CA1265661A - Method of rebuilding a strip mill guide - Google Patents
Method of rebuilding a strip mill guideInfo
- Publication number
- CA1265661A CA1265661A CA000538185A CA538185A CA1265661A CA 1265661 A CA1265661 A CA 1265661A CA 000538185 A CA000538185 A CA 000538185A CA 538185 A CA538185 A CA 538185A CA 1265661 A CA1265661 A CA 1265661A
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- CA
- Canada
- Prior art keywords
- strip mill
- mill guide
- welding rod
- grooves
- rebuilding
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
A method of rebuilding a strip mill guide formed principally of copper and having lead therein, and having longitudinally extending irregularly shaped grooves therein forming a longitudinally extending channel comprises the steps of pre-heating said strip mill guide, providing a welding rod formed principally of copper and having a diameter of one quarter-inch, positioned in an electrode holder, establishing conductors between said electrode holder and a source of arc welding electric current and said strip mill guide, delivering said arc welding electric current to said welding rod and moving said welding rod along said grooves and channel in said strip mill guide so as to maintain an electric arc whereby said strip mill guide is heated and said welding rod is melted and deposited in said grooves and channel.
A method of rebuilding a strip mill guide formed principally of copper and having lead therein, and having longitudinally extending irregularly shaped grooves therein forming a longitudinally extending channel comprises the steps of pre-heating said strip mill guide, providing a welding rod formed principally of copper and having a diameter of one quarter-inch, positioned in an electrode holder, establishing conductors between said electrode holder and a source of arc welding electric current and said strip mill guide, delivering said arc welding electric current to said welding rod and moving said welding rod along said grooves and channel in said strip mill guide so as to maintain an electric arc whereby said strip mill guide is heated and said welding rod is melted and deposited in said grooves and channel.
Description
~6~
MET~IOD OF REBUILDING A STRIP hlIL.L GUIDE
~ackground of the Invention _echnical Field:
This invention relates to strip mill guides of the type normally employed to guide -the edges O:e strip between the stands of a rolling mill and a me~hod o-f rebuilding them.
Description of the Prior Ar-t:
Prior s-tructu:res of this -type are -those s~e~ in my U.S.
Patents 3,289,457, 3,289,292, and 3,583,876 in which built up strip mill guides and the me-thod of making the same are disclosed. The inventions se-t forth in -these paten-ts and particularly in Patent 3,589,876, have been widely commercial.ly adopted by the steel industry and such bui].t up strip mill guides have been reworked according -to Patent 3,589,876. Such rebuilt guides have heretofore been largely limited to those in which the edges of the steel strip being guided have formed relatively uniform longitudinally straight grooves in the guides and wherein the width of the grooves thus -formed may be filled with a suitable alloy integrally welded to -the guide. ~any strip mill guides become incapable of being rebuilt due to the tendency of the steel strip emerging from ~ ~5661 the reducing -rolls to buckle or ripple arld -thereby create an irregular shaped groove in the guide and/or a series of laterally spaced grooves, some of which are longitudinally s-traigh-t and some of which are irregular and undulating longi-tudinally of the guide.
The present inven-tion makes i-t possible -to rework such unusually worn guides and rebuild -the same satisfactorily.
Strip mill guides rebuilt in accordance with the present invention may be repeatedly reworked and rebuilt and found -to be improved in their lifespan characteristics and wearing ability.
Summary o-f the Inven-tion A method of rebuilding a s-trip mill guide having unusual wear imparted configurations longitudinally thereof reshapes the wear conf igUI ations laterally and longitudinally and enlarges the area thereof to the extent that it lS dif-ficult to obtain a good fusion zone for the weld metal to be applied, uses a weld rod of approximately doubl.e -the diar.~eter of the weld wire or weld rods hereto-fore known in the art and with a manual metal arc process weld with increased power 12~i66~
sufficient -to melt not only -the oversized rod, bu-t also supply sufficient heat to penetrate the larger irregular area to be rebuilt.
