TWI616537B - Method of heat treatment for metal - Google Patents

Abstract

A method for heat-treating a metal material, comprising: heating a rod-shaped metal material to a first temperature by using a heating fixture; and performing a rapid cooling process on the rod-shaped metal material by a cooling device, so that the rod-shaped metal material is The first temperature rapidly drops to a second temperature, and the rapid cooling program has a rapid cooling rate for cooling the rod-shaped metal material, and the rapid cooling rate ranges from 80 ° C / sec to 200 ° C / sec. The rod-shaped metal material conforming to specific mechanical properties is produced by the above method.

Description

Metal material heat treatment method

The present invention relates to a metal material heat treatment method, and more particularly to a heat treatment method for controlling the cooling rate to change the mechanical properties of the metal material.

In the processing procedure of the metal material, the heat treatment procedure can change the mechanical properties of the metal material itself. Taking the heat treatment procedure of the steel material as an example, when the steel material is heated to a specific temperature, the steel material can be cooled by a cooling device, and The cooling device can change the structural state of the steel by controlling the cooling temperature of the steel material, thereby conforming the steel material to mechanical properties such as specific rigidity or ductility.

Referring to FIG. 1, there is disclosed a manufacturing apparatus 9 for a hot-rolled steel sheet. The manufacturing apparatus 9 is sequentially provided with a hot rolling mill 91, a rapid cooling unit 92, and a heat cycle according to a conveying direction of a steel material S. The cooling unit 93, after the steel material S is formed into a predetermined shape by the hot rolling processing machine 91, the steel material S can then pass through the rapid cooling unit 92 for rapid cooling, and finally, the steel material S enters the thermal cycle cooling. The unit 93, the heat cycle cooling unit 93, controls the temperature of the steel material S to a predetermined temperature, thereby adjusting the mechanical properties of the steel material S. Regarding the heat treatment method using the above-described manufacturing apparatus 9, reference can be made to the Patent No. I445581 of the Republic of China.

However, the mechanical properties of the steel S may vary depending on the difference in cooling temperature, and may vary depending on the cooling rate. Conventional heat treatment procedures only control the cooling temperature but ignore the cooling rate. The heat treatment procedure does not allow metal materials such as steel to conform to specific mechanical properties.

In view of this, 遂 provides a metal material heat treatment method to solve the problem that the conventional heat treatment process cannot produce a metal material that meets specific mechanical properties.

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal material heat treatment method which can have an effect of producing a metal material conforming to a specific mechanical property by controlling a cooling rate to change a mechanical property of a metal material.

In order to achieve the foregoing object, the technical means for the present invention comprises: a method for heat-treating a metal material, comprising: heating a rod-shaped metal material to a first temperature by a heating fixture; and applying the cooling device to the rod The rapid cooling process is performed to rapidly lower the rod-shaped metal from the first temperature to a second temperature, the rapid cooling program having a rapid cooling rate for cooling the metal material, the range of the rapid cooling rate The system is in the range of 80 ° C / sec to 200 ° C / sec , wherein the cooling device has a conveying mechanism and a jetting mechanism, and the conveying mechanism drives the rod-shaped metal material to move in a conveying direction when the rod-shaped metal material is cooled. The jetting mechanism cools the rod-shaped metal by spraying a cooling liquid, and the jetting mechanism has a fast jet flow rate and a fast jet pressure when the coolant is sprayed, and the fast jet flow rate is between 60 L/min and 1000. L/min , the rapid jet pressure system is between 70 bar and 300 bar , and the coolant has a traveling direction, and the traveling direction has an inclined angle with the conveying direction, The tilt angle is between 15° and 90°. By the above method, the effect of producing a rod-shaped metal material conforming to a specific mechanical property is achieved by controlling the cooling rate of the rod-shaped metal material.

Wherein, the cooling device performs a slow cooling process on the rod-shaped metal material, and the rod-shaped metal material is slowly lowered from the second temperature to a third temperature, and the slow cooling program has the rod shape A slow cooling rate of metal cooling, which ranges from 50 °C/sec to 80 °C/sec , thereby controlling the cooling rate of the rod-shaped metal to achieve a rod shape that meets specific mechanical properties. The effect of metal.

