A bloom online ultrasonic flaw detection device and method for preventing equipment damage

Abstract

The present invention discloses a billet on-line ultrasonic flaw detection device and method for preventing equipment damage, which relates to the field of billet on-line ultrasonic flaw detection. In order to solve the problems that existing billets have out-of-tolerance conditions, which are likely to cause damage to equipment such as probes and billets being stuck. A billet on-line ultrasonic flaw detection device for preventing equipment damage includes a conveying roller table. A billet specification measuring device for incoming materials is arranged on the left side of the conveying roller table. A billet ultrasonic flaw detection watchdog is arranged on the right side of the billet specification measuring device for incoming materials. A pre-wetting device is arranged on the right side of the billet ultrasonic flaw detection watchdog. An ultrasonic flaw detection main machine is arranged on the right side of the pre-wetting device. The billet specification measuring device for incoming materials, the billet ultrasonic flaw detection watchdog, the conveying roller table, the pre-wetting device and the ultrasonic flaw detection main machine are all in communication with a central processor. The present invention can quickly detect the accurate specifications of incoming billets, automatically realize the function of over-tolerance alarm and shutdown, effectively protect the ultrasonic flaw detection equipment, reduce the failure rate, and realize the treatment of removing stuck billets, which is convenient and fast.

Description

Technical Field

[0001] The present invention relates to the technical field of on-line ultrasonic flaw detection for billets, and particularly to an on-line ultrasonic flaw detection device and method for billets to prevent equipment damage. Background Technique

[0002] In the metallurgical industry, ultrasonic flaw detection is the main means to detect the internal quality of steel, and it is mostly used in the quality inspection link after rolling into finished products. A billet is a kind of continuous casting steel billet in metallurgy and is mainly used as the raw material for rolling steel. With the progress of technology and the increasing quality requirements for section steel, train axles and wire products, especially for special steel (such as spring steel, bearing steel, train wheels, etc.), the internal defects of billets directly affect the quality of finished products. Therefore, it is particularly important to use on-line ultrasonic automatic flaw detection to detect the internal defects of billets.

[0003] During the on-line continuous ultrasonic flaw detection of billets in production, due to the variety of incoming billet size specifications, inconsistent sizes, and the influence of water cooling process control in the continuous casting process, the incoming billets have problems such as warping at the head, warping at the tail, excessive twist or flexure. When the out-of-tolerance billets pass through the on-line ultrasonic flaw detection equipment, they are likely to hit the probes, clamping devices, etc. of the ultrasonic flaw detection equipment, causing equipment damage such as probe damage and the billets being stuck. Therefore, it does not meet the existing requirements. For this reason, we propose an on-line ultrasonic flaw detection device and method for billets to prevent equipment damage. Summary of the Invention

[0004] The purpose of the present invention is to provide an on-line ultrasonic flaw detection device and method for billets to prevent equipment damage, which can quickly detect the accurate specifications of incoming billets, so as to judge whether the incoming billets are consistent with the set specifications, automatically realize the function of over-tolerance alarm and shutdown, effectively protect the ultrasonic flaw detection equipment, and can timely notify the on-site operation for processing, meet the requirements of continuous production, prevent out-of-tolerance billets from entering the ultrasonic flaw detection equipment, reduce the failure rate, avoid out-of-tolerance billets hitting the camera of the ultrasonic flaw detection equipment and causing camera damage, greatly improve the benefit efficiency of the ultrasonic flaw detection equipment, and realize the quick removal of stuck billets, which solves the problems raised in the above background technique.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An on-line ultrasonic flaw detection device for billets to prevent equipment damage, including a conveying roller table, a pre-wetting device and an ultrasonic flaw detection main machine. A device for measuring the specifications of incoming billets is arranged on the left side of the conveying roller table, a watchdog for billet ultrasonic flaw detection is arranged on the right side of the device for measuring the specifications of incoming billets, a pre-wetting device is arranged on the right side of the watchdog for billet ultrasonic flaw detection, an ultrasonic flaw detection main machine is arranged on the right side of the pre-wetting device, and the device for measuring the specifications of incoming billets, the watchdog for billet ultrasonic flaw detection, the conveying roller table, the pre-wetting device and the ultrasonic flaw detection main machine are all in communication with the central processor.

