DETAILED ACTION
Response to Amendment
The Amendment filed 03/16/2026 has been entered. Claims 1-7 remain pending in the application. Claim 7 has been withdrawn due to a restriction requirement. No new claims have been added. Applicant's amendments to the drawings have overcome the objections previously set forth in the Non-Final Rejection mailed 11/14/2025. The specification objections previously set forth in the Non-Final Rejection mailed 11/14/2025 in view of Applicant’s remarks (pages 8-9). Applicant's amendments to the claims have overcome the 112(b) rejections previously set forth in the Non-Final Rejection mailed 11/14/2025.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 3 and 5 are rejected under 35 U.S.C. 103 as being unpatentable over JP H03219040 A of Takayama (cited in prior Office action).
Regarding claim 1, Takayama teaches a high-strength sintered steel and its manufacture (Title; a steel is an iron-based alloy and the sintered steel of Takayama reads on the claimed iron-based sintered alloy material; a manufacture reads on the claimed production method).
Takayama therefore reads on the limitation a production method for an iron-based sintered alloy material of claim 1.
Takayama teaches a high-strength sintered steel is obtained by molding and pressing a mixture of a powder of an alloy steel powder containing carbon and/or a powder of an alloy ferroalloy powder not containing carbon and graphite powder into a predetermined shape (claim 1, pages 3-4, Examples 1-2, pages 7-9).
Takayama therefore reads on the limitation molding an iron-based mixed powder into a green compact of a desired shape of claim 1.
Takayama teaches graphite powder is mixed into the alloy iron powder by 0.1 to 1.0% by weight (Abstract, claim 5, page 4 of Description), which overlaps with the claimed 0.1 to 1.2% by mass of a graphite powder. Takayama further teaches the powder contains one or more of 0.05 to 1.5% Si, 0.5 to 2.0% Cr, 0.5 to 5.0% Ni, 0.1 to 1.0% Mo and 0.1 to 2.0% Mn (Abstract, claim 5, page 4 of Description), which overlaps with the claimed 0.15 to 4.5% by mass of chromium, 0.1 to 2.0% by mass of molybdenum, 0.1 to 3.0% by mass of manganese, and 0.2 to 4.5% by mass of nickel.
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Takayama therefore reads on the limitation molding an iron-based mixed powder comprising 0.1 to 1.2% by mass of a graphite powder and at least one alloying component selected from the group consisting of 0.15 to 4.5% by mass of chromium, 0.2 to 4.5% by mass of copper, 0.1 to 2.0% by mass of molybdenum, 0.1 to 3.0% by mass of manganese, and 0.2 to 4.5% by mass of nickel into a green compact of a desired shape of claim 1.
Regarding the production method steps of claim 1, Takayama teaches a method for producing high-strength sintered steel, comprising the steps of: compacting and pressing a mixed powder of a carbon-containing alloy copper powder and/or a carbon-free alloy ferroalloy powder and graphite powder; sintering the compact thus compacted in a non-oxidizing atmosphere; or, after the step of sintering in a non-oxidizing atmosphere, recompressing and
molding the sintered steel and sintering it in a non-oxidizing atmosphere; nitriding or carbonitriding the sintered steel at a temperature of 600°C or higher; and quenching the sintered steel from a temperature above the A1 transformation line and tempering it (Description, end of page 3, start of page 4; compacting and pressing reads on the claimed molding into a green compact of a desired shape; sintering in a non-oxidizing environment reads on the claimed sintering; nitriding reads on the claimed nitriding treatment; quenching reads on the claimed quenching treatment; tempering reads on the claimed tempering).
Regarding the sintering of claim 1, Takayama teaches it is preferable to carry out the sintering in a vacuum atmosphere of 10-2 torr or less under the conditions of 1200 to 1300°C for 60 to 120 minutes (Description, page 5; a vacuum atmosphere is considered non-oxidizing environment).
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Takayama therefore reads on the limitation obtaining an iron-based sintered alloy substrate by heating and sintering the green compact at 1,000 to 1,300°C in a non-oxidizing environment of claim 1.
Regarding the nitriding of claim 1, Takayama teaches nitriding treatment at a temperature of 600°C or higher so that nitrides are unlikely to precipitate on the surface layer and further teaches the nitriding treatment is preferably carried out in an ammonia decomposition gas atmosphere at a temperature range of 800 to 900°C (Description, page 5).
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Takayama therefore reads on the limitation performing a nitriding treatment by heating the iron-based sintered alloy substrate to a nitriding temperature of 650° to 900°C in an atmosphere comprising ammonia of claim 1.
Takayama teaches quenching the sintered steel from a temperature above the A1 transformation line (Description, page 4; A1 is 721°C as stated in Description, page 6 of Takayama). Takayama teaches eutectoid sintered steel can be rapidly cooled from 740°C (Description, page 6). The temperature above A1 (721°C) is slightly above the claimed upper limit of 700°C. A prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). See MPEP 2144.05 I. In this case, absent any clear and convincing evidence and/or arguments to the contrary, one of ordinary skill in the art would expect the method of Takayama and the instant claim to achieve the same results. A prima facie case of obviousness has been properly established herein. As the Patent Office does not possess the laboratory facilities to test any differences in the claimed invention versus that of the reference, the burden shifts to applicant to demonstrate otherwise.
Since Takayama teaches a preferable nitriding temperature of 800-900°C, the quenching temperature of above 721°C is lower than the nitriding temperature.
Takayama therefore reads on the limitation subjecting the iron-based sintered alloy substrate that has undergone the nitriding treatment to a quenching treatment with rapid cooling from a quenching temperature that is a temperature of 640 to 700°C and is lower than the nitriding temperature of claim 1.
Takayama teaches tempering at 150°C (Example 1, Description, page 8), which is within the claimed range of 100 to 200°C.
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Takayama therefore reads on the limitation subjecting the iron-based sintered alloy substrate that has undergone the quenching treatment to tempering by heating at 100 to 200°C of claim 1.
Takayama therefore reads on all the limitations of claim 1.
Regarding claim 3, Takayama teaches the method of claim 1 as described above.
Takayama teaches tempering at 150°C (Example 1, Description, page 8), which is within the claimed range of 100 to 200°C.
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Takayama therefore reads on the limitation wherein the tempering after the quenching is performed by heating the substrate at 150 to 200°C of claim 3.
Regarding claim 5, Takayama teaches the method of claim 1 as described above.
Takayama teaches the powder contains one or more of 0.05 to 1.5% Si, 0.5 to 2.0% Cr, 0.5 to 5.0% Ni, 0.1 to 1.0% Mo and 0.1 to 2.0% Mn (Abstract, claim 5, page 4 of Description; 0.5 to 2.0% Cr overlaps with the claimed 0.15 to 4.5% by mass of chromium).
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Takayama therefore reads on the limitation wherein the at least one alloying component comprises 0.15 to 4.5% by mass of chromium of claim 5.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over JP H03219040 A of Takayama (cited in prior Office action) in view of “Nitrocarburizing and high temperature nitriding of steels in bearing applications” of Flodström (cited in prior Office action) and “Effect of cooling rates on sinter-hardened steels” of Dobrzański (cited in prior Office action).
Takayama teaches the method of claim 1 as described above.
However, Takayama does not explicitly disclose wherein the quenching is conducted after reducing a temperature from the nitriding temperature to the quenching temperature at a temperature reduction rate of 0.6 to 1.0°C/min.
Flodström teaches nitrocarburizing and nitriding of steels (Title) and is considered analogous art to Takayama since they are similarly concerned with nitriding steels. Flodström teaches slower cooling rates are preferred after nitrocarburizing steels if distortions need to be minimized (page 11, first paragraph, nitrocarburizing and nitriding steps are considered analogous treatments). However, Flodström does not explicitly disclose specific ranges for “slower cooling rates”.
It would have been necessary and obvious to look to the prior art for exemplary slow cooling rates used in sintered steels. Dobrzański teaches effect of cooling rates on sinter-hardned steels (Title). Dobrzański teaches a slow cooling rate is 0.3°C/s (Abstract, equivalent to 1.8°C/min). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Takayama with the slow cooling rate of Flodström to minimize distortions between the nitriding and quenching steps, and adjusting and varying the cooling rate to 1.8°C/min or less, such as within the claimed ranges, as taught by Dobrzański, in order to perform a nitriding and sintering treatment using known and tested slow cooling rates predictably suitable for sintered steel.
