DESC:FIELD OF INVENTION:

This invention relates to heat treatment and heat extraction devices and is specifically addressed to provide an improved heat treatment method and means which is time efficient and space efficient for heat extraction from hot longitudinal members with profiled sections such as tubes, and rods and bars which go through the process of heat treatment, including thermo mechanical process. Hence the invention is specifically for improved heat treatment of longitudinal members such as tubes, solid bars, channels, and other profiled sections of predominantly constant cross section and moving at high speeds or moved at high speeds.

BACKGROUND/STATE OF THE ART:

In prior art many obstacles have been identified for achieving rapid heat extraction from longitudinal members moving at high speeds, usually in the range 10-180 km/hr during heat treatment processes including but not limited to thermo mechanical treatment processes which demand supply of large quantity of heat extraction fluid very rapidly. Thereby the heat treatment/heat extraction means were typically involving complicated arrangement of nozzles and inserts to ensure large volume of supply of heat extraction fluid and very rapidly, which in turn demanded large spaces, expensive maintenance and high inventory costs. Also such complicated arrangements typically suffered the “specificity” or “customized” limitations, as they were designed specifically to handle specific “product/products” and demanded larger inventory of heat extraction means in heat treatment process to suit a large range of longitudinal members of different dimensions for different industrial use. More importantly, some materials required drastic heat extraction rates which were difficult if not impossible to achieve even with complex cooling arrangements.

The quality of heat treatment has a major role in deciding certain properties of such heat treated members such as hardness, strength, stress state, ductility, formability, endurance, heterogeneous and/or homogeneous phase composition. A heat treatment process also needs to avoid and at least definitely minimize distortion of the treated longitudinal member.

There is a need for better heat extraction means and method for varied industrial usage. Longitudinal steel reinforcement members are used extensively in building structures. Combinations of properties like strength, ductility, weldability, and corrosion resistance are value propositions for these members. Hence heat treatment needs to be done carefully to achieve the desirable combinations of such properties which typically include a rapid heat extraction step from the hot longitudinal members by bringing it into contact with large volumes of heat extraction fluids within short periods as part of manufacturing process. This is usually achieved by spraying heat extraction fluid on the rapidly moving hot longitudinal member, which is at high temperature and is passed through a hollow or open section of larger size, with a heat extraction fluid also flowing along its length from one end to exit at the other end and thereby extracting heat from the longitudinal member in the process. This process design of the prior art limits the quantity of fresh heat extraction fluid that comes into contact with the rapidly moving longitudinal member and retards heat extraction capability owing to the possible carry over of warm heat extraction fluid for extended lengths in relative proximity to the longitudinal member besides local formation of vapour blankets that retard heat extraction. Typical examples are Continuous induction hardening lines, Continuous casting lines, and other commercially available rebar lines. Each suffers a certain disadvantage for efficient and uniform performance.

OBJECT OF THE INVENTION:

The main object of the invention is to shorten heat extraction time and heat extraction space/required, only to be limited by the conductivity of the longitudinal member travelling at high speed, therefore reducing space, and increasing heat extraction efficiency, which also extends process capability and range.

The other object of the invention is to lower heat extraction time in a heat treatment process and means, which will optimize and even minimize heat extraction time and space.

The other object of the invention is to create a heat extraction process and a means with energy-efficient heat extraction means and heat extraction method.

The other object of the invention is to create an accelerated heat extraction process and a means for a hot longitudinal member and thereby minimizing alterations in the desired micro structure which typically occurs during normal heat extraction process.

The other object of the invention is to create a heat extraction process and a heat extraction means to ensure that the predicted hardness and desired strength and ductility is achieved in the treated longitudinal member.

The other object of the invention is to create a heat extraction process and a means, which may be easily modified for a wide range of longitudinal members to be heat treated.

Another object of the invention is to create a heat extraction process and a means which involve minimal management of operational conditions for heat extraction and thereby is highly process reliable.

Hence the invention teaches an improved means and a method for an improved heat extraction means for heat treatment of longitudinal members moving at high speeds and to achieve the desired improved mechanical, physical and microstructural properties of the said longitudinal members by utilizing “shorter” “intensive” heat extraction zone/zones, thereby making the system compact and efficient.

The invention is relating to heat treatment process and more specifically to heat extraction of the longitudinal members moving at high speed which demands rapid if not instantaneous heat extraction which is also part of heat treatment where the longitudinal members are rapidly cooled in a heat extraction mechanism to obtain certain desired predetermined properties. Since “phase transformation” occur during heat extraction process, there is a need to shorten the heat extraction time thereby preventing the occurrence of undesired phase transformation. Hence the invention attempts to do “heat extraction process” in the shortest possible time frame.

