DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 February 12, 2026 has been entered.
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 .
Priority
Receipt is acknowledged of a certified copy of JP 2021-098118 field June 11, 2021 as required by 37 CFR 1.55. Receipt is also acknowledged of WO 2022/259805, the WIPO publication of PCT/JP2022/020007 filed May 12, 2022.
Claim Status
This Office Action is in response to Applicant’s Claim Amendments and Remarks filed February 12, 2026.
Claims Filing Date
February 12, 2026
Amended
1
New
19-22
Cancelled
4-6, 9-18
Pending
1-3, 7, 8, 19-22
Withdrawn Claim Rejections - 35 USC § 112
The following 112(b) rejections are withdrawn due to claim amendment:
Claim 1 lines 9-10 “atmospheric pressure in the furnace during the denitrification process is adjusted to an atmospheric pressure”.
Response to Remarks filed February 12, 2026
112(a)
Applicant's arguments filed February 12, 2026 with respect to the 112(a) rejection have been fully considered but they are not persuasive.
The applicant argues claim 1 amendment (Remarks p. 5 para. 3) is supported by 6:5-7, 13:24-14:15, and Fig. 8 (Remarks p. 5 para. 4).
As discussed in detail in the below rejections, the claim 1 amendment does not overcome the pending 112(a) rejection. It also introduces new 112(a) rejections.
112(b)
Applicant's arguments filed February 12, 2026 with respect to the 112(b) rejection have been fully considered but they are not persuasive.
The applicant argues claim 1 amendment addresses the atmospheric pressure rejection (Remarks p. 6 para. 2).
While the claim amendment addresses the previous 112(b) rejection regarding atmospheric pressure, it introduces a new 112(b) rejection as presented below.
The applicant argues the claim amendment is consistent with Fig. 8 regarding the temperature of the molten steel and the MgO concentration (Remarks p. 6 para. 3).
The examiner respectfully disagrees. The claim 1 amendment does not clarify the temperature of the molten steel nor the MgO concentration. New claims 19 and 20 recite a MgO upper limit present in the slag, but, for the reasons presented below, are rendered indefinite. New claim 22 limits the reference molten steel temperature to 1600°C, which, for the reasons presented below is rendered indefinite.
Yamaguchi in view of Song and Suk
Applicant’s arguments, see Remarks p. 7 para. 2, filed February 12, 2026, with respect to Yamaguchi in view of Song and Suk have been fully considered and are persuasive. The rejection of Yamaguchi in view of Song and Suk has been withdrawn.
The applicant persuasively argues that Song, with respect to MgO, discloses the melting temperature of the slag is lowered (Remarks p. 7 para. 2).
A machine translation of KR 10-0207859, see excerpt below and also the attached document, supports applicant’s argument that up to a MgO concentration of 13% has an effect of lowering the melting temperature of the slag.
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Yamaguchi in view of Kundrat and Suk
Applicant's arguments filed February 12, 2026 with respect to the Yamaguchi in view of Kundrat and Suk rejection have been fully considered but they are not persuasive.
The applicant argues amended claim 1 recites the molten steel temperature after denitrification treatment is set relative to a reference molten steel temperature that would be required to reduce the nitrogen concentration in the steel to the same amount with the denitrification treatment where there is no MgO in the slag, which is not disclosed or suggested by the applied references (Remarks p. 6 para. 6).
Yamaguchi in view of Kundrat and Suk discloses steel denitrification including adding a MgO-containing substance to molten steel (Yamaguchi [0001], [0017], [0024]-[0025]), where each time the MgO concentration in the slag is increased the slag liquidus temperature increases (Kundrat 10:34-40, 13:53-55, 14:1-5). Denitrification using a liquid state slag easily absorbs inclusions, including nitrogen, improving steel cleanliness (Suk [0010], [0024], [0029]-[0030], Fig. 3). Therefore, one of ordinary skill in the art would understand that denitrification when adding MgO to the slag is performed at a relatively higher temperature compared to a reference molten steel temperature denitrification treatment without MgO.
The applicant argues Kundrat does not relate to denitrification (Remarks p. 8 para. 1).