The present invention not only improves the original me-tal Oe the guide, particularly with respect to wear characteri.stics and grain structure but permi-ts -the guide to be rebuil-t periodically -to replace the worn away metal, and of equal impor-tance, the increased area being rebuilt and -the increased volume of the larger rod employed and the substantially increased power used resul-ts in less tu-rbulence in the melted metal being applied and the elimination o-f the porosity in welds without a cover gas or weld rod coating. ~dditionally, the present invention provides for a greatly improved deposit rate of more than thirty pounds of metal per hour which con-siderably reduces the time necessary to rebuild a worn strip mill guide and thus substantially reduces the cost thereof.
Description of the Drawings Figure 1 is a perspective view of a built up strip mill guide formed in accordance with this invention;
Figure 2 is a perspec-tive view of a strip~mill guide ~S~
showlrlg -the unusual wear-shaped grooves :Eormed -therein when the steel strip being guided moves in other -than a straight line;
Figure 3 is a p~rspective view of -the strip mill guide o~ Figure 2 -following the mechanical reshaping o~ the wear grooves therein;
Figure 4 is a perspective view oE the s-trip mill guide oE Figure 3 during the rebuilding of the reshaped wear grooves therein;
lo Figure 5 is a ver-tical section on line 5-5 oE Figure 2 in enlarged detail;
Figure 6 is a vertical section on ]ine 6-6 o-~ Figure 4 in enlarged detail; and Figure 7 is a vertical section in enlarged detail o-f the section of the guide illustrated in Figure 6 and aiter the excess weld metal has been removed to -form a transversely smooth guide sur-face.
Description o-f the Pre~erred Fmbodiment By reEerring to -the drawings and Figure 1 in particular, it will be seen that a strip mill guide has been disclosed _ c~ _ ~X~c;S6~
which is oF conventional size and shape and iEI -the example chosen For illustration -the guide is approximately -thirty three inches long by -three and one hal:F inches ln width and one inch in thickness. It has a T-head a.-t one end, the guide body being ind.icated by the numeral 10 and the T-head being indica-ted by -the numeral 11 t The T-head is :Eormed with a projec-ting extension 12 of lesser heigh-t than the remainder of the head 11 of the strip mill guide so -that it will fit beneath a mounting member in a conven-tional moun-ting means positioned alongside the pass line of a s-trip mill, for example, and adjacent a stand oi reducing rolls therein.
The opposite end of the strip mill guide 10 has angular end portions 13 and 1~ which angle toward one another and terminate with a rela-tively narrow end portion 15 which is posi-tioned immediately adjacent said reducing rolls. As seen in Figure 1 of the drawings, the strip mill guide is in condition for installation in the guide means of a strip mill.
By referring to Figure 2 of the drawings, the same strip lX~5~
strip mill guide will be seen in perspective elevation with a plurality oi longi-tudinally extending grooves 16 and 17 -therein and which grooves 16 and 17 extend ~rom -the end portion 15 to the T-head portion 11 and -the projecting extension 12 as hereinbe-~ore reEerred to. The grooves 16 and 17 are formed in the strip mill. guide body 10 by the longi-tudinal edges oE steel s-trip traveling between the stands oE rolls in a rolling mill. It will be observed that the grooves 16 and 17 are irregular in longi-tudinal con~Eigura-tion as a resul-t o.E bowing or rippling o-E the steel strip emerging Erom a stand o-E rolls in the rolling mill and that they ~orm unusually wide and deep grooves in the strip mill guide, it being understand tha-t -there are a pair oE such strip mill guides, one on either side o-f -the pass line o-E the rolling mill and arranged to engage and guide the longi-tudinal edges oE the steel strip traveling between the stands o-E rolls in the rolling mill.
Those skilled in the ar-t will observe that the resultant wear pat-tern comprising the irregularly shaped grooves 16 and 17 contrast greatly with the more normal wear pattern . .
~L~6,S6~
occuring in strip mill guides such as illus-t:rated for example in my prior pa'cen-t 3,589,876 wherein the l.ongitudinal groove 16 is longitudinally straight and of relatively narrow wid-th and depth.
