DETAILED ACTION
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 1-7 are rejected under 35 U.S.C. 103 as being unpatentable over Machado et al. (WO 2017/017521 A1), in view of Machado ‘734 (WO 2020/053734).
Regarding applicants’ claims 1-4 and 6-7, Machado et al. disclose a hot-formed aluminum plated steel part, but do not appear to explicitly disclose the compositional proportions of the coating after hot-forming or the formation of an oxide layer having a thickness of less than 1.0µm (claim 1), or less than 0.5µm (claims 4-7).
One of ordinary skill in the art, however, would expect substantially identical materials treated in a substantially identical manner to form substantially identical parts.
Applicants disclose plating steel with a coating comprising (in weight percent): Zn: 10.0 to 75.0 %, Si: 1.1 to 8.0 %, Mg: 2.2 to 7.0 %, and Sr: 0.01 to 2.0 %, with the balance being Al and inevitable impurity (present specification paragraph 0064). The steel sheet for hot-press forming is heated to a heating temperature of the Ac3 transformation temperature or more and 980°C or less. by setting the heating temperature to the Ac3 transformation temperature or more, microstructure of the steel sheet can be austenitized (paragraph 0073), and subsequently hot-pressed. Applicants disclose that “According to the present disclosure, hot press forming conditions are not particularly limited. For example, hot-press forming can be performed at 600 °C to 800 °C, which is a typical temperature range for hot-press forming.” (paragraph 0077).
With regards to the composition of the coating Machado et al. disclose a coating comprising (in weight percent): 4.0 to 20% zinc, 1.0 to 3.5% silicon, 1.0 to 4.0% magnesium (page 4 lines 19-26) but does not appear to explicitly disclose the addition of strontium. Machado ‘734 disclose a plated steel, the plating being an aluminum plating comprising zinc, silicon and magnesium, where the coating can optionally include additional elements such as strontium up to 0.3% (page 4 line 30-page 5 line 5). The additional elements demonstrated in the art to be optionally included in aluminum platings containing zinc, silicon, and magnesium is within the ordinary skill in the art. One of ordinary skill in the art before the effective filing date of applicants’ claimed invention would have found it obvious to include known optional elements including strontium in amounts of up to 0.3% absent a showing of criticality with regards to the claimed strontium content. There is a reasonable expectation of success in including strontium where Machado ‘734 demonstrates the addition of up to 0.3% strontium in an aluminum coating on steel to be hot-pressed, the coating containing zinc, silicon and magnesium.
One of ordinary skill in the art before the effective filing date of applicants’ claimed invention would have found it obvious to select from within the disclosed proportions including values which fall within the presently claimed ranges.
Machado et al. disclose that the coated steel sheet is cut to obtain a blank and a thermal treatment is applied to the blank in a furnace under non protective atmosphere at an austenitization temperature usually between 840 and 950°C, preferably 880 to 930°C (page 6 lines 28-32) where after the thermal treatment, the blank is then transferred to a hot-forming tool and hot-formed at a temperature between 600 and 830°C (page 7 lines 3-7).
Given the treatment of substantially identical materials in a substantially identical manner the hot formed part of Machado et al. would be expected to be substantially identical to applicants’ hot-pressed member including having a coating at least overlapping in composition with applicants’ claimed coating and having an oxide layer with a thickness within applicants’ claimed range.
Regarding applicants’ claim 5, Machado et al. disclose steel sheet with a metallic coating, the coating, comprising (in weight percent): 4.0 to 20% zinc, 1.0 to 3.5% silicon, 1.0 to 4.0% magnesium (page 4 lines 19-26) but does not appear to explicitly disclose the addition of strontium. Machado ‘734 disclose a plated steel, the plating being an aluminum plating comprising zinc, silicon, and magnesium, where the coating can optionally include additional elements such as strontium up to 0.3% (page 4 line 30-page 5 line 5). The addition elements demonstrated in the art to be optionally included in aluminum platings containing zinc, silicon, and magnesium is within the ordinary skill in the art. One of ordinary skill in the art before the effective filing date of applicants’ claimed invention would have found it obvious to include known optional elements including strontium in amounts of up to 0.3% absent a showing of criticality with regards to the claimed strontium content. There is a reasonable expectation of success where Machado ‘734 demonstrates the addition of up to 0.3% strontium in an aluminum coating on steel to be hot pressed, the coating containing zinc, silicon and magnesium.
One of ordinary skill in the art before the effective filing date of applicants’ claimed invention would have found it obvious to select from within the disclosed proportions including values which fall within the presently claimed ranges.
Claims 1, 4, and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Machado et al. (WO 2020/053734 A1).
Regarding applicants’ claims 1 and 4, Machado et al. disclose a press hardened steel part coated with an alloyed coating comprising (in weight percent): 0.1 to 11% zinc, 0.1 to 12% silicon, 0.1 to 10% magnesium, selected elements including strontium at 0.3%, and optionally up to 5% iron (page 4 line 29 – page 5 line 27) where a native oxide layer is present (page 5 lines 12-17).
While Machado et al. do not appear to disclose the exact ranges claimed, one of ordinary skill in the art before the effective filing date of applicants’ claimed invention would have found it obvious to select from the disclosed proportions including proportions which fall within applicants’ claimed ranges.
Machado et al. disclose the native oxide to be very thin, and to be still very thin after austenitization, for example 10 to 100nm (page 3 lines 5-21), therefore the press hardened part would have an oxide layer having a thickness of less than 1.0µm (claim 1) and further less than 0.5µm (claim 4).
Regarding applicants’ claim 5, Machado et al. do not distinguish between the compositional proportions of the coated steel and the composition of the coated press hardened part (page 1 lines 13-25, page 4 lines 29-30, and page 9 lines 1-11), therefore the coating compositions disclosed are understood to represent the proportions of the coating as applied to the steel sheet and of the coating in the subsequently formed press hardened apart. The compositional proportions of the coating on the steel sheet for hot forming are (in weight percent): 0.1 to 11% zinc, 0.1 to 12% silicon, 0.1 to 10% magnesium, selected elements including strontium at 0.3%, and optionally up to 5% iron (page 4 line 29 – page 5 line 27).
Conclusion
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