Yamaguchi in view of Kundrat and Suk discloses a molten steel denitrification method (Yamaguchi [0001]; Suk [0010], [0024]). Therefore, the cited prior art discloses this claim feature.
Kundrat is reasonably pertinent to the problem faced by the inventor of a CaO-Al2O3-MgO-containing slag during molten steel removal of impurities with increasing MgO concentration increasing slag basicity, which increases slag viscosity and liquidus temperature (Kundrat 10:34-40, 13:53-55, 14:1-5; applicant’s claim 1; applicant’s specification [0015], [0031], Fig. 8). Therefore, Kundrat is proper for use in an obviousness rejection under 35 U.S.C. 103. MPEP 2141.01(a)(I).
The applicant argues Kundrat does not indicate that the slag liquidus relates to the temperature at which denitrification should occur (Remarks p. 8 para. 1).
Kundrat in view of Suk discloses adding MgO decreases the relative concentration of CaO and increases the liquidus temperature of the slag (Kundrat 10:34-40, 13:53-55, 14:1-5). Denitrification using slag in the liquid state (Suk [0010], [0024]) easily absorbs inclusions, improving cleanliness of the steel (Suk [0010]), including nitrogen removal (Suk [0029]-[0030], Fig. 3). Therefore, the prior art recognizes elevating denitrification temperature based on an amount of MgO in the slag, and the general conditions of the claim are disclosed. The normal desire of scientists or artisans to improve upon what is already generally known provide the motivation to determine where in a disclosed set of percentages ranges it the optimum combination of percentages. MPEP 2144.05(II)(A).
The rejection of Yamaguchi in view of Kundrat and Suk is maintained.
Double Patenting
Applicant's arguments filed February 12, 2026 with respect to the Double Patenting rejection have been fully considered but they are not persuasive.
The applicant argues a Terminal Disclaimer has been submitted over the reference application (Remarks p. 8 paras. 3-4).
The Terminal Disclaimer filed February 12, 2026 was Disapproved on March 12, 2026 because “The reference application filing date is incorrect.”. Therefore, the double patenting rejection is maintained.
Claim Interpretation
Claims 1-3, 7, 8, and 19-22 “denitrification” is given the broadest reasonable interpretation consistent with applicant’s specification of a method that removes nitrogen from molten steel (applicant’s specification [0001], [0013]).
Claim 1 lines 6-7 “a step of adding a CaO-containing substance separately or together with an MgO-containing substance” is interpreted as the step requiring 1) addition of a CaO-containing substance and, separately, a MgO-containing substance, or 2) addition of a CaO- and MgO-containing substance.
Claim 1 line 26 “the slag” is given the broadest reasonable interpretation of referring to line 3 “a CaO-and-Al2O3-and MgO-containing slag”.
Claim Objection
Claim 1 is objected to because of the following informalities:
Line 3 “CaO-and-Al2O3-and MgO-containing slag” is inconsistent regarding the use of dashes, -, and spaces, .
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-3, 7, 8, and 19-22 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement.
The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claim 1 lines 22-28 “the denitrification treatment reduces the nitrogen concentration in the molten steel to a predetermined value and the molten steel temperature after the denitrification treatment is set relative to a reference molten steel temperature that would be required to reduce the nitrogen concentration in the molten steel to the predetermined value with the denitrification treatment when there is no MgO in the slag, such that the molten steel temperature after the denitrification treatment corresponds to 5°C or more than the reference molten steel temperature for each 1.0 mass % of MgO in the slag” fails to comply with the written description requirement.
Applicant’s specification recites in [0301] that Fig. 8 is a result of “a study…conducted on a molten steel temperature Tg that was required to reduce the nitrogen [N]f in the molten steel to 25 mass ppm when the MgO concentration (MgO) in the CaO-and-Al2O3-containing slag was changed over a range of 0 mass% to a saturated concentration.” These recited conditions are narrower than or not recited in claim 1.
