.0V is to ensure that the additive manufacturing layer is well formed and the structure of the additive manufacturing layer is well controlled within the voltage range; when the value range of the voltage is too large, the adverse effect is that the arc voltage is too high, which indicates that the formability of the additive manufacturing layer is poor due to too high heat input, and the additive manufacturing layer has defects such as hole cracks.
The positive effect of the current for preparing the middle layer being 148-154A is that the welding wire can be well formed and the structure of the additive manufacturing layer is well controlled within the current range; when the value range of the current is too large, the adverse effect is that the current is too large, which indicates that the heat input is too high, the formability of the welding wire is deteriorated, and the additive manufacturing layer has defects of hole cracks and the like.
The positive effect that the lapping rate of the prepared middle layer is 36-43% is to ensure that the additive manufacturing layer is well formed; when the value range of the overlapping ratio is too large or too small, the adverse effect is that the thickness of the additive manufacturing layer is not uniform and the surface flatness is poor.
The positive effect that the inter-channel residence time for preparing the middle layer is 55-65 s is that in the residence time range, the deformation of the additive manufacturing layer caused by thermal stress can be avoided; when the value range of the time is too large, the time is too long, the temperature of a plurality of previous working procedures of additive manufacturing is too low, the cooling speed is too high, the additive manufacturing layer deforms and cracks, when the value range of the time is too small, the retention time is too short, the heat dissipation is insufficient, the thermal stress is too large, and the additive manufacturing layer deforms and cracks.
The positive effect of 200-400 s of interlayer residence time for preparing the intermediate layer is that within the time range, thermal stress can be effectively avoided, and therefore deformation of an additive manufacturing layer caused by thermal stress change is avoided; when the value range of the time is too large, the time is too long, the temperature of a previous layer of working procedure of multiple additive manufacturing is too low, the cooling speed is too high, the additive manufacturing layer is deformed and cracked, when the value range of the time is too small, the retention time is too short, the heat dissipation is insufficient, the thermal stress is too large, and the additive manufacturing layer is deformed and cracked.
The flow of the protective gas for preparing the middle layer is 10L/mm-20L/min, and the positive effect is that in the flow range, the defects of holes, cracks and the like caused by oxidation of materials in the melting and solidifying process in the additive manufacturing process can be avoided; when the value range of the gas flow is too large, the adverse effect is that the gas flow is too fast, the gas flow affects the melting and solidifying process of the material, and when the value range of the gas flow is too small, the adverse effect is that the gas flow is too small, so that in the melting and solidifying process of the material in the additive manufacturing process, an additive manufacturing layer is oxidized, and defects such as holes and cracks are caused.
As an optional embodiment, the wire feeding speed of the preparation of the finishing layer is 3-5 m/min, the welding speed is 0.15-0.25 m/mm, the arc voltage is 21.0-21.5V, the current is 150-155A, the lap joint rate is 36-43%, the inter-lane residence time is 50-60 s, the inter-lane residence time is 200-400 s, and the protective gas flow is 10-20L/min;
the heat input amount for preparing the finishing layer is 12600-22216.67J/m, and the molding volume per unit time is 0.0741-0.1266 m3/min。
In the application, the positive effect that the wire feeding speed of the preparation finishing layer is 3-5 m/min is that the good formation and good organization control are ensured within the wire feeding speed range; when the value range of the speed is too large, the wire feeding speed is too high, the molding area in unit time is too large, and stress cracking of an additive manufacturing layer is caused.
The welding speed of the preparation finishing layer is 0.15-0.25 m/min, and the positive effect is that the forming structure of the additive manufacturing layer can be well controlled within the welding speed range; when the value range of the speed is too large or too small, the adverse effect is that the welding speed is too fast or too slow, the thickness of the additive manufacturing layer is not uniform, and the surface flatness is poor.
The positive effect that the arc voltage of the preparation finishing layer is 21.0-21.5V is to ensure that the welding wire can be well formed and the structure of the additive manufacturing layer can be well controlled within the arc voltage range; when the value range of the voltage is too large, the adverse effect is that the voltage is too high, which indicates that the formability of the welding wire is deteriorated due to too high heat input, and the additive manufacturing layer has defects such as hole cracks.
