WO2022166155A1

WO2022166155A1 - Container crane wheel steel, wheel and preparation method therefor

Info

Publication number: WO2022166155A1
Application number: PCT/CN2021/112950
Authority: WO
Inventors: 陈创业; 朱国和; 陈阳; 董斌
Original assignee: 上海振华港机重工有限公司
Priority date: 2021-02-08
Filing date: 2021-08-17
Publication date: 2022-08-11
Also published as: CN112981260A; CN112981260B

Abstract

Container crane wheel steel, a wheel and a preparation method therefor. By means of designing chemical components of the container crane wheel steel and adding a post-forging preparatory heat treatment between forging forming and rough machining, a container crane wheel that has good robustness and an excellent surface hardening layer is prepared. The wheel tread hardness thereof can be above HRC55, the effective hardening layer depth is greater than or equal to 15mm, and the hardness at a depth of 15mm below the wheel tread is greater than or equal to HRC35, so that the container crane wheel has the advantages of high surface hardness, a deep effective hardening layer and good internal toughness. The service life of the container crane wheel can be increased by more than 50% compared to conventional 45# and 55# carbon steel wheels.

Description

A kind of container crane wheel steel, wheel and preparation method thereof

technical field

The invention relates to a wheel, in particular to a container crane wheel steel, a wheel and a preparation method thereof.

Background technique

Container cranes are important equipment in the port machinery industry, and wheels are the key components of container cranes, which play a role in supporting container cranes to transport trolleys horizontally and ensure the walking of carts; at present, the global demand for quayside container crane wheels exceeds 10,000 pieces.

When the crane is walking, the wheel tread (outer circle) is in rolling contact with the surface of the track, and is subject to greater stress and severe wear. Wheel tread wear is the main reason for the damage to the crane wheel; In this case, when the wheel tread is in contact with the track, it needs to bear a large periodic load and strong rolling friction and wear, so the wheel tread has sufficient strength and toughness and good comprehensive performance;

In recent years, with the rapid development of high-speed rail cranes and high-speed self-propelled trolleys, the friction and wear between the wheels and the rails has become increasingly serious. In the prior art, conventional crane wheels are mainly made of 45# and 55# ordinary carbon carbon steel. Due to the poor hardenability of the material, the hardness of the wheel tread can only reach HB300-380, and the depth of the hardened layer HB260 can only reach 15-20mm, resulting in insufficient wear resistance of the wheel, which seriously restricts the service life of the wheel; Due to insufficient wheel life, it will pose a great threat to the operation safety of container cranes, causing user maintenance costs to increase, resulting in user quality complaints and quality objections.

In view of the above situation, there is an urgent need in the industry to develop a long-life container crane wheel and a preparation method thereof, which can prepare a wheel with good strength and toughness and an excellent surface hardening layer, so as to improve the wear resistance and service life of the wheel.

technical problem

In view of the defects existing in the prior art, the purpose of the present invention is to provide a container crane wheel steel, a wheel and a preparation method thereof. By designing chemical components, pre-forging heat treatment is added between forging and rough machining, and the preparation process is controlled. In order to prepare container crane wheels with good strength and toughness and excellent surface hardening layer, the hardness of the wheel tread can reach above HRC55, the effective hardened layer depth is ≥15mm, and the hardness below the wheel tread is 15mm deep. ≥HRC35, so that the container crane wheel has the advantages of high surface hardness, deep effective hardened layer and good internal toughness. Compared with the conventional 45# and 55# carbon steel wheels, the service life of the container crane wheel can be increased by 50 %above.

technical solutions

In order to achieve the above object, the present invention adopts the following technical scheme:

A first aspect of the present invention provides a container crane wheel steel, which contains the following elements by mass percentage: C: 0.42-0.46%, Si: 0.17-0.37%, Mn: 0.70-0.90%, Cr: 1.0-1.2% , Mo: 0.20～0.30%, Ti: 0.03～0.05%, P≤0.018%, S≤0.008%, N≤0.005%, H≤0.0002%, the balance is iron and inevitable impurity elements.

