CA1244747A - Method for rolling and heat treating small diameter stainless steel rod - Google Patents
Method for rolling and heat treating small diameter stainless steel rodInfo
- Publication number
- CA1244747A CA1244747A CA000486667A CA486667A CA1244747A CA 1244747 A CA1244747 A CA 1244747A CA 000486667 A CA000486667 A CA 000486667A CA 486667 A CA486667 A CA 486667A CA 1244747 A CA1244747 A CA 1244747A
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- Canada
- Prior art keywords
- rod
- rings
- temperature
- offset
- finishing block
- 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.)
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- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method for rolling and heat treating small diameter stainless steel rod, comprising the following sequence of steps: cooling the rod prior to and during finish rolling to increase its stiffness; passing the rod through a sizing mill to achieve close tolerances; sub-jecting the rod to additional water cooling to chill its surface and thereby improve its resistance to surface scratching; forming the rod into rings which are received in an offset pattern on an open moving conveyor; subjecting the offset rings moving along the conveyor to a solid solutioning treatment by reheating and water quenching the same; and then air cooling and drying the rings before collecting them into coils.
A method for rolling and heat treating small diameter stainless steel rod, comprising the following sequence of steps: cooling the rod prior to and during finish rolling to increase its stiffness; passing the rod through a sizing mill to achieve close tolerances; sub-jecting the rod to additional water cooling to chill its surface and thereby improve its resistance to surface scratching; forming the rod into rings which are received in an offset pattern on an open moving conveyor; subjecting the offset rings moving along the conveyor to a solid solutioning treatment by reheating and water quenching the same; and then air cooling and drying the rings before collecting them into coils.
Description
~L2~7~7 BACKGROUND OF T~E INVENTION
This invention relates to the production of small diameter austenitic stainless steel products of the type commonly used in the cold heading trade. As herein employed, the term "small diameter" de~ines products ranging in diameter from about 4.0 to 5.5 mm~
A combination of problems, including lack of stiffness, unacceptable tolerances, surface scratching in the laying heads, etc. has heretofore made it impossible to consistently roll such products as rods on a rod mill.
Thus, such products have been conventionally produced as heat treated drawn wires, for which a price premium is paid.
SUMMARY OF THE PRESENT INVENTION
A basic objective of the present invention is to overcome to above-mentioned problems, thereby making it possible to consistently produce small diameter austenitic stainless steel products as rods on a rod mill, at a considerable cost saving as compared to conventional wire drawing techniques.
In a preferred embodiment of the invention to be described hereinafter in more detail, this is accomplished by continuously hot rolling a process section, for example a reheated billet, into a small diameter rod by passing the ~5 same through a succession of roughing and intermediate stands and then through a finishing block. The process section is water cooled prior to its entry into as well as during its passage through the finishing block. The resulting reduction in rod surface temperature to about 900C is sufficient to advantageously increase the stiffness of the rod emerging 150-lT ~ 7 1244~
from the Einishing block. As herein employed, the term "about", when used in connection with temperatures, defines a range of + 50C.
After being allowed to substantially equalize to a bulk temperature of about 950C, the thus stiffened rod is passed through a sizing mill which imparts to the rod a tolerance of about + .04 mm. As herein employed, the term "bulk temperature" means the equalized temperature between the core end surface of the rod, and the term "sizing mill" means one or more roll passes wherein the total reduction imparted to the rod is 10% or less. The rod exiting from the sizing mill is then subje~ted to additional water cooling prior to being directed through a laying head where it is formed into a continuous series of rings. This additional water cooling will chill the surface of the rod to a temperature of about 650C. This surface chilling enables the rod to resist scratching during passage through the laying head.
The rings formed by the laying head are received on a conveyor along which they are transported in a mutually offset relationship. While moving along the conveyor, the offset rings are sequentially reheated to an elevated bulk temperature of about 1100C. Minimum energy is required to reheat the rod due to the fact that the preceding water quench only affected the surface of the rod, with the core portion remaining at a fairly elevated temperature. After reheating, the rings are water quenched at a rate of between about 200 to 800C/sec. to a surface temperature of about 300C, with an accompanying decrease in core temperature to about 750C. Air cooling of the rings then continues at a more gradual rate while drying the same. The rings are then collected from the delivery end of the conveyor into cylindrical coils.