Applicant’s Sixth Embodiment ([0031], Fig. 8) also does not discuss setting the denitrification temperature after denitrification treatment. Rather, the molten steel temperature appears to be set due to an increase in MgO concentration. According to claim 1, MgO is added to form the slag prior to denitrification.
Therefore, applicant’s disclosure in the specification as originally filed does not support the above cited claim limitation.
Claim 1 line 23 “predetermined value” fails to comply with the written description requirement. Applicant’s specification does not recite a “predetermined value” nor does it discuss a predetermined value of nitrogen concentration in the molten steel.
Claim 1 lines 23-24 “the molten steel temperature after the denitrification treatment is set” fails to comply with the written description requirement. In applicant’s specification the molten steel temperature is set for denitrification, not after. In applicant’s [0031] the set molten steel temperature is that required to reduce the nitrogen. Applicant’s specification does not appear to support setting the molten steel temperature after denitrification.
Claim 1 lines 26-27 “the molten steel temperature after the denitrification treatment” fails to comply with the written description requirement. In applicant’s specification the molten steel temperature is for denitrification, not after. For example, in applicant’s [0031] the molten steel temperature is that required to reduce the nitrogen. Applicant’s specification does not support the molten steel temperature after denitrification.
Claim 1 line 27 “5°C or more” renders the claim indefinite. Applicant’s specification discloses raising the temperature “by about 5°C each time the MgO in the slag was increase by 1.0 mass%” ([0031]). Applicant’s specification does not support the breadth of claim 1 line 27, which includes the temperature being more than 5°C.
Claim 19 line 2 “MgO…up to 17 mass %” fails to comply with the written description requirement. 17 mass % MgO is not recited in applicant’s specification. Applicant’s specification, such as [0024] and [0026], recite “MgO concentration (MgO) in the slag was 10 mass%”. Table 1 supports addition of 0 mass%, 5 mass%, and 10 mass % MgO.
Claims 2, 3, 7, 8, and 20-22 are rejected as depending from claim 1.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-3, 7, 8, and 19-22 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 line 4 “metal-Al-containing substance” renders the claim indefinite. It is unclear if the substance is metal and Al or if the metal in the substance is Al. For the purpose of examination claim 1 will be interpreted in light of applicant’s specification, such as [0021], as the metal in the substance being Al.
Claim 1 lines 10-12 “the furnace internal atmospheric pressure is at an atmospheric pressure of 105 Pa or at a lower depressurized atmospheric pressure” renders the claim indefinite. It is unclear what the “lower depressurized atmospheric pressure” is relative too. It could refer to lower than the recited 105 Pa, it could refer to lower than atmospheric pressure, which is approximately 1.01325 x 105 Pa, or it could refer to lower than an undisclosed atmospheric pressure. For the purpose of examination claim 1 is interpreted in light of [0030] of applicant’s specification as “a lower depressurized atmospheric pressure” being lower than 105 Pa.
Claim 1 line 23 “predetermined value” renders the claim indefinite. It is unclear what the metes and bounds are of a predetermined value and how to determine when a predetermined value is met. A “predetermined value” could refer to any value of nitrogen concentration that is predetermined or it could refer to a specific predetermined value. However, the claim does not clarify what the scope is of the claimed “predetermined value”.
Claim 1 lines 23 and 26-27 “after the denitrification treatment” renders the claim indefinite. It is unclear what denotes being after the denitrification treatment. For example, this limitation could refer to after the start of the denitrification treatment, immediately upon completion of the denitrification treatment, or some time after completion of the denitrification treatment. For the purpose of examination claim 1 will be interpreted as referring to any time that occurs after the start of the denitrification treatment.
Claim 1 lines 24-26 “a reference molten steel temperature that would be required to reduce the nitrogen concentration in the molten steel to the predetermined value with the denitrification treatment when there is no MgO in the slag” renders the claim indefinite. It is unclear what the metes and bounds are of the claimed reference molten steel temperature. The metes and bounds are of a “predetermined value” are unclear. The composition of the slag beyond requiring “no MgO” is not specified. The reduction in nitrogen concentration is not limited. Therefore, it is unclear how to determine a reference temperature given that it is unclear what the reference temperature is relative to.