The current of the preparation finishing layer is 150-155A, and the positive effects that the welding wire can be well formed and the structure of the additive manufacturing layer is well controlled in the current range; when the value range of the current is too large, the adverse effect is that the current is too large, which indicates that the heat input is too high, the formability of the welding wire is deteriorated, and the additive manufacturing layer has defects of hole cracks and the like.
The positive effect that the lap joint rate of the preparation finishing layer is 36-43% is to ensure that the additive manufacturing layer is well formed; when the value range of the overlapping ratio is too large or too small, the adverse effect is that the thickness of the additive manufacturing layer is not uniform and the surface flatness is poor.
The method has the advantages that the inter-channel residence time of the preparation finishing layer is 50-60 s, and the deformation of the additive manufacturing layer caused by thermal stress can be avoided within the residence time range; when the value range of the time is too large, the time is too long, the temperature of a plurality of previous working procedures of additive manufacturing is too low, the cooling speed is too high, the additive manufacturing layer is deformed and cracked, when the value range of the time is too small, the retention time is too short, the heat dissipation is insufficient, the thermal stress is too large, and the additive manufacturing layer is deformed and cracked.
The positive effect of the interlayer residence time of the preparation finishing layer being 200-400 s is that the thermal stress can be effectively avoided in the time range, so that the deformation of the additive manufacturing layer caused by the change of the thermal stress is avoided; when the value range of the time is too large, the time is too long, the temperature of a previous process layer of a plurality of additive manufacturing layers is too low, the cooling speed is too high, the additive manufacturing layers deform and crack, when the value range of the time is too small, the retention time is too short, the heat dissipation is insufficient, the thermal stress is too large, and the additive manufacturing layers deform and crack.
The flow of the protective gas of the preparation finishing layer is 10-20L/min, and the positive effect is that in the flow range, the defects of holes, cracks and the like caused by oxidation of materials in the melting and solidifying process in the additive manufacturing process can be avoided; when the value range of the gas flow is too large, the adverse effect is that the gas flow is too fast, the gas flow affects the melting and solidifying process of the material, and when the value range of the gas flow is too small, the adverse effect is that the gas flow is too small, so that in the melting and solidifying process of the material in the additive manufacturing process, an additive manufacturing layer is oxidized, and defects such as holes and cracks are caused.
As an alternative embodiment, the thickness of each additive manufacturing layer of the starting layer is 10-20 mm, the thickness of each additive manufacturing layer of the intermediate layer is 5-15 mm, and the thickness of each additive manufacturing layer of the finishing layer is 5-10 mm.
As an optional embodiment, the height of the first section is 5-15 mm, the height of the second section is 5-15 mm, and the height of the third section is 5-15 mm.
In the application, the positive effect that the thickness of each additive manufacturing layer of the starting layer is 10-20 mm is to ensure that the additive manufacturing layer is well formed; when the value range of the thickness is too large, the adverse effect is that the thickness is too high, and the additive manufacturing layer is easy to generate defects such as holes and cracks.
The positive effect that the thickness of each additive manufacturing layer of the middle layer is 5-15 mm is to ensure that the additive manufacturing layers are well formed; when the value range of the thickness is too large, the thickness is too high, and the additive manufacturing layer is easy to generate defects such as holes and cracks.
The positive effect that the thickness of each additive manufacturing layer of the finishing layer is 5-10 mm is to ensure that the additive manufacturing layer is well formed and the control of the heat dissipation speed in the preparation stage is facilitated in the thickness range; when the value range of this thickness is too big, the adverse effect that will lead to is that thickness is too high, and vibration material disk layer will produce defects such as hole and crackle easily because of the heat dissipation is too fast and the deflection accumulation easily ftractures, and when the value range of this thickness is too little, the adverse effect that will lead to is vibration material disk layer thickness is too thin, will lead to the heat too concentrated, easily takes place to fuse and cross the phenomenon.