It has become customary in the art to rebuild the strip mill guides as disclosed in my aforesaid U.S. Patent 3,589,876 by electric arc welding wherein a welding rod held by an electric arc torch is supplied su-fficien-t electric current to melt the metal of the welding rod and heat the area of the groove in the strip mill guide so tha-t a desirable fusion of the weld metal with the me-tal of the s-trip mill guide takes place. IIeretofore, the largest diameter welding rod available for use in such welding operations has been three-sixteenth inch with most of the welding rod used commercially being of smaller diameter. In welding with a three-sixteeth inch diameter welding rod, electric curren-t at be-tween 225 to 320 àmperesis necessary to melt the metal and heat a relatively small fusion area of the article to which the welding rod metal is applied. IIeretofore, the largest available electrode holder has been ra-ted at a maximum curren-t capaci-ty of 500 amperes. The prob:Lem of a-ttempting to rebuild a strip mill guide having a badly worn multiple groove or a single enlarged groove condi-tion as hereinbe-Eore described ln connect,ion with Figure 2 of the drawings with the prior state o:E the art equipment has been insurmountable.
The present invention provides a satisfactory solution to this longstanding problem by forming a welding rod oE
a quarter inch diameter or larger and providing an electrode holder capable of safely handling 800 amperes and supplying the electrode holder and the large diameter welding rod with su-Eficien-t electrical current from a pair o-f 600 arnpere welding machines to realize at least 80% duty cycle (~per hour~.
In Figure 4 of the drawings, such an improved and enlarged electrode holder is indicated by -the numeral 18 and -the welding rod having a diameter of at least a quarter inch is indicated by the numeral 19 and the conductor 20 is of a size to safely and e-Eficiently handle the power outpu-t of a pair of 600 ampere electric welding machines which are necessary to develop sufficient power -Eor the purpose.
,5~;61 By referring -to Figure 3 oi the drawings, it will be seen -tha-t the grooves 16 and 17 in the strip metal guide have been machined so as to remove me-tal lying between the grooves 16 and 17 and on opposite sides of the grooves to more uniformly shape the irregular and/or undulating configurations of the grooves 16 and 17 and form a single widened elongated cavity in the strip mill guide 10. Such reshaping of the grooves 16 and 17 is no-t always necessary, bu-t has been found desirable in many instances in providing a more unform channel in which the sub-stantially larger amount of weld metal is deposited as illus-trated in Figure 4 of the drawings.
By referring again -to Figure 4 of the drawings, it will be seen that the deposited metal is generally indicated by the numeral 21 and that it completely fills the channel formed by the grooves 16 and 17 in the preheated strip mill guide.
Prehea-ting to at-- least 800F. is preferred.
In Figure 6 of the drawings, which is a vertical section on line 6-6 of Figure 4, the deposited metal 21 will be seen in cross section as deposited in the channel formed by the grooves 16 and 17 and in Figure 7 of the drawings, the metal 1~6S~
above -the sur~ace of -the strip mill guide 10 has been machined so that there is a uniformly fla-t smooth wearing sur~ace on the rebuilt strip mill guide 10.
The rebuilding of unusually worn strip mill guides, such as -this invention is directed toward, makes possible the economic rebuilding of the strip mill guides and their repeated rebuilding and reuse and results in a rebuilt strip mill guide having improved wearing characteris-tics in -tha-t the rebuilt area of the guide is subs-tantially wider -than the rebuilt areas of strip mill guides as heretofore known in the art as disclosed for e~ample in my a~oresaid Patent 3,589,876. A considerably improved rebuilt metal area results because the increased volume of molten metal being deposited is considerably less turb.ulent than when a small amount is deposited and is therefore free of porosi.ty which improves wear life and at the same time improves iusion with the preheated metal of the strip mill guide.
Of equal importance is the additional benefi-t that while the previous metal deposit rates of four to ~ive pounds per hour for the stick process and ten to twelve pounds per hour , 56~;1 -~or the MIG process are greatly exceeded with the present invention by which, using a one-quar-ter inch dlame-ter welding rod over thir-ty pou.nds per hour of metal can be sa-ti.sfactorily deposited.