A second aspect of the present invention provides a container crane wheel prepared by using the container crane wheel steel according to the first aspect of the present invention.

Preferably, the tread hardness of the container crane wheel is ≥55HRC, and the hardness at 15mm below the tread is ≥35HRC; and/or

The depth of the hardened layer of the container crane wheel is greater than or equal to 15mm.

A third aspect of the present invention provides a method for preparing a container crane wheel, comprising the following steps:

(1) Smelting and casting, according to claim 1, the raw materials for the composition ratio of container crane wheel steel are obtained by successively adopting electric furnace or converter primary smelting, out-of-furnace refining, and vacuum degassing to obtain molten steel, and then adopting die casting or continuous casting to obtain molten steel. billet;

(2) Forging forming, the billet is heated and forged to obtain a forging;

(3) Preparatory heat treatment after forging, the forgings are quickly transferred to the treatment tank for cooling treatment by cooling liquid after forging is stopped, and then the cooled forgings are spheroidized;

(4) Rough machining, according to the requirements of the wheel blank drawing, the forgings are roughed to obtain the wheel blank;

(5) Heat treatment, the wheel blank is heated to 830～870℃ and kept for 4～6h, then after quenching and tempering, it is air-cooled to room temperature;

(6) Finishing, the wheel blank processed in step (5) is finished according to the requirements of the finished product drawing to obtain the container crane wheel.

Preferably, in the step (2), during the heating process, the heating temperature is controlled to be 1160-1200°C, and the holding time is >6h; and/or

In the step (2), die forging or free forging is used in the forging process, the final forging temperature is controlled to be >900°C, and the forging ratio is >4.

Preferably, in the step (3), when the transfer time for the forging to be transferred to the treatment tank after stopping forging is less than or equal to 2 min, the forging is cooled and spheroidized; the forging is transferred to the treatment tank after the forging is stopped. When the transfer time is more than 2min, the forging is firstly air-cooled to below 200°C, then reheated for normalizing treatment, and then the normalized forging is transferred to the reaction tank for cooling treatment within 2min, and then the cooling treatment is carried out. spheroidizing the resulting forgings; and/or

In the step (3), during the cooling process, the cooling liquid adopts an aqueous solution of polyvinylpyrrolidone with a concentration of 10-12%, the temperature of the cooling liquid is controlled to be ≤50 °C, and the forging is controlled to be cooled to below 100 °C post-discharge; and/or

In the step (3), the cooled forgings are transferred to a trolley furnace for spheroidization within 4 hours; and/or

In the step (3), during the spheroidization treatment, the spheroidization temperature is controlled to be 680-700°C, and the spheroidization time is ≥6h.

Preferably, in the step (3), during the cooling process, the temperature of the cooling liquid is controlled to be 20-40°C.

Preferably, in the step (3), the weight ratio of the cooling liquid to the forging is ≥10:1.

Preferably, in the step (5), in the quenching process, a PAG-based UCON E aqueous solution with a concentration of 10-15% is used as the quenching medium for spray quenching, the quenching pressure is controlled to be 0.2-0.4Mpa, and the quenching time is 8 to 10 minutes, with a pause of 1 to 2 minutes in between to wait for the surface to return to temperature; and/or

In the step (5), during the tempering treatment, the tempering temperature is controlled to be 200-300° C., and the holding time is 5-7 hours.

Preferably, it also includes flaw detection, painting, coding, inspection, and delivery.

Preferably, ultrasonic flaw detection and magnetic particle flaw detection are selected for the flaw detection.