Claim 1 lines 26-28 “the molten steel temperature after the denitrification temperature corresponds to 5°C or more than the reference molten steel temperature for each 1.0 mass % of MgO in the slag” renders the claim indefinite. While claim 1 lines 3-8 recite the addition of MgO to the slag, the amount of MgO added is not recited in claim 1. It is unclear how much MgO is required to be added to the slag of claim 1. It also unclear if the added MgO is required to be performed in 1 mass% MgO increments or if any amount of MgO can be added. It is also unclear what the starting MgO concentration is. Further, it is also unclear if this recites a property of the molten steel temperature if MgO is added, but does not actually limit the amount of MgO required to be added.
Claim 19 line 2 “MgO…up to 17 mass %” renders the claim indefinite. Claim 19 depends from claim 1, which only requires molten steel temperature increased for each 1.0 mass% of MgO. The scope of claim 19 includes MgO values of less than 1.0 mass%. It is unclear what the reference temperature corresponds to when less than 1.0 mass% of MgO is added. It is also unclear what the molten steel temperature after denitrification corresponds to when a not 1.0 mass% MgO increment is added.
Claim 20 line 2 “MgO…up to 10 mass %” renders the claim indefinite. Claim 20 depends from claim 1, which only requires molten steel temperature increased for each 1.0 mass% of MgO. The scope of claim 20 includes MgO values of less than 1.0 mass%. It is unclear what the reference temperature corresponds to when less than 1.0 mass% of MgO is added. It is also unclear what the molten steel temperature after denitrification corresponds to when a not 1.0 mass% MgO increment is added.
Claim 22 lines 1-2 “the reference molten steel temperature is 1600°C” renders the claim indefinite. This limitation could refer to claim 1 lines 24-26 “a reference molten steel temperature that would be required to reduce the nitrogen concentration in the molten steel to the predetermined value with the dentification treatment when there is no MgO in the slag” or it would refer to claim 1 lines 27-28 “the reference molten steel temperature for each 1.0 mass% of MgO in the slag”.
Claims 2, 3, 7, 8, and 21 are rejected as depending from claim 1.
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 1-3, 7, 8, and 19-22 are rejected under 35 U.S.C. 103 as being unpatentable over Yamaguchi (JP H08-246024 machine translation) in view of Kundrat (US 5,749,939) and Suk (KR 2012-0072822 machine translation).
Regarding claim 1, Yamaguchi discloses a molten steel denitrification method ([0001]) carried out in a furnace ([0024]), the method comprising:
Forming a CaO-and-Al2O3-and MgO-containing slag ([0008], [0017]) by a combination of a step of adding a metal-Al-containing molten steel ([0009], [0020], [0024]) having a concentration of Al that is in a range of 0.1 to 1.0 mass% ([0018]-[0020]: [Al]>= 0.3 wt%), and a step of adding a CaO-containing substance separately or together with an MgO-containing substance to the molten steel (dolomite is CaMg(CO3)2) ([0017], [0024]-[0025]), and
then blowing an oxygen-containing gas from above and onto the slag to perform a denitrification treatment ([0008]), wherein during the denitrification treatment, the furnace internal atmospheric pressure is at an atmospheric pressure of 105 Pa or at a lower depressurized atmospheric pressure (reduced pressure) ([0021]),
wherein a mass ratio of CaO to Al2O3 in the slag is in a range of from 0.4 to 1.8 ([0017]: 35-65 wt% CaO and 30-55 wt% Al2O3 results in a CaO/Al2O3 ratio of 0.64 to 2.17),
wherein the denitrification treatment reduces the nitrogen concentration in the molten steel to a predetermined value ([0011]-[0016], [0029]).
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Yamaguchi is silent to the molten steel temperature after the denitrification treatment being set relative to a reference molten steel temperature that would be required to reduce the nitrogen concentration in the molten steel to the predetermined value with the denitrification treatment when there is no MgO in the slag, such that the molten steel temperature after the denitrification treatment corresponds to 5°C or more than the reference molten steel temperature for each 1.0 mass% of MgO in the slag.
