阅读说明：本技术 一种合金球铁轧辊的淬火方法 (Quenching method of alloy ductile iron roller ) 是由 梁俊良 于 2021-05-31 设计创作，主要内容包括：本发明公开了一种合金球铁轧辊的淬火方法,金属热处理技术领域,合金球铁轧辊材质为合金球铁,轧辊的表面硬度48～56HSD,热处理淬火温度为920℃～1000℃,采用双级淬火的方式,回火温度450～600℃,保温时间24～40h,配合喷淬设备使用。本发明解决油淬污染问题,有效避免淬火裂纹,提高生产的产品硬度、均匀性和组织性能。(The invention discloses a quenching method of an alloy ductile iron roller, which belongs to the technical field of metal heat treatment, wherein the alloy ductile iron roller is made of alloy ductile iron, the surface hardness of the roller is 48-56 HSD, the heat treatment quenching temperature is 920-1000 ℃, a two-stage quenching mode is adopted, the tempering temperature is 450-600 ℃, the heat preservation time is 24-40 h, and the quenching method is matched with spray quenching equipment for use. The invention solves the problem of oil quenching pollution, effectively avoids quenching cracks, and improves the hardness, uniformity and structure performance of the produced product.)

1. The quenching method of the alloy ductile iron roller is characterized by comprising the following steps of: the method comprises the following steps:

1) annealing and rough machining the roller blank (1);

2) quenching heat treatment, wherein the heating temperature of the quenching heat treatment is 920-1000 ℃;

3) quenching, wherein the spraying capacity of a spray quenching machine is used, the liquid pressure of the spray quenching machine is 0.3-0.6 MPa, the air pressure of the spray quenching machine is 0.3-0.6 MPa, and water and air blowing are stopped when the temperature of the roller blank (1) is reduced to 300-350 ℃;

4) and (4) tempering, wherein the tempering temperature is 450-600 ℃, and the heat preservation time is 24-40 h.

2. The method for quenching the alloy ductile iron roll according to claim 1, wherein: the spray quenching machine comprises three groups of liquid spraying ports surrounding the roller blank (1), the three groups of liquid spraying ports are arranged in the same vertical plane, and the three groups of liquid spraying ports are arranged on the same circumference and are uniformly distributed along the circumference.

3. The method for quenching the alloy ductile iron roll according to claim 2, wherein: the group of liquid spraying ports comprises an oil spraying port (3) and a water spraying port (4) which are arranged side by side.

4. The method for quenching the alloy ductile iron roll according to claim 2, wherein: the roller blank (1) is characterized by further comprising a liquid collecting disc arranged below the roller blank (1).

5. The method for quenching the alloy ductile iron roll according to claim 2, wherein: the rolling mill further comprises supporting balls (2) which are arranged below the rolling mill blank (1) and support the rolling mill blank (1) in pairs.

6. The method for quenching an alloy ductile iron roll according to claim 2 or 5, wherein: one of the three groups of liquid spraying openings is arranged between the supporting balls (2) arranged in pairs and vertically sprays liquid upwards.

Technical Field

The invention relates to the technical field of metal heat treatment, in particular to a quenching method of an alloy ductile iron roller.

Background

With the continuous high-speed development of rolling technology and the continuous improvement of product quality requirements, the requirements on the performance of the alloy ductile iron roller are higher and higher, the alloy content of the alloy ductile iron roller is higher and higher, the hardness requirement is also higher and higher, and domestic famous steel works basically improve the ductile iron hardness to be more than 50 HSD. Because the alloy ductile iron roll is a cast product, the carbon content is higher and the plastic toughness is poor. In order to reduce the risk of quench cracking and keep higher hardness, the traditional process adopts an oil quenching mode, the quenching mode causes greater pollution to the environment, and the mode is eliminated in northern areas along with higher and higher environmental protection requirements.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a quenching method of an alloy ductile iron roller, which solves the problem of oil quenching pollution, effectively avoids quenching cracks and improves the hardness, uniformity and structure performance of the produced product.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a quenching method of an alloy ductile iron roller comprises the following steps:

1) annealing and roughly processing the roller blank;

2) quenching heat treatment, wherein the heating temperature of the quenching heat treatment is 920-1000 ℃;

3) quenching, wherein the spraying capacity of a spray quenching machine is used, the liquid pressure of the spray quenching machine is 0.3-0.6 MPa, the air pressure of the spray quenching machine is 0.3-0.6 MPa, and water blowing is stopped when the temperature of the roller blank is reduced to 300-350 ℃;

4) and (4) tempering, wherein the tempering temperature is 450-600 ℃, and the heat preservation time is 24-40 h.

