CN111172431B - Small-displacement turbocharger impeller and production process thereof - Google Patents

Abstract

The invention discloses a small-displacement turbocharger impeller which is made of a chromium-nickel-iron alloy, wherein the chromium-nickel-iron alloy comprises the following components in percentage by mass: cu, Zr, Mn, V, Fe, Cd, W, P, Si, Ti, Cr, Sc, Mg, Al and the balance of Ni, and is prepared by raw material acceptance, wax mold manufacturing, assembly welding, shell manufacturing, roasting, pouring, shell vibrating and shot blasting, primary sand blasting, cutting, secondary sand blasting, primary inspection, grinding processing, tertiary sand blasting, fluorescent flaw detection and final inspection. The impeller of the small-displacement turbocharger is made of the chromium-nickel-iron alloy which has excellent corrosion resistance, high strength and toughness and high temperature impact resistance, so that the service life of the impeller can be prolonged, and the maintenance rate of the turbocharger is reduced.

Description

Small-displacement turbocharger impeller and production process thereof

Technical Field

The invention belongs to the technical field of turbochargers, and particularly relates to a small-displacement turbocharger impeller and a production tool thereof.

Background

The turbocharger can be regarded as a kind of air compressor in practice, and the intake air amount is increased by compressing air. The engine uses the inertia impulse force of the exhaust gas from the engine to push the turbine in the turbine chamber, the turbine drives the coaxial impeller, the impeller presses the air sent by the air filter pipeline, and the air is pressurized and enters the cylinder. When the rotating speed of the engine is increased, the exhaust gas exhaust speed and the rotating speed of the turbine are also increased synchronously, the impeller compresses more air to enter the air cylinder, the pressure and the density of the air are increased, more fuel can be combusted, and the output power of the engine can be increased by correspondingly increasing the fuel quantity and adjusting the rotating speed of the engine.

The impeller of the turbocharger pressure device belongs to a centrifugal impeller, the rotating speed of the centrifugal impeller is usually high, the high-speed rotor is made of light materials with low density as much as possible, and meanwhile, the requirement of good rigidity of the materials is met. Cast aluminum, stainless steel and titanium alloy are the most commonly used materials for impellers of supercharging devices at present.

The decisive factors for material selection of the centrifugal impeller are more. The diameter of the impeller, the rotating speed and the direction of the curved surface of the blade are all the basis for material selection. And meanwhile, the proper material strength range can be determined through a large amount of calculation. The impeller material with high strength, low cost and excellent mechanical property is a hot spot for the current market research because the material selection can not only pursue the material with the highest strength and needs to be considered from the economical aspect.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a small-displacement turbocharger impeller and a production process thereof, which improve the production process of impeller materials by optimizing the component structure of the impeller materials so as to improve the mechanical properties of the impeller materials.

In order to achieve the purpose, the invention provides the following technical scheme:

the material of the impeller is an inconel, and the inconel comprises the following components in percentage by mass: cu: 5.5 to 6.0 percent; zr: 0.05 to 0.2 percent; mn: 0.2 to 0.4 percent; v: 0.05-0.10%; fe: 10.0 to 15.0 percent; cd: 0.15 to 0.25 percent; w: 0.15 to 0.25 percent; p: 0.05 to 0.1%, Si: 0.05 to 0.2 percent; ti: 0.05 to 0.1 percent; cr: 13.0 to 16.0 percent; and (C) Sc: 0.15 to 0.25 percent; mg: 0.15-0.25%, Al: 0.5-1.0 percent, and the balance of Ni.

Preferably, the phosphorus comprises the following components in percentage by mass: 0.08 percent.

Preferably, the tungsten comprises the following components in percentage by mass: 0.2 percent.

Preferably, the titanium comprises the following components in percentage by mass: 0.07 percent.

Preferably, the scandium comprises the following components in percentage by mass: 0.2 percent.