The composition design and design principle of the container crane wheel of the present invention are as follows: on the basis of 42CrMo, the contents of C, Mn, Cr and Mo elements that affect the hardenability are further improved, the contents of P and S impurity elements are tightened, and the Trace Ti element; Ti has great activity and is easy to combine with C, N, S, etc. to form TiN, Ti4C2S2, TiC compounds, these compounds can effectively prevent the growth of austenite grains and have the beneficial effect of refining grains , which can improve the strength and toughness of wheel steel at the same time; however, it should be noted that titanium is a precious metal, and excessive Ti content in steel will significantly increase the alloy cost; comprehensively consider the production cost and the performance improvement effect of Ti on wheel steel , the mass percentage of Ti element is controlled at 0.03 ~ 0.05wt%; due to the relatively coarse TiN particles, if excessive, the effect of grain refinement will be insignificant. In order to give full play to the beneficial effect of Ti grain refinement, the N content in the composition Controlled below 0.005wt%; in order to prevent the occurrence of 100-point defects, the hydrogen element content is limited to <2ppm.

beneficial effect

The beneficial effects of the present invention are:

1. The container crane wheel of the present invention and its preparation method are prepared by designing chemical components, adding post-forging preparatory heat treatment between forging molding and rough machining, and controlling the process parameters in each process, so as to prepare a wheel with good strength and toughness. Container crane wheels with matching and excellent surface hardening layer, the wheel tread hardness can reach above HRC55, the effective hardened layer depth is ≥15mm, and the hardness at a depth of 15mm below the wheel tread is ≥HRC35, so that the container crane wheel has both surface hardness Compared with conventional 45# and 55# carbon steel wheels, the service life of the container crane wheel can be increased by more than 50%;

2. The preparation method of the container crane wheel of the present invention can significantly refine the structure and improve the comprehensive mechanical properties of the wheel by adding a post-forging preparatory heat treatment between forging forming and rough machining, and adopting a cooling treatment and a spheroidizing treatment for the post-forging preparatory heat treatment. , and save energy consumption and reduce manufacturing costs;

3. In the preparation method of the container crane wheel of the present invention, in the final heat treatment process, surface quenching and low temperature tempering are adopted to further ensure the surface hardness of the wheel.

Description of drawings

Other characteristic objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

Fig. 1 is the schematic flow chart of the preparation method of the container crane wheel of the present invention;

Fig. 2 is the cooling characteristic curve diagram of the polyvinylpyrrolidone aqueous solution of the present invention;

Fig. 3 is the metallographic structure enlarged 500 times after the preparatory heat treatment of the forging in step (3) of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form.

The invention provides a container crane wheel steel, which contains the following elements by mass percentage: C: 0.42-0.46%, Si: 0.17-0.37%, Mn: 0.70-0.90%, Cr: 1.0-1.2%, Mo: 0.20～0.30%, Ti: 0.03～0.05%, P≤0.018%, S≤0.008%, N≤0.005%, H≤0.0002%, the balance is iron and inevitable impurity elements.

The container crane wheel can be prepared by using the container crane wheel steel provided above. The tread hardness of the container crane wheel is ≥55HRC, the hardness at 15mm below the tread is ≥35HRC, and the depth of the hardened layer of the container crane wheel is ≥15mm.

As shown in Figure 1, the above-mentioned preparation method of container crane wheel includes the following steps:

(1) Smelting and casting: According to the composition ratio of container crane wheel steel, raw materials are obtained by electric furnace or converter primary smelting, out-of-furnace refining, and vacuum degassing to obtain molten steel, and then die casting or continuous casting are used to obtain steel billets;

The specific process is as follows: first, according to the composition ratio of the container crane wheel steel, the raw materials are firstly smelted in an electric furnace or a converter→out-of-furnace refining→vacuum degassing to obtain molten steel, and then the billet is obtained by die casting or continuous casting. The composition of crane wheel steel includes the following elements by mass percentage: C: 0.42-0.46%, Si: 0.17-0.37%, Mn: 0.70-0.90%, Cr: 1.0-1.2%, Mo: 0.20-0.30%, Ti : 0.03～0.05%, P≤0.018%, S≤0.008%, N≤0.005%, H≤0.0002%, the balance is iron and inevitable impurity elements;

(2) Forging molding: the billet is heated and forged to obtain a forging;

Forging is an important metal plastic processing method. After the billet is heated, forging equipment is used to apply pressure to the metal material to cause plastic deformation to obtain forgings with certain mechanical properties, shape and size; Defects such as loose as-cast metal produced in the smelting process, optimize the microstructure, and weld holes. Forging includes die forging and free forging. It is usually used for forgings with simple shapes and small production batches, while crane wheels are due to the diameter of the wheel. , width and axle diameter are different and there are many specifications. The manufacturer does not use a single specification wheel in a single time, so it usually adopts the forging method.

