Title of Invention	AN IMLPROVED PORTABLE DEVICE FOR IN-SITU PREHEATING OF DIES IN CLOSED DIE FORGING
Abstract	A system for preheating dies in-situ for preheating both upper and lower dies in-situ without damaging the surface of the dies comprising heating means of predetermined design matching the profile of the dies and having a heating ring adapted to preheat both said upper and lower dies, plurality of hole in the heating means for inleting gas into the heating ring and control means for regulating the flow of gas into the heating ring. The system is particularly effective for preheating the upper and lower dies in-situ in close die wheel forging and also as other areas of use such as preheating of large shafts, rolls, etc. for efficient weld deposition and for preheating the other similar dies which cannot be easily taken out to preheat any closed chamber. The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption.

Title of Invention

AN IMLPROVED PORTABLE DEVICE FOR IN-SITU PREHEATING OF DIES IN CLOSED DIE FORGING

Abstract

A system for preheating dies in-situ for preheating both upper and lower dies in-situ without damaging the surface of the dies comprising heating means of predetermined design matching the profile of the dies and having a heating ring adapted to preheat both said upper and lower dies, plurality of hole in the heating means for inleting gas into the heating ring and control means for regulating the flow of gas into the heating ring. The system is particularly effective for preheating the upper and lower dies in-situ in close die wheel forging and also as other areas of use such as preheating of large shafts, rolls, etc. for efficient weld deposition and for preheating the other similar dies which cannot be easily taken out to preheat any closed chamber. The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption.

