CN103526127B - A guide roller and its manufacturing method - Google Patents

Abstract

The invention discloses a guide roller. The guide roller is an iron-based superalloy expressed in weight percent. The composition of the iron-based superalloy is: C: 2.3-3.2%, Si: 0.6-1.5%, Cr : 29~35%, V: 1.5~2.2%, V: 0.82~1.2%, Mo: 0.2~1.6%, Ni: 7.0~8.8%, Ti: 0.7~1.5%, Nb: 0.2~0.6%, Ta: 0.002~0.006%, rare earth: 0.18~0.28%, and the balance is Fe and unavoidable impurities. Through specific investment casting steps and heat treatment parameter process, the strengthening phase is reasonably distributed and the performance is greatly improved.

Description

A guide roller and its manufacturing method

technical field

The invention relates to the field of rolling mill spare parts, in particular to a guide roll and a manufacturing method thereof.

Background technique

As the rolling speed of the rolling mill increases, the performance requirements of the guide rolls are getting higher and higher. However, due to the complexity of the working environment and the short service life of the guide roller, the guide roller has become the main consumption part on the high-speed wire rod mill. At present, there are three kinds of guide roller materials commonly used at home and abroad. The first is heat-resistant steel with austenitic structure; the second is wear-resistant steel or wear-resistant cast iron with martensitic structure; the third is hard alloy. Austenitic heat-resistant steel has good high temperature stability and toughness, but poor wear resistance and fast wear. Moreover, the austenite and the wire rod (the structure is ferrite or austenite) have a greater tendency to adhere to each other, and steel sticking is prone to occur. Martensitic wear-resistant steel and wear-resistant cast iron have good wear resistance at room temperature, but as the service temperature increases, the martensite will temper and the wear resistance will decrease. The cemented carbide guide roller has good wear resistance and high temperature stability, but its impact toughness is poor.

At present, the most used shells for precision casting can be roughly divided into: graphite shells, tungsten surface ceramic shells, oxide ceramic shells, etc. However, due to the lack of mold forming methods and the unreasonable design of the parameters of the casting process, there are many surface and internal defects of the formed parts.

Contents of the invention

One of the purposes of the present invention is to propose a guide roller;

Two of purpose of the present invention is to propose a kind of manufacture method of guide roller;

For reaching this purpose, the present invention adopts following technical scheme:

A guide roller, the guide roller is an iron-based superalloy, expressed in weight percentage, the composition of the iron-based superalloy is: C: 2.3~3.2%, Si: 0.6~1.5%, Cr: 29~35% %, V: 1.5~2.2%, Mo: 0.2~1.6%, Ni: 7.0~8.8%, Ti: 0.7~1.5%, Nb: 0.2~0.6%, V: 0.82~1.2%, Ta: 0.002~0.006% , rare earth: 0.18~0.28%, the balance is Fe and unavoidable impurities;

The guide roller is prepared by precision casting;

At the cross section 1~2mm below the surface of the iron-based superalloy guide roller, the Ni ₃ (Ti, Al, Nb) phase accounts for 1.2~2.6% of the total area of the cross section. At the central cross-section of the alloy guide roller, the Ni ₃ (Ti, Al, Nb) phase occupies 5.2-7.8% of the total area.

Preferably, at the cross-section of the iron-based superalloy guide roller 1 mm below the surface, the area ratio of the Ni ₃ (Ti, Al) phase is 1.8-2.1% of the total area, and the iron-based superalloy guide roller At the central cross section of , the area proportion of Ni ₃ (Ti, Al) phase is 5.8~6.4% of the total area.

A method of manufacturing a guide roller, comprising the steps of:

1) Precision casting, prepare iron-based superalloy materials according to the chemical composition of iron-based superalloys mentioned above, use water-soluble cores, use existing system design to obtain models, use rapid prototyping machines, and use existing laser sintering to finish step by step Layer sintering polystyrene powder, dipping in wax to make investment pattern, then cleaning the surface and interior of investment pattern; immersing investment pattern in the surface coating and dipping it with slurry, then taking it out, then sanding and drying the surface layer , to obtain the mold shell, put the mold shell into a heating furnace at a temperature of 1080~1180°C, keep it warm for 2.5~3h, and then cool to room temperature with the furnace to obtain a mold; melt the prepared iron-based superalloy material into a liquid state and pour pouring into the model shell, the pouring temperature is 1620 ~ 1650 ℃, after pouring, the guide roller formed by precision casting is naturally cooled to room temperature, and then the pouring system is removed to obtain the guide roller;

2) Hot isostatic pressing is carried out on the obtained guide roller, the temperature is 1130-1165°C, the pressure is 160-200MPa, and the holding time is 3-6 hours.