The specific process is as follows: the billet obtained in step (1) is blanked according to the calculated wheel blanking weight, and then heated and forged to obtain a forging; during the heating process, the heating temperature is controlled to be 1160-1200 °C, and the holding time > 6h; in the forging process, control the final forging temperature > 900 ℃, forging ratio > 4; forging can be die forging or free forging, in one embodiment, in order to improve the utilization rate of materials, die forging is used for forging.

The heat treatment process is usually an important process that affects the performance of wheel steel. It is generally set after finishing. Here, post-forging preparatory heat treatment is added after forging and before roughing. It is different from conventional air cooling and normalizing after forging. The formed residual temperature is cooled by coolant and then spheroidized, which can significantly refine the structure, improve the comprehensive mechanical properties of the wheel, save energy and reduce manufacturing costs;

The specific process is as follows: the forgings are quickly transferred to the treatment tank after stopping forging. When the transfer time for the forgings to be transferred to the treatment tank is ≤2min, the forgings are cooled and spheroidized; when the forgings are stopped forging, they are transferred to the treatment tank. When the time is more than 2min, the forgings are firstly air-cooled to below 200°C, then reheated for normalizing treatment, and then the normalized forgings are transferred to the reaction tank for cooling treatment within 2min, and then the cooling The forgings are spheroidized; the above-mentioned treatment process is mainly to prevent the forgings from coarsening and producing soul crystals, so the maximum transfer time is not more than 2min. If it is too long, the forgings are not allowed to be immersed in coolant for cooling treatment. They should be placed in air-cooled separately until the temperature of the forgings drops below 200 °C, and then placed in a trolley furnace for reheating for normalizing treatment. Transfer the normalized forgings to the treatment tank for cooling within 2 minutes;

In the cooling process, the cooling liquid adopts polyvinylpyrrolidone (PVP) aqueous solution with a concentration of 10-12%. The main reason is that the polyvinylpyrrolidone aqueous solution has the characteristics of fast cooling at high temperature and slow cooling at low temperature, which can significantly reduce residual stress. To prevent cracking of forgings, the cooling characteristic curve of typical PVP (polyvinylpyrrolidone) aqueous solution is shown in Figure 2; the treatment tank used in the cooling treatment process needs to be placed close to the heating furnace, and the temperature of the cooling liquid is controlled to be ≤50 °C. In the preferred solution, the temperature of the cooling liquid is controlled at 20-40 °C; in order to ensure the cooling effect of the forgings, the weight ratio of the cooling liquid to the forgings in the treatment tank should not be less than 10:1; in order to ensure the cooling uniformity of the forgings, the treatment tank should be equipped with flow In addition to the stirring device and cooling circulation system, the forgings are immersed in the cooling liquid and placed on the material frame with a certain height at the bottom of the treatment tank, without contact with the bottom of the treatment tank, to ensure that the cooling liquid at the bottom of the forgings can circulate and flow. ;During the cooling process, control the forgings to cool to below 100℃ and then discharge the liquid. After the cooling treatment, the forgings are transferred to the trolley road for spheroidization within 4 hours. During the spheroidization process, the control The temperature is 680-700℃, and the spheroidization time is ≥6h; the metallographic structure of the forging after preparatory heat treatment after forging is shown in Figure 3, the grains are fine and uniform, and the pearlite is spherical.

