DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 08/25/2025 has been entered.
Response to Amendment
The Amendment filed 08/25/2025 has been entered. Claim 1 is remain pending in the application. Claim 1 is currently amended. Applicant's amendments to the specification have overcome the objections previously set forth in the Final Rejection mailed 07/09/2025.
Claim Interpretation
Formula (I) of claim 1 is interpreted as a critical internal pressure value must be equal or greater to the value obtained by multiplying 0.44 by a tensile strength and by the value of α obtained from Formula (II).
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.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over US 2004/0080156 A1 of Usui (as cited in prior Office action).
Usui teaches a common rail, in which a flow passage in a main pipe rail and portions of branch holes are improved in durability while the portions of branch holes are enhanced in fatigue strength for inner pressures (Abstract).
Usui teaches the main pipe is subjected to autofrettage processes where stresses are applied by exerting pressing forces on a pipe by means of an internal pressure system ([0012]). Usui teaches the rail is made of an S45C steel ([0040]).
Note that the limitation “for pressure piping” is an intended use limitation that does not impart any structural limitations to the claimed steel pipe. “If the body of a claim fully and intrinsically sets forth all of the limitations of the claimed invention, and the preamble merely states, for example, the purpose or intended use of the invention, rather than any distinct definition of any of the claimed invention’s limitations, then the preamble is not considered a limitation and is of no significance to claim construction.” See MPEP §2111.02 (Il).
Usui therefore reads on the limitation “a steel pipe for pressure piping, the steel pipe being subjected to autofrettage” of claim 1.
Regarding the limitation of “the steel pipe being subjected to autofrettage” of claim 1, this is a product-by-process limitation. MPEP § 2113 states that “even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process”. In this instance, the claimed processing limitation of the steel pipe being subjected to autofrettage results in compressive residual stresses which could be achieved by other processes.
Usui teaches the pipe has an outer diameter of 24 mm, an inner diameter of 7 mm or 10 mm, and a yield stress of 450 MPa ([0014], Table 1, the application uses m/m but the table in the original JP 2004/092551 A lists “mm” rather than “m/m” so the “m/m” in the US application is considered a typo; regardless of unit, the D/d ratio remains the same in the US and JP versions). Usui teaches the pipe maintains compressive residual stresses of about 399 Mpa after autofrettage processing ([0018]). Usui therefore reads on the limitation “wherein when an outer diameter of the steel pipe is denoted by D (mm), an inner diameter of the steel pipe is denoted by d (mm), and a yield stress of the steel pipe is denoted by σy (MPa)” of claim 1.
Using the values for the outer diameter, inner diameter of 10 mm, and yield stress of Usui in the given formulas, the D/d ratio is 2.4, which meets the limitation of “D/d is 1.2 or more” of claim 1, F is -0.892, A is 7.3808, and C is -4.4067. Using these values in Formula (v) gives:
-441.54 MPa ≤ σi1 ≤ -321.12 MPa
which fits the expected residual compressive stress of 399 MPa of Usui (a compressive stress would be written as -399 MPa and therefore fits in the ranges of Formula (v) of the instant claim using the values of Usui). While Usui does not explicitly state the residual compressive stress of the pipe is at the inner surface of the pipe, one of ordinary skill in the art would expect this residual stress to be in the internal surface of the pipe since autofrettage processes apply stresses by exerting pressing forces on a pipe by means of an internal pressure system, as taught by Usui.
Usui therefore reads on the limitation of an estimated value σi1 (MPa) of a residual stress at an inner surface of the steel pipe after the autofrettage satisfies Formula (v) of claim 1.
Usui teaches a pipe thickness of 9 mm to 14 mm ([0032], Table 1, the difference between the outer and inner diameter would result in a pipe thickness of 14 mm).
Regarding the critical internal pressure of claim 1, Usui teaches use is not possible at a pressure above 134.6 Mpa ([0016], reads on claimed critical internal pressure). Usui further teaches an example internal pressure of 100 MPa ([0014]) and a calculated internal pressure of 350 MPa ([0015]). While Usui does not explicitly disclose the values of Formulas (I) and (II) of the instant invention, one can calculate their values using the values of Usui for the outer diameter of 24 mm and inner diameter of 10 mm described above, and tensile stress of 650 MPa ([0014]) in the given formulas resulting in Formula (II): α = -0.955 and therefore Formula (I): IP ≥ -273 MPa.
Since Usui teaches use is not possible above a pressure of 134.6 MPa, Formula (I) using the value of Usui reads 134.6 MPa ≥ -273 MPa which satisfies the instant limitation of Formula (I). The Examiner notes that the formula is still satisfied if writing the 134.6 MPa pressure as -134.6 MPa to reflect compression.
Usui therefore reads on the limitation wherein the steel pipe for pressure piping has a critical internal pressure satisfying Formula (1) shown below of claim 1.
However, Usui does not explicitly disclose a measured value of a residual stress at an outer surface of the steel pipe after the autofrettage and halving is denoted by σo2 (MPa), and a measured value of a residual stress at an inner surface of the steel pipe after the autofrettage and the halving is denoted by σi2 (MPa) and to the estimated value σi1 being determined by Formula (i) to Formula (iv) of claim 1.
Although Usui teaches a residual stress after autofrettage, Usui does not explicitly disclose what the residual stress is in the outer surface of the pipe after autofrettage or any residual stresses after autofrettage and halving the steel pipe. While Usui does not explicitly disclose these properties nor the distance “t”, one of ordinary skill in the art would reasonably expect the values to be present even if they are not explicitly measured or disclosed given the overlap in composition (steel), structure (D/d ratio of 1.2 or more), and an estimated value σi1 (MPa) of a residual stress at an inner surface of the steel pipe after the autofrettage satisfies Formula (v), as described above. Absent any clear and convincing evidence and/or arguments to the contrary, one of ordinary skill in the art would expect the pipe of Usui to possess the claimed measured value of residual stress. 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.
Usui therefore reads on all the limitations of claim 1.
Response to Arguments
Applicant's arguments filed 08/25/2025 have been fully considered but they are not persuasive.
Applicant argues that Usui fails to teach a steel pipe that has a critical internal pressure satisfying Formula (I) (remarks, pages 6-7).
In response, Applicant's arguments fail to comply with 37 CFR 1.111(b) because they amount to a general allegation that the claims define a patentable invention without specifically pointing out how the language of the claims patentably distinguishes them from the references. In this case, Usui teaches a critical internal pressure satisfying Formula (I) as outlined in the 35 U.S.C. 103 rejection in this Office action.
Citation of Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 2010/0167086 A1 of Usui (as cited in IDS mailed 09/15/2022 and hereafter US ‘086) is considered relevant to claim 1 of the instant invention since US ‘086 teaches inventive examples of steel pipes with critical internal pressures of 260-285 MPa (Table 2, Specimens 2,5, and 8).
Conclusion
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/M.A./Examiner, Art Unit 1733
/REBECCA JANSSEN/Primary Examiner, Art Unit 1733