Preparation process of high-yield-strength crane rail

Abstract

The invention discloses a preparation process of a high-yield-strength crane rail. A, a steelmaking production process, wherein the steelmaking production process comprises smelting treatment and crane rail pretreatment; wherein the smelting treatment process comprises the steps of molten iron, converter smelting, LF refining, VD vacuum degassing and continuous casting; aluminum-free deoxidation alloying is adopted in converter smelting, and argon is blown normally according to refining in the whole process; the vacuum degree is smaller than or equal to 0.10 KPa, the deep vacuum time is longer than or equal to 18 min, and the superheat degree delta T is smaller than or equal to 35 The crane rail pretreatment process comprises the steps of continuous casting blank heating, high-pressure water descaling and saw cutting, and slow cooling is conducted for 48 hours after continuous casting blank saw cutting; b, a steel rail rolling process: square billet preparation, heating, BD1 rolling, BD2 rolling, continuous rolling by a CCS universal rolling mill, pre-bending cooling and straightening; the method further comprises the steps of opening machine hole pattern design and universal area extension coefficient distribution. Wherein the hole pattern design of the breaking machine adopts a direct rolling mode, and the bottom width size of the relative width is obtained through a forced broadening mode.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical material preparation, and in particular relates to a preparation process of a high-yield strength crane rail. Background Art

[0002] Crane rails are mainly used as large-scale driving tracks in factories, ports, docks, etc. They are mainly produced in China by steel mills such as Panzhihua Iron and Steel, Baotou Steel, Zizhu, and Yongyang, and the market competition is relatively fierce.

[0003] Due to the large difference in cross-sectional area between the head and bottom of the crane rail, problems such as severe uneven deformation during rolling and large curvature after cooling occur. To address the above problems, the rolling process is improved to prepare crane rails with high yield strength, high wear resistance and high fatigue resistance. While ensuring strength and hardness, it is necessary to optimize the chemical composition of high-strength rails, reasonably control the process during the production process, ensure that the performance of high-strength crane rails meets the standards, and improve the pass rate of produced rails, which is of great significance to enhancing the economic benefits of enterprises and improving technical research capabilities.

[0004] In view of the above factors, a preparation process of a high yield strength crane rail is provided to prepare a crane rail with high yield strength, high wear resistance and high fatigue resistance, so that it can be used in high temperature, heavy load and other environments. Summary of the invention

[0005] The object of the present invention is to provide a process for preparing a crane rail with high yield strength to solve the problems raised in the above background technology.

[0006] The object of the present invention is achieved through the following technical solution: A preparation process of a high yield strength crane rail comprises the following steps;

[0007] C. Steelmaking production process: including smelting treatment and crane rail pretreatment;

[0008] Among them, the smelting process is: molten iron → converter smelting → LF refining → VD vacuum degassing → continuous casting; converter smelting adopts aluminum-free deoxidation alloying, and the whole process is argon blowing as normal refining; vacuum degree ≤ 0.10KPa, deep vacuum time ≥ 18min, superheat ΔT ≤ 35℃;

[0009] The crane rail pretreatment process is: continuous casting billet heating - high pressure water descaling - sawing, and the continuous casting billet is slowly cooled for 48 hours after sawing;

[0010] D. Rail rolling process: billet → heating → BD1 rolling → BD2 rolling → CCS universal rolling mill continuous rolling → pre-bending cooling → straightening;

[0011] It also includes two parts: hole design of the opening machine and allocation of the universal area extension coefficient;

[0012] Among them, the hole design of the opening machine adopts the direct rolling method, and the bottom width size of the relative width is obtained by forced widening;

[0013] The continuous rolling passes of CCS universal rolling mill are mainly 5 or 7 passes.

[0014] Furthermore, the continuous rolling extension coefficient of the CCS universal rolling mill is set to 1.05-1.08 and allocated to the rolling passes.

[0015] Furthermore, in the rail rolling process, the BD mill hole profile is configured according to the hole profile wear condition, and the box-shaped holes, trapezoidal holes, and hat-shaped holes that are slightly worn during rolling are concentrated in the BD1 rolling mill.

[0016] Furthermore, in the rail rolling process, the BD mill pass profile is configured according to the pass profile wear condition, and the rail cutting depth, rail extension holes and pilot holes that are severely worn during rolling are concentrated in the BD2 rolling mill.