(4) Rough machining: The forgings prepared for heat treatment after forging are subjected to rough machining (and an appropriate finishing allowance is reserved) according to the requirements of the drawing of the wheel blank to obtain the wheel blank;

(5) Heat treatment: the wheel blank is heated to 830-870°C and kept for 4-6 hours, then after quenching and tempering, it is air-cooled to room temperature;

The specific process is as follows: the heat treatment process includes surface quenching treatment and low temperature tempering treatment. The wheel continuous heating furnace is used to continuously heat and keep the wheel blank as a whole. Wheels are prone to problems of oil quenching not hardening and water quenching cracking. Therefore, PAG UCON E aqueous solution with a concentration of 10-15% is used as the quenching medium to uniformly spray and quench the sinking blank, and the quenching pressure is controlled to be 0.2-0.4Mpa. The time is 8 to 10 minutes, and the intermediate pause is 1 to 2 minutes to wait for the surface layer to return to temperature; after the quenching treatment is completed, the wheel blank is tempered, and the tempering temperature is controlled to be 200 to 300 ° C, and the tempering holding time is 5 to 7 hours; tempering After the treatment, the wheel blanks are air-cooled to room temperature;

When the wheel continuous heating furnace is used to continuously heat the wheel blanks, after heating and holding in the furnace for a certain period of time, they are released from the furnace for cooling. While one wheel blank is released from the furnace and cooled, the next wheel blank can be fed into the furnace at the same time to ensure continuous operation. The heating furnace is always in full load state, which ensures that the heating and holding time of each wheel blank is the same, so that the heating and holding time of each wheel blank is the same, and the quenching quality of each wheel blank is maximized.

(6) Finishing, the wheel blank processed in step (5) is finished according to the size and tolerance requirements of the finished drawing to obtain a container crane wheel.

The specific process is as follows: finishing the heat-treated wheel blank according to the size and tolerance requirements of the designed wheel finished drawing to obtain a container crane wheel.

(7) Flaw detection: non-destructive testing of container crane wheels, such as ultrasonic testing and magnetic particle testing;

(8) Painting, coding, inspection and delivery: sandblasting and surface painting the container crane wheels, then coding, laser engraving anti-counterfeiting signs and serial numbers, and after passing the inspection, they can be sent to the user for installation and use .

The above steps (7) and (8) belong to the inspection process and the delivery process after the container crane wheel is prepared.

The container crane wheel prepared above has good strength and toughness matching and excellent surface hardening layer, the tread hardness of the container crane wheel can reach more than 55HRC, the hardness at 15mm below the tread is ≥35HRC, and the depth of the hardened layer of the container crane wheel is ≥15mm. Compared with conventional 45# and 55# carbon steel wheels, its service life can be increased by more than 50% due to the advantages of wheel spacing, surface hardness, effective hardened layer and internal toughness.

The container crane wheel steel, the wheel and the preparation method thereof of the present invention are further introduced in detail below in conjunction with the examples in the specific actual production process;

实施例Example 11

(1) Smelting and casting: According to the proportion of raw materials of container crane wheel steel, the molten steel is obtained by electric furnace primary smelting, out-of-furnace refining, and vacuum degassing in sequence, and then die casting is used to obtain steel billet; among which container crane wheel steel is shown in Table 1. Show.

(2) Forging molding: The steel billet obtained in step (1) is cut according to the calculated weight of the wheel, and then heated and forged to obtain a forging; in the heating process, the heating temperature is controlled to 1160 ° C, and the holding time is 10h; in the forging process, the final forging temperature is controlled to be 950°C, and the forging ratio is 5; die forging is used for forging.

(3) Preliminary heat treatment after forging, transfer the forgings to the treatment tank within 2 minutes after forging is stopped for cooling treatment and spheroidizing treatment; during the cooling treatment process, the cooling liquid adopts a polyvinylpyrrolidone (PVP) aqueous solution with a concentration of 10% , control the temperature of the cooling liquid at 20 °C; the weight ratio of the cooling liquid to the forging in the treatment tank is 11:1; during the cooling process, the forging is immersed in the cooling liquid and placed on the material frame with a certain height set at the bottom of the treatment tank , Control the forgings to be cooled to below 100 ℃ and then discharge the liquid. After the cooling treatment of the forgings, the liquid will be transferred to the trolley road for spheroidizing treatment within 4 hours. During the spheroidizing treatment The conversion time is 8h;