As an optional embodiment, the height of the first section is 5-15 mm, the height of the second section is 5-15 mm, and the height of the third section is 5-15 mm
In the application, the positive effect that the height of the first section is 5-15 mm is to ensure that the additive manufacturing layer is well formed; when the thickness is too large, the height is too high, and the additive manufacturing layer is prone to generating defects such as holes and cracks.
The positive effect that the height of the second section is 5-15 mm is to ensure that the additive manufacturing layer is well formed; when the value range of the thickness is too large, the height of the additive manufacturing layer is too high, and defects such as holes and cracks are easily generated on the additive manufacturing layer.
The positive effect that the height of the third section is 5-15 mm is to ensure that the additive manufacturing layer is well formed; when the thickness is too large, the height is too high, and the additive manufacturing layer is prone to generating defects such as holes and cracks.
As an alternative embodiment, the chemical compositions of the steel substrate and the welding wire comprise the following components in percentage by mass: c: 0.32-0.45%, Si: 0.80% -1.20%, Mn: 0.20-0.50%, Cr: 4.75-5.50%, Mo: 1.10% -1.75%, V: 0.80-1.20 percent of steel, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, and the balance of Fe and inevitable impurities, wherein the welding WIRE is made of TIG WIRE H13 type steel provided by Drahtwerk ELISENTAL, and the steel substrate is purchased from conventional manufacturers.
In one embodiment of the present application, as shown in fig. 2, there is provided a martensitic mold steel, the mold steel comprising a steel substrate and N additive manufacturing layers covering the steel substrate, the N additive manufacturing layers being arranged in order from bottom to top, wherein N > 7 and is an integer;
the die steel comprises a steel substrate and N additive manufacturing layers covering the steel substrate, wherein the N additive manufacturing layers are sequentially arranged from bottom to top, and N is an integer larger than 7;
the metallographic structure of the die steel comprises, in terms of volume fraction: the martensite accounts for 90-97%, and the retained austenite accounts for 3-10%.
In the application, the positive effects that the volume fraction of martensite is 90-97% are that the structure is uniform and the strength and toughness are good; when the volume fraction value range is too small, the adverse effect is that the content of martensite is too low, which indicates that the metallographic structure of the die steel after molding is not uniform, and the strength is low and the toughness is poor.
The positive effect that the retained austenite accounts for 3-10 percent is that the metallographic structure of the die steel is uniform and the strength and the toughness are good within the volume fraction range; when the volume fraction value range is too large, the adverse effect is that the content of the retained austenite is too high, which indicates that the formed die structure is not uniform, the strength is low and the toughness is poor.
As an alternative embodiment, the Rockwell hardness of the die steel is more than or equal to 47HRC, and the tensile strength is more than or equal to 100 MPa.
Example 1
A preparation method of martensite die steel comprises the following steps:
s1, obtaining a steel substrate and a welding wire;
s2, taking the welding wire as a raw material, and performing electric arc fuse additive manufacturing on the steel substrate layer by using a starting layer, an intermediate layer and an ending layer to obtain die steel;
wherein the arc heat input of the starting layer is larger than that of the intermediate layer, and the arc heat input of the ending layer is larger than that of the intermediate layer;
the unit forming volume of the initial layer is larger than that of the middle layer, and the unit forming volume of the finishing layer is smaller than that of the middle layer.
The method for preparing the initial layer comprises the following steps:
taking any point on the surface of the steel substrate as an arc starting point for electric arc additive manufacturing, and carrying out electric arc fuse additive manufacturing on the steel substrate to obtain a first additive manufacturing layer;
raising the welding wire by a first section of height, and performing arc fuse additive manufacturing on the first additive manufacturing layer, wherein the additive direction is consistent with the direction of the first additive manufacturing layer, so as to obtain a second additive manufacturing layer;
repeating the step of obtaining a second additive manufacturing layer to obtain an initial layer comprising three additive manufacturing layers;
the method of making the interlayer comprises:
raising the welding wire by the height of the second section, and performing arc fuse additive manufacturing on the initial layer, wherein the additive direction is consistent with the direction of the second additive manufacturing layer, so as to obtain a fourth additive manufacturing layer;
repeating the step of obtaining the fourth additive manufacturing layer for M-6 times to obtain an intermediate layer comprising N-6 additive manufacturing layers;
the method for preparing the finishing layer comprises the following steps:
raising the welding wire by the height of the third section, and performing arc fuse additive manufacturing on the middle layer, wherein the additive direction is consistent with the direction of the fourth additive manufacturing layer, so as to obtain an N-2 additive manufacturing layer;
repeating the obtaining of the N-2 th additive manufacturing layer twice to obtain the final layer comprising three additive manufacturing layers, wherein N is 10 and M is 10.