Wherein, in the slow cooling process, the jetting mechanism has a slow jet flow rate when the coolant is sprayed, and the slow jet flow rate is between 20 L/min and 60 L/min , thereby having a slow speed Cooling produces a rod-shaped metal that meets specific mechanical properties.

Wherein, in the slow cooling process, the coolant sprayed by the jet mechanism has a slow jet pressure when contacting the rod-shaped metal material, and the slow jet pressure is between 30 bar and 70 bar , thereby having The effect of making a rod-shaped metal material that meets specific mechanical properties at a slow cooling rate.

Wherein, the inclination angle is 45°, thereby maintaining proper heat exchange, and lifting the effect of the coolant on the gas film on the surface of the rod-shaped metal when performing the rapid cooling process, and performing the slow speed During the cooling process, the effect of the coolant to remove the scale on the surface of the rod-shaped metal material is enhanced.

In the conveying mechanism, when the rod-shaped metal material is cooled, the rod-shaped metal material is driven to rotate in parallel with the axis of the conveying direction while the rod-shaped metal material is moving in the conveying direction, thereby maintaining the rod-shaped metal material in a direction parallel to the conveying direction. Proper heat exchange, and an effect of lifting the coolant to wash the gas film on the surface of the rod-shaped metal when the rapid cooling process is performed, and lifting the coolant to remove the rod metal when performing the slow cooling process The effect of the scale on the surface of the material.

〔this invention〕

1‧‧‧Transportation agency

11‧‧‧Base

111‧‧‧ Feeding end

112‧‧‧Drawing end

12‧‧‧Roller

121‧‧‧Transportation Department

122‧‧‧ shaft

13‧‧‧Drive motor

14‧‧‧Transmission unit

2‧‧‧Spray mechanism

21‧‧‧ nozzle group

211‧‧‧ nozzle

22‧‧‧Support frame

A1‧‧‧ tilt angle

D1‧‧‧ conveying direction

D2‧‧‧ axial direction

D3‧‧‧direction of travel

S‧‧‧Metal

[study]

9‧‧‧ Manufacturing equipment

91‧‧‧ hot rolling machine

92‧‧‧Cooling unit

93‧‧‧thermal cycle cooling unit

S‧‧‧Steel

Figure 1: Schematic diagram of a conventional manufacturing apparatus.

Fig. 2 is a schematic view showing an execution device of the metal material heat treatment method of the present invention.

Fig. 3 is a schematic view showing an execution device of the metal material heat treatment method of the present invention.

Fig. 4 is a schematic view showing an execution device of the metal material heat treatment method of the present invention.

Fig. 5 is a schematic view showing an execution device of the metal material heat treatment method of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt; The temperature of the material refers to the execution of the metal The surface temperature after heating or cooling.

Referring to FIGS. 2 and 3, which are schematic views of a cooling device for performing the metal material heat treatment method of the present invention, the cooling device is for performing a cooling operation on a metal material S, wherein the cooling device includes a conveying device. The mechanism 1 and a jet flow mechanism 2 are disposed on one side of the transport mechanism 1.

The conveying mechanism 1 has a base 11 and a plurality of rollers 12. The base 11 has a receiving end 111, a discharging end 112 and a conveying direction D1. The conveying direction D1 is directed from the feeding end 111. The discharge end 112 extends, and the plurality of rollers 12 are disposed on the base 11. Each of the plurality of rollers 12 has a conveying portion 121. The diameter of the conveying portion 121 of the plurality of rollers 12 is determined by The opposite ends of the conveying portion 121 are gradually decreased toward the center, and the axial direction D2 of the rotating shaft 122 of the plurality of rollers 12 and the conveying direction D1 are not parallel to each other and are not perpendicular. In addition, the conveying mechanism 1 further has a driving motor 13 , and the rotating shaft 122 of the adjacent two rollers 12 is connected by a transmission unit 14 , and the driving motor 13 transmits power to the plurality of rollers by a plurality of the transmission units 14 . The shaft 122 of the wheel 12.

