Energy-efficient production method of an alloy steel

Abstract

The application relates to an energy-efficient production method of alloy steel, which comprises the following steps: after being perforated, a seamless steel pipe is passed through an annealing furnace under the action of an annealing furnace roller, one burner is arranged every 0.5 m on the two sides in the annealing furnace, the annealing furnace sequentially has a heating section, a cooling section and a holding section, the heating section, the cooling section and the holding section each have n1, n3 and n2 burners on one side, the combustion temperature of each burner in the heating section is T1, the combustion temperature of each burner in the holding section is T3-T0, and the combustion temperature of the i-th burner in the cooling section is T i . n1={ v 进 [(T1‑T 穿 ) / (Sv T )]} / 0.5, n3={ v 进 (T1‑T3+T0) / (Sv T )} / 0.5, n2=(t c v 进 ) / 0.5, and T i ={(T1+T3‑T0) / n3}(n3‑i). The application can reduce energy consumption, shorten the production cycle and reduce the hardness of the alloy steel pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal heat treatment, in particular to an efficient and energy-saving production method of alloy steel. BACKGROUND

[0002] Small-sized alloy bars need to be cold-rolled after hot rolling and piercing, and the material needs to be spheroidizing annealed after hot rolling and piercing to reduce the hardness of the material. The existing production process is as follows: bar heating-piercing-cooling to room temperature-annealing in an annealing furnace to 680 DEG C-keeping for 5 hours-cooling to 400 DEG C-air cooling (total time is at least 30 hours). The existing production time cycle is long, fuel consumption is large, the use efficiency of the heat treatment furnace is affected, and the production cost is increased. In order to reduce the cold rolling production pass, the hardness of the steel pipe after annealing should be minimized, so that the cold rolling large reduction can be realized, thereby reducing the process pass.

[0003] Therefore, a new production method is needed to reduce fuel consumption, shorten production cycle, and reduce the hardness of alloy steel pipe to meet the cold rolling condition. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the defects of the prior art and provide an efficient and energy-saving production method of alloy steel, which can reduce energy consumption, shorten production cycle, and reduce the hardness of alloy steel pipe.

[0005] To solve the above technical problems, the technical scheme of the present application is as follows: an efficient and energy-saving production method of alloy steel, comprising:

[0006] The seamless steel pipe after piercing passes through the annealing furnace under the action of the annealing furnace roller; wherein,

[0007] One burner is arranged every 0.5 m on both sides in the annealing furnace, and the annealing furnace sequentially has a heating section, a cooling section and a holding section, the heating section, the cooling section and the holding section each have n1, n3 and n2 burners on one side, the combustion temperature of each burner in the heating section is T1, the combustion temperature of the i th burner in the cooling section is T i , and the combustion temperature of each burner in the holding section is T3-T0;

[0008] The calculation formula of n1 is: n1= { v 进 (T1-T 穿 ) / (S v T )) / 0.5, and the minimum integer is taken upward;

[0009] The calculation formula of n3 is: n3= { v 进 (T1-T3+T0) / (S vT} up to the minimum integer; the calculation formula of n2 is: n2= (t c v 进} up to the minimum integer;

[0010] T i} up to the minimum integer; i = (T1+T3-T0) / n3 (n3-1);

[0011] In the formula, v 进 is the advancing speed of the annealing furnace roller; T1 is the completion temperature of the austenite transformation in the steel heating process; T 穿 is the temperature of the seamless steel pipe after piercing; v T is the heating speed in the heating section; S is the wall thickness of the seamless steel pipe after piercing; t C is the time of the structure transformation; T3 is the nose temperature of the C curve; and T0 is the supercooling degree.

[0012] Further, T1, t C and T3 are obtained based on the continuous cooling transformation CCT curve of the supercooled austenite of the alloy steel pipe to be produced, which is obtained by using a thermal simulation testing machine.

[0013] Further, v T is measured based on the black box test.

[0014] Further, before the pierced seamless steel pipe passes through the annealing furnace under the action of the annealing furnace roller, it further comprises:

[0015] The pierced seamless steel pipe enters the isothermal furnace through the roller, is arranged in the isothermal furnace after being pushed sideways, and n pieces of seamless steel pipes are discharged in one row and then are held together by a flat support to the annealing furnace roller.

[0016] Further, the calculation formula of n is: n = the maximum integer of b / D

[0017] Wherein, b is the width of the annealing furnace roller; and D is the outer diameter of the pierced seamless steel pipe.

[0018] Further, the calculation formula of v 进 is: v 进 =L / t 排

[0019] Wherein, t 排 =n t 穿 ; and L is the length of the pierced seamless steel pipe, and t 穿 is the piercing time of a single seamless pipe.

