EP0356417B1 - Procédé pour la fabrication de pièces tubulaires résistant à la corrosion sous tension, notamment de masses-tiges non magnétisables en acier austénitique et pièces ainsi obtenues - Google Patents
Procédé pour la fabrication de pièces tubulaires résistant à la corrosion sous tension, notamment de masses-tiges non magnétisables en acier austénitique et pièces ainsi obtenues Download PDFInfo
- Publication number
- EP0356417B1 EP0356417B1 EP89890199A EP89890199A EP0356417B1 EP 0356417 B1 EP0356417 B1 EP 0356417B1 EP 89890199 A EP89890199 A EP 89890199A EP 89890199 A EP89890199 A EP 89890199A EP 0356417 B1 EP0356417 B1 EP 0356417B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- temperature
- cooled
- stress corrosion
- stress
- magnetizable
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/14—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes wear-resistant or pressure-resistant pipes
Definitions
- alloys with chrome contents of 20-25%, nickel contents of 10-15% and nitrogen contents of 0.05 were also used in accordance with AT-PS 308 793 for the manufacture of drill collars and rod parts - 0.5% proposed, which are subjected to cold deformation to increase the strength properties.
- precipitation hardened alloys with contents of approx. 33% Ni, 18% Cr, 2% Ti, 0.5% Al and 0.004% N should bring about significant improvements in the performance characteristics of drill collars and drill string parts.
- Another disadvantage is that high local strain hardening of the material, which is formed in the near-surface zone when mechanical pressure is applied, increases the tendency of the material to pitting. In the event of pitting, the compressive stress layer is undermined and stress corrosion cracking of the part increases.
- the mechanical application of residual compressive stresses in the surface layer of parts also has the disadvantage that only simple shapes or contours can be treated accordingly, this method being the last step must be done without subsequent calibration. It is therefore practically not possible to create residual compressive stresses in the near-surface zone on edges, threaded parts, in corners, holes and back-turns as well as on chamfers and discontinuous surface parts in order to prevent stress corrosion cracking.
- the invention had the object of avoiding the above disadvantages and of creating a method for producing tubular bodies which are resistant to stress corrosion cracking, in particular non-magnetizable drill rods and rod parts made of austenitic steels.
- This object is achieved in the inventive method in that the body after solution annealing, quenching and after deformation at a temperature of below 500 ° C to increase the material strength and after machining or drilling a hole to a temperature of 220 to 600 ° C, at least up to a temperature equalization with a temperature difference of at most 10 ° C in the body wall, at most a time t in minutes at a temperature T in ° C according to the context is kept, from this temperature or this starting temperature is cooled by increased removal of thermal energy at least from the inner surface of the tubular body and the cooled surface has a temperature drop of at least 100 ° C / min from the starting temperature to half the value between the starting temperature and room temperature.
- the body is cooled from an initial temperature of 280 to 500 ° C., in particular from 300 to 400 ° C., with a temperature difference in the body wall of at most 6 ° C., preferably at most 3 ° C. It is particularly advantageous if the inner surface and the outer surface of the tubular body are cooled, the inner cooling being carried out at least 5 s, preferably at least 20 s earlier and / or with a higher intensity than that of the outer surface cooling.
- Tubular bodies produced in accordance with this process have local tensile residual stresses of less than 100 N / mm 2 in the zones near the surface to a depth of at least 8 mm. It is particularly preferred if the zones close to the surface have residual compressive stresses to a depth of at least 4 mm, preferably at least 8 mm, and that the tensile residual stresses that may occur in the entire cross-section of the wall are less than 150 N / mm 2 , i.e. below the triggering voltage for Stress corrosion cracking, preferably less than 120 N / mm 2 .
- tubular bodies, in particular collars Due to a deformation of the blank at temperatures below 500 ° C, which serves for work hardening or an increase in the yield strength of the material, tubular bodies, in particular collars, show considerable differences in the local internal stresses in the wall, etc. compressive stresses on the outer surface and high tensile stresses on the surface of the hollow, i.e. the bore, which are well above the limit for triggering stress corrosion cracking.
- a residual stress redistribution surprisingly takes place in the wall without the high strength or high yield strength of the material caused by cold deformation being adversely affected. It is important that the temperature differences in the tube wall after heating to the initial temperature are small, because otherwise the stress redistribution is adversely affected during the intensive cooling or can only take place to a small extent and a desired residual stress state cannot be achieved accordingly. Therefore, the temperature difference in the wall should be kept below 10 ° C. Longer holding times at the initial temperature have an unfavorable effect because this causes the solution-annealed, quenched and work hardened steels, for example austenitic Mn-Cr steel, to be sensitized to inter-crystalline crack corrosion.
