DETAILED ACTION
Examiner’s Note
This office action is in response to applicants’ amendments to the claims and remarks filed October 14, 2025. Claims 1-5 and 14 are new, with claim 14 being new.
Claim Rejections - 35 USC § 112
Applicants’ amendments to the claims filed October 15, 2025 have overcome the rejection under 35 U.S.C. 112(b)
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.
Claims 1 and 4-5 are rejected under 35 U.S.C. 103 as being unpatentable over Mitsunobu (PGPub US 2021/0079498) in view of Mori et al. (US Patent 5,539,180).
Regarding applicants’ claim 1, Mitsunobu discloses a coated steel sheet comprising a Zn-Mg-Al coating comprising an area fraction of MgZn2 up to 20%, MgZn2 being a Zn-Mg based intermetallic compound (paragraph 0031, 0123-130, 0166, and 0170). Mitsunobu do not appear to explicitly disclose constructions using the coated steel sheet where a first and second coated steel sheet are bonded by a welded joint portion, however the use of known techniques applied to known products where the results are predictable is within the ordinary level of skill in the art. Mori et al. disclose that it was known to join zinc plated steel sheets by welding, and further disclose a laser beam welding method for the same purpose (col. 1 lines 1-42). One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to weld a first and second coated steel sheet of Mitsunobu in the forming of zinc plated steel products where welding is a known method of joining zinc plated steel sheets thereby yielding a welded product with predictable results.
The welded product would include a microstructure where a portion of the coating closest to the welded joint portion includes an area fraction of a Zn-Mg based intermetallic which is up to 20% which overlaps applicants’ claimed area fraction range. A weld joint may include a region where the microstructure of the steel sheet and plating have been altered in the welding process. The term closest is not found to limit the exact distance from the weld but is understood to be the area immediately adjacent any region of the sheet and plating altered in microstructure or composition during the welding process. One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to form coated steel sheets having proportions of phases within the disclosed ranges.
Regarding applicants’ claim 4, the area immediately outside the weld area effected by the welding process is considered to be a position closest to the welded joint as discussed above. Therefore the hardness of the plating layer would be the same in the potion closest both before and after welding, or 100%, which falls within the claimed range.
Regarding applicants’ claim 5, Mitsunobu disclose the MgZn2 phase to have an equivalent circle diameter of between 2 and 10µm (paragraph 0171) which falls within applicants’ claimed range of an average diameter of 1 to 30µm.
Allowable Subject Matter
Claims 2 and 3 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Regarding applicants’ claim 2, Mitsunobu discloses coated steel sheets comprising a Zn-Mg-Al coating comprising an area fraction of MgZn2 up to 20%, MgZn2 being a Zn-Mg based intermetallic compound (paragraph 0031, 0123-130, 0166, and 0170) where when welded to each other would satisfy the requirements of claim 1 as discussed above. However Mitsunobu does not disclose that a portion closest to the welded joint has a Zn single phase with an area fraction that is 60% or more (claim 2). Further there is no motivation such that one of ordinary skill in the art would have fond it obvious before the effective filing date of the invention to modify the proportions of the area fractions and phases of the coating of Mitsunobu in order to obtain proportions which include a Zn single phase in a closest portion to a welded joint that is within the range of 60% or more.
Regarding applicants’ claim 3, Mitsunobu discloses coated steel sheets comprising a Zn-Mg-Al coating comprising an area fraction of MgZn2 up to 20%, MgZn2 being a Zn-Mg based intermetallic compound (paragraph 0031, 0123-130, 0166, and 0170) where when welded to each other would satisfy the requirements of claim 1 as discussed above. However Mitsunobu does not disclose a distance between the Zn-Al-Mg based plating to a bead toe portion of the welded joint to be in a range of 3 to 10mm. Further there is no motivation such that one of ordinary skill in the art would have fond it obvious before the effective filing date of the invention to modify the coating and welding process of Mitsunobu in order to obtain a welded structure exhibiting the claimed bead toe portion.
Claim 14 is allowed. Mitsunobu discloses coated steel sheets comprising a Zn-Mg-Al coating comprising an area fraction of MgZn2 up to 20%, MgZn2 being a Zn-Mg based intermetallic compound (paragraph 0031, 0123-130, 0166, and 0170) where when welded to each other would satisfy the requirements of claim 1 as discussed above. However Mitsunobu does not disclose that a portion closest to the welded joint has a Zn single phase with an area fraction that is 60% or more (claim 2). Further there is no motivation such that one of ordinary skill in the art would have fond it obvious before the effective filing date of the invention to modify the proportions of the area fractions and phases of the coating of Mitsunobu in order to obtain proportions which include a Zn single phase in a closest portion to a welded joint that is within the range of 60% or more.
Response to Arguments
Applicants’ arguments filed October 14, 2025 have been considered but have not been found to be persuasive.
Applicants argue that the claimed welded structural member is not obvious because it exhibits unexpectedly superior corrosion resistance and crack resistance by controlling the microstructure of the plating portion closest to the welded joint portion. However evidence of unexpected results must be weighed against evidence supporting prima facie obviousness in making a final determination of the obviousness of the claimed invention (MPEP 716.02(c)). Whether the unexpected results are the result of unexpectedly improved results or a property not taught by the prior art, the "objective evidence of non-obviousness must be commensurate in scope with the claims which the evidence is offered to support" MPEP 716.02(d). The evidence relied upon should establish "that the differences in results are in fact unexpected and unobvious and of both statistical and practical significance (MPEP 716.02(b)). Absent objective evidence there is insufficient basis by which to determine that the results are in fact unexpected and of both statistical and practical significance and that such a result turns on one or more claimed features (is commensurate in scope).
Applicants argue that simply welding a Zn-Al-MG-based plated steel sheet does not necessarily secure the properties of the present embodiment, however it is unclear which claimed feature(s) applicants are alleging would not be present. Substantially identical materials treated in a substantially identical manner are expected to result in substantially identical products. Both applicants and the prior art disclose the application of laser welding. Applicants’ do not point out the specific errors in the examiner position, nor present evidence that the process disclosed in the prior art differs such as to result welded structure distinct from that claimed. What specific parameters are necessary to arrive at the claimed welded structure that are not present in the prior art.
For these reasons and for those reasons as discussed in the rejections above, the rejections of record are maintained and this office action is made final.
Conclusion
THIS ACTION IS MADE FINAL. 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ADAM C KRUPICKA whose telephone number is (571)270-7086. The examiner can normally be reached Monday-Friday 8-5pm EST.
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/Adam Krupicka/Primary Examiner, Art Unit 1784