[0020] By adopting the technical scheme, the method in the application maximizes the ferrite or pearlite transformation of the steel organization of the alloy seamless steel pipe before the nose temperature, forms the least carbide, and further forms the lowest hardness, reduces the cold rolling production pass, and shortens the production cycle, the application reasonably sets the roller speed and the number of opened burners, and the temperature of each burner, further shortens the production cycle, and further reduces the energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A production line for implementing an efficient and energy-saving production method of an alloy steel in the application;

[0022] In the figure, 1, piercing machine; 2, roller; 3, isothermal furnace; 4, side pushing mechanism; 5, annealing furnace; 6, burner; 7, flat support. DETAILED DESCRIPTION

[0023] In order to make the content of the application more easily understood, the application will be further described in detail below according to specific embodiments and in combination with the drawings.

[0024] An efficient and energy-saving production method of an alloy steel, comprising:

[0025] Comprising: the seamless steel pipe after piercing passes through the annealing furnace 5 under the action of the annealing furnace roller; wherein,

[0026] One burner 6 is arranged every 0.5 m on both sides in the annealing furnace 5, the annealing furnace 5 has a heating section, a cooling section and a holding section in sequence, the heating section, the cooling section and the holding section each have n1, n3 and n2 burners 6 on one side respectively, the combustion temperature of each burner 6 in the heating section is T1, the combustion temperature of the i-th burner 6 in the cooling section is T i , and the combustion temperature of each burner 6 in the holding section is T3-T0;

[0027] The calculation formula of n1 is: n1= { v 进 [(T1-T 穿 ) / (S v T )]} / 0.5, and the minimum integer is taken upward;

[0028] The calculation formula of n3 is: n3={ v 进 (T1-T3+T0) / (S v T )} / 0.5, and the minimum integer is taken upward; and the calculation formula of n2 is: n2=(t c v 进 ) / 0.5, and the minimum integer is taken upward;

[0029] T i The calculation formula is: T i = { (T1+T3-T0) / n3} (n3-i);

[0030] To ensure the cooling speed and the heating speed are consistent, n3={ v 进 (T1-T3+T0) / (S / v T )} / 0.5, and the minimum integer is taken upward to form the temperature gradient.

[0031] In the formula, v 进 is the forward speed of the annealing furnace roller; T1 is the completion temperature of the austenite transformation in the steel heating process; T 穿 is the temperature of the seamless steel pipe after piercing; v T is the heating speed in the heating section; S is the wall thickness of the seamless steel pipe after piercing; t C is the transformation time; T3 is the C curve nose temperature; and T0 is the supercooling degree, generally 10℃. The C curve nose temperature refers to the distance between the transformation starting line and the longitudinal axis in the C curve, which is the incubation period, indicating the stability of the supercooled austenite under different supercooling degrees, wherein the incubation period is the shortest, the stability of the supercooled austenite is the lowest, and it is called the "nose" of the C curve.

[0032] Two burners 6 are arranged at the front and rear ends of the isothermal furnace 3 respectively, which play a heat preservation role. Piercing is performed on the piercing machine 1, and side pushing is performed through the side pushing mechanism 4.

[0033] T1, t C and T3 are obtained based on the continuous cooling transformation (CCT) curve of the supercooled austenite of the alloy steel pipe to be produced, which is obtained by using a thermal simulation testing machine.

[0034] v T is measured based on the black box test, which is the time when the seamless steel pipe is heated to the same temperature of the inner surface and the outer surface, i.e. the heating speed per millimeter per minute, the unit is ℃ / (min mm), and the data can be obtained by testing one sample in the early stage, and the test can not be full.

[0035] In this embodiment, the number n1 of burners 6 to be opened is calculated according to the forward speed, the heating speed, and the temperature difference to be heated in the heat preservation process, the time and temperature of cooling to the complete ferrite or pearlite single structure are obtained based on the C curve nose temperature in the annealing cooling process, and the annealing completion temperature and the temperature T i and the number n2 of burners 6 before reaching the annealing completion temperature in the annealing furnace 5 are obtained. n1, n2 and T iThe hardness of the cooled seamless steel pipe can be ensured to reach the minimum, and the energy consumption can be reduced, and the production cycle can be shortened.

[0036] In the embodiment, the perforated seamless steel pipe passes through the annealing furnace 5 under the action of the annealing furnace roller before the perforated seamless steel pipe is annealed.

[0037] The perforated seamless steel pipe enters the isothermal furnace 3 through the roller 2, is arranged in the isothermal furnace 3 after being pushed, and n sets of seamless steel pipes are discharged in one row and are supported together on the annealing furnace roller by the flat support 7.

