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 .
Terminal Disclaimer
The terminal disclaimer filed on 04/24/2026 disclaiming the terminal portion of any patent granted on this application which would extend beyond the expiration date of copending Application No. 18/550459 has been reviewed and is accepted. The terminal disclaimer has been recorded.
Status of Claims
Claims 1 and 7 are amended. Claims 7-9, 11-13 and 19-20 are withdrawn. Claims 2, 5 and 10 are cancelled. Claims 1, 3-4, 6, 14-18 and 21-23 are examined herein.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1, 3-4, 6, 14-18 and 21-23 are rejected under 35 U.S.C. 103 as being unpatentable over DE’434 (DE 102017218434, IDS dated 02/19/2025) in view of WO’915 (WO2020244915, IDS dated 02/19/2025), and further in view of JP’594 (JP4654594, IDS dated 02/19/2025).
Regarding claim 1, DE’434 teaches (Abstract; Page 3) a composite steel plate comprising a high strength steel (i.e. base metal) and an enameling steel (i.e. cladding metal) on front and back surfaces of the high strength steel with composition ranges overlapping with the corresponding ranges of the base metal and the cladding metal recited in claim 1. 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). Thus, the recited composition of the base metal and the cladding metal is a prima facie case of obviousness over DE’434. See MPEP 2144.05 I.
Base Metal Composition
(wt. %)
Cladding Metal Composition
(wt. %)
Claim 1
DE’434
Claim 1
DE’434
C
0.05-0.35
0.01-0.35
C
0-0.1
0.001-0.1
Si
0.02-2.0
0.1-2.5
Si
0-0.6
0.0-0.1
Mn
1.8-3.5
0.5-3
Mn
0.05-2.5
0.1-1.0
P
0.001-0.1
0.001-0.15
P
0.001-0.1
0.0-0.1
S
0-0.02
0.001-0.1
S
0-0.02
0-0.1
Al
0.01-2.0
0.001-3.0
Al
0.01-2.0
0.001-0.1
N
0-0.01
0.0037-0.0045
N
0-0.01
0.0001-0.01
Balance
Fe
Fe
Balance
Fe
Fe
DE’434 discloses that the high strength steel (i.e. base metal) contains preferably at least 95% by area of martensite (Page 9), which meets the limitation that a total area ratio of martensite and tempered martensite is 30 % or more, a volume fraction of retained austenite is 5 % or less and an area ratio of ferrite is 55 % or less as recited in claim 1.
DE’434 discloses that the tensile strength of the high strength steel (i.e. base metal) is preferably 800-1500 MPa (Page 3), which converts to Vicker’s hardness of 250-460 and overlaps the recited hardness in claim 1. 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). See MPEP 2144.05 I.
DE’434 does not explicitly disclose the phase structure and the hardness of enameling steel (i.e. cladding metal). WO’915 teaches a composite plate comprising a high strength plate which is a martensitic steel and a cladding layer which is a ferritic steel and discloses when the high strength plate is a martensitic steel and the cladding layer is a ferritic steel made of 340LA steel, 420LA Steel or 500LA steel, the composite plate has optimal performance (Page 5). Thus, it would be obvious to one of ordinary skill in the art to make the enameling steel with ferritic structure as taught by WO’915 in the composite plates of DE’434 in order to make a composite plate having optimal performance as disclosed by WO’915. The ferritic steel disclosed by WO’915 meets the limitation that the cladding metal has an area ratio of ferrite of 80% or more as recited in claim 1.
In view of the fact that DE’434 in view of WO’915 teaches a steel plate having composition and structure that meets the recited composition and structure of base metal and cladding metal limitations recited in claim 1, one of ordinary skill in the art that the composite plate disclosed by DE’434 in view of WO’915 to meet the recited cladding layer hardness and the hardness ratio of cladding layer to base metal as recited in claim 1. “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established.” In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01 I.
DE’434 in view of WO’915 does not teach that the boundary roughness between the base metal and the cladding metal is 50 µm or less and a number of voids at a boundary between the base metal and the cladding metal is 20 or fewer per 10 mm of boundary length. JP’594 teaches a clad steel plate and discloses that when the roughness of the bonding surface of the clad steel plate is 30 µm or less, microporosity is absent along the bonding interface and the bonding strength between base metal and cladding metal is improved (Page 5, 1st two paragraphs). Thus, it would be obvious to one of ordinary skill in the art to make a clad steel plate with boundary roughness of 30 µm or less as taught by JP’594 in the process of DE’434 in view of WO’915 in order to make a clad steel plate without microporosity between the base metal and the cladding metal and with improved bonding strength as disclosed by JP’594.
Regarding claim 3, DE’434 discloses that the cladding metal has a thickness of 5-20% of the total thickness of the steel plate and the thickness of the base metal is 80-95% of the total thickness of the clad steel plate (Page 5), which meets the recited limitation in claim 3.
Regarding claims 4 and 15, WO’915 discloses that the clad steel plate has a galvanized layer on a surface to improve corrosion resistance (Page 7), which meets the limitation recited in claims 4 and 15.
Regarding claims 6 and 16-18, DE’434 discloses a member made of the composite steel plate (Abstract), which meets the limitation recited in claims 6 and 16-18.
Regarding claims 14 and 21-23, DE’434 discloses that the cladding metal and the base metal are joined by hot rolling (Page 4), which meets the limitation recited in claims 14 and 21-23.
Response to Arguments
Applicant’s arguments date 04/24/2026 have been considered but are moot in view of the new rejection ground.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Tensile Strength to Hardness Conversion Table discloses the relationship between Tensile Strength and Vicker’s Harness.
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 nonprovisional extension fee (37 CFR 1.17(a)) 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 mailing date of this final action.
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/XIAOWEI SU/Primary Examiner, Art Unit 1733
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