- the sensitization depends on diffusion and carbide formation and optionally nitride formation processes, with the temperature (T) the holding time (t) until the material is sensitized logarithmically with the relationship influenced. For this reason, the holding time at the initial temperature should be chosen shorter than the value which results from the following context:
- the tubular body is cooled from the initial temperature by increasing heat removal at least from the inner wall, because in the area of the inner surface of the wall the highest tensile stresses originating from the cold deformation or strain hardening have to be rearranged.
- Low cooling intensities do not result in a sufficient internal stress redistribution, so that the cooled surface of the tube wall must experience a temperature drop from the starting temperature to half the value between the starting temperature and room temperature of at least 100 ° C./min.
- the method according to the invention brings about a residual stress redistribution and can be used for the production of tubular bodies which are resistant to stress corrosion cracking, in particular non-magnetizable drill rods and rod parts made of austenistic steels.
- the prejudices of the professional world had to be overcome, e.g. that heating to higher initial temperatures leads to an unacceptable softening or lowering of the yield point of the cold-formed material and that lower initial temperatures can have no effect because only elastic material deformations occur during the subsequent cooling .
- the increased strength and the high tensile stresses on the inner surface of the tube cause cracks, in particular longitudinal cracks, even when heated to the initial temperature.
- the corrosion specialist feared that renewed heating of a material quenched from solution temperature and work hardened would cause sensitization, which would make the material in chloride-containing media susceptible to grain breakdown or intergranular crack propagation.
- the stress redistribution by intensified cooling of the tube wall from temperatures of, for example, 300 ° C. and 400 ° C. has the effect that the internal stresses in the entire tube wall are below 150 N / mm 2 , namely the triggering voltage of the stress corrosion cracking, and thus the body is completely resistant to stress corrosion cracking. Compressive stresses down to a depth of more than 4 mm are achieved on the inner surface.
- the tubular semi-finished product or the rod (approx. 700 mm minimum length for the above Pro be) was heated in an electric furnace at 415 ° C, with a temperature difference in the tube wall at the end of the heating period of 0.8 ° C.
- jet cooling was initially carried out on the inner surface at a rate of 1500 to 2500 l / min, and after 10 to 30 s, preferably 20 s, also on the outer surface with a cooling water rate of approximately 100 l / min with a temperature drop of the surface of approx. 350 ° C, at least to a temperature below 100 ° C.
- a drill string part was produced from the semi-finished product and further samples were taken from this at the processed points. It was shown in the SCC test that cut-outs made in the pipe wall by milling, turning and planing as well as the NC-cut threads do not cause any cracks, which results from the non-critical residual stress condition in the entire volume of the part.
- the method according to the invention is particularly advantageous for austenitic steels with a directional analysis C: max. 0.2% by weight; Mn: 0-25% by weight; Cr: 12-30% by weight; Mo: 0-5% by weight; Ni: 0-75% by weight; N: 0-1% by weight; Ti: 0-3% by weight; Nb: 0-3% by weight; Cu: 0-3% by weight, rest of iron applicable.
- Mn-Cr austenites with 17-20% by weight Mn and 12-14% by weight Cr and Cr-Ni austenites with 17-24% by weight Cr and 10-20% by weight Ni are particularly preferred .
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Earth Drilling (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
- Coating With Molten Metal (AREA)
- Physical Vapour Deposition (AREA)
- Heat Treatment Of Steel (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
- Prevention Of Electric Corrosion (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT1965/88 | 1988-08-04 | ||
AT1965/88A AT392802B (de) | 1988-08-04 | 1988-08-04 | Verfahren zur herstellung von spannungsrisskorrosionsbestaendigen rohrfoermigen koerpern, insbesondere nichtmagnetisierbaren schwerstangen aus austenitischen staehlen |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0356417A1 EP0356417A1 (fr) | 1990-02-28 |