The wire feeding speed for preparing the initial layer is 6m/min, the welding speed is 0.15m/min, the arc voltage is 21V, the current is 153A, the lapping rate is 39%, the inter-channel residence time is 55s, the interlayer residence time is 300s, and the protective gas flow is 15L/min
Heat input for preparation of the starting layerThe amount is 21420J/m, and the molded volume per unit time is 0.1519m3/min。
The wire feeding speed for preparing the middle layer is 5m/min, the welding speed is 0.2m/min, the arc voltage is 21V, the current is 153A, the lapping rate is 39%, the inter-channel retention time is 60s, the inter-layer retention time is 300s, and the protective gas flow is 15L/min;
the heat input for preparing the intermediate layer was 16065J/m, and the molding volume per unit time was 0.125m3/min。
The wire feeding speed of the prepared layer is 4m/min, the welding speed is 0.22m/min, the arc voltage is 21V, the current is 153A, the lap joint rate is 39%, the inter-lane retention time is 60s, the inter-layer retention time is 300s, and the protective gas flow is 15L/min;
the heat input of the preparation-completed layer was 14604.55J/m, and the molded volume per unit time was 0.0995m3/min。
Each additive manufacturing layer of the starting layer has a thickness of 15mm, each additive manufacturing layer of the intermediate layer has a thickness of 10mm, and each additive manufacturing layer of the finishing layer has a thickness of 5 mm;
the height of the first section is 15mm, the height of the second section is 15mm, and the height of the third section is 10 mm.
The chemical compositions of the steel substrate and the welding wire comprise: c: 0.32-0.45%, Si: 0.80% -1.20%, Mn: 0.20-0.50%, Cr: 4.75% -5.50%, Mo: 1.10% -1.75%, V: 0.80 to 1.20 percent of the total weight of the alloy, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, and the balance of Fe and inevitable impurities.
The die steel comprises a steel substrate and 10 additive manufacturing layers covering the steel substrate, wherein the N additive manufacturing layers are sequentially arranged from bottom to top;
the metallographic structure of the die steel comprises, in volume fraction: the martensite accounts for 90-97%, and the retained austenite accounts for 3-10%.
Example 2
Example 2 is compared to example 1, with example 2 differing from example 1 in that:
the wire feeding speed of the preparation starting layer is 7m/min, the welding speed is 0.1m/min, the arc voltage is 21.5V, the current is 155A, the lap joint rate is 43 percent, the inter-track retention time is 60s, the interlayer retention time is 400s, and the protective gas flow is 10L/min;
the heat input for the preparation of the starting layer was 33325J/m and the molding volume per unit time was 0.1795m3/min。
The wire feeding speed for preparing the middle layer is 6m/min, the welding speed is 0.15m/min, the arc voltage is 21V, the current is 154A, the lapping rate is 43 percent, the inter-channel residence time is 65s, the interlayer residence time is 400s, and the protective gas flow is 10L/min;
the heat input for preparing the intermediate layer was 21560J/m, and the molding volume per unit time was 0.1519m3/min。
The wire feeding speed of the prepared layer is 5m/min, the welding speed is 0.15m/min, the arc voltage is 21.5V, the current is 155A, the lap joint rate is 43 percent, the inter-channel residence time is 60s, the interlayer residence time is 400s, and the protective gas flow is 10L/min;
the heat input of the preparation-completed layer was 22216.67J/m, and the molded volume per unit time was 0.1266m3/min。
The chemical compositions of the steel substrate and the welding wire comprise the following components in percentage by mass: c: 0.32-0.45%, Si: 0.80% -1.20%, Mn: 0.20-0.50%, Cr: 4.75% -5.50%, Mo: 1.10% -1.75%, V: 0.80 to 1.20 percent of the total weight of the alloy, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, and the balance of Fe and inevitable impurities.