[0006] Preferably, the central processing unit includes a software processing module, a control module and an alarm module.

[0007] The software processing module is used to identify the straightness, warping, tail warping, twisting and deflection of the billet.

[0008] The control module is used to control the start and stop of the incoming billet specification determination device, the billet ultrasonic detection watchdog, the conveying roller, the pre-wetting equipment and the ultrasonic flaw detection host.

[0009] The alarm module is used to send out an audible and visual alarm.

[0010] Preferably, the incoming billet specification measuring device includes a light curtain rotating mechanism, a first pair of light curtains, a second pair of light curtains, a swing motor and a motor shaft. The light curtain rotating mechanism is installed on the motor shaft, the motor shaft is installed on the output end of the swing motor, and the swing motor is fixed to the mounting plate through a mounting frame. The first pair of light curtains and the second pair of light curtains are vertically installed on both sides of the light curtain rotating mechanism.

[0011] Preferably, the square billet ultra-detection watchdog includes a watchdog base, an upper V-block, a lower V-block, a V-block slide, a worm gear pressing mechanism, a guide column, a support plate and a top plate. The watchdog base is equipped with a guide column, V-block slides are movably mounted at both ends of the guide column, a lower V-block is mounted on the V-block slide, an upper V-block is provided directly above the lower V-block, the upper V-block is mounted on the support plate, worm gear pressing mechanisms are mounted on both sides of the upper surface of the support plate, and the top end of the worm gear pressing mechanism is mounted on the top plate.

[0012] Preferably, mounting blocks are provided at the front and rear sides of the bottom of the V-block slide, and a buffer spring is sleeved on the outer side of the guide column, and the buffer spring is in contact and connected with the inner side of the mounting block.

[0013] Preferably, the worm gear pressing mechanism is installed on an output shaft, the output shaft is installed at the output end of the pressing motor, the pressing motor is a double-output shaft motor, and a pressing hand wheel is installed at the tail of one of the output shafts.

[0014] Preferably, a depression position sensor is provided on the upper surface of the top plate, a proximity sensor is provided on the right side of the upper surface of the watchdog base, a support column is fixed on the watchdog base, the top plate is fixed on the top of the support column, and the support plate is movably mounted on the support column.

[0015] The present invention provides another solution: a method for using a billet online ultrasonic flaw detection device to prevent equipment from being damaged, comprising the following steps:

[0016] Step 1: First, according to the size of the billet to be inspected, start the pressing motor and the pressing position sensor. The pressing motor drives the worm gear pressing mechanism to work, so that the support plate moves downward along the support column, and automatically adjusts the opening between the upper V-block and the lower V-block to the set value. Then set the swing time of the first and second paired light curtains, the pressing relationship, and the lifting value of the pressing after clamping the steel.

[0017] Step 2: After the billet to be inspected is transported to the first and second paired light curtains through the conveyor roller, the swing motor is started to drive the motor shaft to work, so that the light curtain rotating mechanism starts to rotate left and right within a certain range, and the blocking signals of the first and second paired light curtains are collected. After the set time is reached, the swing motor stops working and the data collection is completed.

[0018] Step three: The collected occlusion data is transmitted to the software processing module. The software processing module identifies the straightness, warping, tail warping, twisting and deflection of the billet, obtains the specifications of the incoming billet, and determines whether it is consistent with the opening specifications between the pre-set upper V-block and the lower V-block. If not, the control module controls the conveyor roller to stop urgently and alarm. If consistent, proceed to step four.

[0019] Step 4: Perform flaw detection on the incoming billet. When the incoming billet is warped, warped, twisted or bent beyond tolerance, it will be stuck between the upper V-block and the lower V-block. Driven by the conveyor roller, the billet moves the watchdog V-block slide along the direction of the guide column and gradually compresses the buffer spring. When the watchdog device V-block slide moves to the proximity sensor, the proximity sensor is triggered, and the signal is transmitted to the control module to control the conveyor roller to stop urgently, so as to avoid the incoming billet with excessive shape entering the flaw detection host and causing an accident. At the same time, an audible and visual alarm is issued to prompt the operator to handle it.