The importance of -the present inven-tion will be recognized by the fact tha-t the excessively worn and irregularly worn strip mill guides can be rebuilt by rewelding and the -rebuilding performed a number of times while maintaining the alloy of the guide in its desirable non-brittle sta-te.
The typical strip mill guide referred to herein is 80% copper, 10% tin, and 10% lead and has a normal fine grain s-tructure which forms a suitable supporting body for the rebuilt area -formed therein by this invention. The alloy of the welding rod 19 shown flowing into the grooves 16 and 17 is high in lead and tin and preferably includes a small amount of nickel, an alloy consisting of 78% copper, 10% lead, 10% tin and 2% nickel is suitable. The lead may be present in the alloy in percentages running from 10% to 12%.
The tin may be from 9% to ll~o of the alloy and the balance 1~6566~
copper except ~or the nickel which can be present in percentage ~rom 1% to 2% and under some conclitions may be eliminated, such as where the lead and tin conten-t are very high.
Those skilled in the art will observe that -the heat necessary to weld the metal in the grooves 16 and 17 or the channel resul-ting ~rom the machining of these grooves as hereinbefore described is su-fficien-t to remove or relocate the tin and lead of the s-trip mill guide 10 wherein dendri.-tic grow-th oi -the grain s-tructure occurs and which resul-ts in an unsatis~actory strip mill guide as i-t becomes brittle, easy broken and subject of rapid wear. By utilizing the alloy disclosed herein which is high in tin and lead and preIerably has nickel as a stabilizer, the heretofore believed normal migration of the tin and lead is prevented and no dendritic grain structure growth occurs. The alloy of the strip mill guide and -the alloy of -the welding rod as disclosed in this invention are similar to those disclosed in my aforesaid Patent 3,589,876, but the desirable charac-teristics obtained by using the alloy of Patent 3,589,876 are greatly improved by the substantially increased area in which the alloy of the welding rod is deposited in increased volume as the ~2656~i1 migration O:e the lead of the tin constituents in a bronze alloy strip mill guide to -the last heat a:f:Eec-ted zone is preven-ted by -the increased area of the deposited metal in the increased channel size resulting -rom the irregular shaped grooves in the unusual wear pattern of the strip mill guides being rebuil-t. In other worcls, the lead-and tin constituents of -the bronze alloy of the strip mil:L guide body 10 tend -to move in-to the areas away -Erom the weld and -towards the center of the guide leaving the areas adjacent the weld relatively free of lead and tin and thus accel.erating ~he dendritic grain structure which leads to the -failure of the strip mill guide as it becomes brittle, easily broken and is subjected to rapid wear. By substan-tially increasing the amount O:e the alloy deposited in the grooves and/or channels in the strip mill guide as required by their sub-stantially greater area, satuation of the guide metal by the migration of -the lead and the tin of the alloy i~hibit the dendritic growth and thus maintain the strip mill guide in desirable condition.
It will thus be.seen that the built up strip mill guide ~LX6~6~1 disclosed herein comprises a substan-tial improvement in the art and makes possible the reuse o~ severely worn gu.ides and those having unusual wear patterns and permits theix continuous use through a series oi rebuilding opexations, none o~ which adversely a~-~ect -the grain structure oi the original guide body.
Although but one embodiment oi the presen-t inven-tion has been illustrated and described, it will be apparent -to those skilled in the art that various changes and modi~ications may be made therein wi-thou-t departing -~rom the spirit oi -the invention and having -thus described my inven-tion, what I
claim is:
MET~IOD OF REBUILDING A STRIP hlIL.L GUIDE
~ackground of the Invention _echnical Field:
This invention relates to strip mill guides of the type normally employed to guide -the edges O:e strip between the stands of a rolling mill and a me~hod o-f rebuilding them.
Description of the Prior Ar-t:
Prior s-tructu:res of this -type are -those s~e~ in my U.S.