Further it is also known that in steel, such sudden drastic change in temperature during heat extraction also toughens the outer layer of the longitudinal member, thus enhancing its tensile strength and durability. Therefore, it is desired to have a heat extraction method and means which is able to optimize the conversion of outer surface of the longitudinal member to Martensite and causing it to shrink, thereby pressurizing the core, which results in a desirable crystal structure and residual stress on the surface. Hence a good heat extraction process will result in having the surface of the treated longitudinal member becoming cold and hardened, while core may continue to still remain hot and soft or become cold and hard too depending on the requirement. The invention attempts to create a heat extraction method and a means accordingly which will advantageously perform heat extraction from the surface layer of longitudinal member which pressurizes and deforms the crystal structure of the intermediate layers.

The method and means of the heat extraction as per invention controls the flow to the heat extraction zones, and predictably manages the temperature differences as desired through the cross-section of the longitudinal member by taking heat extraction rates to the conductivity limitations of the material. The correct temperature difference between the surface and core of the treated longitudinal member assures that all processes reliably occur, and the longitudinal member bar exhibits the necessary and desired mechanical properties at the end of process.

Hence as per the invention the longitudinal member may leave the heat extraction zone with or without a temperature gradient through its cross-section as per the predetermined desired features demanded of the treated longitudinal member. The outer surface of the longitudinal member is cold while core may remain hot or may be cold as per the design requirement. As the longitudinal member moves out of the heat treatment zone, the heat flows from the core to the outer surface of the longitudinal member and further tempering the longitudinal member occurs which helps it to improve yield strength.

The proposed heat extraction method & means as per invention teaches/imparts the ability to improve the speed of thermal processing of controllably movable longitudinal members, thereby reducing processing time and space significantly. Typical processing cases that can benefit from this invention include hot rolling, induction hardening, aluminum extrusion, rebar production, stainless steel annealing etc.

As detailed above, the invention is relating to heat extraction process and is applicable for heat treatment of longitudinal members of different profiles.

However for sake of understanding “a quenching process” one of the many selectable heat extract processes of the invention is detailed below. The scope of the invention shall not be construed narrowly based on the preferred embodiments described below. The invention is not really limited to quenching process and quenching means and none of the words herein after used for describing the embodiment shall be treated as “limiting” of the invention due to this description of this embodiment.

In one aspect of invention it is a system for quenching a hot longitudinal member. It comprises of a quenching fluid source means containing a quenching fluid and a base means, an annular hollow quenching chamber means having two open ends, having a first end and a second end is mounted within the base means. The said hollow quenching chamber means having at least a plurality of annular housing means linearly arranged along its length and on the outer surface of the quenching chamber means. The said each of the said housing means surrounding outwardly and peripherally the quench chamber along its outer surface forming a hollow surrounding passage around the quench chamber. A quenching fluid supply means is arranged for supplying quenching fluid from the quenching fluid source means into the quench chamber at the first end of quench chamber. It also has a conveyer means operably associated with the quenching chamber means supporting the longitudinal member to be quenched by the quenching fluid discharged into the quenching chamber from the quenching fluid supply means. There is also arranged a quenching fluid exhaust means for exhausting quenching fluid out of the quenching chamber.

The arrangement also has a segmental partition which may be solid, fluidic or a force field based partition means adapted to substantially prevent quench fluid free flow longitudinally alongwith the longitudinal member which may be supported moveably within the quenching chamber from first end to the second end of the quenching chamber.

In another aspect the said system is characterized in the quenching chamber means having plurality of annular housing means on its outer surface with a corresponding angular fluid spray surface guide means associated operably with each of the plurality of annular housing means and also in a conical fluid spray terminal guide means associated operably at the first end of the quench chamber, and further in the segmental partition means which is solid having a plurality of generally flat sealing partition disc having a central aperture. The said solid disc is engagingly associated with each of the annular housing means and the said each solid disc having its central aperture sufficient to accommodate the longitudinal member within its aperture and thereby largely hindering free onward motion of the quenching fluid towards the second end of the quenching chamber means.

In another aspect of the invention it is characterized in the said quenching fluid supply means further having an inlet receiving (12) means for receiving quench fluid from the quenching source, and a plurality of spaced supply outlet (13) means for supplying quenching fluid into the quenching chamber.

