Disclosed is a clad steel plate with further improved low temperature toughness along with excellent HIC resistance while ensuring a tensile strength of 535 MPa or more. A clad steel plate includes: a base steel; and a clad metal made of a corrosion resistant alloy bonded to one surface of the base steel, in which the base steel has: a chemical composition with appropriately controlled values of ACR and P.sub.HIC; and a steel microstructure in which bainite is present in an area fraction of 94% or more at a ½ thickness position in a thickness direction of the base steel, and with an average crystal grain size of 25 μm or less, and shear strength at a bonded interface between the base steel and the cladding metal is 300 MPa or more.

Additive manufacturing can involve dispensing a powdered material to form a layer of a powder bed on a support surface of a build platform. A portion of the layer of the powder bed may be selectively melted or fused to form one or more temporary walls out of the fused portion of the layer of the powder bed to contain another portion of the layer of the powder bed on the build platform.

Additive manufacturing can involve dispensing a powdered material to form a layer of a powder bed on a support surface of a build platform. A portion of the layer of the powder bed may be selectively melted or fused to form one or more temporary walls out of the fused portion of the layer of the powder bed to contain another portion of the layer of the powder bed on the build platform.

An additive manufacturing system including a two-dimensional energy patterning system for imaging a powder bed is disclosed. Improved optical systems supporting beam combining, beam steering, and both patterned and unpatterned beam recycling and re-use are described.

An additive manufacturing system including a two-dimensional energy patterning system for imaging a powder bed is disclosed. Improved optical systems supporting beam combining, beam steering, and both patterned and unpatterned beam recycling and re-use are described.

In various aspects, an apparatus for an electron-beam powder bed fusion (EB-PBF) printer includes a radiation collector configured to collect radiation in an ultraviolet (UV) spectrum at a powder bed surface within a vacuum chamber during an electron beam scanning cycle of EB-PBF operation, an optical fiber configured to be transparent to the radiation in the UV spectrum and configured to receive the radiation at the powder bed surface via the radiation collector, and a processor configured to receive one or more extracted wavelengths of radiation in the UV spectrum based on the radiation carried on the optical fiber.

In various aspects, an apparatus for an electron-beam powder bed fusion (EB-PBF) printer includes a radiation collector configured to collect radiation in an ultraviolet (UV) spectrum at a powder bed surface within a vacuum chamber during an electron beam scanning cycle of EB-PBF operation, an optical fiber configured to be transparent to the radiation in the UV spectrum and configured to receive the radiation at the powder bed surface via the radiation collector, and a processor configured to receive one or more extracted wavelengths of radiation in the UV spectrum based on the radiation carried on the optical fiber.

An apparatus and a method for powder bed fusion additive manufacturing involve a multiple-chamber design achieving a high efficiency and throughput. The multiple-chamber design features concurrent printing of one or more print jobs inside one or more build chambers, side removals of printed objects from build chambers allowing quick exchanges of powdered materials, and capabilities of elevated process temperature controls of build chambers and post processing heat treatments of printed objects. The multiple-chamber design also includes a height-adjustable optical assembly in combination with a fixed build platform method suitable for large and heavy printed objects.

An apparatus and a method for powder bed fusion additive manufacturing involve a multiple-chamber design achieving a high efficiency and throughput. The multiple-chamber design features concurrent printing of one or more print jobs inside one or more build chambers, side removals of printed objects from build chambers allowing quick exchanges of powdered materials, and capabilities of elevated process temperature controls of build chambers and post processing heat treatments of printed objects. The multiple-chamber design also includes a height-adjustable optical assembly in combination with a fixed build platform method suitable for large and heavy printed objects.

A High Energy Beam Processing (HEBP) system provides feedback signal monitoring and feedback control for the improvement of process repeatability and three-dimensional (3D) printed part quality. Electrons deflected from a substrate in the processing area impinge on a surface of a sensor. The electrons result from the deflection of an electron beam from the substrate. Either one or both of an initial profile of an electron beam and an initial location of the electron beam relative to the substrate are determined based on a feedback electron signal corresponding to the impingement of the electrons on the surface of the sensor. With an appropriate profile and location of the electron beam, the build structure is fabricated on the substrate.