Kundrat discloses a CaO-and-Al2O3-and MgO-containing slag (10:23-26, 13:46-49, 59-67, 14:1-11) where each time the MgO concentration in the slag is increased the slag liquidus temperature increases (10:34-40, 13:53-55, 14:1-5).
Suk discloses a denitrification process to remove nitrogen from molten steel using a slag in the liquid state ([0010], [0024]).
It would have been obvious to one of ordinary skill in the art in the process of Yamaguchi to increase the temperature of the molten steel based on addition of MgO because adding MgO increases the slag liquidus temperature (Kundrat 10:34-30, 13:53-55, 14:1-5), which may result in trapped droplets of the alloy in the slag (Kundrat 10:34-40) and it makes the slag viscous and difficult to mix (Kundrat 14:1-5), whereas a liquid state slag (Suk [0020]) that covers the molten steel (Suk [0019]) easily absorbs inclusions, improving the cleanliness of the steel (Suk [0010]), including nitrogen removal (Suk [0029]-[0030], Fig. 3).
Therefore, Yamaguchi in view of Kundrat and Suk discloses the molten steel temperature after the denitrification treatment is set (increased) relative to a reference molten steel temperature that would be required to reduce the nitrogen concentration in the molten steel to the predetermined value with the denitrification treatment when there is no MgO in the slag (Kundrat 10:34-40, 13:53-55, 14:1-5; Suk [0010], [0019], [0020], [0029]-[0030]: liquid state slag covers the molten steel, easily absorbing inclusions, including nitrogen, and improving the cleanliness of the steel). With respect to the molten steel temperature after the denitrification treatment corresponding to 5°C or more than the reference molten steel temperature for each 1.0 mass% of MgO in the slag, “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” MPEP 2144.05(II)(A).
The limitation of “T.Fe in the slag after denitrification is set to 3.0 mass% or lower” has been considered and determined to naturally flow from the claimed denitrification process. The prior art discloses a denitrification process that is substantially similar to that claimed, including adding Al, CaO-containing substance, and MgO-containing substance to molten steel (Yamaguchi [0009], [0017], [0020], [0024]-[0025]), denitrifying by “blowing an oxidizing gas onto the surface of the slag so that the gas does not come into direct contact with the molten metal” (Yamaguchi [0008]), and overlapping Al concentration, pressure, and CaO/Al2O3 mass ratio for the slag (Yamaguchi [0017]-[0021]), such that “T.Fe in the slag after denitrification is set to 3.0 mass% or lower” naturally flows from the disclosure of the prior art. Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” MPEP 2144.05(II)(A).
Regarding claim 2, Yamaguchi discloses in the denitrification treatment, the oxygen-containing gas is supplied such that a ratio Ls/Ls0 between a thickness Ls0 of the slag and a depth Ls of a depression in the slag resulting from blowing of the oxygen-containing gas becomes 0.9 or lower ([0008]: oxidizing gas blown onto the surface of the slag so that the gas does not come into direct contact with the molten metal reads on Ls/Ls0 of less than 1).
For Ls/Ls0 of less than 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. MPEP 2144.05(I).
For the blown oxidizing gas not coming into direct contact with the molten metal, “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” MPEP 2144.05(II)(A).
Regarding claims 3 and 8, Yamaguchi discloses in the denitrification treatment, the oxygen-containing gas is an O2 gas diluted with an inert gas other than an N2 gas ([0021]: mixing O2 with Ar).
Regarding claim 7, Yamaguchi in view of Kundrat and Suk and optionally Fujimoto discloses a steel production method wherein molten steel smelted by the molten steel denitrification method according to claim 1 (see claim 1 rejection) is cast (Yamaguchi [0006]).
