阅读说明：本技术 基于步进底式加热炉的不锈钢穿孔前加热方法 (Stainless steel pre-perforation heating method based on stepping bottom type heating furnace ) 是由 韩学军 汪波 裴咏松 陶水松 于 2021-07-29 设计创作，主要内容包括：本发明涉及一种基于步进底式加热炉的不锈钢穿孔前加热方法,S100在步进底运行预留空隙上方炉顶设置炉顶烧嘴,在均热区两侧炉壁上分别设置控温热电偶和监控热电偶；S200点燃加热区侧墙烧嘴,将加热区的炉温升高到圆钢的穿孔温度,均热区侧墙烧嘴关闭；S300调整炉顶烧嘴火焰大小,直至控温热电偶的温度低于穿孔温度50℃-60℃；S400点燃均热区的侧墙烧嘴处于大火燃烧状态,根据控温热电偶的温度调整大火燃烧的大小,直至控温热电偶显示的温度为穿孔温度；S500根据控温热电偶与监控热电偶的温差调整均热区两侧侧墙烧嘴的火焰大小,直至两个热电偶的温度一至。本发明解决了传统步进式加热炉加热后生产的不锈钢无缝钢管存在扭曲及壁厚不均匀等不良状况的问题。(The invention relates to a stainless steel pre-perforation heating method based on a stepping bottom type heating furnace, and the method comprises the following steps of S100, arranging a furnace top burner on a furnace top above a stepping bottom operation reserved gap, and respectively arranging a temperature control thermocouple and a monitoring thermocouple on furnace walls on two sides of a soaking zone; s200, igniting side wall burners of the heating area, raising the furnace temperature of the heating area to the perforation temperature of the round steel, and closing the side wall burners of the soaking area; s300, adjusting the flame size of the furnace top burner until the temperature of the temperature control thermocouple is 50-60 ℃ lower than the perforation temperature; s400, igniting the side wall burner of the soaking zone in a big fire combustion state, and adjusting the big fire combustion size according to the temperature of the temperature control thermocouple until the temperature displayed by the temperature control thermocouple is the perforation temperature; s500, adjusting the flame size of the side wall burners at two sides of the soaking zone according to the temperature difference between the temperature control thermocouple and the monitoring thermocouple until the temperature of the two thermocouples is equal to one. The invention solves the problems of poor conditions of distortion, uneven wall thickness and the like of the stainless steel seamless steel pipe produced after the heating of the traditional stepping heating furnace.)

1. A stainless steel pre-perforation heating method based on a stepping bottom type heating furnace is characterized by comprising the following steps:

s100, modifying a stepping bottom type heating furnace: a row of furnace top burners (2) are arranged on the furnace top right above a stepping bottom operation reserved gap (5) of the stepping bottom type heating furnace, and a temperature control thermocouple (8) and a monitoring thermocouple (9) are respectively arranged on the furnace walls on the two sides of a soaking zone of the stepping bottom type heating furnace;

s200, heating the heating area: igniting the side wall burner (1) of the heating area, raising the furnace temperature of the heating area to the perforation temperature of the round steel, and closing the side wall burner (1) of the soaking area;

s300, initial temperature rise of a soaking zone: igniting the furnace top burner (2), and adjusting the flame size of the furnace top burner (2) until the temperature displayed by the temperature control thermocouple (8) is 50-60 ℃ lower than the perforation temperature;

s400, adjusting the temperature of the soaking zone: igniting the side wall burner (1) of the soaking zone to enable the side wall burner to be in a big fire combustion state, adjusting the big fire combustion size according to the temperature displayed by the temperature control thermocouple (8) until the temperature displayed by the temperature control thermocouple (8) is the perforation temperature, and locking the big fire combustion size;

s500, adjusting the uniformity of the temperature of the soaking zone: and adjusting the flame size of the side wall burners (1) on the two sides of the soaking zone according to the temperature difference between the temperature control thermocouple (8) and the monitoring thermocouple (9) until the temperature of the temperature control thermocouple (8) and the temperature of the monitoring thermocouple (9) are equal.

2. The method of claim 1, wherein the stainless steel is heated before piercing by a walking-beam furnace, and the method comprises: and in the step S400, igniting the side wall burner (1) of the soaking zone to enable the side wall burner to be in a big fire combustion state, wherein the big fire combustion state is not less than 15 seconds.