(5) Heat treatment: The wheel continuous heating furnace is used to continuously heat and keep the wheel blank as a whole. The heating temperature is controlled at 830 ° C and the holding time is controlled at 6h; the PAG type UCON E aqueous solution with a concentration of 10% is used as the quenching medium. Carry out uniform spray quenching treatment, control the quenching pressure to 0.2MPa, quenching time to 8min, pause for 1min in the middle to wait for the surface to return to temperature; after the quenching treatment is completed, the wheel blank is tempered, and the tempering temperature is controlled to 250 ℃, tempering and heat preservation The time is 5h; after the tempering treatment is completed, the wheel blank is treated with air cooling to room temperature;

(6) Finishing: Finishing the heat-treated wheel blanks according to the size and tolerance requirements of the designed wheel finished drawings to obtain container crane wheels.

(7) Flaw detection: non-destructive testing of container crane wheels through ultrasonic testing and magnetic particle testing;

The container crane wheel prepared above has good strength and toughness matching and excellent surface hardening layer, the tread hardness is 55HRC, the effective hardened layer depth is 15mm; the hardness at 15mm below the tread surface is 35HRC; the container crane wheel of this embodiment has both With the advantages of high surface hardness, deep effective hardening layer and good internal toughness, its service life can be increased by more than 50% compared with conventional 45# and 55# carbon steel wheels.

实施例Example 22

(1) Smelting and casting: According to the proportion of raw materials of container crane wheel steel, the molten steel is obtained by electric furnace primary smelting, out-of-furnace refining, and vacuum degassing in sequence, and then die casting is used to obtain steel billet; among which container crane wheel steel is shown in Table 1. Show;

(2) Forging molding: The billet obtained in step (1) is cut according to the calculated weight of the wheel, and then heated and forged to obtain a forging; in the heating process, the heating temperature is controlled to 1200 ° C, and the holding time is 7 hours. ; During the forging process, the final forging temperature is controlled to be 1050°C, and the forging ratio is 5.5; die forging is used for forging.

(3) Preliminary heat treatment after forging, transfer the forgings to the treatment tank within 2 minutes after forging, for cooling treatment and spheroidizing treatment; during the cooling treatment, the cooling liquid adopts a polyvinylpyrrolidone (PVP) aqueous solution with a concentration of 12% , control the temperature of the cooling liquid at 40 °C; the weight ratio of the cooling liquid to the forging in the treatment tank is 13:1; during the cooling process, the forging is immersed in the cooling liquid and placed on the material frame with a certain height set at the bottom of the treatment tank , Control the forgings to be cooled to below 100 ℃ and then discharge the liquid, and the cooled forgings will be transferred to the trolley road for spheroidization within 4 hours after the liquid is discharged. During the spheroidization process, the spheroidization temperature is controlled to The conversion time is 4h;

(5) Heat treatment: The wheel continuous heating furnace is used to continuously heat and keep the wheel blank as a whole. The heating temperature is controlled at 870 ° C and the holding time is controlled at 4h; the PAG type UCON E aqueous solution with a concentration of 15% is used as the quenching medium. Carry out uniform spray quenching treatment, control the quenching pressure to 0.4MPa, quenching time to 10min, pause for 2min in the middle and wait for the surface layer to return to temperature; after the quenching treatment is completed, the wheel blank is tempered, and the tempering temperature is controlled to 200 ℃, tempering and heat preservation The time is 5h; after the tempering treatment is completed, the wheel blank is treated with air cooling to room temperature;

The container crane wheel prepared above has good strength and toughness matching and excellent surface hardening layer, the tread hardness is 57HRC, the effective hardened layer depth is 17mm; the hardness at 15mm below the tread surface is 37HRC; the container crane wheel of this embodiment has both With the advantages of high surface hardness, deep effective hardening layer and good internal toughness, its service life can be increased by more than 50% compared with conventional 45# and 55# carbon steel wheels.

实施例Example 33

(1) Smelting and casting: According to the proportion of raw materials of container crane wheel steel, the molten steel is obtained by converter smelting, out-of-furnace refining, and vacuum degassing in sequence, and then continuous casting is used to obtain steel billet; the container crane wheel steel is shown in Table 1. ;

(2) Forging molding: The steel billet obtained in step (1) is cut according to the calculated wheel cutting weight, and then heated and forged to obtain forgings; during the heating process, the heating temperature is controlled to be 1180 ° C, and the holding time is 4.5h; in the forging process, the final forging temperature is controlled to 920℃, and the forging ratio is 4.8; the forging adopts free forging.