[0017] Furthermore, the chemical composition of the high yield strength crane rail includes: C 0.65-0.85%; Si≤0.5%; Mn 0.90-1.30%; P≤0.04%; S≤0.04%; Cr 0.10-0.40%, V 0.06-0.20%; and the rest is Fe, with a total mass fraction of 100%.

[0018] Furthermore, the temperature of the billet heating preheating section is not greater than 800°C, the heating time is not less than 3 hours, and the furnace discharge temperature is not less than 1150°C;

[0019] Among them, the starting rolling temperature is ≥1100℃, the final rolling temperature is 920~950℃, the starting temperature of pre-bending cooling is 840℃~890℃, the cooling bed step distance during the cooling process is not less than 600mm, and the rail tensile test specimen is placed for more than 24 hours.

[0020] Furthermore, the billet is heated in sections, which are divided into three sections. The temperature of the first heating section is ≤1200°C, the temperature of the second heating section is 1100-1280°C, and the soaking section is 1150-1260°C.

[0021] A preparation process of a high yield strength crane rail is used to prepare a crane rail with high yield strength, high wear resistance and high fatigue resistance, so that it can be used in high temperature, heavy load and other environments.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The invention prepares a crane rail with high yield strength, high wear resistance and high fatigue resistance through a preparation process of a crane rail with high yield strength, so that the crane rail can be applied in high temperature, heavy load and other environments. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] A preparation process for a crane rail with high yield strength comprises the following steps;

[0026] A. Steelmaking production process: including smelting treatment and crane rail pretreatment;

[0027] Among them, the smelting process is: molten iron → converter smelting → LF refining → VD vacuum degassing → continuous casting; converter smelting adopts aluminum-free deoxidation alloying, and the whole process is argon blowing as normal refining; vacuum degree ≤ 0.10KPa, deep vacuum time ≥ 18min, superheat ΔT ≤ 35℃;

[0028] The crane rail pretreatment process is: continuous casting billet heating - high pressure water descaling - sawing, and the continuous casting billet is slowly cooled for 48 hours after sawing;

[0029] B. Rail rolling process: billet → heating → BD1 rolling → BD2 rolling → CCS universal rolling mill continuous rolling → pre-bending cooling → straightening;

[0030] It also includes two parts: hole design of the opening machine and allocation of the universal area extension coefficient;

[0031] Among them, the hole design of the opening machine adopts the direct rolling method, and the bottom width size of the relative width is obtained by forced widening;

[0032] The continuous rolling passes of CCS universal rolling mill are mainly 5 or 7 passes.

[0033] The continuous rolling extension coefficient of the CCS universal rolling mill is set to 1.05-1.08 and allocated to the rolling passes.

[0034] In the rail rolling process, the BD mill hole profile is configured according to the hole profile wear condition, and the box-shaped holes, trapezoidal holes, and hat-shaped holes that are slightly worn during rolling are concentrated in the BD1 rolling mill.

[0035] In the rail rolling process, the BD mill hole profile is configured according to the hole profile wear condition, and the rail profile cutting depth, rail profile extension holes and pilot holes which are seriously worn during rolling are concentratedly configured in the BD2 rolling mill.

[0036] The chemical composition of the high yield strength crane rail includes: C 0.65-0.85%; Si≤0.5%; Mn 0.90-1.30%; P≤0.04%; S≤0.04%; Cr 0.10-0.40%, V0.06-0.20%; the rest is Fe, with a total mass fraction of 100%.

[0037] The temperature of the billet heating preheating section is not more than 800°C, the heating time is not less than 3 hours, and the furnace discharge temperature is not less than 1150°C;

[0038] Among them, the starting rolling temperature is ≥1100℃, the final rolling temperature is 920~950℃, the starting temperature of pre-bending cooling is 840℃~890℃, the cooling bed step distance during the cooling process is not less than 600mm, and the rail tensile test specimen is placed for more than 24 hours.