Regarding claim 19, Yamaguchi in view of Kundrat and Suk discloses MgO is present in the slag at a concentration of up to 17 mass % (10 and 20 wt%) (Kundrat 10:40, 13:66 to 14:5). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claim 20, Yamaguchi in view of Kundrat and Suk discloses MgO is present in the slag at a concentration of up to 10 mass % (10 and 20 wt%) (Kundrat 10:40, 13:66 to 14:5). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claim 21, Yamaguchi in view of Kundrat and Suk discloses MgO is present in the slag at a concentration in a range of from 5 to 10 mass % (10 and 20 wt%) (Kundrat 10:40, 13:66 to 14:5). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claim 22, Yamaguchi in view of Kundrat and Suk discloses the reference molten steel (Yamaguchi [0010], [0014]) temperature is 1600°C (at least 1500°C, preferably between 1500 and 1750°C, with examples at 1600°C) (Kundrat 9:15-18, 10:15-22, 17:40 to 18:57, Tables V-VI).
Claims 1-3, 7, 8, and 19-22 are rejected under 35 U.S.C. 103 as being unpatentable over Yamaguchi (JP H08-246024 machine translation) in view of Kundrat (US 5,749,939), Suk (KR 2012-0072822 machine translation), and Zhao (CN 113373278 machine translation).
In the event it is determined that the T.Fe in the slag after denitrification being set to 3.0 mass% or lower does not naturally flow from the disclosure of Yamaguchi in view of Kundrat and Suk, then the below rejection including Zhao is applied.
Regarding claim 1, Yamaguchi discloses a molten steel denitrification method ([0001]) carried out in a furnace ([0024]), the method comprising:
Forming a CaO-and-Al2O3-and MgO-containing slag ([0008], [0017]) by a combination of a step of adding a metal-Al-containing molten steel ([0009], [0020], [0024]) having a concentration of Al that is in a range of 0.1 to 1.0 mass% ([0018]-[0020]: [Al]>= 0.3 wt%), and a step of adding a CaO-containing substance separately or together with an MgO-containing substance to the molten steel (dolomite is CaMg(CO3)2) ([0017], [0024]-[0025]), and
then blowing an oxygen-containing gas from above and onto the slag to perform a denitrification treatment ([0008]), wherein during the denitrification treatment, the furnace internal atmospheric pressure is at an atmospheric pressure of 105 Pa or at a lower depressurized atmospheric pressure (reduced pressure) ([0021]),
wherein a mass ratio of CaO to Al2O3 in the slag is in a range of from 0.4 to 1.8 ([0017]: 35-65 wt% CaO and 30-55 wt% Al2O3 results in a CaO/Al2O3 ratio of 0.64 to 2.17),
wherein the denitrification treatment reduces the nitrogen concentration in the molten steel to a predetermined value ([0011]-[0016], [0029]).
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Yamaguchi is silent to the molten steel temperature after the denitrification treatment being set relative to a reference molten steel temperature that would be required to reduce the nitrogen concentration in the molten steel to the predetermined value with the denitrification treatment when there is no MgO in the slag, such that the molten steel temperature after the denitrification treatment corresponds to 5°C or more than the reference molten steel temperature for each 1.0 mass% of MgO in the slag.
Kundrat discloses a CaO-and-Al2O3-and MgO-containing slag (10:23-26, 13:46-49, 59-67, 14:1-11) where each time the MgO concentration in the slag is increased the slag liquidus temperature increases (10:34-40, 13:53-55, 14:1-5).
Suk discloses a denitrification process to remove nitrogen from molten steel using a slag in the liquid state ([0010], [0024]).
It would have been obvious to one of ordinary skill in the art in the process of Yamaguchi to increase the temperature of the molten steel based on addition of MgO because adding MgO increases the slag liquidus temperature (Kundrat 10:34-30, 13:53-55, 14:1-5), which may result in trapped droplets of the alloy in the slag (Kundrat 10:34-40) and it makes the slag viscous and difficult to mix (Kundrat 14:1-5), whereas a liquid state slag (Suk [0020]) that covers the molten steel (Suk [0019]) easily absorbs inclusions, improving the cleanliness of the steel (Suk [0010]), including nitrogen removal (Suk [0029]-[0030], Fig. 3).