Full Text	Field of the invention : The present invention relates to 4 for the preheating dies in-situ. More particularly, the invention relates to a novel pre-heating system for pre-heating both upper and lower dies in-situ without damaging the surface of the dies. Description of known art: Presently preheating of dies is done in following manner :- i) An ingot block is forged in the dies to be preheated and kept aside for preheating as and when required. ii) Prior to preheating of dies, the pre-forged block is required to be heated up to approx. 1000° C in a batch type furnace. iii) Dies are put in open position. The distance between the lower and upper dies is approx. 1.5 meter. iv) Then this heated forged block is placed on the lower die with the help of mobile charger. v) The upper die is then lowered and put in closed position for a fixed duration of approx. 1 hour. vi) Then upper die is allowed to move upward. vii) The heated block placed on the lower die is taken out with the help of the mobile charger and kept aside for future use. 2 Drawbacks of the known art: System of preheating dies by placing heated metal block has many drawbacks. When die surface is in direct contact with heated block the surface temperature of the die is suddenly rises while interior still remain cool. The surface temperature some time exceeds tempering temperature of the die and hardness drops drastically. Above 500°C of temperature, hardness of dies starts deteriorating. As 700°C it is to as low as 30 RC from an initial hardness of 50-55 RC. The resulting soft surface of the dies cannot withstand the high forging stresses in 63MN press. Large heat-checks and cracks set in the dies resulting in poor surface quality of the forged wheel besides premature failure of the costly dies. This also results in large production interruption due to changing delay. Also to make the heated block ready it requires few hours furnace operation. It is therefore the principal object of the present invention to provide a novel system for pre-heating dies in-situ at temperature which does not damage the surface of the dies. The other objects would be apparent from the text herein. Thus the present invention relates to a novel system for pre-heating dies in-situ comprising : a heating means having a predetermined design matching the profile of the dies, said heating ring adapted to pre-heat both upper and lower dies ; a plurality of holes in the heating means for inletting gas into the heating ring; control means for regulating the flow of gas into the heating means. According to preferred embodiment, the system comprises means for placing and removing the heating means which is a ring shaped burner. The uniform heating by the heating element depends on the control of process variable e.g., time and flow rate of the gas and the size and the number of holes in the heating element. These factors are variable and are selected depending upon the size and configuration of the dies. The heating element is a burner and the numbers, size, distribution and angle of the holes form the burner design. The design of the dies to be heated form the basic for determining the design of the burner. The burning ring is further adapted to heat both the upper and lower dies. The heat transfer rate in the upper and lower dies also form basis for determining the burner design and the desired temperatures are achieved by regulating the flow of the gas. The system of the invention is based on the principle of indirect flame heating. This allows penetration of heat into the dies slowly without raising the surface temperature exceedingly high as was the case earlier. It is a portable system and as such may be adopted to preheat various components for in-situ weld deposition and repair. Temperature can be controlled by regulating a gas flow valve. Uniformity of heating is being achieved by the position, size and angle of the heating ring. Enhanced die life is achieved and die changing delay is reduced. Improvement in wheel forge quality is also achieved together with substantial economy. The invention will now be described with the help of illustrations, for a better understanding of the invention, by way of figures shown in accompanying drawings, in which Fig. 1 is a schematic diagram of a die-preheating system according to the invention. 4 Fig. 2 is a sectional view of the heating ring placed in the upper and lower dies. Fig. 3 shows different heating locations in an upper die tool. Figs. 1 and 2 gives the schematic diagram of die preheating system. The heating ring 1 is placed to heat 63Mn press used to forge railroad wheels. It basically consists of two parts. One is the heating ring 1 with basic dimensions mentioned in Fig.2. Second is the mixed (Coke oven + Blast furnace) gas pipe line 9. Both are connected with steel embedded hose pipe with flexible couplings. The heating ring 1 is placed on the lower die 12 and upper die 11 is lowered so that its distance with heating ring becomes about 150 mm. Then gas valve 10 is opened and burner is lighted with a burning torch. Flame height can be controlled with the help of the gas valve 10. After a pre-set duration the gas valve 10 is closed, upper die 11 is lifted and heating ring 1 is manually withdrawn. In this manner the die preheating temperature is achieved. According to a typical design, the heating ring 1 is a circular pipe of 40NB The gas inlet 2 is connected at centre through pipe 7 with three axially pipes 4, 5 and 6 having 120° angles in between them. Central inlet of gas ensures uniform supply of gas throughout the ring and connecting pipes 4, 5 and 6. Uniform pre-heating temperature is achieved with the control of process variables like time, flow rate and size and number of hole in the heating system. The gas is drawn from the 150NB main line 'A' furnace heating zone header with suitable reducers and gate valves 8. Gas pipe line 9 is connected with steel embedded hose pipe with flexible couplings. Heating ring design can be changed depending upon the size, grade, profile and other locational features of the die. 5 The block heating used conventionally was compared with the pre-heating system according to the invention and the temperature at various locations A to H as shown in Fig. 3 was measure. The results are as follows : Location Block heating Temperature in °C Indirect heating A 503 245 B 495 258 C 509 240 D 495 244 E 396 262 F 460 252 G 515 267 H 473 260 The results show that the newly developed die pre heating system is capable of uniformly heating dies in the range of 240 to 267°C. In the old system of die heating with the use of heated block surface temperature of dies rises more than tempering temperature resulting in deterioration of die properties. The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption. The system is particularly effective for preheating both upper and lower dies in-situ in close die wheel forging. Other areas of use of the system are in-situ preheating of large shafts, rolls etc. for efficient weld deposition and for preheating other similar dies which cannot to be easily taken out to preheat in any closed chamber. The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption. 6 We claim: 1. An improved portable device for in-situ pre-heating of dies in closed die forging wherein the dies have upper and lower elements, said device comprising : a heating means (1) being a gas burner having a configuration matching the profile of the dies and provided with heating rings adapted to preheat both upper (11) and lower dies ; a plurality of holes disposed in the heating means for inletting gas into the heating ring ; control means (10) for regulating the flow of gas into the heating means to thereby regulate the temperature of heating by the heating ring. 2. A device as claimed in Claim 1, wherein the burner is ring shaped. 3. A device as claimed in Claim 2, wherein the burner has a plurality of holes of predetermined size and angle for the flow of gas thereof. 4. A device as claimed in Claim 1, wherein the control means for the flow of gas is a gas valve. A system for preheating dies in-situ for preheating both upper and lower dies in-situ without damaging the surface of the dies comprising heating means of predetermined design matching the profile of the dies and having a heating ring adapted to preheat both said upper and lower dies, plurality of hole in the heating means for inleting gas into the heating ring and control means for regulating the flow of gas into the heating ring. The system is particularly effective for preheating the upper and lower dies in-situ in close die wheel forging and also as other areas of use such as preheating of large shafts, rolls, etc. for efficient weld deposition and for preheating the other similar dies which cannot be easily taken out to preheat any closed chamber. The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption.