(3) Preliminary heat treatment after forging, transfer the forgings to the treatment tank within 2 minutes after forging is stopped for cooling treatment and spheroidizing treatment; during the cooling treatment process, the cooling liquid adopts an aqueous solution of polyvinylpyrrolidone (PVP) with a concentration of 11% , control the temperature of the cooling liquid at 30 °C; the weight ratio of the cooling liquid to the forging in the treatment tank is 14:1; during the cooling process, the forging is immersed in the cooling liquid and placed on the material frame with a certain height set at the bottom of the treatment tank , Control the forgings to be cooled to below 100 ℃ and then discharge the liquid, and the cooled forgings will be transferred to the trolley road for spheroidizing treatment within 4 hours after the liquid is discharged. The curing time is 7h.

(5) Heat treatment: The wheel continuous heating furnace is used to continuously heat and keep the wheel blank as a whole. The heating temperature is controlled at 850 ° C and the holding time is controlled for 5h; the PAG type UCON E aqueous solution with a concentration of 12% is used as the quenching medium. Carry out uniform spray quenching treatment, control the quenching pressure to 0.3MPa, quenching time to 9min, pause for 1.5min in the middle to wait for the surface layer to return to temperature; The holding time is 6.5h; after the tempering treatment, the wheel blank is air-cooled to room temperature;

实施例Example 44

(2) Forging molding: The steel billet obtained in step (1) is cut according to the calculated wheel cutting weight, and then heated and forged to obtain forgings; during the heating process, the heating temperature is controlled to 1190 ° C, and the holding time is 6.5h; in the forging process, the final forging temperature is controlled to 980℃, and the forging ratio is 5; the forging adopts free forging.

(3) Preliminary heat treatment after forging, transfer the forgings to the treatment tank within 2 minutes after forging is stopped for cooling treatment and spheroidizing treatment; during the cooling treatment process, the cooling liquid adopts an aqueous solution of polyvinylpyrrolidone (PVP) with a concentration of 11% , control the temperature of the cooling liquid at 25 °C; the weight ratio of the cooling liquid to the forging in the treatment tank is 16:1; during the cooling process, the forging is immersed in the cooling liquid and placed on the material frame with a certain height set at the bottom of the treatment tank , Control the forgings to be cooled to below 100 ℃ and then discharge the liquid. After the cooling treatment of the forgings, the liquid will be transferred to the trolley road for spheroidizing treatment within 4 hours. During the spheroidizing treatment The conversion time is 9h;

(5) Heat treatment: The wheel continuous heating furnace is used to continuously heat and keep the wheel blank as a whole. The heating temperature is controlled at 860 ° C, and the control holding time is 5h; the PAG type UCON E aqueous solution with a concentration of 14% is used as the quenching medium. Carry out uniform spray quenching treatment, control the quenching pressure to 0.3MPa, quenching time to 9min, pause for 2min in the middle and wait for the surface to return to temperature; after the quenching treatment is completed, the wheel blank is tempered, and the tempering temperature is controlled to 220 ℃, tempering and heat preservation The time is 6h; after the tempering treatment is completed, the wheel blank is air-cooled to room temperature;

Table 1 Composition and content of container crane wheel steel (wt%)

To sum up, the above-mentioned embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be Modifications or equivalent substitutions without departing from the spirit and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

A container crane wheel steel, characterized in that it contains the following elements by mass percentage: C: 0.42-0.46%, Si: 0.17-0.37%, Mn: 0.70-0.90%, Cr: 1.0-1.2%, Mo: 0.20～0.30%, Ti: 0.03～0.05%, P≤0.018%, S≤0.008%, N≤0.005%, H≤0.0002%, the balance is iron and inevitable impurity elements.
A container crane wheel prepared by using the container crane wheel steel according to claim 1.
The container crane wheel according to claim 2, wherein the tread surface hardness of the container crane wheel is ≥55HRC, and the hardness at 15 mm below the tread surface is ≥35HRC; and/or