Patents 3,289,457, 3,289,292, and 3,583,876 in which built up strip mill guides and the me-thod of making the same are disclosed. The inventions se-t forth in -these paten-ts and particularly in Patent 3,589,876, have been widely commercial.ly adopted by the steel industry and such bui].t up strip mill guides have been reworked according -to Patent 3,589,876. Such rebuilt guides have heretofore been largely limited to those in which the edges of the steel strip being guided have formed relatively uniform longitudinally straight grooves in the guides and wherein the width of the grooves thus -formed may be filled with a suitable alloy integrally welded to -the guide. ~any strip mill guides become incapable of being rebuilt due to the tendency of the steel strip emerging from ~ ~5661 the reducing -rolls to buckle or ripple arld -thereby create an irregular shaped groove in the guide and/or a series of laterally spaced grooves, some of which are longitudinally s-traigh-t and some of which are irregular and undulating longi-tudinally of the guide.
The present inven-tion makes i-t possible -to rework such unusually worn guides and rebuild -the same satisfactorily.
Strip mill guides rebuilt in accordance with the present invention may be repeatedly reworked and rebuilt and found -to be improved in their lifespan characteristics and wearing ability.
Summary o-f the Inven-tion A method of rebuilding a s-trip mill guide having unusual wear imparted configurations longitudinally thereof reshapes the wear conf igUI ations laterally and longitudinally and enlarges the area thereof to the extent that it lS dif-ficult to obtain a good fusion zone for the weld metal to be applied, uses a weld rod of approximately doubl.e -the diar.~eter of the weld wire or weld rods hereto-fore known in the art and with a manual metal arc process weld with increased power 12~i66~
sufficient -to melt not only -the oversized rod, bu-t also supply sufficient heat to penetrate the larger irregular area to be rebuilt.
The present invention not only improves the original me-tal Oe the guide, particularly with respect to wear characteri.stics and grain structure but permi-ts -the guide to be rebuil-t periodically -to replace the worn away metal, and of equal impor-tance, the increased area being rebuilt and -the increased volume of the larger rod employed and the substantially increased power used resul-ts in less tu-rbulence in the melted metal being applied and the elimination o-f the porosity in welds without a cover gas or weld rod coating. ~dditionally, the present invention provides for a greatly improved deposit rate of more than thirty pounds of metal per hour which con-siderably reduces the time necessary to rebuild a worn strip mill guide and thus substantially reduces the cost thereof.
Description of the Drawings Figure 1 is a perspective view of a built up strip mill guide formed in accordance with this invention;
Figure 2 is a perspec-tive view of a strip~mill guide ~S~
showlrlg -the unusual wear-shaped grooves :Eormed -therein when the steel strip being guided moves in other -than a straight line;
Figure 3 is a p~rspective view of -the strip mill guide o~ Figure 2 -following the mechanical reshaping o~ the wear grooves therein;
Figure 4 is a perspective view oE the s-trip mill guide oE Figure 3 during the rebuilding of the reshaped wear grooves therein;
lo Figure 5 is a ver-tical section on line 5-5 oE Figure 2 in enlarged detail;
Figure 6 is a vertical section on ]ine 6-6 o-~ Figure 4 in enlarged detail; and Figure 7 is a vertical section in enlarged detail o-f the section of the guide illustrated in Figure 6 and aiter the excess weld metal has been removed to -form a transversely smooth guide sur-face.
Description o-f the Pre~erred Fmbodiment By reEerring to -the drawings and Figure 1 in particular, it will be seen that a strip mill guide has been disclosed _ c~ _ ~X~c;S6~
which is oF conventional size and shape and iEI -the example chosen For illustration -the guide is approximately -thirty three inches long by -three and one hal:F inches ln width and one inch in thickness. It has a T-head a.-t one end, the guide body being ind.icated by the numeral 10 and the T-head being indica-ted by -the numeral 11 t The T-head is :Eormed with a projec-ting extension 12 of lesser heigh-t than the remainder of the head 11 of the strip mill guide so -that it will fit beneath a mounting member in a conven-tional moun-ting means positioned alongside the pass line of a s-trip mill, for example, and adjacent a stand oi reducing rolls therein.