EP0356417B1 true EP0356417B1 (fr) | 1993-05-26 |
Family
ID=3524888
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89890199A Expired - Lifetime EP0356417B1 (fr) | 1988-08-04 | 1989-07-27 | Procédé pour la fabrication de pièces tubulaires résistant à la corrosion sous tension, notamment de masses-tiges non magnétisables en acier austénitique et pièces ainsi obtenues |
Country Status (10)
Country | Link |
---|---|
US (1) | US5026436A (fr) |
EP (1) | EP0356417B1 (fr) |
JP (1) | JPH0270884A (fr) |
KR (1) | KR900003387A (fr) |
AT (2) | AT392802B (fr) |
BR (1) | BR8903914A (fr) |
CA (1) | CA1334572C (fr) |
DE (1) | DE58904473D1 (fr) |
MX (1) | MX173658B (fr) |
NO (1) | NO174163C (fr) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999019522A1 (fr) * | 1997-10-08 | 1999-04-22 | Mannesmann Ag | Procede pour eviter des tapures de trempe a la surface interieure d'un corps creux cylindrique |
JP3186678B2 (ja) * | 1997-12-10 | 2001-07-11 | 日産自動車株式会社 | ベルト式無段変速機用金属帯の製造方法 |
US6406570B1 (en) * | 1998-03-26 | 2002-06-18 | Mettler-Toledo, Gmbh | Elastic component for a precision instrument and process for its manufacture |
DE19813459A1 (de) * | 1998-03-26 | 1999-09-30 | Mettler Toledo Gmbh | Elastisch verformbares Bauteil und Verfahren zu seiner Herstellung |
US6012744A (en) * | 1998-05-01 | 2000-01-11 | Grant Prideco, Inc. | Heavy weight drill pipe |
KR100472931B1 (ko) * | 2002-08-09 | 2005-03-10 | 정동택 | 세라믹구 제조방법 |
JP4759302B2 (ja) * | 2004-04-06 | 2011-08-31 | 日立Geニュークリア・エナジー株式会社 | 熱処理方法及びその装置 |
GB201304771D0 (en) * | 2013-03-15 | 2013-05-01 | Petrowell Ltd | Heat treat production fixture |
CN110317941B (zh) * | 2019-08-13 | 2020-12-15 | 上海亦又新能源科技有限公司 | 一种地质钻杆公接头增强螺纹根部加工方法及其应用 |
DE102019123174A1 (de) * | 2019-08-29 | 2021-03-04 | Mannesmann Stainless Tubes GmbH | Austenitische Stahllegierung mit verbesserter Korrosionsbeständigkeit bei Hochtemperaturbeanspruchung |
JP7385174B2 (ja) * | 2019-12-11 | 2023-11-22 | Tdk株式会社 | 磁性シート、および、磁性シートを備えるコイルモジュール、並びに非接触給電装置。 |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE671131C (de) * | 1932-08-26 | 1939-02-01 | Kohle Und Eisenforschung G M B | Verfahren zur Erzeugung von elastischen Vorspannungen in Gegenstaenden aus Stahl |
JPS55122825A (en) * | 1979-03-15 | 1980-09-20 | Usui Internatl Ind Co Ltd | High pressure fluid pipe and manufacture thereof |
AT364592B (de) * | 1980-01-25 | 1981-10-27 | Ver Edelstahlwerke Ag | Verfahren zur herstellung von spannungsrisskorrosionsbestaendigen, nichtmagnetisierbaren schwerstangen aus austenitischen staehlen und vorrichtung zur durchfuehrung des verfahrens |
GB2115834B (en) * | 1982-03-02 | 1985-11-20 | British Steel Corp | Non-magnetic austenitic alloy steels |
JPS58167724A (ja) * | 1982-03-26 | 1983-10-04 | Kobe Steel Ltd | 石油掘削スタビライザ−用素材の製造方法 |
US4502886A (en) * | 1983-01-06 | 1985-03-05 | Armco Inc. | Austenitic stainless steel and drill collar |
EP0205828B1 (fr) * | 1985-06-10 | 1989-10-18 | Hoesch Aktiengesellschaft | Procédé et utilisation d'un acier pour la fabrication de tubes en acier à haute résistance aux gaz acides |
AT381658B (de) * | 1985-06-25 | 1986-11-10 | Ver Edelstahlwerke Ag | Verfahren zur herstellung von amagnetischen bohrstrangteilen |
-
1988
- 1988-08-04 AT AT1965/88A patent/AT392802B/de not_active IP Right Cessation
-
1989
- 1989-07-27 DE DE8989890199T patent/DE58904473D1/de not_active Expired - Fee Related
- 1989-07-27 AT AT89890199T patent/ATE89870T1/de not_active IP Right Cessation
- 1989-07-27 EP EP89890199A patent/EP0356417B1/fr not_active Expired - Lifetime
- 1989-07-31 MX MX016993A patent/MX173658B/es unknown
- 1989-08-03 NO NO893152A patent/NO174163C/no unknown
- 1989-08-03 BR BR898903914A patent/BR8903914A/pt not_active Application Discontinuation
- 1989-08-03 CA CA000607498A patent/CA1334572C/fr not_active Expired - Fee Related
- 1989-08-03 JP JP1202283A patent/JPH0270884A/ja active Pending
- 1989-08-03 US US07/388,868 patent/US5026436A/en not_active Expired - Fee Related
- 1989-08-04 KR KR1019890011152A patent/KR900003387A/ko not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
NO893152L (no) | 1990-02-05 |
DE58904473D1 (de) | 1993-07-01 |
BR8903914A (pt) | 1990-03-27 |
KR900003387A (ko) | 1990-03-26 |
AT392802B (de) | 1991-06-25 |
NO174163C (no) | 1994-03-23 |
NO893152D0 (no) | 1989-08-03 |
JPH0270884A (ja) | 1990-03-09 |
ATA196588A (de) | 1990-11-15 |
CA1334572C (fr) | 1995-02-28 |
ATE89870T1 (de) | 1993-06-15 |
NO174163B (no) | 1993-12-13 |
