A polishing method for an inner wall of a hollow metal part, including: firstly, placing a coaxial cathode in an inner hole of a metal part when a metal part model is designed, and printing the metal part model and the coaxial cathode together; then, sealing two ends of an inner hole cavity of the metal part by using a light curing part, fixing the coaxial cathode, filling the cavity with a polishing solution, and performing polishing treatment by using an electrochemical polishing method; and finally, reversing an electrode to break the coaxial cathode and take out the broken coaxial cathode to obtain a polished metal part. The polishing of a complex-shaped inner hole of a 3D-printed metal part is realized, the defect that an inner hole of a 3D-printed metal part with a complex-shaped hollow part cannot be polished by using a traditional machining method is overcome, the problem that an inner wall of a metal part polished by using an electrochemical method is non-uniform is solved, the surface quality of the inner hole of the 3D-printed metal part with the complex-shaped hollow part is improved, and the application prospect and postprocessing technology of the 3D-printed metal part are expanded.

A polishing method for an inner wall of a hollow metal part, including: firstly, placing a coaxial cathode in an inner hole of a metal part when a metal part model is designed, and printing the metal part model and the coaxial cathode together; then, sealing two ends of an inner hole cavity of the metal part by using a light curing part, fixing the coaxial cathode, filling the cavity with a polishing solution, and performing polishing treatment by using an electrochemical polishing method; and finally, reversing an electrode to break the coaxial cathode and take out the broken coaxial cathode to obtain a polished metal part. The polishing of a complex-shaped inner hole of a 3D-printed metal part is realized, the defect that an inner hole of a 3D-printed metal part with a complex-shaped hollow part cannot be polished by using a traditional machining method is overcome, the problem that an inner wall of a metal part polished by using an electrochemical method is non-uniform is solved, the surface quality of the inner hole of the 3D-printed metal part with the complex-shaped hollow part is improved, and the application prospect and postprocessing technology of the 3D-printed metal part are expanded.

An iron-based sintered alloy material having, at the surface of the material, a hardened layer exhibiting a martensite phase containing a solid solution of nitrogen in a supersaturated state. The iron-based sintered alloy material may contain at least one of chromium, copper, molybdenum, manganese and nickel. A production method for the iron-based sintered alloy material includes: subjecting an iron-based sintered alloy substrate containing carbon to a nitriding treatment by heating the substrate to a nitriding temperature of at least 590° C. in an atmosphere containing ammonia, and then performing quenching by rapidly cooling the substrate.

An iron-based sintered alloy material having, at the surface of the material, a hardened layer exhibiting a martensite phase containing a solid solution of nitrogen in a supersaturated state. The iron-based sintered alloy material may contain at least one of chromium, copper, molybdenum, manganese and nickel. A production method for the iron-based sintered alloy material includes: subjecting an iron-based sintered alloy substrate containing carbon to a nitriding treatment by heating the substrate to a nitriding temperature of at least 590° C. in an atmosphere containing ammonia, and then performing quenching by rapidly cooling the substrate.

An expeditionary additive manufacturing (ExAM) system [10] for manufacturing metal parts [20] includes a mobile foundry system [12] configured to produce an alloy powder [14] from a feedstock [16], and an additive manufacturing system [18] configured to fabricate a part using the alloy powder [14]. The additive manufacturing system [18] includes a computer system [50] having parts data and machine learning programs in signal communication with a cloud service. The parts data [56] can include material specifications, drawings, process specifications, assembly instructions, and product verification requirements for the part [20]. An expeditionary additive manufacturing (ExAM) method for making metal parts [20] includes the steps of transporting the mobile foundry system [12] and the additive manufacturing system [18] to a desired location; making the alloy powder [14] at the location using the mobile foundry system; and building a part [20] at the location using the additive manufacturing system [18].

An expeditionary additive manufacturing (ExAM) system [10] for manufacturing metal parts [20] includes a mobile foundry system [12] configured to produce an alloy powder [14] from a feedstock [16], and an additive manufacturing system [18] configured to fabricate a part using the alloy powder [14]. The additive manufacturing system [18] includes a computer system [50] having parts data and machine learning programs in signal communication with a cloud service. The parts data [56] can include material specifications, drawings, process specifications, assembly instructions, and product verification requirements for the part [20]. An expeditionary additive manufacturing (ExAM) method for making metal parts [20] includes the steps of transporting the mobile foundry system [12] and the additive manufacturing system [18] to a desired location; making the alloy powder [14] at the location using the mobile foundry system; and building a part [20] at the location using the additive manufacturing system [18].

The invention relates to an electrolyte for electropolishing metal surfaces, said electrolyte comprising methanesulphonic acid and additionally at least one phosphonic acid, as well as to an electropolishing method for same.

A steel, a steel mechanical part, an electronic device, and a preparation method for a steel mechanical part are provided. The steel includes components of the following mass percentages: chromium: 7% to 11%, nickel: 2% to 7.5%, cobalt: 6% to 15%, molybdenum: 4% to 7%, oxygen: a trace to 0.4%, carbon: a trace to 0.35%, and iron: 50% to 80%. The steel provided in this application has relatively high mechanical strength and is not easily deformed, and therefore a risk of fracture caused when an electronic device using the steel falls off from a height is reduced.

A method for producing an impact-resistant component, in particular a component of a turbomachine, such as an aircraft engine, and a corresponding component. The component is produced at least partially by an additive manufacturing method from a powder material in such a way that the component is formed at least in a first region from a material with a first toughness and at least in a second region from a material with a second toughness, the second toughness being greater than the first toughness, and wherein the second region is formed, at least in a part of the component, as a continuous or interrupted layer, preferably parallel to the surface of the component, at a distance from the surface of the component.

A method for producing an impact-resistant component, in particular a component of a turbomachine, such as an aircraft engine, and a corresponding component. The component is produced at least partially by an additive manufacturing method from a powder material in such a way that the component is formed at least in a first region from a material with a first toughness and at least in a second region from a material with a second toughness, the second toughness being greater than the first toughness, and wherein the second region is formed, at least in a part of the component, as a continuous or interrupted layer, preferably parallel to the surface of the component, at a distance from the surface of the component.