150-lT -2-l ~447~7 D-831 This combination of steps will enable small diameter, close tolerance, scratch-free, heat treated stain-less steel rod to be rolled on a rolling mill at significantly~
reduced costs as compared to conventional wire drawing methods. For example, it is conservatively estimated that, with the cost of all other things being equal, e.g., raw materials, fuel and labor, the above-describe~ process will make it possible to achieve approximately a S0% cost savings per ton as compared to the production of conventional heat treated drawn wires.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure lA is an illustration of one portion of a rod mill in accordance with the present invention, including the billet reheat furnace and the roughing and intermediate mill stan~s; and Figure lB is a graph illustrating surface, core and bulk temperatures of a rod being processed through the remaining portion of the same rod mill, with the mill com-ponents being shown along the horizontal axis of the graph, and with the vertical axis of the graph being incrementally subdivided into C.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENT
It will be understood that the components in the illustrated rod mill are well known to those skilled in the art. Consequently, they have been shown in diagrammatric form, since the invention resides not in the specific form of such components, but rather in the method or process of operating them in combination.
Referring initially to Figure lA, one portion of a rod mill is shown comprising a furnace 2 in which process sections such as discrete billets are reheated to a rolling ~LZ9~4~47 temperature of above about 1040 to 1260C. The billets are extracted from the furnace by conventional means (not shown) and are continuously rolled along the mill pass line 4 through a series of roughing stands 6, and then through a series of intermediate st2nds 8. Thereafter, and with reference to Figure lB, the semifinished product continues through a finishing block lO.
Although the successive work roll pairs of the finishing block have been illustrated horizontally, those skilled in the art will appreciate that in actual practice, the roll axes of successive roll pairs are offset by 90 so as to eliminate any twisting of the product as it progresses through the finishing block. A typical finishing block of this type is shown, for example, in U. S. Patent No. RE
28,107.
In accordance with the present invention, the finishing block lO has been modified to incorporate water cooling nozzles between the successive roll pairs. As . schematically depicted by the arrows in the drawing, these nozzles apply water to the surface of the product as it passes through the finishing block.
The finishing block 10 is preceded by a water box 12 which also can be of conventional design, having a succession of water nozzles through which the product is directed after leaving the last roll stand 8 of the preceding intermediate train. ~gain, as schematically depicted by the arrows in the drawing, the water nozzles of cooling box 12 apply cooling water to the surface of the product passing therethrough.
The finishing block lO is followed by a sizing lS0-1T -4-~LZ~4~7 mill 14 which in turn is followed by another water box 16.
The water box 16 is followed by a set of driven pinch rolls 18 which propel the product into and through a laying head 20.
The laying head forms the product into a continuous series of rings 22 which are received on an open conveyor 24. The con-veyor, which may be of any conventional chain or roller type, transports the rings in a mutually offset relationship along a path leading to a reforming station 26. As the offset rings move along the conveyor path, they ~ass through a furnace 28 which may be of conventional design and heated by gas burners, radiant heaters or the like. As the offset rings exit from the furnace, they are quenched by water spray nozzles 30, and then air cooled by means of a fan 32 acting through a plenum 34 underlying the conveyor. The rings are then collected from the delivery end of the conveyor into coils at the reforming station 26.
The operation of the foregoing installation will now be described with reference to a typical example wherein 5.5 mmO diameter stainless steel rod is finish rolled at a mill delivery speed of 80m./sec. As the product enters the water box 12, it has a diameter of approximately 18mm, a surface temperature o about 1140C, and it is travelling at a speed of about 7~5m./sec. The water noz~les of the water box 12 operate to lower the surface temperature of the product to about 925C, with an accompanying lowering of the core temper-ature down to about 1120C. Thereafter, the surface and core temperatures are allowed to substantially equalize to about 1037VC before the product enters the finishing block 10.
As the product progresses through the roll passes of the finishing block, it experiences successive 150-lT _5_ ~L Z ~ 7 D - 8 31 elongations accompanied by reductions in cross-sectional area.