[0020] Step 5: When the incoming billet has a new specification, re-enter the new specification, check the table to determine the pressing position, and then determine the direction of the pressing motor, determine whether the upper V-block is currently lifted or pressed down, and determine whether it has reached the set position. Once a steel jam occurs during the flaw detection process, the upper V-block will be lifted up to the set steel jam upper lifting position. After the steel jam is processed, if flaw detection is still required, the upper V-block will be pressed down to the original specification setting position to continue flaw detection until the stop signal is input and the entire process ends.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. An on-line ultrasonic flaw detection device and method for billets to prevent equipment damage. By rotating the first pair of light curtains and the second pair of light curtains, the blocked width on the light curtain can be obtained, and the accurate specifications of the incoming billets can be quickly detected, so as to judge whether the incoming billets are consistent with the set specifications. The whole detection process is fast and accurate. At the same time, the minimum cross-sections of the incoming billets in two directions are detected by the swing of the light curtain rotation mechanism, realizing the specification determination of twisted, warped or bent billets. It is simple and practical, with low cost, high reliability and stability.

[0023] 2. An on-line ultrasonic flaw detection device and method for billets to prevent equipment damage. The control module is used to realize the signal acquisition of the first pair of light curtains and the second pair of light curtains and the control of the swing motor. At the same time, the control module realizes the full-automatic control of the incoming material specifications, the adjustment of the incoming billet specifications, the pressing down and the release of the billet after clamping. The over-tolerance alarm and shutdown function is automatically realized, effectively protecting the ultrasonic flaw detection equipment and being able to timely notify the on-site operation for processing, meeting the requirements of continuous production.

[0024] 3. An on-line ultrasonic flaw detection device and method for billets to prevent equipment damage. The pressing motor and the pressing position sensor are used to automatically complete the setting and adjustment of the upper V-shaped block and the lower V-shaped block, so as to intercept billets with over-tolerance in warping at the head or tail, twist or flexure. The design is ingenious and the structure is reasonable, which is very suitable for the technological process of billet ultrasonic flaw detection. It realizes preventing over-tolerance billets from entering the ultrasonic flaw detection equipment, reducing the failure rate, and avoiding over-tolerance billets hitting the camera of the ultrasonic flaw detection equipment, resulting in camera damage. It greatly improves the benefit efficiency of the ultrasonic flaw detection equipment. When removing the stuck over-tolerance billets, only need to lift the upper V-shaped block, realizing the removal treatment of the stuck billets, which is convenient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The overall structure of the on-line ultrasonic flaw detection equipment for billets of the present invention;

[0026] Figure 2 The schematic diagram of the module of the on-line ultrasonic flaw detection equipment for billets of the present invention;

[0027] Figure 3 The schematic diagram of the structure of the incoming billet specification measurement device of the present invention;

[0028] Figure 4 The front view of the incoming billet specification measurement device of the present invention;

[0029] Figure 5 The A-A schematic diagram of the incoming billet specification measurement device of the present invention;

[0030] Figure 6 The schematic diagram of the structure of the billet ultrasonic flaw detection watchdog of the present invention;

[0031] Figure 7Front view of the bloom ultrasonic flaw detector watchdog of the present invention;

[0032] Figure 8 Flow chart of the program for determining the specifications of the incoming bloom of the present invention;

[0033] Figure 9 Flow chart of the program for adjusting the reduction of the incoming bloom specifications and separating the bloom after jamming of the present invention.