3. The method of claim 1, wherein the stainless steel is heated before piercing by a walking-beam furnace, and the method comprises: adjusting the flame size of the side wall burners (1) on the two sides of the soaking zone in the step S500 comprises the following steps: when the temperature of the left side is high, the right side wall burner (1) is adjusted to be small; when the temperature of the left side is low, the right side wall burner (1) is enlarged; until the temperature of the temperature control thermocouple (8) and the monitoring thermocouple (9) is equal.

4. The method of claim 1, wherein the stainless steel is heated before piercing by a walking-beam furnace, and the method comprises: the method further comprises the following steps of S600, automatic temperature control state: when the temperature of the temperature control thermocouple (8) and the temperature of the monitoring thermocouple (9) reach the perforation temperature, the furnace top burner (2) is still in a combustion state, meanwhile, the side wall burner (1) of the soaking zone is switched to a small-fire combustion state, and the small-fire combustion is adjusted to be in a minimum state. At the moment, the temperature of the side wall burner (1) in a low-fire state and the temperature of the furnace top burner (2) in a normal combustion state are required to be not higher than the perforation temperature; and when the display temperature of the temperature-controlled thermocouple (8) is 3-5 ℃ lower than the perforation temperature, repeating the steps S300 and S400.

5. The method of claim 1, wherein the stainless steel is heated before piercing by a walking-beam furnace, and the method comprises: the side wall burners (1) on the furnace walls at the left side and the right side of the heating area are arranged in a staggered manner.

6. The stainless steel pre-piercing heating method based on the walking-hearth furnace according to claim 1 or 5, wherein: the side wall burners (1) on the furnace walls at the left side and the right side of the soaking zone are arranged in a staggered manner.

7. The method of claim 1, wherein the stainless steel is heated before piercing by a walking-beam furnace, and the method comprises: the temperature control thermocouple (8) and the monitoring thermocouple (9) are both connected with an industrial personal computer, and the industrial personal computer is connected with the side wall burner (1) of the soaking zone.

8. The method of claim 1, wherein the stainless steel is heated before piercing by a walking-beam furnace, and the method comprises: the temperature control thermocouple (8) is positioned on one side of the discharge hole, and the monitoring thermocouple (9) is positioned on one side of the tapping machine (7).

9. The method of claim 1, wherein the stainless steel is heated before piercing by a walking-beam furnace, and the method comprises: the elevations of the temperature control thermocouple (8) and the monitoring thermocouple (9) at the position away from the highest operation point of the workpiece (3) in the furnace are both 250 mm.

Technical Field

The invention belongs to the technical field of stainless steel seamless steel pipe perforation, and particularly relates to a heating method before stainless steel perforation based on a stepping bottom type heating furnace.

Background

Stainless steel seamless steel pipe is a common metallurgical metal product, and is a round, square or rectangular steel product with a hollow cross section and no seam at the periphery. The seamless steel pipe is made up by using steel ingot (stainless steel round steel) or solid pipe blank to make tubular billet, then making hot rolling, cold rolling or cold drawing. In the production process of seamless tubes, steel materials need to be heated at high temperature, generally to about 1200 ℃. At present, most of stainless steel seamless tubes are produced by adopting a traditional inclined-bottom heating furnace, the traditional inclined-bottom heating furnace which needs manual material stirring is heated by slowly moving downwards by the gravity of steel materials, the stroke is uncontrollable, the heating time cannot be controlled, and part of the steel materials cannot reach the temperature required by the process, such as the energy-saving inclined-bottom heating furnace of the Chinese invention patent application, the application number of which is 201210146496.4.

Therefore, a stepping heating furnace is proposed to heat the stainless steel round steel, for example, the chinese utility model patent application "a heating apparatus for seamless steel pipe piercing process", application No. 201922462477.2. However, the stainless steel seamless steel tube which is heated and penetrated out before the stainless steel round steel is perforated by the traditional stepping heating furnace has the defects of distortion, uneven wall thickness and the like.

Disclosure of Invention

The invention aims to provide a stainless steel pre-piercing heating method based on a walking beam type heating furnace, which applies the walking beam type heating furnace to a stainless steel seamless pipe production line and solves the problems of poor conditions of distortion, uneven wall thickness and the like of a stainless steel seamless pipe produced after the stainless steel seamless pipe is heated by a traditional walking beam type heating furnace.