In the diagrammatic representation of Figure lB, the finishing block is illustrated as having three successive roll passes.
Those skilled in the art will appreciate, however, that in actual practice the finishing block will normally include 8-10 roll passes. During this finish rolling, the water cooling nozzles between the successive roll pairs of the finishing block operate to intermittently lower the surface temperature ~f the product by increments averaging about 50C. ~owever, because of the energy being imparted to the product during finish rolling, the surface temperature rises between each water application, and the core temperature only gradually decreases with the net result being that as the rod emerges from the finishing block, its surface temperature is about 930C, and its core temperature is about 1000C. The surface and core temperatures then equalize to a bulk temperature of about 960C as the product enters and passes through the sizing mill 14. Since little if any reduction is being taken in the sizing mill, the core and surface temperatures remain relatively constant until the product enters the next water box 16. At a bulk temperature of about 960C, the product has sufficient inherent stiffness to enter and pass through both the si~ing mill 14 and the water box 16 without cobbling or breaking out.
The cooling in water box 16 rapidly and drastically reduces the surface temperature of the product to about 660C, with an accompanying relatively modest decrease in the core temperature to about 940C. Thereafter, the surface and core temperatures equalize to a bulk temperature about 870C as the product continues through the driven pinch rolls 18 and the laying head 20. The reduced surface temperature -~ D-831 ~L24~7~
allows the product to resist scratching or marking that might otherwise result from frictional contact with the internal guide surfaces of the laying head.
As previously indicated, the product rings 22 form-ed by the laying head are received in an offset pattern on the conveyor 24. As the offset rings move along the conveyor, the~ enter the furnace 28 where they experience reheating to a bulk temperature of about 1080C. Since the rings had rapidly equalized to a bulk temperature of about 870C after the pre-ceding water quench, minimum energy is consumed in reheating the rings in the furnace 28. As the rings emerge from the furnace, they are subjected to the water sprays 30 which reduce their surface temperature at a rate of approximately 200C/sec to about 320C, with an accompanying decrease in core temperature to just above 750C. As the rings emerge from beneath the water noz~les 30, they pass over the plenum 34 which directs an upward flow of air from fan 32 through the rings. This further reduces the surface temperature of the rings to under 200C while also drying the rings. This sequential reheating and rapid surface quenching is effective in achieving the solid solution treatment required for stain-less steel products. The rings are then accumulated into coils at the reforming station 26. As an alternative, the rings could be water cooled such that the core temperature is brought down to about 300C. However, this would create a substantial difference in temperature between the surface and the core. Hence, the combination of water and air cooling is preferred.
It thus will be seen that the successive steps of the above-described process cooperate with one another to D-83l 3L~4~7~
achieve the desired result. More particularly, the water cooling in water box 12 and finishing block 10 increases the stiffness of the small diameter product, thereby enabling the product to pass through downstream equipment, including the sizing mill 14 and the water box 16 without cobbling or breaking out. The sizing mill imparts the required close tolerance of about + 0.04 mm. to the rod. The additional cooling in water box 16 chills the product surface, thereby enabling the product to withstand surface scratching in the laying head 20. The laying head cooperates with the conveyor 24 in arranging the product in a continuous series of offset rings moving along the conveyor path. The furnace 28 and water sprays 30 operate sequentially on the moving offset rings to achieve a substantially uniform solid solution treatment, with minimum energy consumption being involved in the reheating cycle, and the fan 32 and plenum 34 operate to further cool and dry the offset rings before they are finally gathered into coil form.
The resulting product is a hot rolled, heat-treated, scratch-free, close tolerance, small-diameter stainless steel rod.
I claim:
150-lT - a -
This invention relates to the production of small diameter austenitic stainless steel products of the type commonly used in the cold heading trade. As herein employed, the term "small diameter" de~ines products ranging in diameter from about 4.0 to 5.5 mm~
A combination of problems, including lack of stiffness, unacceptable tolerances, surface scratching in the laying heads, etc. has heretofore made it impossible to consistently roll such products as rods on a rod mill.