[0039] The billet heating is carried out in sections, which are divided into three sections. The temperature of the first heating section is ≤1200°C, the temperature of the second heating section is 1100-1280°C, and the soaking section is 1150-1260°C. Specific embodiment one:

[0041] A preparation process for a crane rail with high yield strength comprises the following steps;

[0042] The chemical composition of the crane rail by mass percentage includes: C 0.65-0.85%; Si≤0.5%; Mn0.90-1.30%; P≤0.04%; S≤0.04%; Cr 0.10-0.40%, V 0.06-0.20%; and the rest is Fe, with a total mass fraction of 100%.

[0043] A. Steelmaking production process: including smelting treatment and crane rail pretreatment;

[0044] Among them, the smelting process is: molten iron → converter smelting → LF refining → VD vacuum degassing → continuous casting; converter smelting adopts aluminum-free deoxidation alloying, and the whole process is argon blowing as normal refining; vacuum degree ≤ 0.10KPa, deep vacuum time ≥ 18min, superheat ΔT ≤ 35℃;

[0045] The crane rail pretreatment process is: continuous casting billet heating - high pressure water descaling - sawing, and the continuous casting billet is slowly cooled for 48 hours after sawing;

[0046] B. Rail rolling process: billet → heating → BD1 rolling → BD2 rolling → CCS universal rolling mill continuous rolling → pre-bending cooling → straightening;

[0047] It also includes two parts: hole design of the opening machine and allocation of the universal area extension coefficient;

[0048] Among them, the hole design of the opening machine adopts the direct rolling method, and the bottom width size of the relative width is obtained by forced widening;

[0049] The continuous rolling extension coefficient of the CCS universal rolling mill is set to 1.05-1.08 and allocated to the rolling passes.

[0050] Among them, the temperature of the square billet heating and preheating section is not more than 800℃, the heating time is 240min, the furnace discharge temperature is not less than 1350℃, the square billet heating adopts a segmented type, which is divided into three sections, the temperature of the first heating section is 1100℃, the temperature of the second heating section is 1100℃, and the soaking section is 1150℃. In the rail rolling process, the BD machine hole type is configured according to the hole wear condition, and the box-shaped holes, trapezoidal holes, and hat-shaped holes that are slightly worn during rolling are concentrated in the BD1 rolling mill; the BD machine hole type is configured according to the hole wear condition, and the rail cutting depth, rail extension holes, and pilot holes that are severely worn during rolling are concentrated in the BD2 rolling mill.

[0051] Among them, the starting rolling temperature is 1100℃, the final rolling temperature is 920℃, the pre-bending cooling start temperature is 840℃, the cooling bed step distance during the cooling process is not less than 600mm, and the rail tensile test specimens are placed for more than 24 hours. Specific embodiment 2:

[0053] A preparation process for a crane rail with high yield strength comprises the following steps;

[0054] The chemical composition of the crane rail by mass percentage includes: C 0.65-0.85%; Si≤0.5%; Mn0.90-1.30%; P≤0.04%; S≤0.04%; Cr 0.10-0.40%, V 0.06-0.20%; and the rest is Fe, with a total mass fraction of 100%.

[0055] A. Steelmaking production process: including smelting treatment and crane rail pretreatment;

[0056] Among them, the smelting process is: molten iron → converter smelting → LF refining → VD vacuum degassing → continuous casting; converter smelting adopts aluminum-free deoxidation alloying, and the whole process is argon blowing as normal refining; vacuum degree ≤ 0.10KPa, deep vacuum time ≥ 18min, superheat ΔT ≤ 35℃;

[0057] The crane rail pretreatment process is: continuous casting billet heating - high pressure water descaling - sawing, and the continuous casting billet is slowly cooled for 48 hours after sawing;

[0058] C. Rail rolling process: billet → heating → BD1 rolling → BD2 rolling → CCS universal rolling mill continuous rolling → pre-bending cooling → straightening;

[0059] It also includes two parts: hole design of the opening machine and allocation of the universal area extension coefficient;

[0060] Among them, the hole design of the opening machine adopts the direct rolling method, and the bottom width size of the relative width is obtained by forced widening;

[0061] The continuous rolling extension coefficient of the CCS universal rolling mill is set to 1.05-1.08 and allocated to the rolling passes.

