Aging treatment for Ni-Cr-Mo alloys
AssigneeHaynes International, Inc.
InventorsLee M. Pike JR., Dwaine L. Klarstrom
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Abstract
A single step heat treatment for Ni—Cr—Mo alloys containing from 12% to 19% chromium and from 18% to 23% molybdenum provides higher yield strength, high tensile strength and other mechanical properties comparable to those observed in similar alloys age-hardened according to current practices. This treatment is done over a total time of at least 24 hours and preferably less than 50 hours. However, the treatment works for only those alloys having alloying elements present in amounts according to an equation here disclosed.
Claims21
A nickel-chromium-molybdenum alloy comprised of:
- from 12% to 19% chromium;
- from 18% to 23% molybdenum;
- up to about 0.5% aluminum;
- up to 0.02% carbon;
- up to about 1.5% manganese;
- up to about 3.0% iron;
- up to about 2.5% cobalt;
- up to about 4.5% tungsten;
- up to about 0.015% boron;
- and
- a balance of nickel plus impurities;
- wherein the alloy has a P value of from 31.2 to 35.9, P being defined as:
- 3 P = 2.46 Al + 0.19 Co + 0.83 Cr - 0.16 Cu + 0.39 Fe + 0.59 Mn + 1.0 Mo + 0.81 Zr + 2.15 Si + 1.06 V + 0.39 W + 0.68 Nb + 0.52 Hf + 0.45 Ta + 1.35 Ti
- and the alloy is age hardened at about 1100° F. to about 1225° F. for at least 24 hours then cooled to room temperature.
A nickel- chromium-molybdenum alloy comprised of:
- from 12% to 19% chromium;
- from 18% to 23% molybdenum;
- up to 3% iron;
- at least one alloying element selected from the group consisting of aluminum, boron, carbon, cobalt, copper, hafnium, iron, manganese, niobium, silicon, tantalum, tungsten, vanadium and zirconium;
- and
- a balance of nickel plus impurities;
- wherein the alloy has a P value of from 31.2 to 35.9, P being defined as:
- 4 P = 2.46 Al + 0.19 Co + 0.83 Cr - 0.16 Cu + 0.39 Fe + 0.59 Mn + 1.0 Mo + 0.81 Zr + 2.15 Si + 1.06 V + 0.39 W + 0.68 Nb + 0.52 Hf + 0.45 Ta + 1.35 Ti
- and the alloy is age hardened at about 1100° F. to about 1225° F. for at least 24 hours then cooled to room temperature.
A nickel- chromium-molybdenum alloy comprised of:
- from 12% to 19% chromium;
- from 18% to 23% molybdenum;
- up to about 0.5% aluminum;
- up to 0.02% carbon;
- up to about 1.5% manganese;
- up to about 3% iron;
- up to about 2.5% cobalt;
- up to about 4.5% tungsten;
- up to about 0.015% boron;
- and
- a balance of nickel plus impurities;
- wherein the alloy has a P value of from 31.2 to 35.9, P being defined as:
- 5 P = 2.46 Al + 0.19 Co + 0.83 Cr - 0.16 Cu + 0.39 Fe + 0.59 Mn + 1.0 Mo + 0.81 Zr + 2.15 Si + 1.06 V + 0.39 W + 0.68 Nb + 0.52 Hf + 0.45 Ta + 1.35 Ti
- and the alloy is age hardened at about 1100° F. to about 1225° F. for at least 24 hours then cooled to room temperature.
A method for treating an alloy having a composition comprised of from 12% to 19% chromium, from 18% to 23% molybdenum, up to about 0.5% aluminum, up to about 0.015% boron, up to 0.02% carbon, up to about 2.5% cobalt, up to about 3% iron up to about 1.5% manganese, up to about 1.25% niobium, up to about 0.75% silicon, up to about 2.2% tantalum, up to about 0.7% titanium, up to about 4.5% tungsten, and the balance nickel plus impurities, wherein the alloy has a P value of from 31.2 to 35.9, P being defined as:
- 6 P = 2.46 Al + 0.19 Co + 0.83 Cr - 0.16 Cu + 0.39 Fe + 0.59 Mn + 1.0 Mo + 0.81 Zr + 2.15 Si + 1.06 V + 0.39 W + 0.68 Nb + 0.52 Hf + 0.45 Ta + 1.35 Ti
- the method comprised of:
- age hardening the alloy at about 1100° F. to about 1225° F. for at least 24 hours;
- and
- cooling the alloy to room temperature.
A method for treating an alloy having a composition comprised of
- from 12% to 19% chromium;
- from 18% to 23% molybdenum;
- up to about 0.5% aluminum;
- up to about 0.015% boron;
- up to 0.02% carbon;
- up to about 2.5% cobalt;
- up to about 3% iron;
- up to about 1.25% niobium;
- up to about 0.75% silicon
- up to about 2.2% tantalum;
- up to about 0.7% titanium;
- up to about 1.5% manganese;
- up to about 4.5% tungsten;
- and
- a balance of nickel plus impurities;
- wherein the alloy has a P value of from 31.2 to 35.9, P being defined as:
- 7 P = 2.46 Al + 0.19 Co + 0.83 Cr - 0.16 Cu + 0.39 Fe + 0.59 Mn + 1.0 Mo + 0.81 Zr + 2.15 Si + 1.06 V + 0.39 W + 0.68 Nb + 0.52 Hf + 0.45 Ta + 1.35 Ti
- the method comprised of:
- age hardening the alloy at about 1100° F. to about 1225° F. for at least 24 hours;
- and
- cooling the alloy to room temperature.
Dependencies are inferred from the claim text.