Example 3
Comparing example 3 with example 1, example 3 differs from example 1 in that:
the wire feeding speed of the initial layer is 5m/min, the welding speed is 0.2m/min, the arc voltage is 21V, the current is 150A, the lap joint rate is 36%, the inter-lane residence time is 50s, the inter-layer residence time is 200s, and the protective gas flow is 20L/min;
the heat input for the preparation of the starting layer was 15750J/m, the molding volume per unit time was 0.1250m 3/min.
The wire feeding speed for preparing the middle layer is 4m/min, the welding speed is 0.25m/min, the arc voltage is 20V, the current is 148A, the lapping rate is 36%, the inter-channel retention time is 55s, the inter-layer retention time is 200s, and the protective gas flow is 20L/min;
the heat input for the preparation of the intermediate layer was 11840J/m, the molded volume per unit time was 0.0988m3/min。
The wire feeding speed of the prepared layer is 3m/min, the welding speed is 0.25m/min, the arc voltage is 21V, the current is 150A, the lap joint rate is 36%, the inter-lane retention time is 50s, the inter-layer retention time is 200s, and the protective gas flow is 20L/min;
the heat input of the preparation-finished layer was 12600J/m, and the molding volume per unit time was 0.0741m3/min。
The chemical compositions of the steel substrate and the welding wire comprise the following components in percentage by mass: c: 0.32-0.45%, Si: 0.80% -1.20%, Mn: 0.20-0.50%, Cr: 4.75% -5.50%, Mo: 1.10% -1.75%, V: 0.80 to 1.20 percent of the total weight of the alloy, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, and the balance of Fe and inevitable impurities.
Comparative example 1
Comparative example 1 and example 1 were compared, and comparative example 1 and example 1 were distinguished in that:
the arc fuse additive manufacturing is directly carried out without adopting the segmented arc fuse additive manufacturing for preparing the starting layer, the middle layer and the finishing layer.
Comparative example 2
Comparative example 2 is compared with example 1, and comparative example 2 differs from example 1 in that:
inputting heat: preparing a starting layer, preparing an intermediate layer, and preparing an ending layer; unit molding volume: preparation of the starting layer, preparation of the intermediate layer, and preparation of the finishing layer.
Comparative example 3
Comparative example 3 is compared with example 1, and comparative example 3 differs from example 1 in that:
the first through third additive manufacturing layers are prepared using the conditions for preparing the starting layer, and the fourth through tenth additive manufacturing layers are prepared using the conditions for preparing the intermediate layer.
Comparative example 4
Comparative example 4 is compared with example 1, and comparative example 4 differs from example 1 in that:
the first to third additive manufacturing layers are prepared using the conditions for preparing the intermediate layer, and the fourth to tenth additive manufacturing layers are prepared using the conditions for preparing the finish layer.
Related experiments: the die steels prepared in examples 1 to 5 and comparative examples 1 to 4 were collected, and the performance test was performed on each die steel, the results of which are shown in table 1.
Test methods of the related experiments: on the surface of the formed die steel
Test method for average rockwell hardness: on the die steel after molding, eight positions are randomly selected on the initial layer, the middle layer and the end layer, the Rockwell hardness corresponding to each position is respectively detected and averaged, and the result is shown in Table 1.
A method for testing tensile strength; the tensile strength in the corresponding direction was measured in 3 directions selected from the inside of the molded die steel, and the results are shown in table 1.
TABLE 1
Specific analysis of table 1:
the average Rockwell hardness is the average Rockwell hardness of each layer of the prepared die steel, when the difference of the average Rockwell hardness of each layer is not large, the more uniform the mechanical property of each layer is, the more uniform the tissue of each layer is also,
the tensile strength refers to the tensile properties of the prepared die steel in different directions, and when the differences of the tensile strength in the three directions are not large, the prepared die steel is uniform and good in mechanical property, and the overall structure of the die steel is uniform.