3) Annealing: Heat the guide roller obtained after hot isostatic pressing to 865~885°C for 2~4h, then lower the temperature to 600~680°C for 1~1.8h, then lower it to 580~595°C and leave the furnace. Naturally cool to room temperature afterward;

4) Finishing: Finishing the annealed guide rollers with cemented carbide cutters into finished guide rollers.

Preferably, after annealing and before finishing, quenching and tempering heat treatment are also carried out, the quenching is: heating the guide roller to 980~1020°C for 1~2h, and then taking it out of the furnace for oil quenching; the tempering is: The quenched guide roller is heated to 245~298°C for 2~3 hours, and then it is taken out of the furnace and air cooled to room temperature.

As a preference, the surface coating is zirconium oxide, zirconium diacetate, fatty alcohol polyoxyethylene ether and n-butanol according to the ratio of 4.5~5.2:1:0.0012~0.0018:0.0006~0.0012 by weight. obtained by setting.

Preferably, in the annealing heating step, first heat to 380-420° C., keep the temperature for 0.8-1.5 hours, and then heat to 865-885° C.

Effect of the present invention is:

Through the selection of specific precision casting and annealing temperature, the Ni ₃ (Ti, Al, Nb) phase and the strengthening phase of Ni ₃ (Ti, Al) phase can be reasonably distributed on the surface and inside of the guide roller, so that the strength of the guide roller can be improved. and durability have been greatly improved;

By increasing the carbon content, the strength and hardness of the guide roller are greatly improved, but due to the reasonable setting of the heat treatment temperature and the ratio of other elements (such as Ta, Ni, Nb, etc.), the toughness also meets the performance requirements of the guide roller.

Detailed ways

Example 1

A guide roller, characterized in that the guide roller is an iron-based superalloy, expressed in weight percentage, the composition of the iron-based superalloy is: C: 2.8%, Si: 0.95%, Cr: 32%, V: 1.92%, V: 0.88%, Mo: 0.86%, Ni: 7.98%, Ti: 0.95%, Nb: 0.56%, Ta: 0.0046%, rare earth: 0.19%, the balance is Fe and unavoidable impurities;

The guide roller is prepared by precision casting;

At the cross-section 1.5mm below the surface of the iron-based superalloy guide roller, the Ni ₃ (Ti, Al, Nb) phase accounts for 1.8% of the total area of the cross-section. In the iron-based superalloy guide roller At the central cross-section of the guide roller, the Ni ₃ (Ti, Al, Nb) phase occupies 5.8% of the total area; at the cross-section 1 mm below the surface of the iron-based superalloy guide roller, the Ni ₃ The proportion of the area occupied by the (Ti, Al) phase is 1.88% of the total area, and at the central cross-section of the iron-based superalloy guide roller, the area proportion of the Ni ₃ (Ti, Al) phase is 5.98% of the total area .

Example 2:

A guide roller, the guide roller is an iron-based superalloy, expressed in weight percentage, the composition of the iron-based superalloy is: C: 2.92%, Si: 0.85%, Cr: 32.5%, V: 1.982% , V: 1.12%, Mo: 1.52%, Ni: 7.98%, Ti: 1.28%, Nb: 0.56%, Ta: 0.0055%, rare earth: 0.25%, the balance is Fe and unavoidable impurities;

The guide roller is prepared by precision casting;

At the cross-section 1mm below the surface of the iron-based superalloy guide roller, the Ni ₃ (Ti, Al, Nb) phase accounts for 2.1% of the total area of the cross-section. At the central cross-section, the Ni ₃ (Ti, Al, Nb) phase accounts for 6.8% of the total area; at the cross-section 1 mm below the surface of the iron-based superalloy guide roller, the Ni ₃ (Ti, The area proportion of Al) phase is 1.92% of the total area, and the area proportion of Ni ₃ (Ti, Al) phase is 5.88% of the total area at the central cross-section of the iron-based superalloy guide roller.

Example 3:

The manufacture method of guide roller, comprises the following steps:

1) Precision casting, preparing iron-based superalloy materials according to the chemical composition of iron-based superalloys described in Example 1, using water-soluble cores, using existing system designs to obtain models, using rapid prototyping machines, and using existing laser sintering After sintering the polystyrene powder layer by layer, the investment mold is made after dipping in wax, and then the surface and interior of the investment mold are cleaned; Zirconium, zirconium diacetate, fatty alcohol polyoxyethylene ether and n-butanol are obtained by stirring and standing according to the ratio of 4.9:1:0.0016:0.0008 by weight; then sanding and drying the surface layer to obtain Mold shell, put the mold shell into a heating furnace at a temperature of 1098°C, keep it warm for 2.8 hours, and then cool it to room temperature with the furnace to obtain a mold; melt the prepared iron-based superalloy material into a liquid state and pour it into the model shell Carry out pouring, the pouring temperature is 1640 ℃, after pouring, the guide roller formed by precision casting is naturally cooled to room temperature, and then the pouring system is removed to obtain the guide roller;

2) Hot isostatic pressing is carried out on the obtained guide roller, the temperature is 1155° C., the pressure is 180 MPa, and the holding time is 5 hours.