Therefore, Yamaguchi in view of Kundrat and Suk discloses the molten steel temperature after the denitrification treatment is set (increased) relative to a reference molten steel temperature that would be required to reduce the nitrogen concentration in the molten steel to the predetermined value with the denitrification treatment when there is no MgO in the slag (Kundrat 10:34-40, 13:53-55, 14:1-5; Suk [0010], [0019], [0020], [0029]-[0030]: liquid state slag covers the molten steel, easily absorbing inclusions, including nitrogen, and improving the cleanliness of the steel). With respect to the molten steel temperature after the denitrification treatment corresponding to 5°C or more than the reference molten steel temperature for each 1.0 mass% of MgO in the slag, “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” MPEP 2144.05(II)(A).
Yamaguchi is silent to T.Fe in the slag after denitrification being set to 3.0 mass% or lower.
Zhao discloses molten steel with a CaO-and-Al2O3-and MgO-containing slag ([n0008], [n0010]) wherein T.Fe in the slag after the denitrification treatment is set to 3.0 mass% or lower ([n0012]).
It would have been obvious to one of ordinary skill in the art in the process of Yamaguchi to control the T.Fe in the slag after denitrification to 3.0 mass% or lower to ensure that the slag surface deoxidizer fully melts and reacts with the original oxidizing slag, and then significantly reduces the oxidizing properties of the slag (Zhao [n0016]).
Regarding claim 2, Yamaguchi discloses in the denitrification treatment, the oxygen-containing gas is supplied such that a ratio Ls/Ls0 between a thickness Ls0 of the slag and a depth Ls of a depression in the slag resulting from blowing of the oxygen-containing gas becomes 0.9 or lower ([0008]: oxidizing gas blown onto the surface of the slag so that the gas does not come into direct contact with the molten metal reads on Ls/Ls0 of less than 1).
For Ls/Ls0 of less than 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. MPEP 2144.05(I).
For the blown oxidizing gas not coming into direct contact with the molten metal, “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” MPEP 2144.05(II)(A).
Regarding claims 3 and 8, Yamaguchi discloses in the denitrification treatment, the oxygen-containing gas is an O2 gas diluted with an inert gas other than an N2 gas ([0021]: mixing O2 with Ar).
Regarding claim 7, Yamaguchi in view of Kundrat and Suk and optionally Fujimoto discloses a steel production method wherein molten steel smelted by the molten steel denitrification method according to claim 1 (see claim 1 rejection) is cast (Yamaguchi [0006]).
Regarding claim 19, Yamaguchi in view of Kundrat and Suk discloses MgO is present in the slag at a concentration of up to 17 mass % (10 and 20 wt%) (Kundrat 10:40, 13:66 to 14:5). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claim 20, Yamaguchi in view of Kundrat and Suk discloses MgO is present in the slag at a concentration of up to 10 mass % (10 and 20 wt%) (Kundrat 10:40, 13:66 to 14:5). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claim 21, Yamaguchi in view of Kundrat and Suk discloses MgO is present in the slag at a concentration in a range of from 5 to 10 mass % (10 and 20 wt%) (Kundrat 10:40, 13:66 to 14:5). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claim 22, Yamaguchi in view of Kundrat and Suk discloses the reference molten steel (Yamaguchi [0010], [0014]) temperature is 1600°C (at least 1500°C, preferably between 1500 and 1750°C, with examples at 1600°C) (Kundrat 9:15-18, 10:15-22, 17:40 to 18:57, Tables V-VI).
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 1-3, 7, 8, and 19-22 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-5 of U.S. Patent No. 12,252,754 (US ‘574, US App No 18/560,737) in view of Yamaguchi (JP H08-246024 machine translation).
US ‘574 claims a molten steel denitrification method forming a CaO-and-Al2O3-and-MgO-containing slag (claim 1) with a temperature of the molten steel adjusted based on the MgO concentration (claim 1) in a depressurized atmosphere (claim 2) with a controlled [Al] concentration (claims 3, 4) that undergoes casting (claim 5).
US ‘754 is silent to the T.Fe in the slag after the denitrification treatment is set to 3.0 mass% or lower.
Yamaguchi discloses a molten steel denitrification method ([0001]) including denitrifying by “blowing an oxidizing gas onto the surface of the slag so that the gas does not come into direct contact with the molten metal” (Yamaguchi [0008]).