Full Text

Field of the invention :
The present invention relates to 4 for the preheating dies in-situ. More particularly, the invention relates to a novel pre-heating system for pre-heating both upper and lower dies in-situ without damaging the surface of the dies.
Description of known art:
Presently preheating of dies is done in following manner :-
i) An ingot block is forged in the dies to be preheated and kept aside for preheating as and when required.
ii) Prior to preheating of dies, the pre-forged block is required to be heated up to approx. 1000° C in a batch type furnace.
iii) Dies are put in open position. The distance between the lower and upper dies is approx. 1.5 meter.
iv) Then this heated forged block is placed on the lower die with the help of mobile charger.
v) The upper die is then lowered and put in closed position for a fixed duration of approx. 1 hour.
vi) Then upper die is allowed to move upward.
vii) The heated block placed on the lower die is taken out with the help of the mobile charger and kept aside for future use.
2

Drawbacks of the known art:
System of preheating dies by placing heated metal block has many drawbacks. When die surface is in direct contact with heated block the surface temperature of the die is suddenly rises while interior still remain cool. The surface temperature some time exceeds tempering temperature of the die and hardness drops drastically. Above 500°C of temperature, hardness of dies starts deteriorating. As 700°C it is to as low as 30 RC from an initial hardness of 50-55 RC. The resulting soft surface of the dies cannot withstand the high forging stresses in 63MN press. Large heat-checks and cracks set in the dies resulting in poor surface quality of the forged wheel besides premature failure of the costly dies. This also results in large production interruption due to changing delay. Also to make the heated block ready it requires few hours furnace operation.
It is therefore the principal object of the present invention to provide a novel system for pre-heating dies in-situ at temperature which does not damage the surface of the dies. The other objects would be apparent from the text herein.
Thus the present invention relates to a novel system for pre-heating dies in-situ comprising :
a heating means having a predetermined design matching the profile of the dies, said heating ring adapted to pre-heat both upper and lower dies ;
a plurality of holes in the heating means for inletting gas into the heating ring;
control means for regulating the flow of gas into the heating means.

According to preferred embodiment, the system comprises means for placing and removing the heating means which is a ring shaped burner.
The uniform heating by the heating element depends on the control of process variable e.g., time and flow rate of the gas and the size and the number of holes in the heating element. These factors are variable and are selected depending upon the size and configuration of the dies. The heating element is a burner and the numbers, size, distribution and angle of the holes form the burner design. The design of the dies to be heated form the basic for determining the design of the burner. The burning ring is further adapted to heat both the upper and lower dies. The heat transfer rate in the upper and lower dies also form basis for determining the burner design and the desired temperatures are achieved by regulating the flow of the gas.
The system of the invention is based on the principle of indirect flame heating. This allows penetration of heat into the dies slowly without raising the surface temperature exceedingly high as was the case earlier. It is a portable system and as such may be adopted to preheat various components for in-situ weld deposition and repair. Temperature can be controlled by regulating a gas flow valve. Uniformity of heating is being achieved by the position, size and angle of the heating ring. Enhanced die life is achieved and die changing delay is reduced. Improvement in wheel forge quality is also achieved together with substantial economy.
The invention will now be described with the help of illustrations, for a better understanding of the invention, by way of figures shown in accompanying drawings, in which
Fig. 1 is a schematic diagram of a die-preheating system according to the invention.
4

Fig. 2 is a sectional view of the heating ring placed in the upper and lower dies.
Fig. 3 shows different heating locations in an upper die tool.
Figs. 1 and 2 gives the schematic diagram of die preheating system. The heating ring 1 is placed to heat 63Mn press used to forge railroad wheels. It basically consists of two parts. One is the heating ring 1 with basic dimensions mentioned in Fig.2. Second is the mixed (Coke oven + Blast furnace) gas pipe line 9. Both are connected with steel embedded hose pipe with flexible couplings. The heating ring 1 is placed on the lower die 12 and upper die 11 is lowered so that its distance with heating ring becomes about 150 mm. Then gas valve 10 is opened and burner is lighted with a burning torch. Flame height can be controlled with the help of the gas valve 10. After a pre-set duration the gas valve 10 is closed, upper die 11 is lifted and heating ring 1 is manually withdrawn. In this manner the die preheating temperature is achieved.
According to a typical design, the heating ring 1 is a circular pipe of 40NB The gas inlet 2 is connected at centre through pipe 7 with three axially pipes 4, 5 and 6 having 120° angles in between them. Central inlet of gas ensures uniform supply of gas throughout the ring and connecting pipes 4, 5 and 6. Uniform pre-heating temperature is achieved with the control of process variables like time, flow rate and size and number of hole in the heating system. The gas is drawn from the 150NB main line 'A' furnace heating zone header with suitable reducers and gate valves 8. Gas pipe line 9 is connected with steel embedded hose pipe with flexible couplings. Heating ring design can be changed depending upon the size, grade, profile and other locational features of the die.
5