3) Annealing: Heat the guide roller obtained after hot isostatic pressing to 390°C, keep it warm for 1.2h, then heat it to 875°C and keep it for 3h, then lower the temperature to 660°C and keep it for 1.6h, then drop it to 588°C and leave the furnace , and naturally cool to room temperature after taking out of the oven;

3.1) Quenching and tempering heat treatment, the quenching is: heating the guide roller to 990°C for 1.5h, and then taking it out of the furnace for oil quenching; the tempering is: heating the quenched guide roller to 288°C for 2.8h, Then take it out of the oven and air cool to room temperature;

4) Finishing: Finishing the annealed guide rollers with cemented carbide cutters into finished guide rollers.

Claims (6)

1. A guide roller, characterized in that the guide roller is an iron-based superalloy, expressed in weight percent, the composition of the iron-based superalloy is: C: 2.3~3.2%, Si: 0.6~1.5% , Cr: 29~35%, V: 1.5~2.2%, V: 0.82~1.2%, Mo: 0.2~1.6%, Ni: 7.0~8.8%, Ti: 0.7~1.5%, Nb: 0.2~0.6%, Ta: 0.002~0.006%, rare earth: 0.18~0.28%, the balance is Fe and unavoidable impurities; The guide roller is prepared by precision casting; At the cross section 1~2mm below the surface of the iron-based superalloy guide roller, the Ni ₃ (Ti, Al, Nb) phase accounts for 1.2~2.6% of the total area of the cross section. At the central cross-section of the alloy guide roller, the Ni ₃ (Ti, Al, Nb) phase occupies 5.2-7.8% of the total area. 2. The guide roller according to claim 1, characterized in that, at the cross-section 1mm below the surface of the iron-based superalloy guide roller, the ratio of the area occupied by the Ni ₃ (Ti, Al) phase to the total area is 1.8~2.1%, at the central cross-section of the iron-based superalloy guide roller, the area ratio of the Ni ₃ (Ti, Al) phase is 5.8~6.4% of the total area. 3. A manufacturing method of the guide roller according to claim 1, characterized in that, comprising the following steps: 1) Precision casting, preparing iron-based superalloy materials according to the chemical composition of the iron-based superalloy described in claim 1 or 2, using water-soluble cores, adopting existing system designs to obtain models, using rapid prototyping machines, using existing After laser sintering, the polystyrene powder is sintered layer by layer, and then dipped in wax to make an investment pattern, and then the surface and interior of the investment pattern are cleaned; the investment pattern is immersed in the surface coating and dipped in paste, then taken out, and then the surface layer is cleaned. Sprinkle sand and dry to get the mold shell, put the mold shell into the heating furnace at a temperature of 1080~1180°C, keep it warm for 2.5~3h, then cool down to room temperature with the furnace to get the mold; melt the prepared iron-based superalloy material After it becomes liquid, it is poured into the model shell for pouring. The pouring temperature is 1620-1650°C. After pouring, the precision-cast guide roller is naturally cooled to room temperature, and then the pouring system is removed to obtain the guide roller; 2) Hot isostatic pressing is carried out on the obtained guide roller, the temperature is 1130~1165°C, the pressure is 160~200MPa, and the holding time is 3~6 hours; 3) Annealing: Heat the guide roller obtained after hot isostatic pressing to 865~885°C for 2~4h, then lower the temperature to 600~680°C for 1~1.8h, then lower it to 580~595°C and leave the furnace. Naturally cool to room temperature afterward; 4) Finishing: Finishing the annealed guide rollers with cemented carbide cutters into finished guide rollers. 4. The manufacturing method according to claim 3, characterized in that quenching and tempering heat treatment are carried out after the annealing and before finishing, the quenching is: heating the guide roller to 980-1020° C. for 1-2 hours, Then take it out of the furnace for oil quenching; the tempering is: heat the quenched guide roller to 245~298°C for 2~3h, and then take it out of the furnace and air cool it to room temperature. 5. The manufacturing method according to claim 3 or 4, wherein the surface coating is zirconia, zirconium diacetate, fatty alcohol polyoxyethylene ether and n-butanol in a ratio of 4.5 to 5.2:1 in parts by weight : 0.0012~0.0018: 0.0006~0.0012 The ratio is obtained by stirring and standing still. 6. The manufacturing method according to claim 3 or 5, characterized in that, in the heating step of annealing, firstly heat to 380-420°C, keep warm for 0.8-1.5h, and then heat to 865-885°C.