EP0356417A1 (fr) | 1990-02-28 |
MX173658B (es) | 1994-03-22 |
US5026436A (en) | 1991-06-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0207068B1 (fr) | Procédé de fabrication de tiges de forage amagnétiques | |
DE3445371C2 (fr) | ||
EP1109637B1 (fr) | Vis autotaraudeuse en alliage leger et son procede de production | |
DE69410223T2 (de) | Federstahl von hoher Festigkeit und hoher Korrosionsbeständigkeit | |
DE1508416C3 (de) | Verfahren zur Herstellung von Stahlteilen wie Bolzen, Schrauben, Zapfen u.dgl. | |
EP0356417B1 (fr) | Procédé pour la fabrication de pièces tubulaires résistant à la corrosion sous tension, notamment de masses-tiges non magnétisables en acier austénitique et pièces ainsi obtenues | |
DE2907677A1 (de) | Superlegierungen mit verbesserter bestaendigkeit gegen wasserstoffversproedung | |
DE3224865A1 (de) | Verfahren zur herstellung von hochbelastbaren verrohrungen fuer tiefbohrungen oder dergleichen | |
DE2010998A1 (de) | Verfahren zur Wärmebehandlung von Ferromaterial | |
DE1533239B1 (de) | Verwendung eines stahles fuer tellerventile | |
GB2118869A (en) | Manufacture of a drilling stabilizer | |
DE3235447A1 (de) | Bohrschraube | |
DE69203228T2 (de) | Metalldraht aus einem stahlsubstrat mit kaltgehärteter geglühter martensitischer struktur und beschichtung. | |
DE2427038A1 (de) | Nichtrostender stahl und verfahren zu seiner herstellung | |
DE3247873C2 (fr) | ||
DE1957375B2 (de) | Austenitische chrom-nickel-stickstoff-stahllegierung fuer nichtmagnetisierbare schwerstangen und gestaengeteile | |
EP2414552B1 (fr) | Pivots à rotule en aciers à structure bainitique pour de véhicules à usage personnel et de véhicules utilitaires légers | |
DE2435463A1 (de) | Hochdruckgefaess und verfahren zu seiner herstellung | |
DE2815349C2 (de) | Erhöhung der Beständigkeit gegen Spannungsrißkorrosion von rohrförmigen Gegenständen zum Tiefbohren | |
DE3311606C2 (fr) | ||
DE8701403U1 (de) | Stahlstift in einem Befestigungsmittel | |
DE112017006053T5 (de) | Hochfestes und hochzähes rohr für eine perforier-pistole und herstellungsverfahren dafür | |
DE3730379A1 (de) | Verfahren zur herstellung eines halbzeugs oder endproduktes aus einphasigem, hochlegiertem martensitischem chromstahl durch warm- und/oder kaltverformung | |
DE69022523T2 (de) | Rostfreie Stähle mit hoher Zähigkeit und Verfahren zu ihrer Herstellung. | |
DE2720805C2 (de) | Verfahren zur Herstellung von Werkstücken aus legiertem Stahl |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT DE FR GB IT NL SE |
|
17P | Request for examination filed |
Effective date: 19900327 |
|
17Q | First examination report despatched |
Effective date: 19920722 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT DE FR GB IT NL SE |
|
REF | Corresponds to: |
Ref document number: 89870 Country of ref document: AT Date of ref document: 19930615 Kind code of ref document: T |
|
REF | Corresponds to: |
Ref document number: 58904473 Country of ref document: DE Date of ref document: 19930701 |
|
ITF | It: translation for a ep patent filed |
Owner name: STUDIO TORTA SOCIETA' SEMPLICE |
|
ET | Fr: translation filed | ||
GBT | Gb: translation of ep patent filed (gb section 77(6)(a)/1977) |
Effective date: 19930908 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19940613 Year of fee payment: 6 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19940616 Year of fee payment: 6 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19940617 Year of fee payment: 6 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: AT Payment date: 19940621 Year of fee payment: 6 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 19940623 Year of fee payment: 6 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 19940731 Year of fee payment: 6 |
|
EAL | Se: european patent in force in sweden |
Ref document number: 89890199.6 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19950727 Ref country code: AT Effective date: 19950727 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Effective date: 19950728 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19960201 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 19950727 |
|
NLV4 | Nl: lapsed or anulled due to non-payment of the annual fee |
Effective date: 19960201 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Effective date: 19960402 |
|
EUG | Se: european patent has lapsed |
Ref document number: 89890199.6 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Effective date: 19960430 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 20050727 |