Analysis of examples 1-3 in Table 1:
(1) the method provided by the embodiment of the application can obtain the die steel which has the martensite content of more than 90% in the metallographic structure and does not contain irregular ferrite, and meanwhile, the die steel does not have defects such as crack holes and the like.
(2) The die steel provided by the embodiment of the application has good uniform structure formability, the Rockwell hardness of the die steel reaches over 47HRC, and the tensile strength reaches 1000 MPa.
Analysis of comparative examples 1 to 4 in Table 1:
without the method provided by the embodiment of the application, the obtained structure has irregular ferrite, uneven performance and poor formability, and the phenomena of macroscopic cracking, holes and the like even appear in comparative examples 1 and 2, so that the obtained structure becomes defective.
One or more technical solutions in the embodiments of the present application at least have the following technical effects or advantages:
(1) the method provided by the embodiment of the application can obtain the die steel which has the martensite content of more than 90% in the metallographic structure and does not contain irregular ferrite, and meanwhile, the die steel does not have defects such as crack holes and the like.
(2) The Rockwell hardness of the die steel provided by the embodiment of the application reaches above 47HRC, and the tensile strength reaches 1000 MPa.
(3) According to the method provided by the embodiment of the application, the whole automatic production of the die steel can be realized by integrating the process parameters of the electric arc fuse additive manufacturing on a production line and matching with machining and die manufacturing procedures, and the production period and the production cost are saved.
The drawings illustrate:
fig. 2 is a macroscopic schematic view of a top of a martensitic die steel provided in an embodiment of the present application, and as can be seen from fig. 2, the surface topography of the entire die steel is uniform, and the flatness is good, which indicates that the die steel is macroscopically uniform.
Fig. 3 is a schematic microstructure diagram of a martensitic die steel according to an embodiment of the present application, and as can be seen from fig. 3, the microstructure of the die steel has a large amount of martensite, and the martensite is uniformly distributed, which illustrates the structural uniformity of the die steel according to the present application.
Fig. 4 is a schematic diagram of a phase detection result of a microstructure of a martensitic die steel provided in an embodiment of the present application, and as can be seen from fig. 4, in the metallographic structure of the die steel, martensite contains a part of remaining austenite, but the remaining austenite is regularly distributed and has a uniform size, and irregular ferrite is not present, which indicates that the metallographic structure of the die steel is good in uniformity.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method of making a martensitic die steel, the method comprising:
obtaining a steel substrate and a welding wire;
taking the welding wire as a raw material, and performing electric arc fuse wire additive manufacturing on the steel substrate layer by using a starting layer, an intermediate layer and an ending layer to obtain die steel;
wherein the arc heat input of the starting layer is greater than the arc heat input of the intermediate layer, and the arc heat input of the ending layer is greater than the arc heat input of the intermediate layer;
the unit forming volume of the starting layer is larger than that of the intermediate layer, and the unit forming volume of the finishing layer is smaller than that of the intermediate layer.
2. The method of claim 1, wherein the method of preparing the initiation layer comprises:
taking any point on the surface of the steel substrate as an arc starting point for electric arc additive manufacturing, and carrying out electric arc fuse additive manufacturing on the steel substrate to obtain a first additive manufacturing layer;
raising the welding wire by a first height, and performing arc fuse additive manufacturing on the first additive manufacturing layer, wherein the additive direction is consistent with the direction of the first additive manufacturing layer, so as to obtain a second additive manufacturing layer;
repeating the step of obtaining a second additive manufacturing layer to obtain an initial layer comprising three additive manufacturing layers;
the method of making the interlayer comprises:
raising the welding wire by a second section of height, and performing arc fuse additive manufacturing on the initial layer, wherein the additive direction is consistent with the direction of the second additive manufacturing layer, so as to obtain a fourth additive manufacturing layer;
repeating the step of obtaining the fourth additive manufacturing layer for M-6 times to obtain an intermediate layer comprising N-6 additive manufacturing layers;
the method for preparing the finishing layer comprises the following steps:
raising the welding wire by a third section of height, and performing arc fuse additive manufacturing on the middle layer, wherein the additive direction is consistent with the direction of the fourth additive manufacturing layer, so as to obtain an N-2 additive manufacturing layer;
repeating the obtaining of the N-2 th additive manufacturing layer twice to obtain a finishing layer comprising three additive manufacturing layers, wherein N is the total number of additive manufacturing layers, and N is greater than 7 and is an integer; m is the total number of additive manufacturing times, M > 7 and is an integer.