The block heating used conventionally was compared with the pre-heating system according to the invention and the temperature at various locations A to H as shown in Fig. 3 was measure. The results are as follows :

Location Block heating Temperature in °C Indirect heating
A 503 245
B 495 258
C 509 240
D 495 244
E 396 262
F 460 252
G 515 267
H 473 260
The results show that the newly developed die pre heating system is capable of uniformly heating dies in the range of 240 to 267°C. In the old system of die heating with the use of heated block surface temperature of dies rises more than tempering temperature resulting in deterioration of die properties.
The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption.
The system is particularly effective for preheating both upper and lower dies in-situ in close die wheel forging. Other areas of use of the system are in-situ preheating of large shafts, rolls etc. for efficient weld deposition and for preheating other similar dies which cannot to be easily taken out to preheat in any closed chamber. The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption.
6

We claim:
1. An improved portable device for in-situ pre-heating of dies in closed die
forging wherein the dies have upper and lower elements, said device
comprising :
a heating means (1) being a gas burner having a configuration matching the profile of the dies and provided with heating rings adapted to preheat both upper (11) and lower dies ;
a plurality of holes disposed in the heating means for inletting gas into the heating ring ;
control means (10) for regulating the flow of gas into the heating means to thereby regulate the temperature of heating by the heating ring.
2. A device as claimed in Claim 1, wherein the burner is ring shaped.
3. A device as claimed in Claim 2, wherein the burner has a plurality of holes
of predetermined size and angle for the flow of gas thereof.
4. A device as claimed in Claim 1, wherein the control means for the flow of
gas is a gas valve.
A system for preheating dies in-situ for preheating both upper and lower dies in-situ without damaging the surface of the dies comprising heating means of predetermined design matching the profile of the dies and having a heating ring adapted to preheat both said upper and lower dies, plurality of hole in the heating means for inleting gas into the heating ring and control means for regulating the flow of gas into the heating ring. The system is particularly effective for preheating the upper and lower dies in-situ in close die wheel forging and also as other areas of use such as preheating of large shafts, rolls, etc. for efficient weld deposition and for preheating the other similar dies which cannot be easily taken out to preheat any closed chamber. The system can be adopted in any closed die forging industry for preheating of dies to reduce the tool consumption.

Documents:

00187-cal-2000-abstract.pdf

00187-cal-2000-claims.pdf

00187-cal-2000-correspondence.pdf

00187-cal-2000-description(complete).pdf

00187-cal-2000-drawings.pdf

00187-cal-2000-form-1.pdf

00187-cal-2000-form-18.pdf

00187-cal-2000-form-2.pdf

00187-cal-2000-form-3.pdf

00187-cal-2000-p.a.pdf

187-cal-2000-granted-abstract.pdf

187-cal-2000-granted-claims.pdf

187-cal-2000-granted-correspondence.pdf

187-cal-2000-granted-description (complete).pdf

187-cal-2000-granted-drawings.pdf

187-cal-2000-granted-examination report.pdf

187-cal-2000-granted-form 1.pdf

187-cal-2000-granted-form 19.pdf

187-cal-2000-granted-form 2.pdf

187-cal-2000-granted-form 3.pdf

187-cal-2000-granted-letter patent.pdf

187-cal-2000-granted-pa.pdf

187-cal-2000-granted-reply to examination report.pdf

187-cal-2000-granted-specification.pdf

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Patent Number

195402

Indian Patent Application Number

187/CAL/2000

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

24-Nov-2006

Date of Filing

30-Mar-2000

Name of Patentee

STEEL AUTHORITY OF INDIA LIMITED

Applicant Address

RESEARCH & DEVELOPMENT CENTRE FOR LRON & STEEL, DORANDA, RANCHI

Inventors:

#	Inventor's Name	Inventor's Address
1	JAIN DINESH KUMAR	RESEARCH & DEVELOPMENT CENTRE FOR LRON & STEEL, DORANDA, RANCHI-834002
2	JHA SAMIR KUMAR	RESEARCH & DEVELOPMENT CENTRE FOR LRON & STEEL,DORANDA,RANCHI-834002
3	ROY BASUDEO	RESEARCH & DEVELOPMENT CENTRE FOR LRON & STEEL,DORANDA,RANCHI-834002

PCT International Classification Number

B21J 1/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA