A flexible process rolling method for disc screw production

Abstract

The application discloses a flexible process rolling method for disc screw production, and comprises the following steps: A, chemical composition internal control is carried out during electric arc furnace smelting; B, heating system and open rolling temperature control are carried out, the heating system adopts continuous casting billet heating, and the open rolling temperature is controlled to be 1000 DEG C-930 DEG C; C, the temperature of the rolling process is controlled; D, the finish rolling temperature is controlled to be 900 DEG C+ / -20 DEG C; E, the cooling rate of the rolled steel, the initial temperature and the final temperature of the rapid cooling after rolling are strengthened, and the wire laying temperature is controlled to be 880 DEG C-920 DEG C; F, the disc screw is cooled on a Stelmor conveyor, rapid cooling is carried out first, then slow cooling is carried out, and the cooling is carried out at a cooling speed of 4 DEG C / s-7 DEG C / s, and after cooling, the disc screw is packed, stored and stacked. The problem that the product does not reach the standard due to the rough process control of the existing process is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rolling process, in particular to a flexible process rolling method for disc screw production. BACKGROUND

[0002] The flexible process rolling technology was proposed by Academician Wang Guodong of Northeastern University in 2006 and was again proposed in the August 2023 Academic Report on Threaded Steel Industry Development (flexible manufacturing technology is a new concept model and new development trend to realize future factory). In recent years, the flexible process rolling technology has begun to be valued by steel enterprises, and has been applied to production process control by a few large steel enterprises, and good results have been achieved.

[0003] When using the existing flexible process rolling method for production, the control of chemical composition internal control, opening rolling temperature, finishing rolling temperature and cooling speed is relatively rough, and the products rolled do not meet the expected requirements in terms of tensile strength, yield strength and toughness, etc. Therefore, the existing process needs to be improved. SUMMARY

[0004] The purpose of the present application is to provide a flexible process rolling method for disc screw production, which solves the problem of rough process control of the existing process causing the produced products to be out of standard.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] A flexible process rolling method for disc screw production, comprising the following steps: A, chemical composition internal control during electric arc furnace smelting; B, control of heating system and opening rolling temperature, the heating system adopts continuous casting billet heating, and the opening rolling temperature is controlled at 1000℃-930℃; C, control of the temperature of the rolling process; D, control of the finishing rolling temperature at 900℃±20℃; E, strengthen control of the cooling rate of the rolled steel, the initial temperature and the final temperature of the post-rolling rapid cooling, and the wire feeding temperature is controlled at 880℃-920℃; F, when the disc screw is cooled on the Stelmor conveyor, it is first rapidly cooled and then slowly cooled, and the cooling speed is 4℃ / s-7℃ / s, and after cooling, it is packed and stored for stacking.

[0007] In the present application, through the control of chemical composition, opening rolling temperature, temperature of rolling process, finishing rolling temperature and wire feeding temperature, the grain size is controlled after large deformation and rapid cooling in the rolling process, the grain size and organization precipitation in the steel are controlled, and the mechanical properties are stabilized, so as to realize the flexible control of the material organization performance, and the rolling chemical composition, mechanical properties and metallographic structure can all meet the higher standard requirements.

[0008] By adjusting the heating temperature to control the austenite grain size, the austenite grain is refined, the dynamic recrystallization process is completed through controlled rolling and controlled cooling, the fine-grain strengthening effect is achieved, the yield strength is improved, the Stelmor fan air volume (Stelmor model) is controlled to control the amount and uniformity of the organization precipitation, the high-quality product with stable mechanical properties is obtained, the reasonable stacking of the disc screw product is selected to control the temperature below the solidus and the long-time holding purpose, the rolling residual stress is reduced or eliminated, the residual atmosphere in a small part of the steel is removed, the process performance and toughness are improved, the purpose of stabilizing the yield strength and the ratio of strength to yield is achieved.

[0009] As a further preferred embodiment of the present application, the mass fraction of each component in the chemical composition in step A is as follows: C 0.16-0.25 parts; Si 0.4-0.6 parts; Mn 1-1.25 parts; P 0-0.07 parts; S 0-0.04 parts; Ceq 0.39-0.54 parts.

[0010] In view of the high content of residual elements (nitrogen, molybdenum, chromium, copper, nickel, etc.) after smelting products by the direct current electric arc furnace, when the residual elements are high, the addition amount of manganese alloy can be reduced, and carbon and silicon manganese alloy are added, without adding vanadium, titanium and niobium, thereby reducing the use amount of high-speed wire micro-alloy on the original basis, and realizing composite micro-alloying.

[0011] In combination with the high content of H and N in the finished product of the direct current electric arc furnace, by reasonably matching the chemical composition, controlling the heating and rolling process and stacking, the partial H content in the steel is reduced, the N content in the steel is fixed, the rolled disc screw has good weldability, good stability of yield strength and strength to yield ratio, and certain corrosion resistance on the surface, and no cracks in cold bending.

[0012] As a further preferred embodiment of the present application, the temperature control of the rolling process in step C is specifically performed when more than half of the rolling deformation of the disc screw micro-alloying is performed at ≤950 ℃.

[0013] The advantage is that the disc screw is deformed in the austenite unrecrystallized zone with sufficient deformation, and the austenite can be dynamically recrystallized through multi-pass cumulative plastic deformation.

[0014] As a further preferred embodiment of the present application, in addition to controlling the heating temperature and the starting rolling temperature in the final rolling temperature in step D, the water amount between the water cooling box before the finishing mill and the finishing mill group is also applied to realize the control.

[0015] The purpose is to control the rolling temperature of the final rolling pass at the austenite to ferrite transformation temperature (and deformation-induced phase change), and the grain is coarse and the strength is low when the final rolling temperature is high.

[0016] As a further preferred embodiment of the present application, the cooling rate after rolling in step E requires a first stage to be high, and a second stage to be controlled according to the yield property.

[0017] To obtain the desired microstructure, the cooling rate of the rolled steel, the initial temperature of the rapid cooling after rolling and the final temperature of the rapid cooling must be controlled (to prevent grain coarsening).

[0018] As a further preferred embodiment of the present application, the cooling of the coiled coil on the Stelmor conveyor in step F is specifically adjusted by the air volume according to the spooling temperature, so as to reduce the coiling temperature, and the temperature is controlled to be less than 220 DEG C.

[0019] The mechanical properties and process properties meet the requirements of the national standard.

[0020] As a further preferred embodiment of the present application, the coiled coil is stacked for no more than 4 hours at <200 DEG C, and the deformation residual stress is eliminated after slow cooling.

[0021] The deformation residual stress is eliminated after slow cooling.

[0022] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0023] 1. In the present application, the grain size is controlled after large deformation and rapid cooling in the rolling process by controlling the composition, the opening rolling temperature, the temperature during rolling, the finish rolling temperature and the spooling temperature, the grain size and the microstructure in the steel are controlled, the mechanical properties are stabilized, and the flexible control of the material microstructure and properties is realized, so that the rolling chemical composition, the mechanical properties and the microstructure can all meet the high standard requirements.

[0024] 2. The residual element content (nitrogen, molybdenum, chromium, copper, nickel, etc.) is high after smelting the product by the direct current arc furnace, when the residual element content is high, the addition amount of manganese alloy can be reduced, carbon and silicon manganese alloy are added, vanadium, titanium and niobium are not added, the use amount of high-speed wire micro-alloy is reduced on the basis of the original, and composite micro-alloying can also be realized.

[0025] 3. The mechanical properties and process properties meet the requirements of the national standard.

[0026] 4. The deformation residual stress is eliminated after slow cooling. DETAILED DESCRIPTION

[0027] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. The components of the embodiments of the present application described herein can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present application provided is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0029] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0030] In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "arrange", "mount", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. Specific embodiment 1:

[0032] A flexible process rolling method for disc screw production, comprising the following steps: A, chemical composition internal control during electric arc furnace smelting; B, control of heating system and opening rolling temperature, the heating system adopts continuous casting billet heating, and the opening rolling temperature is controlled at 1000 DEG C; C, control of the temperature of the rolling process; D, control of the finish rolling temperature at 900 DEG C; E, strengthen control of the cooling rate of the rolled steel, the initial temperature and the final temperature of the rapid cooling after rolling, and the wire drawing temperature is controlled at 920 DEG C; F, when the disc screw is cooled on the Stelmor conveyor, it is first rapidly cooled and then slowly cooled, and the cooling is carried out at a cooling speed of 7 DEG C / s, and after cooling, it is packed and stored in the warehouse for stacking;

[0033] The chemical composition internal control in the step A is as follows: C 0.25 parts; Si 0.4 parts; Mn 1 part; P 0.05 parts; S 0.04 parts; Ceq 0.39 parts;

[0034] The temperature control of the rolling process in the step C specifically represents that more than half of the rolling deformation of the disc screw micro-alloying is required to be carried out at 950 DEG C;

[0035] The finishing temperature in the step D is controlled by the heating temperature, the starting rolling temperature, a water cooling box before the finishing mill and the water amount between the finishing mill groups.

[0036] The first stage of the cooling speed after rolling in the step E is required to be large, and the second stage is controlled according to the yield property.

[0037] In the step F, the cooling of the coil on the Stelmor conveyor is specifically adjusted according to the wire rod temperature, so as to reduce the coil temperature, and the temperature is controlled at 200℃.

[0038] The coil is stacked for not more than 4 hours at 50℃, and the deformation residual stress is eliminated after slow cooling. Embodiment 2:

[0040] A flexible process rolling method for coil production, comprising the following steps: A, chemical composition internal control during electric arc furnace smelting; B, control of heating system and starting rolling temperature, the heating system adopts continuous casting billet heating, and the starting rolling temperature is controlled at 930℃; C, control of the temperature during rolling; D, control of the finishing temperature at 920℃; E, strengthened control of the cooling speed of the rolled steel, the initial temperature and the final temperature of the post-rolling fast cooling, and the wire rod temperature is controlled at 880℃; F, the coil is cooled on the Stelmor conveyor, first fast cooling and then slow cooling, and the cooling speed is 4℃ / s, and the coil is packed and stacked after cooling.

[0041] The chemical composition internal control in the step A is that the mass fraction of each component is as follows: C 0.2 parts; Si 0.6 parts; Mn 1.1 parts; P 0 parts; S 0.02 parts; Ceq 0.54 parts.

[0042] The temperature control during rolling in the step C specifically shows that more than half of the rolling deformation of the coil micro-alloying is required to be at 940℃.

[0043] The finishing temperature in the step D is controlled by the heating temperature, the starting rolling temperature, a water cooling box before the finishing mill and the water amount between the finishing mill groups.

[0044] The first stage of the cooling speed after rolling in the step E is required to be large, and the second stage is controlled according to the yield property.

[0045] In the step F, the cooling of the coil on the Stelmor conveyor is specifically adjusted according to the wire rod temperature, so as to reduce the coil temperature, and the temperature is controlled at <150℃.

[0046] The disc screw is stacked for not more than 4 hours at 150 DEG C, and the deformation residual stress is eliminated after slow cooling. Specific embodiment 3:

[0048] A flexible process rolling method for disc screw production, comprising the following steps: A, chemical composition internal control during electric arc furnace smelting; B, heating system and open rolling temperature control, the heating system adopts continuous casting billet heating, and the open rolling temperature is controlled at 950 DEG C; C, temperature control of the rolling process; D, the finish rolling temperature is controlled at 880 DEG C; E, the rolling steel cooling rate, post-rolling rapid cooling initial temperature and rapid cooling final temperature are strengthened controlled, and the wire feeding temperature is controlled at 900 DEG C; F, the disc screw is cooled on the Stelmor conveyor, first rapid cooling and then slow cooling, and the cooling is carried out at a cooling speed of 5 DEG C / s, and after cooling, it is packed and stacked in the warehouse;

[0049] The chemical composition internal control in the step A is that the mass fraction of each component is as follows: C 0.16 parts; Si 0.5 parts; Mn 1.25 parts; P 0.07 parts; S 0 parts; Ceq 0.45 parts;

[0050] The temperature control of the rolling process in the step C specifically represents that more than half of the rolling deformation of the disc screw micro-alloying is carried out at 950 DEG C;

[0051] In addition to the heating temperature and open rolling temperature, the finish rolling temperature in the step D is also controlled by applying the water amount between the water cooling box before the finish rolling mill and the finish rolling mill group;

[0052] The rolling cooling speed in the step E requires that the first stage is large, and the second stage is controlled according to the yield performance;

[0053] In the step F, the disc screw is cooled on the Stelmor conveyor, and the cooling is adjusted by adjusting the air volume of the disc screw on the Stelmor conveyor according to the wire feeding temperature, so as to reduce the coil temperature, and the temperature is controlled at 190 DEG C;

[0054] The disc screw is stacked for not more than 4 hours at <190 DEG C, and the deformation residual stress is eliminated after slow cooling.

[0055] Although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A flexible rolling process for producing coiled rebar, characterized in that: The process includes the following steps: A. Internal control of chemical composition during electric arc furnace smelting; B. Control of heating regime and initial rolling temperature, using continuous casting billet heating, with the initial rolling temperature controlled at 1000℃-930℃; C. Control of temperature during rolling; D. Control of final rolling temperature at 900℃±20℃; E. Enhanced control of cooling rate, initial rapid cooling temperature, and final rapid cooling temperature of rolled steel, with the wire drawing temperature controlled at 880℃-920℃; F. When the coiled rebar is cooled on the Steyrmo transporter, it is first rapidly cooled and then slowly cooled at a cooling rate of 4℃ / s-7℃ / s, and after cooling, it is packaged and stacked in the warehouse; the internal control of chemical composition in step A is as follows: C 0.16-0.25 parts; Si 0.4-0.6 parts; Mn 1-1.25 parts; P 0-0.07 parts; S0-0.04 parts; Ceq 0.39-0.54 parts; In step C, the temperature control of the rolling process is specifically manifested in that the micro-alloying of the coiled rebar requires more than half of the rolling deformation to be ≤950 ℃; In step D, in addition to controlling the heating temperature and the initial rolling temperature, the final rolling temperature is also controlled by the water volume between the water cooling box in front of the finishing mill and the finishing mill unit; In step E, the post-rolling cooling rate requires a large first stage, while the second stage is controlled according to the yield performance; In step F, when the coiled rebar is cooled on the Steyrmo transporter, the air volume of the coiled rebar on the Steyrmo transporter is adjusted according to the wire drawing temperature to achieve the purpose of reducing the coiling temperature, and the temperature is controlled at <220℃; The coiled rebar is stacked at <200℃ for no more than 4 hours, and the residual stress of deformation is eliminated after slow cooling.