U.S. patent application number 12/609522 was filed with the patent office on 2010-05-06 for ultra-high strength stainless alloy strip, a method of making same, and a method of using same for making a golf club head.
Invention is credited to Theodore Kosa, David E. Wert.
Application Number | 20100108203 12/609522 |
Document ID | / |
Family ID | 41346080 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100108203 |
Kind Code |
A1 |
Kosa; Theodore ; et
al. |
May 6, 2010 |
Ultra-High Strength Stainless Alloy Strip, a Method of Making Same,
and a Method of Using Same for Making a Golf Club Head
Abstract
A stainless steel strip article is disclosed. The article is
formed from a corrosion resistant alloy having the following
composition in weight percent, about: TABLE-US-00001 C 0.03 max. Mn
1.0 max. Si 0.75 max. P 0.040 max. S 0.020 max. Cr 10.9-11.1 Ni
10.9-11.1 Mo 0.9-1.1 Ti 1.5-1.6 Al 0.25 max. Nb 0.7-0.8 Cu 1 max. B
0.010 max. N 0.030 max. The balance is iron and usual impurities.
The elongated thin strip article provides a room temperature
tensile strength of at least about 280 ksi in the solution treated
and age hardened condition. A method of making the strip article
and a method of using it to make a golf club are also
disclosed.
Inventors: |
Kosa; Theodore; (Moosic,
PA) ; Wert; David E.; (Wyomissing, PA) |
Correspondence
Address: |
DANN, DORFMAN, HERRELL & SKILLMAN
1601 MARKET STREET, SUITE 2400
PHILADELPHIA
PA
19103-2307
US
|
Family ID: |
41346080 |
Appl. No.: |
12/609522 |
Filed: |
October 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61110034 |
Oct 31, 2008 |
|
|
|
Current U.S.
Class: |
148/542 ;
148/326 |
Current CPC
Class: |
C22C 38/02 20130101;
C22C 38/42 20130101; C21D 8/021 20130101; C21D 8/0226 20130101;
C22C 38/50 20130101; C22C 38/04 20130101; C21D 6/02 20130101; C22C
38/48 20130101; C22C 38/06 20130101; C22C 38/54 20130101; C21D
9/0068 20130101; C21D 2211/008 20130101; C21D 6/001 20130101; C22C
38/001 20130101; C22C 38/44 20130101; C21D 8/0236 20130101 |
Class at
Publication: |
148/542 ;
148/326 |
International
Class: |
C21D 9/00 20060101
C21D009/00; C22C 38/50 20060101 C22C038/50; C21D 8/02 20060101
C21D008/02; C22C 38/44 20060101 C22C038/44; C22C 38/48 20060101
C22C038/48; C22C 38/42 20060101 C22C038/42 |
Claims
1. An elongated, thin strip article that is formed from corrosion
resistant alloy comprising, in weight percent, about:
TABLE-US-00008 C 0.03 max. Mn 1.0 max. Si 0.75 max. P 0.040 max. S
0.020 max. Cr 10.9-11.1 Ni 10.9-11.1 Mo 0.9-1.1 Ti 1.5-1.6 Al 0.25
max. Nb 0.7-0.8 Cu 1 max. B 0.010 max. N 0.030 max.
and the balance is iron and usual impurities, said elongated thin
strip article having a room temperature tensile strength of at
least about 280 ksi in the solution treated and age hardened
condition.
2. An elongated strip article as claimed in claim 1 wherein the
strip has a thickness of about 0.02 to 0.16 inches.
3. An elongated strip article as claimed in claim 1 wherein the
alloy has an average grain size not greater than about ASTM 7-8 in
major dimension.
4. An elongated strip article as claimed in claim 1 which has a
hardness of about 53-54 HRC.
5. A method of making a thin strip article comprising the steps of
casting a corrosion resistant alloy comprising, in weight percent,
about TABLE-US-00009 C 0.03 max. Mn 1.0 max. Si 0.75 max. P 0.040
max. S 0.020 max. Cr 10.9-11.1 Ni 10.9-11.1 Mo 0.9-1.1 Ti 1.5-1.6
Al 0.25 max. Nb 0.7-0.8 Cu 1 max. B 0.010 max. N 0.030 max.
and the balance being iron and usual impurities to form an ingot;
mechanically working said ingot to form an elongated strip
material; and then heat treating said elongated strip material
under conditions of time and temperature to provide an ultimate
tensile strength of at least about 280 ksi at room temperature.