Thus, such products have been conventionally produced as heat treated drawn wires, for which a price premium is paid.
SUMMARY OF THE PRESENT INVENTION
A basic objective of the present invention is to overcome to above-mentioned problems, thereby making it possible to consistently produce small diameter austenitic stainless steel products as rods on a rod mill, at a considerable cost saving as compared to conventional wire drawing techniques.
In a preferred embodiment of the invention to be described hereinafter in more detail, this is accomplished by continuously hot rolling a process section, for example a reheated billet, into a small diameter rod by passing the ~5 same through a succession of roughing and intermediate stands and then through a finishing block. The process section is water cooled prior to its entry into as well as during its passage through the finishing block. The resulting reduction in rod surface temperature to about 900C is sufficient to advantageously increase the stiffness of the rod emerging 150-lT ~ 7 1244~
from the Einishing block. As herein employed, the term "about", when used in connection with temperatures, defines a range of + 50C.
After being allowed to substantially equalize to a bulk temperature of about 950C, the thus stiffened rod is passed through a sizing mill which imparts to the rod a tolerance of about + .04 mm. As herein employed, the term "bulk temperature" means the equalized temperature between the core end surface of the rod, and the term "sizing mill" means one or more roll passes wherein the total reduction imparted to the rod is 10% or less. The rod exiting from the sizing mill is then subje~ted to additional water cooling prior to being directed through a laying head where it is formed into a continuous series of rings. This additional water cooling will chill the surface of the rod to a temperature of about 650C. This surface chilling enables the rod to resist scratching during passage through the laying head.
The rings formed by the laying head are received on a conveyor along which they are transported in a mutually offset relationship. While moving along the conveyor, the offset rings are sequentially reheated to an elevated bulk temperature of about 1100C. Minimum energy is required to reheat the rod due to the fact that the preceding water quench only affected the surface of the rod, with the core portion remaining at a fairly elevated temperature. After reheating, the rings are water quenched at a rate of between about 200 to 800C/sec. to a surface temperature of about 300C, with an accompanying decrease in core temperature to about 750C. Air cooling of the rings then continues at a more gradual rate while drying the same. The rings are then collected from the delivery end of the conveyor into cylindrical coils.
150-lT -2-l ~447~7 D-831 This combination of steps will enable small diameter, close tolerance, scratch-free, heat treated stain-less steel rod to be rolled on a rolling mill at significantly~
reduced costs as compared to conventional wire drawing methods. For example, it is conservatively estimated that, with the cost of all other things being equal, e.g., raw materials, fuel and labor, the above-describe~ process will make it possible to achieve approximately a S0% cost savings per ton as compared to the production of conventional heat treated drawn wires.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure lA is an illustration of one portion of a rod mill in accordance with the present invention, including the billet reheat furnace and the roughing and intermediate mill stan~s; and Figure lB is a graph illustrating surface, core and bulk temperatures of a rod being processed through the remaining portion of the same rod mill, with the mill com-ponents being shown along the horizontal axis of the graph, and with the vertical axis of the graph being incrementally subdivided into C.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENT
It will be understood that the components in the illustrated rod mill are well known to those skilled in the art. Consequently, they have been shown in diagrammatric form, since the invention resides not in the specific form of such components, but rather in the method or process of operating them in combination.
Referring initially to Figure lA, one portion of a rod mill is shown comprising a furnace 2 in which process sections such as discrete billets are reheated to a rolling ~LZ9~4~47 temperature of above about 1040 to 1260C. The billets are extracted from the furnace by conventional means (not shown) and are continuously rolled along the mill pass line 4 through a series of roughing stands 6, and then through a series of intermediate st2nds 8. Thereafter, and with reference to Figure lB, the semifinished product continues through a finishing block lO.
Although the successive work roll pairs of the finishing block have been illustrated horizontally, those skilled in the art will appreciate that in actual practice, the roll axes of successive roll pairs are offset by 90 so as to eliminate any twisting of the product as it progresses through the finishing block. A typical finishing block of this type is shown, for example, in U. S. Patent No. RE
28,107.