The opposite end of the strip mill guide 10 has angular end portions 13 and 1~ which angle toward one another and terminate with a rela-tively narrow end portion 15 which is posi-tioned immediately adjacent said reducing rolls. As seen in Figure 1 of the drawings, the strip mill guide is in condition for installation in the guide means of a strip mill.
By referring to Figure 2 of the drawings, the same strip lX~5~
strip mill guide will be seen in perspective elevation with a plurality oi longi-tudinally extending grooves 16 and 17 -therein and which grooves 16 and 17 extend ~rom -the end portion 15 to the T-head portion 11 and -the projecting extension 12 as hereinbe-~ore reEerred to. The grooves 16 and 17 are formed in the strip mill. guide body 10 by the longi-tudinal edges oE steel s-trip traveling between the stands oE rolls in a rolling mill. It will be observed that the grooves 16 and 17 are irregular in longi-tudinal con~Eigura-tion as a resul-t o.E bowing or rippling o-E the steel strip emerging Erom a stand o-E rolls in the rolling mill and that they ~orm unusually wide and deep grooves in the strip mill guide, it being understand tha-t -there are a pair oE such strip mill guides, one on either side o-f -the pass line o-E the rolling mill and arranged to engage and guide the longi-tudinal edges oE the steel strip traveling between the stands o-E rolls in the rolling mill.
Those skilled in the ar-t will observe that the resultant wear pat-tern comprising the irregularly shaped grooves 16 and 17 contrast greatly with the more normal wear pattern . .
~L~6,S6~
occuring in strip mill guides such as illus-t:rated for example in my prior pa'cen-t 3,589,876 wherein the l.ongitudinal groove 16 is longitudinally straight and of relatively narrow wid-th and depth.
It has become customary in the art to rebuild the strip mill guides as disclosed in my aforesaid U.S. Patent 3,589,876 by electric arc welding wherein a welding rod held by an electric arc torch is supplied su-fficien-t electric current to melt the metal of the welding rod and heat the area of the groove in the strip mill guide so tha-t a desirable fusion of the weld metal with the me-tal of the s-trip mill guide takes place. IIeretofore, the largest diameter welding rod available for use in such welding operations has been three-sixteenth inch with most of the welding rod used commercially being of smaller diameter. In welding with a three-sixteeth inch diameter welding rod, electric curren-t at be-tween 225 to 320 àmperesis necessary to melt the metal and heat a relatively small fusion area of the article to which the welding rod metal is applied. IIeretofore, the largest available electrode holder has been ra-ted at a maximum curren-t capaci-ty of 500 amperes. The prob:Lem of a-ttempting to rebuild a strip mill guide having a badly worn multiple groove or a single enlarged groove condi-tion as hereinbe-Eore described ln connect,ion with Figure 2 of the drawings with the prior state o:E the art equipment has been insurmountable.
The present invention provides a satisfactory solution to this longstanding problem by forming a welding rod oE
a quarter inch diameter or larger and providing an electrode holder capable of safely handling 800 amperes and supplying the electrode holder and the large diameter welding rod with su-Eficien-t electrical current from a pair o-f 600 arnpere welding machines to realize at least 80% duty cycle (~per hour~.
In Figure 4 of the drawings, such an improved and enlarged electrode holder is indicated by -the numeral 18 and -the welding rod having a diameter of at least a quarter inch is indicated by the numeral 19 and the conductor 20 is of a size to safely and e-Eficiently handle the power outpu-t of a pair of 600 ampere electric welding machines which are necessary to develop sufficient power -Eor the purpose.
,5~;61 By referring -to Figure 3 oi the drawings, it will be seen -tha-t the grooves 16 and 17 in the strip metal guide have been machined so as to remove me-tal lying between the grooves 16 and 17 and on opposite sides of the grooves to more uniformly shape the irregular and/or undulating configurations of the grooves 16 and 17 and form a single widened elongated cavity in the strip mill guide 10. Such reshaping of the grooves 16 and 17 is no-t always necessary, bu-t has been found desirable in many instances in providing a more unform channel in which the sub-stantially larger amount of weld metal is deposited as illus-trated in Figure 4 of the drawings.
