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 .
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.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 2021/0187583).
Regarding claim 1, Kim discloses a hot stamping component (¶ 6). The component comprises a base steel plate and a plated layer on the steel plate (¶ 6). The plated layer includes a first layer (corresponding to the diffusion layer) and a second layer (corresponding to the Al-Fe intermetallic layer) in this order from the steel plate (¶ 6). Kim states the plated layer is formed after hot stamping (see ¶ 52). Kim teaches the second layer comprises intermetallic compound phases such as FeAl3 or Fe2Al5 (¶ 7) which comprises 59% and 55% Al, respectively. The second layer also comprises an “intermetallic compound portion” which comprises 62%-67% Fe and 30%-34% Al (¶ 9). This intermetallic compound portion has a 1 μm – 5 μm unit length and corresponds to the claimed length of the Fe-rich phase. Kim teaches the thickness of the plated layer is 10 μm – 50 μm (¶ 50), with the thickness of the second layer being 1.6-3.6 times the thickness of the first layer (¶ 52). The thickness of the second layer is therefore about 6 μm – 39 μm. The prior art ranges either overlap or lie within the claimed ranges, creating a prima facie case of obviousness. See MPEP 2144.05 I.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 2021/0187583), as applied to claim 1, further in view of Oh et al. (US 2022/0049338).
Regarding claim 2, the limitations of claim 1 have been addressed above. Kim does not teach a diffusible hydrogen content in the steel is 0.30 mass ppm or less. Oh teaches a hot press forming member having a content of diffusible hydrogen of 0.1 ppm or less (¶ 16). It would have been obvious at the effective time of filing of the claimed invention for one of ordinary skill in the art to modify the diffusible hydrogen content of the steel of Kim according to the teachings of Oh because a lower diffusible hydrogen content is associated with increased hydrogen embrittlement resistance and improved weldability (¶¶ 92, 94).
Claims 3-4 and 6-7 are rejected under 35 U.S.C. 103 as being unpatentable over Sung et al. (US 2021/0402740).
Regarding claim 3, Sung teaches a steel sheet for hot pressing (¶ 8). The steel sheet includes a plating layer having a diffusion layer (corresponding to the claimed interfacial layer) and a surface layer (corresponding to the metal layer) (¶ 8). The surface layer contains at least 80% wt aluminum (¶ 48) and the diffusion layer contains 0.1%-40% wt silicon (¶ 48). Accordingly, there must be Si-rich phases containing at least 4% mass silicon, absent objective evidence to the contrary. See MPEP 2112.
Sung does not teach or suggest a cross-section area fraction of Si-rich phases in the diffusion layer is 5%-30%. However, the instant specification obtains the claimed area fraction of Si-rich phases by setting the Si content in the coating bath (¶ 131), and either coiling after hot rolling at 600°C -800°C (¶ 142), recrystallization annealing at a dew point of 0°C-20°C (¶ 145), or forming a Fe pre-coat layer (¶ 146). Sung teaches coiling after hot rolling at a temperature of 550°C -800°C (¶ 71). This is substantially similar to the claimed process. Accordingly, one of ordinary skill in the art would expect the claimed cross-section area fraction of Si-rich phases in the prior art steel, absent objective evidence to the contrary. See MPEP 2112.
Regarding claim 4, Sung teaches the surface layer is at least 80% wt Al (¶ 48). Therefore, the surface layer must contain at most 20% Si and Fe, absent objective evidence to the contrary. This overlaps the claimed ranges, creating a prima facie case of obviousness. See MPEP 2144.05 I.
Regarding claims 6-7, since Sung teaches a steel sheet for hot pressing (¶ 8), a method of hot pressing the steel sheet to obtain a hot-pressed member is implicitly taught.
Claims 5 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Sung et al. (US 2021/0402740), as applied to claim 4, further in view of Oh et al. (US 2022/0049338).
Regarding claim 5, the limitations of claim 4 have been addressed above. Sung teaches including Mg in the plating bath (¶ 77), but does not teach or suggest the amount to include. Oh teaches including up to 1.1% wt Mg (¶ 40) for plating aluminum alloy on steel sheet for hot pressing (¶ 39) in order to improve the corrosion resistance of the steel (¶ 40). It would have been obvious at the effective time of filing for one of ordinary skill in the art to include Mg as taught by Oh in the metal layer of Sung to improve corrosion resistance.
Regarding claim 8, since Sung teaches a steel sheet for hot pressing (¶ 8), a method of hot pressing the steel sheet to obtain a hot pressed member is implicitly taught.
Conclusion
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/XIAOBEI WANG/Primary Examiner, Art Unit 1784