In accordance with the present invention, the finishing block lO has been modified to incorporate water cooling nozzles between the successive roll pairs. As . schematically depicted by the arrows in the drawing, these nozzles apply water to the surface of the product as it passes through the finishing block.
The finishing block 10 is preceded by a water box 12 which also can be of conventional design, having a succession of water nozzles through which the product is directed after leaving the last roll stand 8 of the preceding intermediate train. ~gain, as schematically depicted by the arrows in the drawing, the water nozzles of cooling box 12 apply cooling water to the surface of the product passing therethrough.
The finishing block lO is followed by a sizing lS0-1T -4-~LZ~4~7 mill 14 which in turn is followed by another water box 16.
The water box 16 is followed by a set of driven pinch rolls 18 which propel the product into and through a laying head 20.
The laying head forms the product into a continuous series of rings 22 which are received on an open conveyor 24. The con-veyor, which may be of any conventional chain or roller type, transports the rings in a mutually offset relationship along a path leading to a reforming station 26. As the offset rings move along the conveyor path, they ~ass through a furnace 28 which may be of conventional design and heated by gas burners, radiant heaters or the like. As the offset rings exit from the furnace, they are quenched by water spray nozzles 30, and then air cooled by means of a fan 32 acting through a plenum 34 underlying the conveyor. The rings are then collected from the delivery end of the conveyor into coils at the reforming station 26.
The operation of the foregoing installation will now be described with reference to a typical example wherein 5.5 mmO diameter stainless steel rod is finish rolled at a mill delivery speed of 80m./sec. As the product enters the water box 12, it has a diameter of approximately 18mm, a surface temperature o about 1140C, and it is travelling at a speed of about 7~5m./sec. The water noz~les of the water box 12 operate to lower the surface temperature of the product to about 925C, with an accompanying lowering of the core temper-ature down to about 1120C. Thereafter, the surface and core temperatures are allowed to substantially equalize to about 1037VC before the product enters the finishing block 10.
As the product progresses through the roll passes of the finishing block, it experiences successive 150-lT _5_ ~L Z ~ 7 D - 8 31 elongations accompanied by reductions in cross-sectional area.
In the diagrammatic representation of Figure lB, the finishing block is illustrated as having three successive roll passes.
Those skilled in the art will appreciate, however, that in actual practice the finishing block will normally include 8-10 roll passes. During this finish rolling, the water cooling nozzles between the successive roll pairs of the finishing block operate to intermittently lower the surface temperature ~f the product by increments averaging about 50C. ~owever, because of the energy being imparted to the product during finish rolling, the surface temperature rises between each water application, and the core temperature only gradually decreases with the net result being that as the rod emerges from the finishing block, its surface temperature is about 930C, and its core temperature is about 1000C. The surface and core temperatures then equalize to a bulk temperature of about 960C as the product enters and passes through the sizing mill 14. Since little if any reduction is being taken in the sizing mill, the core and surface temperatures remain relatively constant until the product enters the next water box 16. At a bulk temperature of about 960C, the product has sufficient inherent stiffness to enter and pass through both the si~ing mill 14 and the water box 16 without cobbling or breaking out.
The cooling in water box 16 rapidly and drastically reduces the surface temperature of the product to about 660C, with an accompanying relatively modest decrease in the core temperature to about 940C. Thereafter, the surface and core temperatures equalize to a bulk temperature about 870C as the product continues through the driven pinch rolls 18 and the laying head 20. The reduced surface temperature -~ D-831 ~L24~7~
allows the product to resist scratching or marking that might otherwise result from frictional contact with the internal guide surfaces of the laying head.