By referring again -to Figure 4 of the drawings, it will be seen that the deposited metal is generally indicated by the numeral 21 and that it completely fills the channel formed by the grooves 16 and 17 in the preheated strip mill guide.
Prehea-ting to at-- least 800F. is preferred.
In Figure 6 of the drawings, which is a vertical section on line 6-6 of Figure 4, the deposited metal 21 will be seen in cross section as deposited in the channel formed by the grooves 16 and 17 and in Figure 7 of the drawings, the metal 1~6S~
above -the sur~ace of -the strip mill guide 10 has been machined so that there is a uniformly fla-t smooth wearing sur~ace on the rebuilt strip mill guide 10.
The rebuilding of unusually worn strip mill guides, such as -this invention is directed toward, makes possible the economic rebuilding of the strip mill guides and their repeated rebuilding and reuse and results in a rebuilt strip mill guide having improved wearing characteris-tics in -tha-t the rebuilt area of the guide is subs-tantially wider -than the rebuilt areas of strip mill guides as heretofore known in the art as disclosed for e~ample in my a~oresaid Patent 3,589,876. A considerably improved rebuilt metal area results because the increased volume of molten metal being deposited is considerably less turb.ulent than when a small amount is deposited and is therefore free of porosi.ty which improves wear life and at the same time improves iusion with the preheated metal of the strip mill guide.
Of equal importance is the additional benefi-t that while the previous metal deposit rates of four to ~ive pounds per hour for the stick process and ten to twelve pounds per hour , 56~;1 -~or the MIG process are greatly exceeded with the present invention by which, using a one-quar-ter inch dlame-ter welding rod over thir-ty pou.nds per hour of metal can be sa-ti.sfactorily deposited.
The importance of -the present inven-tion will be recognized by the fact tha-t the excessively worn and irregularly worn strip mill guides can be rebuilt by rewelding and the -rebuilding performed a number of times while maintaining the alloy of the guide in its desirable non-brittle sta-te.
The typical strip mill guide referred to herein is 80% copper, 10% tin, and 10% lead and has a normal fine grain s-tructure which forms a suitable supporting body for the rebuilt area -formed therein by this invention. The alloy of the welding rod 19 shown flowing into the grooves 16 and 17 is high in lead and tin and preferably includes a small amount of nickel, an alloy consisting of 78% copper, 10% lead, 10% tin and 2% nickel is suitable. The lead may be present in the alloy in percentages running from 10% to 12%.
The tin may be from 9% to ll~o of the alloy and the balance 1~6566~
copper except ~or the nickel which can be present in percentage ~rom 1% to 2% and under some conclitions may be eliminated, such as where the lead and tin conten-t are very high.
Those skilled in the art will observe that -the heat necessary to weld the metal in the grooves 16 and 17 or the channel resul-ting ~rom the machining of these grooves as hereinbefore described is su-fficien-t to remove or relocate the tin and lead of the s-trip mill guide 10 wherein dendri.-tic grow-th oi -the grain s-tructure occurs and which resul-ts in an unsatis~actory strip mill guide as i-t becomes brittle, easy broken and subject of rapid wear. By utilizing the alloy disclosed herein which is high in tin and lead and preIerably has nickel as a stabilizer, the heretofore believed normal migration of the tin and lead is prevented and no dendritic grain structure growth occurs. The alloy of the strip mill guide and -the alloy of -the welding rod as disclosed in this invention are similar to those disclosed in my aforesaid Patent 3,589,876, but the desirable charac-teristics obtained by using the alloy of Patent 3,589,876 are greatly improved by the substantially increased area in which the alloy of the welding rod is deposited in increased volume as the ~2656~i1 migration O:e the lead of the tin constituents in a bronze alloy strip mill guide to -the last heat a:f:Eec-ted zone is preven-ted by -the increased area of the deposited metal in the increased channel size resulting -rom the irregular shaped grooves in the unusual wear pattern of the strip mill guides being rebuil-t. In other worcls, the lead-and tin constituents of -the bronze alloy of the strip mil:L guide body 10 tend -to move in-to the areas away -Erom the weld and -towards the center of the guide leaving the areas adjacent the weld relatively free of lead and tin and thus accel.erating ~he dendritic grain structure which leads to the -failure of the strip mill guide as it becomes brittle, easily broken and is subjected to rapid wear. By substan-tially increasing the amount O:e the alloy deposited in the grooves and/or channels in the strip mill guide as required by their sub-stantially greater area, satuation of the guide metal by the migration of -the lead and the tin of the alloy i~hibit the dendritic growth and thus maintain the strip mill guide in desirable condition.