It would have been obvious to one of ordinary skill in the art in the process of US ‘574 to blow an oxidizing gas onto the surface of the slag so that the gas does not come into direct contact with the molten metal, which helps maintain the Al concentration at 0.5% or more (Yamaguchi [0009]) and removes N from the slag by the slag-molten steel reaction while keeping the N concentration in a low range (Yamaguchi [0014]).
The limitation of “T.Fe in the slag after denitrification is set to 3.0 mass% or lower” has been considered and determined to naturally flow from the claimed denitrification process. The prior art discloses a denitrification process that is substantially similar to that claimed (US ‘574 claims 1-5), including denitrifying by “blowing an oxidizing gas onto the surface of the slag so that the gas does not come into direct contact with the molten metal” (Yamaguchi [0008]), such that “T.Fe in the slag after denitrification is set to 3.0 mass% or lower” naturally flows from the disclosure of the prior art. Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” MPEP 2144.05(II)(A).
This is a provisional nonstatutory double patenting rejection.
Related Art
Tada (US 2009/0019968)
Tada discloses a molten steel denitrification method ([0001], [0019]) in which CaO-and-Al2O3-containing slag ([0064], [0085]) is formed by a combination of an Al addition step of adding a metal-Al-containing substance to molten steel to deoxidize and turn the molten steel into Al-containing molten steel ([0077]-[0081]) and a CaO addition step of adding CaO-containing substance to the molten steel ([0077], [0082]-[0084]), and then an oxygen-containing gas is blown from above and through the slag to perform a denitrification treatment ([0088]-[0091]) without using carbide denitrification flux ([0077]-[0087]), wherein the Al concentration is adjusted to a predetermined range in the Al addition step ([0078]), the atmospheric pressure in the furnace during the denitrification process is adjusted to a predetermined range ([0028], [0055], [0057], [0092]-[0100]), the mass ratio C/A of CaO/Al2O3 is within a predetermined range for the slag composition ([0084]).
Numata (US 2013/084205)
Numata discloses a slag with not less than 40% CaO, not less than 5% MgO, and total content of Fe oxides and Mn oxides of not more than 3% ([0091]), where limiting the Fe oxides and Mn oxides subjects the slag to reducing reaction and prevents an issue with oxygen activity at the slag-metal interface ([0094]). Numata also discloses the content of Al in the molten steel is about 0.01 to 0.05% ([0097]).
Kim (KR 2013-0034253 machine translation)
Kim discloses a flux for steelmaking that reduces the T.Fe in the slag ([0001]) by adding Mg, which generates oxidation reaction heat ([0005]). Kim also discloses that steel properties deteriorate due to non-metallic inclusions, where preventing molten melt from coming into contact with the atmosphere prevents molten metal oxidation ([0002]). Kim also discloses flux covering molten metal prevents directed contact between molten metal and the atmosphere ([0003]).
Yonezawa (JP H11-269524 machine translation)
Yonezawa discloses pretreatment of molten iron ([0001]) so that the T.Fe content of the slag is 3% to 20% ([0011]) to increase the degree of oxidation of the slag and keep the molten iron temperature low ([0013]) and to achieve sufficient dephosphorization reaction ([0022]).
Zhao (CN 113373278 machine translation)
Zhao discloses a slag modification process ([n0001], [n0005]) using slag that includes 40 to 50% CaO and 15 to 25% Al2O3 (CaO/Al2O3, C/A, is 1.6 to 3.3, 40/25 to 50/15) ([n0008], [n0010]) with a T.Fe in the ladle slag below 3% ([n0012]) to significantly reduce the oxidizing properties of the slag by fully melting and reacting the original oxidizing ladle slag ([n0016]).
Ban-Ya (US 2011/0167960)
Ban-Ya discloses a flux (slag) for refining steel of low nitrogen ([0002]) with 5 to 17% MgO ([0009]) and a refining temperature of approximately 1600°C ([0016], [0042], Table 3).
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/STEPHANI HILL/Examiner, Art Unit 1735
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