As previously indicated, the product rings 22 form-ed by the laying head are received in an offset pattern on the conveyor 24. As the offset rings move along the conveyor, the~ enter the furnace 28 where they experience reheating to a bulk temperature of about 1080C. Since the rings had rapidly equalized to a bulk temperature of about 870C after the pre-ceding water quench, minimum energy is consumed in reheating the rings in the furnace 28. As the rings emerge from the furnace, they are subjected to the water sprays 30 which reduce their surface temperature at a rate of approximately 200C/sec to about 320C, with an accompanying decrease in core temperature to just above 750C. As the rings emerge from beneath the water noz~les 30, they pass over the plenum 34 which directs an upward flow of air from fan 32 through the rings. This further reduces the surface temperature of the rings to under 200C while also drying the rings. This sequential reheating and rapid surface quenching is effective in achieving the solid solution treatment required for stain-less steel products. The rings are then accumulated into coils at the reforming station 26. As an alternative, the rings could be water cooled such that the core temperature is brought down to about 300C. However, this would create a substantial difference in temperature between the surface and the core. Hence, the combination of water and air cooling is preferred.
It thus will be seen that the successive steps of the above-described process cooperate with one another to D-83l 3L~4~7~
achieve the desired result. More particularly, the water cooling in water box 12 and finishing block 10 increases the stiffness of the small diameter product, thereby enabling the product to pass through downstream equipment, including the sizing mill 14 and the water box 16 without cobbling or breaking out. The sizing mill imparts the required close tolerance of about + 0.04 mm. to the rod. The additional cooling in water box 16 chills the product surface, thereby enabling the product to withstand surface scratching in the laying head 20. The laying head cooperates with the conveyor 24 in arranging the product in a continuous series of offset rings moving along the conveyor path. The furnace 28 and water sprays 30 operate sequentially on the moving offset rings to achieve a substantially uniform solid solution treatment, with minimum energy consumption being involved in the reheating cycle, and the fan 32 and plenum 34 operate to further cool and dry the offset rings before they are finally gathered into coil form.
The resulting product is a hot rolled, heat-treated, scratch-free, close tolerance, small-diameter stainless steel rod.
I claim:
150-lT - a -
Claims (7)
1. A method of rolling and heat treating small diameter stainless steel rod, comprising:
(a) rolling a process section into a rod by passing the same through a succession of conventional roughing and intermediate stands and then through a conventional finishing block;
(b) water cooling the process section prior to its entry into as well as during its passage through the finishing block, with the resultant reduction in temperature being sufficient to increase the stiffness of the rod emerging from the finishing block;
(c) directing the rod emerging from the finishing block through a sizing mill which imparts to the rod a tolerance of at least about ? .04 mm.;
(d) subjecting the rod emerging from the sizing mill to additional water cooling to further reduce the temperature thereof;
(e) directing the rod through a laying head which forms the rod into a continuous series of rings, the temperature reduction resulting from the aforesaid additional cooling being such as to increase the resistance of the rod to surface scratching during its passage through the laying head;
(f) receiving the rings from said laying head on a conveyor which transports the rings in a mutually offset relationship along a selected path;
(g) reheating the offset rings during the transport thereof along said path;
(h) subjecting the reheated offset rings to additional water cooling during the continued transport thereof along said path, the said reheating and subsequent water cooling being effective to achieve a solid solution treatment of said offset rings;
(i) blowing air through the thus treated offset rings during the continued transport thereof along said path in order to further cool and dry the same; and (j) collecting said rings from said conveyor into upstanding cylindrical coils.
(a) rolling a process section into a rod by passing the same through a succession of conventional roughing and intermediate stands and then through a conventional finishing block;
(b) water cooling the process section prior to its entry into as well as during its passage through the finishing block, with the resultant reduction in temperature being sufficient to increase the stiffness of the rod emerging from the finishing block;
(c) directing the rod emerging from the finishing block through a sizing mill which imparts to the rod a tolerance of at least about ? .04 mm.;
(d) subjecting the rod emerging from the sizing mill to additional water cooling to further reduce the temperature thereof;
(e) directing the rod through a laying head which forms the rod into a continuous series of rings, the temperature reduction resulting from the aforesaid additional cooling being such as to increase the resistance of the rod to surface scratching during its passage through the laying head;
(f) receiving the rings from said laying head on a conveyor which transports the rings in a mutually offset relationship along a selected path;
(g) reheating the offset rings during the transport thereof along said path;
(h) subjecting the reheated offset rings to additional water cooling during the continued transport thereof along said path, the said reheating and subsequent water cooling being effective to achieve a solid solution treatment of said offset rings;
(i) blowing air through the thus treated offset rings during the continued transport thereof along said path in order to further cool and dry the same; and (j) collecting said rings from said conveyor into upstanding cylindrical coils.