It will thus be.seen that the built up strip mill guide ~LX6~6~1 disclosed herein comprises a substan-tial improvement in the art and makes possible the reuse o~ severely worn gu.ides and those having unusual wear patterns and permits theix continuous use through a series oi rebuilding opexations, none o~ which adversely a~-~ect -the grain structure oi the original guide body.
Although but one embodiment oi the presen-t inven-tion has been illustrated and described, it will be apparent -to those skilled in the art that various changes and modi~ications may be made therein wi-thou-t departing -~rom the spirit oi -the invention and having -thus described my inven-tion, what I
claim is:
Claims (6)
1. The method of rebuilding a strip mill guide formed principally of copper and having lead therein, and having more than one longitudinally extending irregularly shaped groove therein forming at least one longitudinally extending channel in at least one location longitudinally of said strip mill guide comprising steps of preheating said strip mill guide, providing a welding rod formed principally of copper and having a diameter of one quarter inch, positioning the welding rod in an electrode holder capable of conducting at least 800 ampere arc welding electric current to said welding rod, establishing conductors between said electrode holder and a source of at least 600 ampere arc welding electric current and said strip mill guide, energizing said source of arc welding current so as to deliver between 600 and 800 amperes arc welding electric current to said welding rod and moving said welding rod along said grooves and channel in said strip mill guide so as to maintain an electric arc whereby said strip mill guide is heated and said welding rod is melted and deposited in said grooves and channel.
2. The method of rebuilding a strip mill guide set-forth in claim 1 and wherein said strip mill guide is preheated to about 800°F. prior to depositing said melted welding rod in said grooves and channel.
3. The method of rebuilding a strip mill guide set forth in claim 1 and wherein said source of said 600 to 800 amperes arc welding electric current consists of a pair of 600 ampere machines.
4. The method of rebuilding a strip mill guide set forth in claim 1 and wherein sections of said strip mill guide between said longitudinally extending irregularly shaped grooves are removed to form a single longitudinally extending channel in said strip mill guide.
5. The method of rebuilding a strip mill guide set forth in claim 1 and wherein sections of said strip mill guide on opposite sides of said longitudinally extending irregularly shaped grooves are removed to form oppositely disposed undulating sides of said grooves and a widened channel therebetween.
6. The method of rebuilding a strip mill guide set forth in claim 1 wherein said strip mill guide comprises an elongated member consisting essentially of 80% copper, 10% lead and 10% tin and wherein said welding rod consists essentially of copper in an amount between 25% and 77%, lead in an amount between 11% and 45% and tin in an amount between 11% and 30%.
... . . .
... . . .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000538185A CA1265661A (en) | 1987-05-27 | 1987-05-27 | Method of rebuilding a strip mill guide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000538185A CA1265661A (en) | 1987-05-27 | 1987-05-27 | Method of rebuilding a strip mill guide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1265661A true CA1265661A (en) | 1990-02-13 |
Family
ID=4135762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000538185A Expired CA1265661A (en) | 1987-05-27 | 1987-05-27 | Method of rebuilding a strip mill guide |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1265661A (en) |
-
1987
- 1987-05-27 CA CA000538185A patent/CA1265661A/en not_active Expired
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