[0038] The calculation formula of n is: n = the maximum integer of b / D.

[0039] Wherein, b is the width of the annealing furnace roller, and D is the outer diameter of the perforated seamless steel pipe.

[0040] v 进 The calculation formula of v is: v 进 =L / t 排

[0041] Wherein, t 排 =n t 穿 ; L is the length of the perforated seamless steel pipe, and t 穿 is the perforation time of a single seamless pipe.

[0042] After n sets of the perforated seamless steel pipes are arranged in the isothermal furnace 3, the n sets of the perforated seamless steel pipes are sent into the annealing furnace 5 together, and the formula is used to ensure the continuity of production.

[0043] The technical solutions related to the above embodiments will be described in detail through specific embodiments.

[0044] A high-efficiency and energy-saving production method of a 23CrNi3Mo steel pipe, a T1 measured by a thermal simulation tester is 825℃, a T3 of a C curve nose temperature is 715℃, a t C for microstructure transformation is 4500s, a heating speed v T of a heating section of the annealing furnace 5 is 3℃ / (min mm), the outer diameter D of the steel pipe after perforation is 70mm, the wall thickness S is 7mm, the length L is 5000mm, the T 穿 is 700℃, the steel pipe directly enters the isothermal furnace 3 at a temperature of 700℃, the width of the isothermal furnace 3 and the width of the annealing furnace roller are 1200mm, the perforation time is 38s, the number of sets in one row is 17, and the total time t 排For 646s, the number n1 of burners 6 heated to 825℃ after entering the annealing furnace 5 is 14, the time is 904s, the n3 and n1 data are equal to 14, the time is 904s, annealed to 705℃ and then kept for 4500s, then n2 is 70, and the total time is 1.76h, which can be shortened by 28.4h. After the time required to reach the target temperature and the holding time are met, the furnace is discharged and air-cooled to room temperature. The hardness value HRB80 meets the requirements.

[0045] The above is based on the ideal embodiment of the present application. Through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. An energy-efficient production method of alloy steel, characterized in that, comprising: the perforated seamless steel pipe passes through the annealing furnace under the action of the annealing furnace roller; wherein, Two burners are arranged every 0.5 m on both sides in the annealing furnace, the annealing furnace sequentially has a heating section, a cooling section and a holding section, the heating section, the cooling section and the holding section each have n1, n3 and n2 burners on one side, the combustion temperature of each burner in the heating section is T1, the combustion temperature of each burner in the holding section is T3-T0, and the combustion temperature of the i-th burner in the cooling section is T i . The calculation formula of n1 is: n1= { v 进 [ (T1-T 穿 ) / (S v T ) ] / 0.5, and the minimum integer is taken upward. The calculation formula of n3 is: n3={ v 进 (T1-T3+T0) / (S v T )} / 0.5, and the minimum integer is taken upward. The calculation formula of n2 is: n2= (t c v 进 ) / 0.5, rounding up to the minimum integer; T i The calculation formula is: T i = (T1+T3-T0) / n3 (n3-i); In the formula, v 进 is the forward speed of the annealing furnace roller; T1 is the completion temperature of the austenite transformation in the steel heating process; T 穿 is the temperature of the seamless steel pipe after piercing; v T is the heating speed in the heating section; S is the wall thickness of the seamless steel pipe after piercing; t C is the time of the structure transformation; T3 is the C curve nose temperature; T0 is the supercooling degree.

2. The energy-efficient production method of alloy steel according to claim 1, characterized in that, T1, t C and T3 are obtained based on a continuous cooling transformation CCT curve of a supercooled austenite of an alloy steel pipe to be produced, which is obtained by a thermal simulator test.

3. The energy-efficient production method of alloy steel according to claim 1, characterized in that, v T For black box test based on the measured.

4. The energy-efficient production method of alloy steel according to claim 1, characterized in that, Before the perforated seamless steel pipe passes through the annealing furnace under the action of the annealing furnace roller, it further comprises: the perforated seamless steel pipe enters the isothermal furnace through the roller, is arranged in the isothermal furnace after being pushed sideways, and n sets of seamless steel pipes are discharged in a row and then held together by the flat support to the annealing furnace roller.

5. The energy-efficient production method of alloy steel according to claim 4, characterized in that, the calculation formula of n is: n = the maximum integer of b / D; wherein, b is the width of the annealing furnace roller; D is the outer diameter of the perforated seamless steel pipe.

6. The energy-efficient production method of alloy steel according to claim 5, characterized in that, v 进 The calculation formula is:v 进 = L / t 排 where t 排 = t 0 - t 穿 0, L is the length of the seamless steel pipe after piercing, t 穿 is the piercing time of a single seamless pipe.

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