In order to achieve the purpose, the invention provides the following technical scheme:

a stainless steel pre-perforation heating method based on a stepping bottom type heating furnace is characterized by comprising the following steps:

s100, modifying a stepping bottom type heating furnace: a row of furnace top burners 2 are arranged on the furnace top right above a stepping bottom operation reserved gap 5 of the stepping bottom type heating furnace, and a temperature control thermocouple 8 and a monitoring thermocouple 9 are respectively arranged on the furnace walls on the two sides of a soaking zone of the stepping bottom type heating furnace;

s200, heating the heating area: igniting the side wall burner 1 of the heating area, raising the furnace temperature of the heating area to the perforation temperature of the round steel, and closing the side wall burner 1 of the soaking area;

s300, initial temperature rise of a soaking zone: igniting the furnace top burner 2, and adjusting the flame size of the furnace top burner 2 until the temperature displayed by the temperature control thermocouple 8 is 50-60 ℃ lower than the perforation temperature;

s400, adjusting the temperature of the soaking zone: igniting the side wall burner 1 of the soaking zone to enable the side wall burner to be in a big fire combustion state, adjusting the big fire combustion size according to the temperature displayed by the temperature control thermocouple 8 until the temperature displayed by the temperature control thermocouple 8 is the perforation temperature, and locking the big fire combustion size;

s500, adjusting the uniformity of the temperature of the soaking zone: and adjusting the flame size of the side wall burners 1 on the two sides of the soaking zone according to the temperature difference between the temperature control thermocouple 8 and the monitoring thermocouple 9 until the temperature of the temperature control thermocouple 8 and the temperature of the monitoring thermocouple 9 are equal.

Further, in the step S400, the side wall burners 1 in the soaking zone are ignited to be in a big fire combustion state, wherein the big fire combustion state is not less than 15 seconds.

Further, adjusting the flame size of the side wall burners 1 on both sides of the soaking zone in the step S500 includes: when the temperature of the left side is high, the right side wall burner 1 is adjusted to be small; when the temperature of the left side is low, the right side wall burner 1 is enlarged; until the temperature of the temperature control thermocouple 8 and the monitoring thermocouple 9 is reached.

Further, the method also comprises a step S600 of automatically controlling the temperature: when the temperature of the temperature control thermocouple 8 and the temperature of the monitoring thermocouple 9 reach the perforation temperature, the furnace top burner 2 is still in a combustion state, meanwhile, the side wall burner 1 of the soaking zone is switched to a small-fire combustion state, and the small-fire combustion is adjusted to be in a minimum state. At the moment, the temperature of the side wall burner 1 in a low-fire state and the temperature of the furnace top burner 2 in a normal combustion state are required to be not higher than the perforation temperature; when the display temperature of the temperature-controlled thermocouple 8 is 3-5 deg.c lower than the piercing temperature, steps S300 and S400 are repeated.

Further, the side wall burners 1 on the furnace walls on the left side and the right side of the heating area are arranged in a staggered mode.

Further, the side wall burners 1 on the furnace walls at the left side and the right side of the soaking zone are arranged in a staggered mode.

Further, the temperature control thermocouple 8 and the monitoring thermocouple 9 are both connected with an industrial personal computer, and the industrial personal computer is connected with the side wall burner 1 of the soaking zone.

Further, the temperature control thermocouple 8 is positioned on one side of the discharge hole, and the monitoring thermocouple 9 is positioned on one side of the tapping machine 7.

Furthermore, the elevations of the temperature control thermocouple 8 and the monitoring thermocouple 9, which are far from the position of the highest operation point of the workpiece 3 in the furnace, are both 250 mm.

Compared with the prior art, the invention has the following beneficial effects: the invention modifies the stepping bottom type heating furnace, applies the stepping bottom type heating furnace to a stainless steel seamless pipe production line through a temperature control adjustment method, and solves the problems of poor conditions of distortion, uneven wall thickness and the like of a stainless steel seamless pipe produced after the stepping bottom type heating furnace is heated in the traditional stepping type heating furnace. Realize the automation of firing equipment, replace the oblique bottom formula heating furnace of the tradition that needs artifical stirring material, realize the automation of perforation firing equipment in the stainless steel field, reduce the input of manpower resources.

Drawings

FIG. 1 is a schematic side view of a walking-beam furnace modified in the examples.

Fig. 2 is an enlarged schematic view of a portion a in fig. 1.