3. The method according to claim 1 or 2, characterized in that the wire feeding speed for preparing the initial layer is 5m/min to 7m/min, the welding speed is 0.10m/min to 0.20m/min, the arc voltage is 21.0V to 21.5V, the current is 150A to 155A, the overlapping ratio is 36% to 43%, the inter-lane residence time is 50 to 60s, the inter-layer residence time is 200 to 400s, and the protective gas flow is 10L/min to 20L/min;
the heat input for preparing the initial layer is 15750J/m-33325J/m, and the molding volume per unit time is 0.1250m3/min～0.1795m3/min。
4. The method according to claim 1 or 2, wherein the wire feeding speed for preparing the intermediate layer is 4m/min to 6m/min, the welding speed is 0.15m/min to 0.25m/min, the arc voltage is 20.0V to 21.0V, the current is 148A to 154A, the overlapping ratio is 36% to 43%, the inter-lane residence time is 55s to 65s, the inter-lane residence time is 200s to 400s, and the protective gas flow is 10L/min to 20L/min;
the heat input for preparing the intermediate layer is 11840J/m-21560J/m, and the forming volume per unit time is 0.0988m3/min～0.1519m3/min。
5. The method according to claim 1 or 2, characterized in that the wire feeding speed for preparing the end layer is 3m/min to 5m/min, the welding speed is 0.15m/min to 0.25m/min, the arc voltage is 21.0V to 21.5V, the current is 150A to 155A, the lap joint ratio is 36% to 43%, the inter-lane residence time is 50s to 60s, the inter-lane residence time is 200s to 400s, and the protective gas flow is 10L/min to 20L/min;
the heat input for preparing the finishing layer is 12600J/m-22216.67J/m, and the molding volume per unit time is 0.0741m3/min～0.1266m3/min。
6. The method of claim 2, wherein each additive manufacturing layer of the starting layer has a thickness of 10mm to 20mm, each additive manufacturing layer of the intermediate layer has a thickness of 5mm to 15mm, and each additive manufacturing layer of the finishing layer has a thickness of 5mm to 10 mm.
7. The method of claim 1, wherein the first section has a height of 5mm to 15mm, the second section has a height of 5mm to 15mm, and the third section has a height of 5mm to 15 mm.
8. The method of claim 1, wherein the chemical compositions of the steel substrate and the welding wire comprise, in mass fraction: c: 0.32-0.45%, Si: 0.80% -1.20%, Mn: 0.20-0.50%, Cr: 4.75-5.50%, Mo: 1.10% -1.75%, V: 0.80 to 1.20 percent of the total weight of the alloy, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, and the balance of Fe and inevitable impurities.
9. A die steel obtained by the method of any one of claims 1 to 7, wherein the die steel comprises a steel substrate and N additive manufacturing layers covering the steel substrate, the N additive manufacturing layers are arranged from bottom to top, wherein N is greater than 7 and is an integer;
the metallographic structure of the die steel comprises, in terms of volume fraction: the martensite is 90-97%, and the retained austenite is 3-10%.
10. The die steel according to claim 8, wherein the die steel has a Rockwell hardness of 47HRC or more and a tensile strength of 100MPa or more.
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| WO2021004185A1 (en) * | 2019-07-09 | 2021-01-14 | 南京中科煜宸激光技术有限公司 | Method for gradient regulation and control of technological parameter in additive manufacturing process |
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| CN112643047A (en) * | 2020-12-08 | 2021-04-13 | 首钢集团有限公司 | Hollow structure support-free CMT arc forming method |
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| CN115319105A (en) * | 2022-08-26 | 2022-11-11 | 南京理工大学 | Electric arc additive manufacturing maraging steel toughening and crack arresting method |
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