In another aspect of the invention it also comprises a first quenching inlet (10) opening port means positioned at first end of quenching chamber to allow flow of quenching fluid into quenching chamber from one of the supply outlet means, and a plurality of spaced second quenching inlet opening port (11) means also positioned at first end of quenching chamber to allow flow of quenching fluid into quenching chamber from one of the supply outlet means. A first delivery inlet port means operably associated with first quench inlet opening port means for receiving the quenching fluid at first end of quenching chamber and delivering into quench chamber and operably associated with the conical fluid spray terminal guide means further associated with first delivery inlet port means of quenching chamber means to spray deliver the received quenching fluid from the first delivery inlet port of quenching chamber into the quenching chamber whereby the sprayed fluid will contact radially the proximate surface of the longitudinal member to be cooled, a plurality of second delivery inlet pipe means, each pipe operably associated with one of the plurality of second quenching inlet opening port (11) means and each of the second delivery inlet pipes means having at least an open end towards the fluid supply means and extending longitudinally along one of the sides of quench chamber and parallel to the quench chamber, the said pipe means also having a plurality of outlet port means arranged linearly along its length and on its surface which is proximate to the quench chamber, the said plurality of second delivery inlet pipe means operably associated with its second quench inlet opening port means for receiving the quench fluid at its open end proximate to first end of quench chamber, and also arranged such that each of the linearly arranged outlet port means opening on this linear pipe coincides with at least one of annular surface housing means of a corresponding set of peripherally arranged housing (14) means on the hollow quench chamber thereby delivering the quench fluid through the associated annular peripherally arranged surface housing means into the quenching chamber, and the said plurality of second delivery inlet pipe means operably associated with the plurality of angular fluid spray surface guide means combinedly formed with the plurality of peripherally arranged surface housing means enclosed around the quench chamber, wherein the plurality of peripherally arranged surface housing means are such that the quench fluid delivered angularly into the quenching chamber from the each of the plurality of second delivery inlet pipe means will contact radially the proximate surface of the longitudinal member to be cooled.

In another aspect of the invention it has segmental partition (3) means which are such that each of the plurality of flat disc sealing partition is disposed proximate to one of the plurality of surrounding surface housing means on the quench chamber and mounted within the quench chamber.

In another aspect of the invention it has a plurality of surface exhaust (9) means arranged on the upper surface of the quench chamber as an opening means, each surface means exhaust is arranged between two angular fluid spray surface guides means and at least one surface exhaust (9) means is arranged between the angular fluid spray terminal guide means which is nearest to the conical fluid spray surface guide means, and a first terminal exhaust means arranged at the second end of the quench chamber for exhausting the residual quench fluid from the quenching chamber.

In another aspect of the invention the longitudinal member is always fully submerged in the heat extracting fluid through its presence in the hollow chamber.

In another aspect of the invention, it has the angular fluid spray guide means which is a conical fluid spray guide means.

In another aspect of the invention, it includes hollow quenching chamber (1) means which is preferably cylindrical, oval, square, rectangular or polygonal

In another aspect of the invention, it includes number of second quenching inlet opening port (11) means which may be one or more and correspondingly the second delivery inlet pipe means may be one or more.

Though the previous paras do give details and description with respect to “quenching process” and “quenching system”, it is only one of the preferred embodiments of the heat extraction process of the invention and scope of the invention is not limited to this embodiment.

The invention as such is applicable generally for any “heat treatment process” and/or heat treatment system and it is to be understood that “quenching process” and/or “quenching system” is one such heat treatment process selected herein for sake of explanation and description of invention only. The description and disclosure of the invention as a whole should be construed to encompass all methods of “heat treatment” and all means of heat treatment and beyond “quenching process” and quenching means which is one of the preferred embodiment selected herein for sake of describing of the working of the invention.

The description may have largely explained the “quenching process” and “quenching means” in the above paragraphs but this shall not cause as surrender of other known “heat extraction” beyond “quenching” in the invention.

As per the invention, the final structure of the treated longitudinal members post the “heat extraction process” is consisting and advantageously of an optimum combination of strong outer layer with ductile core thereby exhibiting the most desired features which is combination of higher strength and ductility.

This superior, simple and advantageous technology also ensures simple process monitoring with a simple arrangement to achieve uniform properties in a treated member repeatedly which is the demand in the market – as “standards-compliance” has become essential for commercial exploitation of products like heat treated members, thermo-mechanically treated solid bars, tubes and other hollow or solid longitudinal profiled sections and members.

DESCRIPTION OF THE DRAWINGS:

Figure 1 illustrates various components and parts of the invention.