FIG. 3 is a schematic front view of a walking-beam furnace modified in the examples.

FIG. 4 is a schematic top view of a modified walking-beam furnace (tail section) in the example.

In the figure, 1, a side wall burner; 2. a furnace top burner; 3. a workpiece (round steel); 4. a discharge chute; 5. a step bottom operation reserved gap; 6. water sealing the tank; 7. a tapping machine; 8. a temperature control thermocouple; 9. the thermocouples were monitored.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

To the defect that exists in the heating of present step-by-step end formula heating furnace before the perforation of heating stainless steel round steel, this company has analyzed the leading factor that leads to its defect through the heating characteristic of the structure of studying step-by-step end formula heating furnace and stainless steel and is:

(1) the heating characteristic of stainless steel is that the heat conductivity coefficient is relatively small under the low temperature state, and the heat conductivity coefficient is gradually increased along with the increase of the temperature. The perforation temperature of the stainless steel round steel is about 1200 ℃, the heat conductivity coefficient at the temperature is far higher than that at normal temperature, and the heat conduction speed is much higher.

(2) The structure of the traditional stepping bottom type heating furnace: be feed inlet, the zone of heating and soaking zone in proper order along the advancing direction of work piece 3, the back end in soaking zone is equipped with blown down tank 4 the bottom in soaking zone back end is for step-by-step end operation reserved space 5 (the interval between the foremost position of step-by-step end operation and the initial position, give the operating space that step-by-step end was reserved, step-by-step end also is called step-by-step stove bottom), step-by-step end operation reserved space 5 departments are equipped with water seal tank 6. The furnace walls on the left side and the right side of the heating zone and the soaking zone are respectively provided with a plurality of side wall burners 1. The water seal device (namely the water seal groove 6) is arranged below the discharge chute 4, the water seal device is filled with circulating cooling water, the water seal device and the furnace inner space at the position are communicated, under the action of water vapor of the water seal device, the temperature of a hearth at the position above the water seal device is reduced, the heat conduction speed of stainless steel in a high-temperature state is faster due to the combination of the reason (1), the stainless steel round steel which is heated is influenced by the water seal device in a discharge area to cause great temperature drop, the temperature difference of the stainless steel round steel core surface is larger, and the quality defects of distortion, uneven wall thickness and the like of a seamless pipe which is penetrated out are overcome.

The characteristics of stainless steel are combined with the structural characteristics of the traditional stepping bottom type heating furnace, and certain technical difficulties exist when the method is applied to heating before the stainless steel round steel is perforated. Based on the analysis of the reasons, the invention provides a stainless steel pre-perforation heating method based on a stepping bottom type heating furnace, which comprises the following steps:

s100, modifying a stepping bottom type heating furnace:

for the analysis of the problems, the company modifies the existing stepping bottom type heating furnace, as shown in fig. 1, 2, 3 and 4, the modified stepping bottom type heating furnace sequentially comprises a feeding hole, a heating region and a soaking region along the advancing direction of a workpiece 3, the tail section of the soaking region is provided with a discharging groove 4, one side wall of the stepping bottom type heating furnace is provided with a discharging hole, the other side wall of the stepping bottom type heating furnace is provided with a pushing hole, and the discharging hole and the pushing hole are positioned at two ends of the discharging groove 4; and a steel tapping machine 7 is arranged outside the material pushing opening, and the steel tapping machine 7 is used for penetrating through the material pushing opening to push the workpiece 3 out of the material discharging opening along the material discharging groove 4. And a water seal groove 6 is arranged at the position of the stepping bottom operation reserved gap 5. As shown in fig. 4, the furnace walls on the left and right sides of the heating zone and the soaking zone are respectively provided with a plurality of side wall burners 1, and the side wall burners 1 on the furnace walls on the two sides of the heating zone and the soaking zone are respectively arranged in a staggered manner. Two furnace top burners 2 are arranged on the furnace top right above the step bottom operation reserved gap 5.