The depth of the hardened layer of the container crane wheel is greater than or equal to 15mm.
A method for preparing a container crane wheel, comprising the following steps:

(1) Smelting and casting, according to claim 1, the raw materials for the composition ratio of container crane wheel steel are obtained by successively adopting electric furnace or converter primary smelting, out-of-furnace refining, and vacuum degassing to obtain molten steel, and then adopting die casting or continuous casting to obtain molten steel. billet;

(2) Forging forming, the billet is heated and forged to obtain a forging;

(3) Preparatory heat treatment after forging, the forgings are quickly transferred to the treatment tank for cooling treatment by cooling liquid after forging is stopped, and then the cooled forgings are spheroidized;

(4) Rough machining, according to the requirements of the wheel blank drawing, the forgings are roughed to obtain the wheel blank;

(5) Heat treatment, the wheel blank is heated to 830～870℃ and kept for 4～6h, then after quenching and tempering, it is air-cooled to room temperature;

(6) Finishing, the wheel blank processed in step (5) is finished according to the requirements of the finished product drawing to obtain the container crane wheel.
The method for preparing a container crane wheel according to claim 4, wherein in the step (2), in the heating process, the heating temperature is controlled to be 1160-1200°C, and the holding time is >6h; and/or

In the step (2), die forging or free forging is used in the forging process, the final forging temperature is controlled to be >900°C, and the forging ratio is >4.
The method for preparing a container crane wheel according to claim 4, characterized in that, in the step (3), when the transfer time for transferring the forging to the treatment tank after stopping forging is ≤ 2 min, the forging is cooled, Spheroidizing treatment; when the transfer time for the forging to be transferred to the treatment tank after stopping forging is more than 2 min, the forging is firstly air-cooled to below 200°C, then reheated for normalizing treatment, and then the normalized forging is treated Transfer to the reaction tank for cooling treatment within 2 minutes, and then spheroidize the cooled forgings; and/or

In the step (3), during the cooling process, the cooling liquid is an aqueous solution of polyvinylpyrrolidone with a concentration of 10-12%, the temperature of the cooling liquid is controlled to be ≤50 °C, and the forging is controlled to be cooled to below 100 °C post-discharge; and/or

In the step (3), the cooled forgings are transferred to a trolley furnace for spheroidizing treatment within 4 hours; and/or

In the step (3), during the spheroidization treatment, the spheroidization temperature is controlled to be 680-700°C, and the spheroidization time is ≥6h.
The method for preparing a container crane wheel according to claim 6, characterized in that, in the step (3), during the cooling process, the temperature of the cooling liquid is controlled to be 20-40°C.
The method for preparing a container crane wheel according to claim 6, characterized in that, in the step (3), the weight ratio of the cooling liquid to the forging is ≥10:1.
The method for preparing a container crane wheel according to claim 4, characterized in that, in the step (5), in the quenching process, a PAG-based UCON E aqueous solution with a concentration of 10-15% is used as a quenching medium to carry out the quenching process. Spray quenching, control the quenching pressure to be 0.2-0.4Mpa, the quenching time to be 8-10min, and pause for 1-2min in the middle to wait for the surface layer to return to temperature; and/or

In the step (5), during the tempering treatment, the tempering temperature is controlled to be 200-300° C., and the holding time is 5-7 hours.
The method for preparing a container crane wheel according to any one of claims 4 to 9, further comprising flaw detection, painting, coding, inspection, and delivery.

11. The method for preparing a container crane wheel according to claim 10, wherein the flaw detection is ultrasonic flaw detection and magnetic particle flaw detection.

12. The method for preparing a container crane wheel according to claims 4 to 9, wherein the tread surface hardness of the container crane wheel is ≥55HRC, and the hardness at 15 mm below the tread surface is ≥35HRC; and/or

The depth of the hardened layer of the container crane wheel is ≥15mm.