The technical scheme of the invention is further improved as follows: the spray quenching machine comprises three groups of liquid spraying ports surrounding a roller blank, the three groups of liquid spraying ports are arranged in the same vertical plane, and the three groups of liquid spraying ports are arranged on the same circumference and are uniformly distributed along the circumference.

The technical scheme of the invention is further improved as follows: the group of liquid spraying ports comprises an oil spraying port and a water spraying port which are arranged side by side.

The technical scheme of the invention is further improved as follows: the roller blank forming device further comprises a liquid collecting disc arranged below the roller blank.

The technical scheme of the invention is further improved as follows: the rolling mill further comprises supporting balls which are arranged below the rolling blank and used for supporting the rolling blank in pairs.

The technical scheme of the invention is further improved as follows: one of the three groups of liquid spraying openings is arranged between the support balls arranged in pairs and vertically sprays liquid upwards.

Due to the adoption of the technical scheme, the invention has the technical progress that:

the invention adopts a heat treatment cooling mode of spraying and quenching machine water spraying and quenching machine air blowing to replace an oil quenching mode for the alloy ductile iron product, solves the problem of oil quenching pollution, effectively solves the problem of quenching crack, and improves the hardness, uniformity and structure performance of the produced product.

The three groups of liquid spraying ports are convenient for spraying and quenching water, oil or emulsion simultaneously, so that the liquid is prevented from being mixed in advance, the proportion of the water, the oil or other emulsions is convenient to adjust, and the spraying and quenching effect is improved. The liquid collecting disc prevents the sprayed and quenched liquid from splashing to the ground, and effectively prevents the liquid from being polluted. The supporting balls reduce the contact area with the roller blank, increase the adaptability of moving the roller blanks with different sizes, reduce the jolt of the moving roller blank process, increase the stability of the moving roller blank and be favorable for realizing the spray quenching of the roller blank by 360 degrees. One of the three groups of liquid spraying openings is arranged between the support balls arranged in pairs and vertically sprays liquid upwards to facilitate the realization of 360-degree spray quenching of the roller blank.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is the corrosion diagram of FIG. 1;

the device comprises a roller blank 1, a roller blank 2, a supporting ball 3, an oil nozzle 4 and a water nozzle.

Detailed Description

The present invention will be described in further detail with reference to the following examples:

as shown in fig. 1 and 2, a method for quenching an alloy ductile iron roll comprises the following steps:

1) annealing and rough machining the roller blank (1);

2) quenching heat treatment, wherein the heating temperature of the quenching heat treatment is 920-1000 ℃;

3) quenching, wherein the spraying capacity of a spray quenching machine is used, the liquid pressure of the spray quenching machine is 0.3-0.6 MPa, the air pressure of the spray quenching machine is 0.3-0.6 MPa, and water and air blowing are stopped when the temperature of the roller blank (1) is reduced to 300-350 ℃;

4, tempering, wherein the tempering temperature is 450-600 ℃, and the heat preservation time is 24-40 h.

The spray quenching machine comprises three groups of liquid spraying ports, a liquid collecting disc and supporting balls 2.

Three liquid spouts of group encircle roll blank 1 and set up, and three liquid spouts of group set up in same vertical plane, and three liquid spouts of group set up on same circumference and along the circumference equipartition, and three liquid spouts of group are fixed in same circular frame, and the frame is rotatory round roll blank 1, and rotation angle is no longer than 120, rotatory rotation to reciprocating for spout and quench evenly. The group of liquid spray openings comprises an oil spray opening 3 and a water spray opening 4 which are arranged side by side. The liquid collecting disc is arranged below the roller blank 1. The supporting balls 2 are arranged below the roller blank 1, the supporting balls 2 support the roller blank 1, the supporting balls 2 are symmetrically arranged in pairs, the supporting balls 2 are totally provided with three pairs, a rotating shaft of each supporting ball 2 and the horizontal plane form 45 degrees, and the roller blank 1 moves forwards in the rotation of the supporting balls 2. One of the three sets of liquid ejecting ports is arranged between the support balls 2 arranged in pairs and ejects liquid vertically upwards.

Example 1:

in the 1360mm diameter alloy ductile iron roll of this embodiment, the alloy ductile iron has a diameter of 1360mm, a roll body length of 3000mm, a full length of 7100mm, and is made of alloy ductile iron.

The heat treatment process of the ductile iron of the embodiment comprises the following steps:

1) and (3) annealing the casting roller, wherein the annealing temperature is 650 ℃, and the heat preservation time is 36 hours.

2) And processing the casting roller to a size close to that of a finished product, and controlling the allowance to be 5 mm.

3) Carrying out heat treatment, wherein the quenching heating temperature is 1000 ℃, and the heat preservation time is 30 hours.

4) The water pressure and the wind pressure of the front quenching cooling section are respectively 0.6MPa and 0.6MPa respectively. And after 10min of spray quenching, closing a water supply valve. And a blowing mode is adopted, so that the air pressure is unchanged. Blowing for 80 min.

5) Adopting a single tempering mode, wherein the tempering temperature is 500 ℃, and the time is 40 h.

6) And detecting the hardness and the metallographic structure of the product. The hardness detection result is 54-58 HSD, and the metallographic structure is tempered martensite, carbide and graphite. The detection result meets the technical requirements.

Example 2:

in the small-tonnage ductile iron roller of the embodiment, the alloy ductile iron has the size of 1000mm in diameter, the length of the roller body of 2000mm and the total length of 4800mm, and is made of the alloy ductile iron.

The production process of the product of the embodiment comprises the following steps:

1) and (3) annealing the casting roller, wherein the annealing temperature is 650 ℃, and the heat preservation time is 20 hours.

2) And processing the casting roller to a size close to that of a finished product, and controlling the allowance to be 5 mm.

3) Carrying out heat treatment, wherein the quenching heating temperature is 920 ℃, and the heat preservation time is 20 hours.

4) The front quenching cooling section adopts a spray quenching machine to spray water, the water pressure is 0.3MPa, and the wind pressure is 0.4 MPa. And after 10min of spray quenching, closing a water supply valve. And a blowing mode is adopted, so that the air pressure is unchanged. Blowing for 60 min.

5) Adopting a single tempering mode, wherein the tempering temperature is 600 ℃, and the time is 30 h.

6) And detecting the hardness and the metallographic structure of the product. The hardness detection result is 45-48 HSD, and the metallographic structure is tempered martensite, carbide and graphite. The detection result meets the technical requirements.

Example 3:

in the small-tonnage ductile iron roller, the alloy ductile iron has the size of 1200mm in diameter, the roller body is 2100mm in length and 5000mm in total length, and the material is the alloy ductile iron.

The production process of the product of the embodiment comprises the following steps:

1) and (3) annealing the casting roller, wherein the annealing temperature is 650 ℃, and the heat preservation time is 20 hours.

2) And processing the casting roller to a size close to that of a finished product, and controlling the allowance to be 5 mm.

3) Carrying out heat treatment, wherein the quenching heating temperature is 980 ℃, and the heat preservation time is 25 hours.

4) The water pressure and the wind pressure of the front quenching cooling section are respectively 0.45MPa and 0.3 MPa. And after 10min of spray quenching, closing a water supply valve. And a blowing mode is adopted, so that the air pressure is unchanged. Blowing for 60 min.

5) The single tempering mode is adopted, the tempering temperature is 450 ℃, and the time is 24 hours.

6) And detecting the hardness and the metallographic structure of the product. The hardness detection result is 42-45 HSD, and the metallographic structure is tempered martensite, carbide and graphite. The detection result meets the technical requirements.

Under the condition, a quenching mode of spraying and quenching machine water spraying and quenching machine air blowing is invented, a plurality of products are produced at present, and practice proves that the hardness and the structure of key indexes of the alloy ductile iron can meet the technical requirements by using an optimized heat treatment mode, and the performance indexes of the product are not reduced compared with those of the product using oil cooling.