In the conventional heating process of the traditional stepping bottom type heating furnace, each temperature-controlled burner is controlled by one temperature-controlled thermocouple in a centralized manner, namely, all the burners in the whole subarea are adjusted under the condition of high or low temperature. In response to this situation, the present invention further takes the following improvements: the furnace wall on the two sides of the soaking zone is respectively provided with a temperature control thermocouple 8 and a monitoring thermocouple 9, the temperature control thermocouple 8 is positioned on one side of the discharge hole, the monitoring thermocouple 9 is positioned on one side of the tapping machine 7, and the elevations of the temperature control thermocouple 8 and the monitoring thermocouple 9, which are away from the highest position of the operation of the workpiece 3 in the furnace, are both 250 mm. The temperature control thermocouple 8 and the monitoring thermocouple 9 are both connected with an industrial personal computer, and the industrial personal computer is connected with the side wall burner 1 of the soaking zone. The industrial personal computer is mainly used for: displaying the temperature of the temperature control thermocouple 8 and the temperature of the monitoring thermocouple 9, comparing the temperature difference between the temperature control thermocouple 8 and the temperature difference between the monitoring thermocouple 9, and respectively and independently controlling the side wall burners 1 on the two sides of the soaking zone according to the temperature of the temperature control thermocouple 8 and the temperature difference.

S200, heating the heating area: and igniting the side wall burner 1 of the heating area, raising the furnace temperature of the heating area to 1200 ℃ of the perforation temperature of the round steel, closing the side wall burner 1 of the soaking area, and controlling the side wall burner 1 of the soaking area by a temperature control thermocouple 8.

S300, initial temperature rise of a soaking zone: igniting the furnace top burner 2, and adjusting the flame size of the furnace top burner 2 until the temperature displayed by the temperature control thermocouple 8 is 50-60 ℃ lower than the perforation temperature, namely the displayed temperature is 1140-1150 ℃.

S400, adjusting the temperature of the soaking zone: and igniting the side wall burner 1 in the soaking zone to enable the side wall burner to be in a big fire combustion state (the big fire combustion state is not less than 15 seconds), adjusting the big fire combustion size according to the temperature displayed by the temperature control thermocouple 8 until the temperature displayed by the temperature control thermocouple 8 is 1200 ℃, and locking the big fire combustion size.

S500, adjusting the uniformity of the temperature of the soaking zone: according to the temperature difference of the temperature control thermocouple 8 and the monitoring thermocouple 9, adjusting the flame size of the side wall burners 1 on the two sides of the soaking zone: when the temperature of the left side is high, the right side wall burner 1 is adjusted to be small; when the temperature of the left side is low, the right side wall burner 1 is enlarged; finally, the temperatures of the two thermocouples tend to be consistent, and the two thermocouples can be put into an automatic temperature control state.

S600, automatic temperature control state:

when the temperature of the temperature control thermocouple 8 and the temperature of the monitoring thermocouple 9 both reach the perforation temperature of 1200 ℃, the furnace top burner 2 is still in a combustion state, meanwhile, the side wall burner 1 of the soaking zone is switched to a small-fire combustion state, and the small-fire combustion is adjusted to be in a minimum state. At the moment, the temperature of the side wall burner 1 in a low-fire state and the temperature of the furnace top burner 2 in a normal combustion state are required to be not higher than the perforation temperature;

when the displayed temperature of the temperature-controlled thermocouple 8 is 3-5 c lower than the piercing temperature, steps S300 and S400 are repeated until the temperature returns to the piercing temperature of 1200 c.

Big and small fire are the common technical terms in the field, wherein the small fire is mainly used for igniting the big fire, and the big fire is used for heating and warming. When the side wall burner 1 is of a single-tube structure, small fire exists when the opening degree of the valve is below 20%; when the side wall burner 1 is of a double-pipe structure, the flame of the main pipe is big fire, and the flame of the auxiliary pipe is small fire.

The principle and the effect of the scheme are as follows: according to the method, the two furnace top burners 2 and the soaking zone side wall burners 1 are controlled and adjusted, wherein the two furnace top burners 2 are always in the working state, so that the round steel in the furnace can be prevented from being cooled due to the generation of water vapor in the water seal tank 6, the surface temperature of the stainless steel round steel core is uniform, and the quality defects of distortion, uneven wall thickness and the like of a penetrated seamless pipe can be prevented. The temperature control of the soaking zone is realized by controlling the size of the side-wall burner 1 by the temperature control thermocouple 8 and controlling the switching combustion of the fire. The temperature difference conditions of the thermocouple 9 and the temperature control thermocouple 8 are monitored, the big-fire combustion size of the side wall burner 1 is adjusted, the convection heat transfer effect is enhanced, and the uniformity of the furnace temperature is improved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.