[0034] In the figure: 1. Device for measuring the specifications of the incoming bloom; 11. Light curtain rotating mechanism; 12. First pair of opposed light curtains; 13. Second pair of opposed light curtains; 14. Swing motor; 15. Motor shaft; 2. Bloom ultrasonic flaw detector watchdog; 21. Reduction position sensor; 22. Reduction motor; 23. Reduction handwheel; 24. Upper V-shaped block; 25. Lower V-shaped block; 26. V-shaped block slide; 27. Watchdog base; 28. Worm and gear reduction mechanism; 29. Guide post; 210. Buffer spring; 211. Proximity sensor; 212. Support plate; 213. Top plate; 214. Support column; 3. Conveyor roller table; 4. Pre-wetting equipment; 5. Ultrasonic flaw detection host. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] In order to solve the problems of warping at the head and tail, excessive twist or flexure during on-line continuous ultrasonic flaw detection of the incoming bloom, please refer to Figures 1-5 , the following technical solutions are provided in this embodiment:

[0037] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an online ultrasonic flaw detection device for billets to prevent equipment from being damaged, comprising a conveying roller 3, a pre-wetting device 4 and an ultrasonic flaw detection host 5, a device 1 for determining the specifications of incoming billets is arranged on the left side of the conveying roller 3, the device 1 for determining the specifications of incoming billets comprises a light curtain rotating mechanism 11, a first pair of light curtains 12, a second pair of light curtains 13, a swing motor 14 and a motor shaft 15, the light curtain rotating mechanism 11 is mounted on the motor shaft 15, the motor shaft 15 is mounted on the output end of the swing motor 14, the swing motor 14 is fixed to the mounting plate through a mounting frame, first pair of light curtains 12 and second pair of light curtains 13 are vertically mounted on both sides of the light curtain rotating mechanism 11, the first pair of light curtains 12 and the second pair of light curtains 13 are used to determine the shielding range on both sides of the incoming billets, the minimum cross-section of the incoming billets in two directions is detected by the swing of the light curtain rotating mechanism 11, and the specification determination of the twisted, warped or bent billets is realized, the whole method is simple and practical, low in cost, high in reliability and stability, once the billets enter the light curtain, through By rotating the two vertically mounted first and second paired light curtains 12 and 13, the blocked width on the light curtain can be immediately obtained, and the accurate specifications of the incoming billet can be quickly detected, so as to determine whether the incoming billet is consistent with the set specifications. The entire detection process is fast and accurate, with high reliability and stability. A billet ultra-detection watchdog 2 is arranged on the right side of the incoming billet specification determination device 1, a pre-wetting device 4 is arranged on the right side of the billet ultra-detection watchdog 2, and an ultrasonic flaw detection host 5 is arranged on the right side of the pre-wetting device 4. The incoming billet specifications The measuring device 1, the billet ultrasonic detection watchdog 2, the conveying roller 3, the pre-wetting device 4 and the ultrasonic flaw detection host 5 all communicate with the central processing unit, which includes a software processing module, a control module and an alarm module. The software processing module is used to identify the straightness, warping, tail warping, twisting and deflection of the billet. The control module is used to control the start and stop of the incoming billet specification measuring device 1, the billet ultrasonic detection watchdog 2, the conveying roller 3, the pre-wetting device 4 and the ultrasonic flaw detection host 5. The alarm module is used to send out sound and light alarms.

[0038] In order to solve the problem that the out-of-tolerance billet is easy to hit the probe and clamping device of the online ultra-detection equipment when passing through the online ultra-detection equipment, causing damage to the probe and other equipment, and the billet is stuck, please refer to Figure 1 , Figure 6 and Figure 7 , this embodiment provides the following technical solutions:

[0039] The bloom ultrasonic flaw detector watchdog 2 includes a watchdog base 27, an upper V-block 24, a lower V-block 25, a V-block slide 26, a worm and gear pressing mechanism 28, a guide post 29, a support plate 212, and a top plate 213. A guide post 29 is installed on the watchdog base 27. V-block slides 26 are movably installed at both ends of the guide post 29. Installation blocks are provided on the front and rear sides of the bottom of the V-block slide 26. A buffer spring 210 is sleeved outside the guide post 29, and the buffer spring 210 is in contact connection with the inner side of the installation block. Through the control module, full-automatic control of the incoming material specification, adjustment of the incoming bloom specification for pressing down, and the separation of the bloom after jamming is realized. The function of automatically alarming and stopping when the tolerance is exceeded is realized, effectively protecting the ultrasonic flaw detector equipment, and can timely notify the on-site operation for processing, meeting the requirements of continuous production. An upper V-block 24 is installed on the V-block slide 26, and a lower V-block 25 is provided directly above the upper V-block 24. The upper V-block 24 is installed on the support plate 212. Worm and gear pressing mechanisms 28 are installed on both sides of the upper surface of the support plate 212. The top ends of the worm and gear pressing mechanisms 28 are installed on the top plate 213. The worm and gear pressing mechanisms 28 are installed on the output shaft, and the output shaft is installed at the output end of the pressing motor 22. The pressing motor 22 is a double-output shaft motor. A pressing handwheel 23 is installed at the tail of one of the output shafts. The opening degree between the upper V-block 24 and the lower V-block 25 can be automatically adjusted through the pressing motor 22, or manually adjusted through the pressing handwheel 23. The operation is simple and convenient to use. Once the warping head, warping tail, twist or flexure of the incoming bloom exceeds the tolerance, it can be clamped between the upper V-block 24 and the lower V-block 25. When the bloom is clamped and runs, the buffer spring 210 is compressed. The position of the V-block slide 26 is sensed by the proximity sensor 211. When it exceeds the safety set position, the proximity sensor 211 transmits the information to the control module. The control module controls the conveyor roller table 3 to stop urgently and issues an audible and visual alarm through the alarm module. When it is necessary to withdraw the jammed bloom with tolerance exceeded, only need to lift the upper V-block 24 upward. The structure is simple, the processing and manufacturing cost is low, it is not easy to be damaged, and the treatment of withdrawing the jammed bloom is convenient and fast. A pressing position sensor 21 is arranged on the upper surface of the top plate 213. A proximity sensor 211 is arranged on the upper surface of the watchdog base 27 near the right side. A support column 214 is fixed on the watchdog base 27, and the top plate 213 is fixed on the top of the support column 214. The support plate 212 is movably installed on the support column 214. The setting adjustment of the upper V-block 24 and the lower V-block 25 is automatically completed by using the pressing motor 22 and the pressing position sensor 21 to intercept the bloom with warping head, warping tail, twist or flexure exceeding the tolerance. The design is ingenious and the structure is reasonable, which is very suitable for the technological process of bloom ultrasonic flaw detection, realizing the prevention of the bloom with tolerance exceeded from entering the ultrasonic flaw detector equipment, reducing the failure rate, and avoiding the damage of the camera of the ultrasonic flaw detector equipment caused by the bloom with tolerance exceeded hitting the camera, greatly improving the benefit efficiency of the ultrasonic flaw detector equipment.

[0040] Refer to Figures 8-9In order to better realize a method for using a billet online ultrasonic flaw detection device to prevent equipment from being damaged, the method comprises the following steps:

[0041] Step 1: First, according to the size of the square billet to be inspected, start the pressing motor 22 and the pressing position sensor 21. The pressing motor 22 drives the worm gear pressing mechanism 28 to work, so that the support plate 212 moves downward along the support column 214, and automatically adjusts the opening between the upper V-block 24 and the lower V-block 25 to the set value, and then sets the swing time of the first and second paired light curtains 12 and 13, the pressing relationship, and the lifting value of the pressing after clamping the steel.

[0042] Step 2: After the billet to be inspected is conveyed to the first and second light curtains 12 and 13 through the conveyor roller 3, the swing motor 14 is started to drive the motor shaft 15 to work, so that the light curtain rotating mechanism 11 starts to rotate left and right within a certain range, and the blocking signals of the first and second light curtains 12 and 13 are collected. After the set time is reached, the swing motor 14 stops working and the data collection is completed.

[0043] Step 3: The collected occlusion data is transmitted to the software processing module, which identifies the straightness, warping, tail warping, twisting and deflection of the billet, obtains the specifications of the incoming billet, and determines whether it is consistent with the opening specifications between the pre-set upper V-block 24 and the lower V-block 25. If not, the control module controls the conveyor roller 3 to stop urgently and alarm. If consistent, proceed to step 4.

[0044] Step 4: Perform flaw detection on the incoming billet. When the incoming billet is warped, warped, twisted or bent beyond tolerance, it is stuck between the upper V-block 24 and the lower V-block 25. Driven by the conveyor roller 3, the billet moves the watchdog V-block slide 26 along the direction of the guide column 29 and gradually compresses the buffer spring 210. When the watchdog device V-block slide 26 moves to the proximity sensor 211, the proximity sensor 211 is triggered, and the signal is transmitted to the control module to control the conveyor roller 3 to stop urgently, so as to avoid the incoming billet with excessive shape entering the flaw detection host and causing an accident. At the same time, an audible and visual alarm is issued to prompt the operator to handle it.

[0045] Step 5: When the incoming billet has a new specification, re-enter the new specification, check the table to determine the pressing position, and then determine the direction of the pressing motor 22, determine whether the upper V-block 24 is currently lifted or pressed down, and determine whether it has reached the set position. Once a steel jam occurs during the flaw detection process, the upper V-block 24 is lifted up to the set steel jam upper lifting position. After the steel jam is processed, if flaw detection needs to be continued, the upper V-block 24 is pressed down to the original specification setting position to continue flaw detection until the stop signal is input and the entire process ends.

[0046] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0047] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for using an on-line ultrasonic flaw detection device for billets to prevent equipment from being damaged. Features: The following steps are involved: Step 1: First, according to the size of the square billet to be inspected, the pressing motor (22) and the pressing position sensor (21) are started, and the pressing motor (22) drives the worm gear pressing mechanism (28) to work, so that the support plate (212) moves downward along the support column (214), and the opening between the upper V-shaped block (24) and the lower V-shaped block (25) is automatically adjusted to a set value, and then the swing time of the first and second light curtains (12) and the second light curtains (13), the pressing relationship and the lifting value of the pressing after the steel is clamped are set; Step 2: After the billet to be inspected is transported to the first pair of light curtains (12) and the second pair of light curtains (13) via a conveying roller (3), the swing motor (14) is started to drive the motor shaft (15) to work, so that the light curtain rotating mechanism (11) starts to rotate left and right within a certain range, and the blocking signals of the first pair of light curtains (12) and the second pair of light curtains (13) are collected. After the set time is reached, the swing motor (14) stops working, and the data collection is completed; Step 3: The collected occlusion data is transmitted to the software processing module, and the software processing module identifies the straightness, warping, warping, twisting and deflection of the billet, obtains the specifications of the incoming billet, and determines whether the specifications are consistent with the opening specifications of the upper V-shaped block (24) and the lower V-shaped block (25) set in advance. If they are inconsistent, the control module controls the conveying roller (3) to stop urgently and alarm. If they are consistent, the process proceeds to step 4. Step 4: flaw detection is performed on the incoming billet. When the incoming billet is warped, warped, twisted or bent beyond tolerance, it is stuck between the upper V-block (24) and the lower V-block (25). Driven by the conveyor roller (3), the billet moves the watchdog V-block slide (26) along the direction of the guide column (29) and gradually compresses the buffer spring (210). When the watchdog device V-block slide (26) moves to the proximity sensor (211), the proximity sensor (211) is triggered, and a signal is transmitted to the control module to control the conveyor roller (3) to stop suddenly, so as to prevent the incoming billet with an excessive shape from entering the flaw detection host and causing an accident. At the same time as the machine stops, an audible and visual alarm is issued to prompt the operator to handle the problem. Step 5: When the incoming billet has a new specification, the new specification is re-entered, the table is checked to determine the pressing position, and then the direction of the pressing motor (22) is determined to determine whether the upper V-shaped block (24) is currently lifted or pressed down, and whether it has reached the set position. Once a steel jam occurs during the flaw detection process, the upper V-shaped block (24) is lifted up to the set steel jam upper lifting position. After the steel jam is processed, if flaw detection is still required, the upper V-shaped block (24) is pressed down to the original specification setting position to continue flaw detection until the stop signal is input and the entire process is terminated.

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