6. A method as claimed in claim 5 wherein the step of heat treating
the elongated strip material comprises the steps of: heating the
elongated strip material at a temperature of about
1900-2000.degree. F.; and then heating the elongated strip material
at a temperature of about 900.degree. F. to about 950.degree.
F.
7. A method as claimed in claim 6 wherein the first heating step
comprises heating the alloy at a temperature of about
1900-1950.degree. F. and the method comprises the following steps
between the heating steps: rapidly cooling the alloy to about
-100.degree. F.; and then holding the alloy at about -100.degree.
F. for a period of time to substantially completely transform any
austenite in the alloy to martensite.
8. A method as claimed in claim 5 wherein the step of mechanically
working the ingot comprises the steps of: pressing the ingot to
form a billet; and then hot rolling the billet to form the
elongated strip material.
9. A method as claimed in claim 5 wherein the step of mechanically
working the ingot comprises hot rolling the ingot to form the
elongated strip material.
10. A method as claimed in claim 9 wherein the hot rolling step
comprises heating the billet to about 1900-2250.degree. F.
11. A method of making a golf club head comprising the steps of
casting a corrosion resistant alloy comprising, in weight percent,
about TABLE-US-00010 C 0.03 max. Mn 1.0 max. Si 0.75 max. P 0.040
max. S 0.020 max. Cr 10.9-11.1 Ni 10.9-11.1 Mo 0.9-1.1 Ti 1.5-1.6
Al 0.25 max. Nb 0.7-0.8 Cu 1 max. B 0.010 max. N 0.030 max.
and the balance being iron and usual impurities to form an ingot;
mechanically working said ingot to form an elongated strip
material; heat treating said elongated strip material under
conditions of time and temperature to improve the machinability and
processability of the material; cutting said elongated strip
material to form a faceplate for a golf club head; forming a golf
club head body from a corrosion resistant precipitation hardenable
steel alloy; bonding said faceplate to said golf club head body to
form a golf club head assembly; and then heat treating said golf
club head assembly under conditions of time and temperature to
provide hardness and strength in the golf club head assembly and an
ultimate tensile strength of at least about 280 ksi at room
temperature in said faceplate.
12. A method as claimed in claim 11 wherein the step of heat
treating the golf club heat assembly comprises the steps of:
heating the elongated strip material at a temperature of about
1900-2000.degree. F.; and then heating the elongated strip material
at a temperature of about 900.degree. F. to about 950.degree.
F.
13. A method as claimed in claim 12 wherein the first heating step
comprises heating the golf club heat assembly at a temperature of
about 1900-1950.degree. F. and the method comprises the following
steps between the heating steps: rapidly cooling the golf club head
assembly to about -100.degree. F.; and then holding the golf club
head assembly at about -100.degree. F. for a period of time to
substantially completely transform any austenite in the alloy to
martensite.
14. A method as claimed in claim 11 wherein the step of
mechanically working the ingot comprises the steps of pressing the
ingot to form a billet; and then hot rolling the billet to form the
elongated strip material.
15. A method as claimed in claim 11 wherein the step of
mechanically working the ingot comprises hot rolling the ingot to
form the elongated strip material.
16. A method as claimed in claim 15 wherein the hot rolling step
comprises heating the billet to about 1900-2250.degree. F.
17. A method as claimed in claim 11 wherein the step of heat
treating the elongated strip material comprises the step of
overaging the strip material at about 1100-1350.degree. F.
18. A method as claimed in any of claims 11 to 13 wherein the step
of mechanically working the ingot comprises the steps of: pressing
the ingot to form a billet; hot rolling the billet to form the
elongated strip material; and then cold rolling the elongated strip
material to reduce its thickness to final or near final
dimension.
19. A method as claimed in any of claims 11 to 13 wherein the step
of mechanically working the ingot comprises the steps of: hot
rolling the ingot to form elongated strip material; and then cold
rolling the elongated strip material to reduce its thickness to
final or near final dimension.
20. A method as claimed in claim 18 or claim 19 wherein the hot
rolling step comprises heating the ingot or billet to about
1038-1232.degree. C.