Referring to FIG. 4, in the embodiment, the conveying portion 121 of the plurality of rollers 12 has a change in the diameter, and the outer surface of the conveying portion 121 preferably forms a continuous curved surface by linear projection, for example, the number The outer surface of the conveying portion 121 of each of the rollers 12 is a concave curved surface. With the above arrangement, when the metal material S is in the shape of a rod and placed on the conveying portion 121 of the plurality of rollers 12, in the case where the plurality of rollers 12 rotate according to the rotating shaft 122, the plurality of rollers The conveying portion 121 of the wheel 12 can simultaneously apply a moving force and a rotating force to the metal material S, which can not only drive the metal material S to move along the conveying direction D1, but also drive the metal material S to the conveying. The concave surface of the portion 121 is rotated, and has an effect of driving the metal material S to simultaneously move and rotate. The rate of change in the diameter of the conveying portion 121 of the plurality of rollers 12 is not limited thereto, and is preferably appropriately adjusted depending on the shape of the metal material S.

Referring again to Figures 2 and 3, the jet mechanism 2 has a plurality of nozzle groups. 21, the plurality of nozzle groups 21 are disposed between the feeding end 111 of the base 11 and the discharging end 112. Each of the plurality of head groups 21 has a plurality of nozzles 211 that are oriented toward the metal material S conveyed by the conveying portion 121 of the plurality of rollers 12. The plurality of nozzles 211 can spray a coolant, which can be any working fluid capable of heat exchange, and is not limited herein. In the embodiment, the coolant is a liquid water. In addition, the spray mechanism 2 further has a support frame 22, the plurality of spray head sets 21 are disposed on the support frame 22, and the support frame 22 is coupled to the base 11 of the transport mechanism 1, and the support frame 22 is also The coolant can be simultaneously transported as a coolant conveying pipe, and the plurality of nozzle groups 21 can communicate with the coolant conveying pipe, so that the coolant in the coolant conveying pipe can be output by the plurality of nozzle groups 21.

Referring to FIG. 5, the manner in which the plurality of nozzles 211 are disposed is not limited thereto. The plurality of nozzles 211 may be disposed perpendicular to the conveying direction D1, so that the traveling direction of the coolant of the plurality of nozzles 211 is D3. The conveying direction D1 is perpendicular, or as in the embodiment, the plurality of nozzles 211 are inclined from the discharging end 112 toward the feeding end 111, thereby causing the traveling direction of the coolant of the plurality of nozzles 211. D3 includes a horizontal component and a vertical component (in terms of the drawing), and the horizontal component of the traveling direction D3 of the coolant is opposite to the conveying direction D1, so that the coolant sprayed by the plurality of nozzles 211 can The rod-shaped metal material S moving in the conveying direction D1 provides a larger impact force to cool the metal material S through the cooling liquid or remove the gas film or scale on the surface of the metal material S, and has a smooth heat treatment process Effect.

The metal material heat treatment method of the present invention comprises a heating step and a rapid cooling step.

In the heating step, the metal material S is heated to a first temperature by a heating fixture. The type of the metal material S is not limited thereto, and the first temperature can be flexibly adjusted according to the type and characteristics of the metal material S. In the embodiment, the metal material S is a steel material. The first temperature is between 800 ° C and 1200 ° C; and when the metal S is to be heated to the first temperature, the first temperature is the surface temperature of the metal S.

The rapid cooling step is performed by the cooling device to perform a rapid cooling process on the metal material S, so that the metal material S is rapidly lowered from the first temperature to a second temperature. Wherein, the rapid cooling program has a rapid cooling rate for cooling the metal material, and the rapid cooling rate ranges from 80 ° C/sec to 200 ° C/sec .

More specifically, the jetting mechanism 2 of the cooling device performs the rapid cooling process by injecting the cooling liquid, in which each nozzle 211 of the jet mechanism 2 has a spray when the coolant is sprayed. a rapid jet flow rate of 60 L/min to 1000 L/min , the coolant sprayed by the jet mechanism 2 having a rapid jet pressure when contacting the metal material S, the fast jet pressure system From 70 bar to 300 bar . According to the above embodiment, not only a large amount of cooling fluid can be transmitted to enhance the heat exchange effect, but also the mechanical properties of the metal material S can be adjusted, and the surface of the metal material S can be impacted by the high-pressure cooling fluid to wash the metal material S. The gas film produced in this heating step, in turn, has the effect of producing a metal material S conforming to a specific mechanical property by rapid cooling, and has an effect of maintaining the surface integrity of the metal material S.

