Precipitation-hardening-type austenitic alloy steel material and method for manufacturing same, and precipitation-hardening-type austenitic alloy heat-treated steel material and method for manufacturing same

A precipitation-hardening austenitic alloy steel material,

• wherein an area ratio of grains having a GOS (Grain Orientation Spread) value of 1.0° or more is 50% or more,
• wherein a shape of the precipitation-hardening austenitic alloy steel material is columnar, and an equivalent area diameter of a cross section in a direction perpendicular to an axis of the precipitation-hardening austenitic alloy steel material is 100 mm or more.

A precipitation-hardening austenitic alloy heat-treated steel material, wherein

• when an equivalent area diameter of a cross section in a direction perpendicular to an axis of the heat-treated steel material is designated as D, the precipitation-hardening austenitic alloy heat-treated steel material has a grain size number of 4.0 or more, a 0.2% yield strength of 590 MPa or more, a tensile strength of 900 MPa or more, and an elongation of 15% or more at positions of depth D/4 and depth D/2 from a surface of the heat-treated steel material, and
• a shape of the precipitation-hardening austenitic alloy heat-treated steel material is columnar, and an equivalent area diameter of a cross section in a direction perpendicular to an axis of the precipitation-hardening austenitic alloy heat-treated steel material is 100 mm or more.