2. The method of claim 1 wherein said rod is in the austenitic stainless series, with a diameter ranging from about 4.0 to 5.5 m.m.
3. The method of claim 1 wherein the rod exiting from said finishing block equalizes to a bulk temperature of about 950°C before entering said sizing mill.
4. The method of claim 1 wherein the surface temperature of the rod entering said laying head is about 650°C.
5. The method of claim 1 wherein the offset rings on said conveyor are reheated to an elevated bulk temperature of about 1100°C.
6. The method of claim 5 wherein the reheated offset rings are water cooled at a rate of about 200 to 800°C/sec. to a surface temperature of about 300°C, with an accompanying decrease in core temperature to about 750°C.
7. A method of rolling and heat treating a small diameter stainless steel rod, comprising:
(a) rolling a process section into a rod by passing the same through a succession of conventional roughing and intermediate stands and then through a conventional finishing block;
(b) subjecting the process section to a first water cooling application prior to its entry into the finishing block as well as to a second cooling application during its passage through the finishing block, with the resultant reduction in temperature being sufficient to increase the stiffness of the rod emerging from the finishing block;
(c) directing the rod emerging from the finishing block through a sizing mill to obtain tolerances of about ? .04;
(d) subjecting the rod emerging from the sizing mill to a third water cooling application to further reduce the temperature thereof;
(e) directing the rod through a laying head which forms the rod into a continuous series of rings, the temperature reduction resulting from said third water cooling application being such as to increase the resistance of the rod to surface scratching during its passage through the laying head;
(f) receiving the rings from said laying head on a conveyor which transports the rings in a mutually offset relationship along a given path;
(g) reheating the offset rings during the transport thereof along said path;
(h) subjecting the reheated offset rings to a fourth water cooling application during the transport thereof along said path, the said reheating and fourth water cooling application being effective to achieve a solid solution treatment of said offset rings;
(i) blowing air through the thus treated offset rings during the continued transport thereof along said path in order to futher cool and dry the same; and (j) collecting said rings from said conveyor into upstanding cylindrical coils.
(a) rolling a process section into a rod by passing the same through a succession of conventional roughing and intermediate stands and then through a conventional finishing block;
(b) subjecting the process section to a first water cooling application prior to its entry into the finishing block as well as to a second cooling application during its passage through the finishing block, with the resultant reduction in temperature being sufficient to increase the stiffness of the rod emerging from the finishing block;
(c) directing the rod emerging from the finishing block through a sizing mill to obtain tolerances of about ? .04;
(d) subjecting the rod emerging from the sizing mill to a third water cooling application to further reduce the temperature thereof;
(e) directing the rod through a laying head which forms the rod into a continuous series of rings, the temperature reduction resulting from said third water cooling application being such as to increase the resistance of the rod to surface scratching during its passage through the laying head;
(f) receiving the rings from said laying head on a conveyor which transports the rings in a mutually offset relationship along a given path;
(g) reheating the offset rings during the transport thereof along said path;
(h) subjecting the reheated offset rings to a fourth water cooling application during the transport thereof along said path, the said reheating and fourth water cooling application being effective to achieve a solid solution treatment of said offset rings;
(i) blowing air through the thus treated offset rings during the continued transport thereof along said path in order to futher cool and dry the same; and (j) collecting said rings from said conveyor into upstanding cylindrical coils.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000486667A CA1244747A (en) | 1985-07-11 | 1985-07-11 | Method for rolling and heat treating small diameter stainless steel rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000486667A CA1244747A (en) | 1985-07-11 | 1985-07-11 | Method for rolling and heat treating small diameter stainless steel rod |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1244747A true CA1244747A (en) | 1988-11-15 |
Family
ID=4130966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000486667A Expired CA1244747A (en) | 1985-07-11 | 1985-07-11 | Method for rolling and heat treating small diameter stainless steel rod |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1244747A (en) |
-
1985
- 1985-07-11 CA CA000486667A patent/CA1244747A/en not_active Expired
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