Moreover, the second temperature can be flexibly adjusted according to the type and characteristics of the metal material S, and is not limited thereto. In the embodiment, when the metal material S is the steel material, the second temperature system is One phase of the steel changes the critical temperature. By the rapid cooling step, the steel is cooled to a critical temperature of the phase change at a specific cooling rate, and the mechanical properties of the steel can be adjusted to have the effect of producing a steel material that conforms to specific mechanical properties.

Further, the metal material heat treatment method of the present invention may further perform a slow cooling step after performing the rapid cooling step. The slow cooling step is performed by the cooling device to perform a slow cooling process on the metal material S, so that the metal material S is slowly lowered from the second temperature to a third temperature. Wherein, the slow cooling program has a slow cooling rate for lowering the metal material S, and the slow cooling rate ranges from 50 ° C/sec to 80 ° C/sec .

More specifically, the jetting mechanism 2 of the cooling device performs the slow cooling process by injecting the cooling liquid, in which the nozzle 211 of the jetting mechanism 2 is sprayed with the cooling liquid. The method has a slow jet flow rate of 20 L/min to 60 L/min , and the coolant sprayed by the jet mechanism 2 has a slow jet pressure when contacting the metal material S. The slow jet pressure system is between 30 bar and 70 bar , and the third temperature can be flexibly adjusted according to the type and characteristics of the metal material S, and is not limited thereto. With the above arrangement, not only a relatively small amount of cooling fluid can be transmitted to slow down the heat exchange effect, but also the mechanical properties of the metal material S can be adjusted, and the surface of the metal material S can be impacted by a suitable pressure cooling fluid to remove the The scale of the surface of the metal material S has an effect of producing a metal material S conforming to a specific mechanical property at a slow temperature drop, and an effect of removing the scale of the surface of the metal material S.

Further, the metal material heat treatment method of the present invention may further perform a temperature maintaining step after performing the heating step, and then perform the rapid cooling step. The temperature maintaining step is such that after the metal material S is heated to the first temperature, the metal material S is maintained at the first temperature for a predetermined time. In the embodiment, when the metal material S is a steel material and heated When the temperature is from 800 ° C to 1200 ° C , the predetermined time for maintaining the first temperature is 10 min to 60 min . By the above steps, the mechanical properties of the steel material can be adjusted, and the effect of producing a steel material conforming to a specific mechanical property can be obtained.

Referring to FIG. 2 and FIG. 3 again, in the cooling device of the present invention, the plurality of nozzle groups 21 of the jet flow mechanism 2 can correspondingly spray the coolant according to the rapid cooling program and the slow cooling program. Preferably, as shown in FIG. 2, the plurality of nozzle groups 21 of the jetting mechanism 2 adjacent to the feeding end 111 are configured to perform the rapid cooling process, and the jetting mechanism 2 adjacent to the discharging end 112 The plurality of nozzle groups 21 are configured to perform the slow cooling process, so that the metal material S conveyed through the conveying mechanism 1 can sequentially execute the rapid cooling program and the slow cooling program, thereby continuously performing rapid cooling and slowing. In the case of rapid temperature drop, the effect of producing a metal material S conforming to a specific mechanical property is achieved.

Referring to FIG. 5 again, when the rapid cooling program and the slow cooling program are executed, the conveying mechanism 1 drives the metal material S to move in the conveying direction D1. The jetting mechanism 2 sprays the cooling liquid in the traveling direction D3, and the traveling direction D3 has an inclination angle A1 with the conveying direction D1, and the inclination angle A1 is between 15° and 90°. In this embodiment, It is preferably 45°. With the above arrangement, not only the cooling liquid and the metal material S can maintain an appropriate heat exchange effect, but also the effect of the coolant on the gas film on the surface of the metal material S can be improved when the rapid cooling process is performed, and When the slow cooling process is performed, the effect of removing the scale of the surface of the metal material S by the coolant is increased.

Further, in the structure of the cooling device of the present invention, when the rapid cooling program and the slow cooling program are executed, if the shape of the metal material S is a rod shape, the roller 12 of the conveying mechanism 1 can be used not only The rod-shaped metal material S moves along the conveying direction D1, and is further permeable to the concave curved surface of the conveying portion 121 to drive the rod-shaped metal material S to rotate in parallel with the axis of the conveying direction D1, thereby making the coolant The more uniform contact with the metal material S can not only maintain the proper heat exchange effect between the coolant and the metal material S, but also enhance the gas flushing the surface of the metal material S when the rapid cooling process is performed. The effect of the film, and the effect of removing the scale of the surface of the metal material S by the coolant when the slow cooling process is performed.