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Modified Takeyama reads on wherein the quenching is conducted after reducing a temperature from the nitriding temperature to the quenching temperature at a temperature reduction rate of 0.6 to 1.0°C/min of claim 2.
Claims 4 and 6 are rejected under 35 U.S.C. 103 as being unpatentable over JPH03219040A of Takayama (cited in prior Office action), as applied to claim 1 above, in view of US 2013/0136646 A1 of Berg (cited in prior Office action).
Regarding claim 4, Takayama teaches the method of claim 1 as described above.
Takayama teaches nitriding significantly improves the fatigue limit strength of the sintered steel and increases its toughness (Description, end of page 6 and start of page 7). Takayama teaches examples with a nitriding time of 4 hours (Example 1, page 9) and a comparative example with no nitriding treatment (end of page 9).
However, Takayama does not explicitly disclose wherein the nitriding treatment is performed at the nitriding temperature for 120 to 180 minutes.
Berg teaches nitrided sintered steels (Title) and is considered analogous art since it is similarly concerned with sintered steels with nitriding treatments and has nitriding temperatures overlapping with those of Takayama. Berg teaches the nitriding process is performed with a soaking time of less than 3 hours and preferably at least 10 minutes ([0077]). Berg teaches the nitriding process is performed to obtain a desired microstructure and that the resulting nitride component achieves a case depth and hardness that gives a good wear resistance ([0077]-[0086]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to perform the method of Takayama, and adjusting and varying the nitriding time, such as within the claimed ranges, as taught by Berg, to form a sintered steel with a desired microstructure and nitriding case depth and hardness to achieve good wear resistance, as taught by Berg.
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Modified Takayama therefore reads on the limitation wherein the nitriding treatment is performed at the nitriding temperature for 120 to 180 minutes of claim 4.
Regarding claim 6, Takayama teaches the method of claim 1 as described above.
However, Takayama does not explicitly disclose wherein the at least one alloying component comprises 0.2 to 4.5% by mass of copper.
It would have been necessary and obvious to look to the prior art for exemplary copper contents used in sintered steels. Berg provides this teaching showing nitrided sintered steels (Title) and is considered analogous art since it is similarly concerned with sintered steels with nitriding treatments and has a similar powder composition and processing to Takayama. Berg teaches adding Cu preferably in an amount of 0.2-5% by weight to enhance the strength and hardness of the steel through solid solution hardening ([0066]). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to perform the method of Takayama, and adjusting and varying the copper content of its powder, such as within the claimed ranges, as taught by Berg, in order to form a conventional sintered steel using known and tested copper amounts predictably suitable for sintered steels and increase strength and hardness of the sintered steel, as taught by Berg.
In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Modified Takayama therefore reads on the limitation wherein the at least one alloying component comprises 0.2 to 4.5% by mass of copper of claim 6.
Response to Arguments
Applicant's arguments filed 03/16/2026 have been fully considered but they are not persuasive.
Applicant argues that the Takayama publication does not disclose the presently claimed invention, including subjecting the iron-based sintered alloy substrate that has undergone the nitriding treatment to a quenching treatment from a quenching temperature that is a temperature of 640 to 700°C and that nothing in Berg remedies the deficiencies of Takayama (remarks, pages 10-11). Applicant further argues that Takayama teaches quenching the sintered steel from a temperature above the A1 transformation line (Description, page 4; A1 is 721°C as stated in Description, page 6 of Takayama)" and that, according to the presently claimed invention, the iron-based sintered alloy substrate that has undergone the nitriding treatment I subjected to a quenching treatment from a quenching temperature that is a temperature of 640 to 700°C (remarks, page 10).
In response, the temperature above A1 (721°C) of Takayama is slightly above the claimed upper limit of 700°C. A prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). See MPEP 2144.05 I. Absent any clear and convincing evidence and/or arguments to the contrary, one of ordinary skill in the art would expect the method of Takayama and the instant claim to achieve the same results. A prima facie case of obviousness has been properly established herein. As the Patent Office does not possess the laboratory facilities to test any differences in the claimed invention versus that of the reference, the burden shifts to applicant to demonstrate otherwise.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
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/M.A./Examiner, Art Unit 1733
/REBECCA JANSSEN/Primary Examiner, Art Unit 1733
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