21. A method as claimed in claim 19 wherein the hot rolling step
comprises heating the ingot or billet to about 1038-1232.degree. C.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/110,034 filed Oct. 31, 2008, the entirety
of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to stainless steel strip material and
in particular to a stainless steel strip article having very high
tensile strength, a method of making same, and a method of using
the strip material for making a golf club head.
[0004] 2. Description of the Related Art
[0005] Golf club manufacturers are constantly looking for a high
strength faceplate material. Very high strength allows the
faceplate section to be made thinner, and therefore lighter, which
provides designers more leeway in club head design. In addition,
corrosion-resistant materials are preferable to non-stainless
materials because surface coatings or plating, which could be
removed during use, are not required.
[0006] Current solutions to this problem include the use of
standard PH stainless steel alloys such as the CUSTOM 455 alloy and
newly designed stainless alloys such as the CUSTOM 465 and CUSTOM
475 alloys. However, the CUSTOM 455 and CUSTOM 465 alloys do not
provide the strength levels desired in new club designs. The CUSTOM
475 alloy provides very high strength, but it is also highly
alloyed, making it both expensive for the club manufacturer as well
as less forgiving in the golf club manufacturing process.
[0007] In addition, many club heads are typically manufactured
using a cast body with a faceplate. The cast body material is
typically formed of a precipitation hardenable stainless steel such
as 17-4 PH or 15-5 PH stainless steel. Golf clubs are typically
manufactured by welding the faceplate to the cast body and then
heat treating the entire assembly to develop final properties. The
alloys typically used for the cast body of the club have solution
temperatures of about 1900.degree. F., whereas the known faceplate
materials have solution temperatures ranging from 1550.degree. F.
to 1800.degree. F. This mismatch in heat treating temperatures
results in either the club body, or the faceplate material, or
possibly both, providing less than optimum properties in the
as-heat treated condition after assembly of the club head. In
addition, the CUSTOM 475 alloy often requires a different
manufacturing process altogether, because the alloy cannot be
re-solutioned after club head assembly.
BRIEF SUMMARY OF THE INVENTION
[0008] The disadvantages of the known materials are overcome to a
large degree by a stainless steel strip article according to this
invention. In accordance with the one aspect of the present
invention, there is provided a stainless steel strip article that
is formed from a corrosion resistant alloy comprising, in weight
percent, about:
TABLE-US-00002 C 0.03 max. Mn 1.0 max. Si 0.75 max. P 0.040 max. S
0.020 max. Cr 10.9-11.1 Ni 10.9-11.1 Mo 0.9-1.1 Ti 1.5-1.6 Al 0.25
max. Nb 0.7-0.8 Cu 1 max. B 0.010 max. N 0.030 max.
and the balance is iron and usual impurities. The elongated thin
strip article provides a room temperature tensile strength of at
least about 280 ksi in the solution treated and age hardened
condition.
[0009] In accordance with another aspect of this invention there is
provided a method of making a thin strip article. The method
comprises the steps of casting a corrosion resistant alloy having
the weight percent composition set forth above to form an ingot.
The ingot is hot worked to form an elongated strip material. The
strip material is then heat treated under conditions of time and
temperature to provide an ultimate tensile strength of at least
about 280 ksi at room temperature.
[0010] In accordance with a further aspect of this invention there
is provided a method of making a golf club head. The method
includes the step of casting a corrosion resistant alloy having the
weight percent composition set forth above to form an ingot. The
ingot is hot worked to form an elongated strip article which is
then heat treated under conditions of time and temperature to
benefit the machinability and processability of the strip material.
The strip material is then machined to form a faceplate for a golf
club head. The method includes the further step of forming a golf
club head body from a corrosion resistant precipitation hardenable
steel alloy. The faceplate is bonded to golf club head body. The
assembly is then heat treated under conditions of time and
temperature sufficient to provide a desired level of hardness and
strength in the golf club head body and an ultimate tensile
strength of at least about 280 ksi at room temperature in the
faceplate.
BRIEF DESCRIPTION OF THE DRAWING
[0011] The drawing is a graph of tensile strength as a function of
aging temperature.
DETAILED DESCRIPTION
[0012] A preferred embodiment of the invention includes an
elongated strip article having the following composition in weight
percent:
TABLE-US-00003 C 0.03 max. Mn 1.0 max. Si 0.75 max. P 0.040 max. S
0.020 max. Cr 10.9-11.1 Ni 10.9-11.1 Mo 0.9-1.1 Ti 1.5-1.6 Al 0.25
max. Nb 0.7-0.8 Cu 1 max. B 0.010 max. N 0.030 max.
The balance is iron and the usual impurities.
[0013] The alloy composition is preferably melted using vacuum
induction melting (VIM). The steel is cast into one or more ingot
molds. For additional cleanness, the alloy is vacuum arc remelted
(VAR) after the VIM step. After solidification, the alloy is formed
into strip by intermediate pressing of the ingot to form a billet
and then hot rolling the billet to form elongated strip.
Alternatively, the strip material can be formed by hot rolling the
ingot from a starting temperature of about 1900.degree. F. to
2250.degree. F. The strip can be provided in the overaged condition
by heating at about 1100.degree. F. to 1350.degree. F. for about 2
to 8 hours and then cooling in air. Alternatively, and for better
machinability and processability, the strip material is heated at
about 1900.degree. F. to 1950.degree. F. for about 1 hour, cooled
in air, refrigerated at about -100.degree. F. for about 8 hours,
and then warmed in air to room temperature. Preferably, the strip
material is cold rolled to final or near final thickness prior to
being heat treated. The strip material according to this invention
can be solution treated in a continuous furnace with times and
temperatures adjusted accordingly. For the golf club application,
the strip material is processed to a thickness of about 0.02-0.16
inches, preferably about 0.10-0.12 inches.
[0014] Unlike the known high strength stainless steel alloys such
as the CUSTOM 475 stainless alloy, the alloy strip according to
this invention can be double solution treated with no significant
loss in properties, particularly no loss of strength. In other
words, the stainless steel strip material of this invention can be
provided in the solution treated plus refrigerated condition,
processed into components, and then re-solutioned, re-refrigerated,
and age hardened after being assembled into a golf club head to
provide the desired high strength and hardness.
[0015] As an example of the elongated strip article according to
the present invention, a small heat was melted and processed. The
400 lb heat was melted by VIM+VAR and cast as an 8-inch diameter
ingot. The weight percent composition of the VAR ingot is given
below in Table I. The balance of the alloy was iron and usual
impurities.
TABLE-US-00004 TABLE I C Mn Si P S Cr Ni Mo Ti Cb B N Ce 0.005 0.05
0.04 <0.005 <0.0005 11.05 11.02 1.01 1.56 0.79 0.0019 0.0016
0.001
[0016] The ingot was homogenized at 2300.degree. F. for 16 hours,
and then pressed to a 4-in.times.8-in billet from a starting
temperature of 2000.degree. F. The billet was hot rolled to 7.5 in.
wide.times.0.15 in. thick strip from a starting temperature of
2250.degree. F. The strip was then ground to 0.135 in. thick and
then cold rolled to 0.1103 in. thick. The strip was given an
overaging treatment by heating at 1146.degree. F. for 5.5 hours.
After cooling to room temperature, the strip material was ground to
a final thickness of 0.1083 in.
[0017] Standard strip tensile blanks were rough cut in the
longitudinal and transverse orientations from the overaged strip.
Groups of the blanks were solution treated at 1850.degree. F.,
1900.degree. F., 1950.degree. F., and 2000.degree. F.,
respectively, for 1 hour and air cooled. The solution treated
blanks were deep chilled at -100.degree. F. for 8 hours and then
warmed in air to room temperature. The blanks were then rough
machined to provide a gage section about 1/2 inch wide.times.2
inches long. Groups of the rough machined blanks from each solution
treatment were aged at temperatures ranging from about 900.degree.
F. to about 975.degree. F. for 4 hours and then air cooled. The
test specimens were finish machined after aging and tested at room
temperature.
[0018] The results of room temperature tensile and hardness testing
are presented in Tables 2-4 below including the solution treatment
temperature (Solution Temp.) and the aging temperature (Age Temp.)
in .degree. F., the 0.2% offset yield strength (Y.S.) and ultimate
tensile strength (U.T.S.) in ksi, and the Rockwell C-scale hardness
(Hardness) as HRC.
TABLE-US-00005 TABLE 2 Solution Age Y.S. U.T.S. Hardness Temp.
Temp. Orient. (ksi) (ksi) % El. (HRC) 1850.degree. F. 950.degree.
F. L 258 266 -- 52.0 258 267 -- 258 268 -- T 260 272 -- 260 273 --
245 272 -- 975.degree. F. L 244 252 -- 50.5 244 253 -- 245 253 -- T
248 258 -- 246 256 -- 245 255 --
TABLE-US-00006 TABLE 3 Solution Age Y.S. U.T.S. Hardness Temp.
Temp. Orient. (ksi) (ksi) % El. (HRC) 1900.degree. F. 900.degree.
F. L 260 284 4.8 53.5 261 286 4.3 259 284 4.8 T 264 287 4.3 257 282
2.8 258 285 4.2 925.degree. F. L 259 282 4.0 53.5 257 281 4.2 256
281 4.1 T 247 285 3.9 260 285 4.1 257 285 4.2 950.degree. F. L 250
274 6.2 52.0 252 273 6.7 249 273 6.4 T 251 277 6.5 250 277 6.0 251
276 6.7 975.degree. F. L 234 258 7.3 50.5 235 256 7.1 235 259 6.9 T
243 264 6.8 240 261 6.6 242 263 6.6
TABLE-US-00007 TABLE 4 Solution Age Y.S. U.T.S. Hardness Temp.
Temp. Orient. (ksi) (ksi) % El. (HRC) 1950.degree. F. 900.degree.
F. L * * 4.6 53.5 * * 4.1 * * 4.7 T * * 5.4 * * 4.2 * * 4.8
950.degree. F. L * * 5.3 52.5 * * 5.2 * * 4.3 T 264 275 5.3 267 279
4.9 260 276 5.3 2000.degree. F. 900.degree. F. L 248 282 5.9 53.5
253 283 5.0 255 282 5.5 T 261 286 4.6 258 291 5.1 260 287 4.7
950.degree. F. L 253 276 5.7 53.0 254 277 5.2 255 276 5.2 T 260 281
4.7 261 282 4.6 263 282 5.0 * Strength data was lost for these
samples. However, the test operator recalls that the U.T.S. for the
H900 samples was above 280 ksi and that the U.T.S. for the H950
samples was slightly under 280 ksi
[0019] Metallographic analysis of the test specimens showed that
the material solution treated at 1850.degree. F. and 1900.degree.
F. had a grain size of about ASTM 8. The material solution treated
at 1950.degree. F. had a grain size of about ASTM 7-8. The material
solution treated at 2000.degree. F. had a grain size of about ASTM
2-3. Here and throughout this application, the ASTM grain size
means average grain size as determined in accordance with ASTM
Standard Test Procedure E-112.
[0020] The results presented in Tables 2, 3, and 4 show that the
preferred solution temperature is about 1900.degree. F. to about
1950.degree. F. Likewise, the preferred aging temperature is about
900.degree. F. to 925.degree. F. in order for the material to
provide the desired 280 ksi U.T.S. A graph of U.T.S. versus
solution and aging temperature combinations is shown in the
drawing.
[0021] The data presented in the tables show that a strip article
made from the alloy composition described in this application is
capable of attaining an U.T.S. 280 ksi or higher. The strip
material is much less heavily alloyed than other stainless
compositions capable of that strength level, resulting in a lower
alloy cost. In addition, the strip material is capable of being
solution heat treated more than once without sacrificing strength
or toughness properties. The strip material of this invention is
preferably solution heat treated at a temperature in range of about
1900-1950.degree. F., making golf club faceplates of this
composition fully compatible with the solution treating temperature
for the precipitation hardenable stainless casting alloys most
often used for the body of golf club head. Therefore, the faceplate
and the club head body can be solution treated and age hardened in
the assembled configuration to develop maximum hardness and
strength, not only in the body of the club head, but also in the
faceplate which makes contact with a golf ball.
[0022] It will be recognized by those skilled in the art that
changes or modifications may be made to the above-described
embodiments without departing from the broad inventive concepts of
the invention. It is understood, therefore, that the invention is
not limited to the particular embodiments that are described, but
is intended to cover all modifications and changes within the scope
and spirit of the invention as described above and set forth in the
appended claims.
* * * * *