In order to prove that the metal material heat treatment method of the present invention has the effect of producing a metal material conforming to a specific mechanical property, the following steps are performed with a rod-shaped steel material (SCM440) having a diameter of 60 mm, and the relevant mechanical properties are organized as follows:

In the above two tables, four sets of SCM440 rod-shaped steel billets are heated to 1100 ° C (first temperature), and then the temperature is maintained for a period of time, the four sets of SCM440 rod-shaped steel billets are transported at a billet conveying speed, and then jetted. The flow rate is 1000 L/min, the jet pressure is 120 bar, and the mechanical properties obtained by cooling the above four sets of SCM440 bar-shaped steel billets to the temperature (Ms) (second temperature) of the granulated iron are controlled, wherein the number is S1-1. The embryo system holds the temperature for 30 min, the S1-2 system holds the temperature for 35 min, the S1-3 system holds the temperature for 15 min, the S1-4 system holds the temperature for 20 min, and the S1-1 has a feed rate of 5 M/min, S1-2, S1- The feed rate of the blanks of 3 and S1-4 is 7M/min; A and B respectively represent two different sampling points on the same blank, which refers to the distance from the surface of the rod-shaped steel to the axis. . It can be seen from Tables 1 and 2 that when the heat treatment method of the present invention is performed on the rod-shaped steel material of SCM440, the mechanical strength (pull strength and the strength of the tensile strength) of the rod-shaped steel material can be effectively increased by 40% or more, and The hardness of the rod-shaped steel material is increased by more than 20%, and the above experimental data can prove that the metal material heat treatment method of the present invention can achieve the production of metal conforming to specific mechanical properties. The effect of the material S.

As described above, in the metal material heat treatment method of the present invention, the metal material S is cooled at a specific cooling rate, and the structure change of the metal material S is controlled to achieve the effect of producing the metal material S conforming to specific mechanical properties.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

Claims (7)

A method for heat-treating a metal material, comprising: heating a rod-shaped metal material to a first temperature by using a heating fixture; and performing a rapid cooling process on the rod-shaped metal material by a cooling device, so that the rod-shaped metal material is The rapid temperature is rapidly decreased to a second temperature, and the rapid cooling program has a rapid cooling rate for cooling the rod-shaped metal, and the rapid cooling rate ranges from 80 ° C/sec to 200 ° C/sec . The cooling device has a conveying mechanism and a jetting mechanism, and the conveying mechanism drives the rod-shaped metal material to move in a conveying direction when the rod-shaped metal material is cooled, and the jetting mechanism transmits a cooling liquid to cool the rod-shaped metal The jet mechanism has a fast jet flow rate and a fast jet pressure when the coolant is sprayed, the fast jet flow rate is between 60 L/min and 1000 L/min , and the rapid jet flow pressure is between 70 bar and 300 Bar , the coolant has a traveling direction, and the traveling direction has an inclined angle with the conveying direction, and the inclination angle is between 15° and 90°. The method for heat-treating a metal material according to claim 1, wherein the cooling device performs a slow cooling process on the rod-shaped metal material, and the rod-shaped metal material is slowly lowered from the second temperature to a second temperature. The third temperature, the slow cooling program has a slow cooling rate for cooling the metal material, the slow cooling rate ranging from 50 ° C / sec to 80 ° C / sec . The metal material heat treatment method according to claim 2, wherein the cooling device has a jet flow mechanism that performs a slow cooling process by injecting a coolant. The metal material heat treatment method according to claim 3, wherein in the slow cooling process, the jet mechanism has a slow jet flow rate when the coolant is sprayed, and the slow jet flow rate is 20 L /min ~60 L/min . The metal material heat treatment method according to claim 3, wherein in the slow cooling process, the coolant sprayed by the jet mechanism has a slow jet pressure when contacting the rod-shaped metal material, the slow speed The jet pressure is between 30 bar and 70 bar . The metal material heat treatment method according to claim 1, wherein the inclination angle is 45°. The method for heat-treating a metal material according to claim 1, wherein the conveying mechanism drives the rod-shaped metal in a state in which the rod-shaped metal material moves in the conveying direction when the rod-shaped metal material is cooled. The material rotates in parallel with the axis of the conveying direction.