1. Annular hollow quenching chamber
2. Annular housing
3. Segmental partition – solid, fluidic or force field
4. Angular fluid spray surface
5. Conical fluid spray terminal guide
6. Fluidic sealing partition/solid disc
7. Hot longitudinal member
8. Base means
9. Surface exhaust
10. First quenching inlet port
11. Second quenching inlet port
12. Inlet receiving member
13. Spaced supply outlet
14. Peripherally arranged housing
15. Angularly arranged spray guides
16. Delivery inlets.

INVENTIVE STEP OF THE INVENTION:

The method and device for heat extraction from a hot rapidly moving longitudinal member as per invention involves segmenting the heat extraction process into a series of small, hollow fluidic chambers through which longitudinal members can pass at high speed without obstruction, arranged sequentially one behind the other, segmented one from the other by a barrier which may be a material barrier, a pressurized fluidic barrier or a force field barrier and having apertures for inlet of fresh cooling fluid in each segment. It is further characterized by being vented from the upper side for predominant fluid exit by volume, thus effectively keeping the longitudinal member moving at high speed submerged in fresh, agitated & turbulent heat extraction fluid and achieved by suitable relative dimensions of entry and exit apertures in said fluid chambers relative to longitudinal member size, with pressure/volume rates of flow adequate to prevent the fluid vaporization in the hollow fluidic chambers.

TECHNICAL ADVANTAGES OF THE INVENTION:

In typical cases involving steel longitudinal members, the heat extraction length, time and space required is brought down by a factor of 2 to 4. Additionally, where the selection of fluidic variables can develop a surface heat extraction rate in excess of the thermal conductivity of the longitudinal member, the cooling process or the heat extraction is stabilized by the conductivity of the material itself and thereby becomes independent of transient setting errors in fluidic parameters. In the cases of steel longitudinal members, hardening results in particular are rendered superior, with the formation of higher favourable compressive stresses on the surface which is considered desirable from the point of view of endurance.

Not only does the specification herewith put forth describe the construction and functional details covered by the invention but it also describes the specific advantages gained over prior art. As per the invention, the treatment (i.e., “a heat extraction process and a means.”) of a longitudinal member is a “rapid heat extraction” process with a heat extraction fluid which may be water, oil or air to obtain certain desired material properties. Hence invention is workable with a ‘fluid’. Quenching is one such heating treating process and the invention is workable as “quenching process and quenching means” as one of the variants workable with the invention. The accelerated heating treatment method and means as per the invention prevents undesired low-temperature processes, such as phase transformations from occurring by reducing the “window of time” during which these undesired reactions are both thermo dynamically favourable and kinetically accessible. The heat treatment process and means as per invention achieves to reduce grain size of the longitudinal member due to accelerated heat extraction thereby increasing hardness of the treated longitudinal member, as the extremely rapid cooling will aid the formation of crystal structure resulting in enhanced hardness.

Some of the arrangements and methods of heat extraction as per invention which provide the significant advantages is disclosed to the best of knowledge of the inventors, and quenching is only one of many preferred embodiments for sake of putting forth one embodiment. It will be understood by those skilled in the art that other variants may be made thereto without departing from the spirit of the invention or the scope of the invention.

