Aluminum alloy forging material, aluminum alloy forged product and method of producing same

An aluminum alloy forging material having an alloy composition including Cu in a range of 0.25 mass % or more and 0.55 mass % or less, Mg in a range of 0.85 mass % or more and 1.25 mass % or less, Si in a range of 1.02 mass % or more and 1.4 mass % or less, Mn in a range of 0.55 mass % or more and 1.0 mass % or less, Fe in a range of 0.32 mass % or more and 0.65 mass % or less, Zn in a range of 0.25 mass % or less, Cr in a range of 0.050 mass % or more and 0.30 mass % or less, Ti in a range of 0.01 mass % or more and 0.1 mass % or less, B in a range of 0.0010 mass % or more and 0.030 mass % or less, and Zr in a range of 0.0010 mass % or more and 0.050 mass % or less, and having a ratio Fe/Mn of the Fe content to the Mn content (mass ratio) of 0.3 or more and 1.2 or less, and with the remainder being made up of Al and unavoidable impurities,

• wherein the number density of precipitates containing Mn within a range of 1.5 μm including crystal grain boundaries in an alloy structure after forging is 4 particles/μm2 or less.

An aluminum alloy forging material having an alloy composition including Cu in a range of 0.25 mass % or more and 0.55 mass % or less, Mg in a range of 0.85 mass % or more and 1.25 mass % or less, Si in a range of 1.02 mass % or more and 1.4 mass % or less, Mn in a range of 0.61 mass % or more and 1.0 mass % or less, Fe in a range of 0.32 mass % or more and 0.65 mass % or less, Zn in a range of 0.25 mass % or less, Cr in a range of 0.050 mass % or more and 0.30 mass % or less, Ti in a range of 0.01 mass % or more and 0.1 mass % or less, B in a range of 0.0010 mass % or more and 0.030 mass % or less, and Zr in a range of 0.0010 mass % or more and 0.050 mass % or less, and having a ratio Fe/Mn of the Fe content to the Mn content (mass ratio) of 0.3 or more and 1.2 or less, and with the remainder being made up of Al and unavoidable impurities,

• wherein the number density of precipitates containing Mn within a range of 1.5 μm including crystal grain boundaries in an alloy structure after forging is 4 particles/μm2 or less.

An aluminum alloy forged product having an elongated part and a connecting part and an aluminum alloy composition having an alloy composition including Cu in a range of 0.30 mass % or more and 1.0 mass % or less, Mg in a range of 0.80 mass % or more and 1.8 mass % or less, Si in a range of 0.90 mass % or more and 1.9 mass % or less, Mn in a range of 0.30 mass % or more and 1.2 mass % or less, Fe in a range of 0.20 mass % or more and 0.65 mass % or less, Zn in a range of 0.25 mass % or less, Cr in a range of 0.050 mass % or more and 0.30 mass % or less, Ti in a range of 0.01 mass % or more and 0.1 mass % or less, B in a range of 0.0010 mass % or more and 0.030 mass % or less, and Zr in a range of 0.0010 mass % or more and 0.050 mass % or less, and having a ratio Fe/Mn of the Fe content to the Mn content (mass ratio) of less than 1.4, and with the remainder being made up of Al and unavoidable impurities,

• wherein, when the crystal particle size of a central part of the elongated part in a longitudinal direction is S1, and the crystal particle size of a boundary part between the elongated part and the connecting part in the longitudinal direction is S2, the value of S1/S2 is in a range of 0.7 or more and 1.0 or less.

An aluminum alloy forged product having an elongated part and a connecting part and having an alloy composition including Cu in a range of 0.25 mass % or more and 0.55 mass % or less, Mg in a range of 0.85 mass % or more and 1.25 mass % or less, Si in a range of 1.02 mass % or more and 1.4 mass % or less, Mn in a range of 0.55 mass % or more and 1.0 mass % or less, Fe in a range of 0.32 mass % or more and 0.65 mass % or less, Zn in a range of 0.25 mass % or less, Cr in a range of 0.050 mass % or more and 0.30 mass % or less, Ti in a range of 0.01 mass % or more and 0.1 mass % or less, B in a range of 0.0010 mass % or more and 0.030 mass % or less, and Zr in a range of 0.0010 mass % or more and 0.050 mass % or less, and having a ratio Fe/Mn of the Fe content to the Mn content (mass ratio) of 0.3 or more and 1.2 or less, and with the remainder being made up of Al and unavoidable impurities,

• wherein, when the crystal particle size of a central part of the elongated part in a longitudinal direction is S1, and the crystal particle size of a boundary part between the elongated part and the connecting part in the longitudinal direction is S2, the value of S1/S2 is in a range of 0.7 or more and 1.0 or less.

An aluminum alloy forged product having an elongated part and a connecting part and having an alloy composition including Cu in a range of 0.25 mass % or more and 0.55 mass % or less, Mg in a range of 0.85 mass % or more and 1.25 mass % or less, Si in a range of 1.02 mass % or more and 1.4 mass % or less, Mn in a range of 0.61 mass % or more and 1.0 mass % or less, Fe in a range of 0.32 mass % or more and 0.65 mass % or less, Zn in a range of 0.25 mass % or less, Cr in a range of 0.050 mass % or more and 0.30 mass % or less, Ti in a range of 0.01 mass % or more and 0.1 mass % or less, B in a range of 0.0010 mass % or more and 0.030 mass % or less, and Zr in a range of 0.0010 mass % or more and 0.050 mass % or less, and having a ratio Fe/Mn of the Fe content to the Mn content (mass ratio) of 0.3 or more and 1.2 or less, and with the remainder being made up of Al and unavoidable impurities,

• wherein, when the crystal particle size of a central part of the elongated part in a longitudinal direction is S1, and the crystal particle size of a boundary part between the elongated part and the connecting part in the longitudinal direction is S2, the value of S1/S2 is in a range of 0.7 or more and 1.0 or less.