[0062] Among them, the temperature of the square billet heating and preheating section is not more than 800℃, the heating time is 220min, the furnace temperature is not less than 1250℃, the square billet heating adopts a segmented type, which is divided into three sections, the temperature of the first heating section is 1000℃, the temperature of the second heating section is 1280℃, and the soaking section is 1260℃. In the rail rolling process, the BD machine hole type is configured according to the hole wear condition, and the box-shaped holes, trapezoidal holes, and hat-shaped holes that are slightly worn during rolling are concentrated in the BD1 rolling mill; the BD machine hole type is configured according to the hole wear condition, and the rail cutting depth, rail extension holes, and pilot holes that are severely worn during rolling are concentrated in the BD2 rolling mill.

[0063] Among them, the starting rolling temperature is 1200℃, the final rolling temperature is 950℃, the pre-bending cooling start temperature is 860℃, the cooling bed step distance during the cooling process is not less than 600mm, and the rail tensile test specimens are placed for more than 24 hours. Specific embodiment three:

[0065] A preparation process of a high yield strength crane rail is used to prepare a crane rail with high yield strength, high wear resistance and high fatigue resistance, so that it can be used in high temperature, heavy load and other environments.

[0066] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0067] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A process for preparing a crane rail with high yield strength, characterized in that: The method comprises the following steps: A. Steelmaking production process: including smelting treatment and crane rail pretreatment; Among them, the smelting process is: molten iron → converter smelting → LF refining → VD vacuum degassing → continuous casting; converter smelting adopts aluminum-free deoxidation alloying, and the whole process is argon blowing as normal refining; vacuum degree ≤ 0.10KPa, deep vacuum time ≥ 18min, superheat ΔT ≤ 35℃; The crane rail pretreatment process is: continuous casting billet heating - high pressure water descaling - sawing, and the continuous casting billet is slowly cooled for 48 hours after sawing; B. Rail rolling process: billet → heating → BD1 rolling → BD2 rolling → CCS universal rolling mill continuous rolling → pre-bending cooling → straightening; It also includes two parts: hole design of the opening machine and allocation of the universal area extension coefficient; Among them, the hole design of the opening machine adopts the direct rolling method, and the bottom width size of the relative width is obtained by forced widening; The continuous rolling passes of CCS universal rolling mill are mainly 5 or 7 passes.

2. The process for preparing a high yield strength crane rail according to claim 1, characterized in that: The continuous rolling extension coefficient of the CCS universal rolling mill is set to 1.05-1.08 and allocated to the rolling passes.

3. The process for preparing a high yield strength crane rail according to claim 2, characterized in that: In the rail rolling process, the BD mill hole profile is configured according to the hole profile wear condition, and the box-shaped holes, trapezoidal holes, and hat-shaped holes that are slightly worn during rolling are concentrated in the BD1 rolling mill.

4. The process for preparing a high yield strength crane rail according to claim 3, characterized in that: In the rail rolling process, the BD mill hole profile is configured according to the hole profile wear condition, and the rail profile cutting depth, rail profile extension holes and pilot holes which are seriously worn during rolling are concentratedly configured in the BD2 rolling mill.

5. The process for preparing a high yield strength crane rail according to claim 4, characterized in that: The chemical composition of the high yield strength crane rail includes: C 0.65-0.85%; Si≤0.5%; Mn 0.90-1.30%; P≤0.04%; S≤0.04%; Cr0.10-0.40%, V 0.06-0.20%; the rest is Fe, and the total mass fraction is 100%.

6. The process for preparing a crane rail with high yield strength according to claim 5, characterized in that: The temperature of the billet heating preheating section is not more than 800°C, the heating time is not less than 3 hours, and the furnace discharge temperature is not less than 1150°C; Among them, the starting rolling temperature is ≥1100℃, the final rolling temperature is 920~950℃, the starting temperature of pre-bending cooling is 840℃~890℃, the cooling bed step distance during the cooling process is not less than 600mm, and the rail tensile test specimen is placed for more than 24 hours.

7. The process for preparing a crane rail with high yield strength according to claim 6, characterized in that: The billet heating is carried out in sections, which are divided into three sections. The temperature of the first heating section is ≤1200°C, the temperature of the second heating section is 1100-1280°C, and the soaking section is 1150-1260°C.

8. A process for preparing a high yield strength crane rail according to any one of claims 1 to 7, which is used to prepare a crane rail with high yield strength, high wear resistance and high fatigue resistance, so that it can be used in high temperature, heavy load and other environments.