The examples and embodiments are provided only for the purpose of understanding and none of them shall limit the scope of the invention. All variants and modifications as will be envisaged by a skilled person are also within the spirit and scope of the invention.
,CLAIMS:1. A system for quenching a hot longitudinal member (7) comprising:
a) a quenching fluid source means containing a quenching fluid,
b) a base means (8),
c) an annular hollow quenching chamber means (1) with two open ends, having a first end and a second end and mounted within the base means, the said hollow quenching chamber means having at least a plurality of annular housing means (2) linearly arranged along its length and on the outer surface of the quenching chamber means, the said each of the said housing means surrounding outwardly and peripherally the quench chamber along its outer surface forming a hollow surrounding passage around the quench chamber,
d) a quenching fluid supply means for supplying quenching fluid from the quenching fluid source means into the quench chamber at the first end of quench chamber,
e) a conveyer means operably associated with the quenching chamber means supporting the longitudinal member to be quenched by the quenching fluid discharged into the quenching chamber from the quenching fluid supply means,
f) a quenching fluid exhaust means for exhausting quenching fluid out of the quenching chamber, and
g) a segmental partition means (3) adapted to substantially prevent quench fluid free flow longitudinally alongwith the longitudinal member supported moveably within the quenching chamber from first end to the second end of the quenching chamber,
h) the said system characterized in the quenching chamber means having a plurality of annular housing means (4) on its outer surface with a corresponding angular fluid spray surface guide means (15) associated operably with each of the plurality of annular housing means and also in a conical fluid spray terminal guide means (5) associated operably at the first end of the quench chamber, and further in the segmental partition means having a plurality of generally flat sealing partition solid disc (6) having a central aperture, the said solid disc engagingly associated with each of the annular housing (2) means, the said each disc having its central aperture sufficient to accomodate the bar within its aperture and thereby preventing free onward motion of the quenching fluid towards the second end of the quenching chamber means.
2. The system for quenching a longitudinal member as claimed in claim 1 wherein the said quenching fluid supply means further comprising of:
- an inlet receiving (12) means for receiving quench fluid from the quenching source, and
- a plurality of spaced supply outlet means (13) for supplying quenching fluid into the quenching chamber.
3. The system for quenching a longitudinal member as claimed in claim 1 wherein the said quenching chamber means further comprising of:
- a first quenching inlet opening port means (10) positioned at first end of quenching chamber to allow flow of quenching fluid into quenching chamber from one of the supply outlet means (13),
- a plurality of spaced second quenching inlet opening port (11) means also positioned at first end of quenching chamber to allow flow of quenching fluid into quenching chamber from one of the supply outlet means (13),
- a plurality of delivery inlet port means (16) with a first delivery inlet port means operably associated with first quench inlet opening port means for receiving the quenching fluid at first end of quenching chamber and delivering into quench chamber and operably associated with the conical fluid spray terminal guide (5) means further associated with first delivery inlet port means of quenching chamber means to spray deliver the received quenching fluid from the first delivery inlet port of quenching chamber into the quenching chamber whereby the sprayed fluid will contact radially the proximate surface of the longitudinal member to be cooled, and a plurality of second delivery inlet pipe means, each pipe operably associated with one of the plurality of second quenching inlet opening port (11) means and each of the second delivery inlet pipes means having atleast an open end towards the fluid supply means and extending longitudinally along one of the sides of quench chamber and parallel to the quench chamber, the said pipe means also having a plurality of outlet port means arranged linearly along its length and on its surface which is proximate to the quench chamber, the said plurality of second delivery inlet pipe means operably associated with its second quench inlet opening port means for receiving the quench fluid at its open end proximate to first end of quench chamber, and also arranged such that each of the linearly arranged outlet port means opening on this linear pipe coincides with at least one of annular surface housing means of a corresponding set of peripherally arranged housing (14) means on the hollow quench chamber thereby delivering the quench fluid through the associated annular peripherally arranged surface housing means into the quenching chamber, and the said plurality of second delivery inlet pipe means operably associated with the plurality of angular fluid spray surface guide means (4) combinedly formed with the plurality of peripherally arranged surface housing means enclosed around the quench chamber, wherein the plurality of peripherally arranged surface housing means are such that the quench fluid delivered angularly into the quenching chamber from the each of the plurality of second delivery inlet pipe means will contact radially the proximate surface of the longitudinal member to be cooled.
4. The system for quenching a longitudinal member as claimed in claim 1 wherein the said segmental partition (3) means is such that of each of the plurality of flat disc sealing partition (6) is disposed proximate to one of the plurality of surrounding surface housing means on the quench chamber and mounted within the quench chamber.
5. The system for quenching a longitudinal member as claimed in claim 1 wherein the said quench fluid exhaust means comprising:
- a plurality of surface exhaust means (9) arranged on the upper surface of the quench chamber as an opening means, each surface means exhaust is arranged between two angular fluid spray surface guides means and atleast one surface exhaust means (9) is arranged between the angular fluid spray terminal guide (4) means which is nearest to the conical fluid spray surface guide means, and
- a first terminal exhaust means arranged at the second end of the quench chamber for exhausting the residual quench fluid from the quenching chamber.
6. The system for quenching a longitudinal member as claimed in claim 1 wherein the angular fluid spray guide means of claim 1(h) is a conical fluid spray guide means.
7. The system for quenching a longitudinal member as claimed in claim 1 wherein the hollow quenching chamber means is preferably a cylindrical, square or rectangular.
8. The system for quenching a longitudinal member as claimed in claim 3 wherein the number of second quenching inlet opening port (11) means may be one or more and correspondingly the second delivery inlet pipe means may be one or more.
9. The system for quenching a longitudinal member as claimed in claim 1 wherein the said segmented portion means of claim 1 (h) is either solid, fluidic or a force field based portion means.