A production process of the small-displacement turbocharger impeller comprises the following steps: the method comprises the following steps of raw material acceptance, wax mold manufacturing, assembly welding, shell manufacturing, roasting, pouring, shell vibrating and shot blasting, primary sand blasting, cutting, secondary sand blasting, primary inspection, grinding, tertiary sand blasting, fluorescent flaw detection and final inspection; the closed impeller mould shell is placed into a roasting furnace to be roasted for 1-1.5h at 1050 ℃ and 1000-; and in the pouring step, the melted chromium-nickel-iron alloy is poured into a roasted closed impeller mould shell, and a closed impeller casting crude product is obtained after cooling.

Preferably, the first sand blasting is to use a sand blasting machine to spray quartz sand to the surface of the rough product of the impeller die casting; the second sand blasting is to use a sand blasting machine to spray iron sand to the surface of the crude product of the impeller die casting; and the third sand blasting is to spray carborundum on the surface of the crude product of the impeller die casting by using a sand blasting machine.

Preferably, the production method of the inconel comprises the following steps:

step 1, preparing materials, namely preparing raw materials according to the weight percentage of each component in the ferrochrome alloy;

step 2, melting, namely pouring Fe, Cr and Ni into a melting furnace, heating to melt at 1550-;

step 3, deslagging and degassing for the first time, controlling the furnace temperature to 1350-;

step 4, standing: standing the refined chromium-nickel-iron alloy melt until the temperature of the chromium-nickel-iron alloy melt is reduced to 1250 ℃;

step 5, primary refining, namely heating the temperature in the vacuum induction furnace to 1450-;

step 6, deslagging and degassing for the second time, controlling the temperature of the vacuum induction furnace to 1250-;

step 7, secondary refining, namely heating the temperature in the vacuum induction furnace to 1500-;

step 8, deslagging and degassing for the third time, controlling the furnace temperature to 1300-;

and 9, refining, namely controlling the furnace temperature to be 1600-1630 ℃, adding P, uniformly discharging liquid nitrogen into the vacuum induction furnace, and preserving the temperature for 20-30min to obtain the smelted and melted chromium-nickel-iron alloy.

More preferably, the degasifier A in the step 3 is CaCO₃。

More preferably, the degasifier B in the step 6 is Cl₂。

In summary, the invention has the following advantages:

1. the small-displacement turbocharger impeller provided by the invention has the advantages that the service life of the impeller can be prolonged by adopting the high-temperature impact resistant inconel as a material, which has excellent corrosion resistance, the strength and the toughness are also kept at a higher level, so that the maintenance rate of the turbocharger is reduced, and meanwhile, the surface of a crude product of an impeller die casting is subjected to three times of sand blasting, so that the fatigue resistance, the high-temperature impact resistance and the corrosion resistance of an impeller workpiece are improved.

2. As can be seen from the examples, the CrNi-Fe alloy produced by the invention has tensile strength of 679-.

In the invention, the added part of alloy components and the principle of improving the alloy performance are explained as follows:

TI, titanium element preferentially reacts with Ni in the casting process of the chromium-nickel-iron alloy to form a Ni-Ti grain refiner, which can convert Ni grains from thick dendrites into fine and uniform equiaxed crystals and improve the strength and plasticity of the chromium-nickel-iron alloy;

w, adding a proper amount of tungsten into the chromium-nickel-iron alloy, so that the oxidation resistance of the alloy can be improved;

the application of V and vanadium in the inconel improves the hardness and shock resistance of the inconel, and can prevent the generation of particles, so that the content of V is as follows: 0.05-0.10%;

zr is applied to the chromium-nickel-iron alloy, so that the heat resistance of the chromium-nickel-iron alloy is improved, the grain fineness is improved, and the thermal fracture is prevented;

sc is applied to the inconel to improve the heat resistance and the corrosion resistance of the alloy;

p, certain phosphorus element is added into the chromium-nickel-iron alloy, so that the workability and hardness of the alloy are facilitated, and the alloy can be cracked when the concentration is too high, so that the content of P selected by the invention is as follows: 0.05 to 0.1 percent;

Detailed Description

The technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all, embodiments of the present invention.

Example 1

The material of the impeller is an inconel, and the inconel comprises the following components in percentage by mass: cu: 5.5 percent; zr: 0.05 percent; mn: 0.2 percent; v: 0.05 percent; fe: 10.0 percent; cd: 0.15 percent; w: 0.15 percent; p: 0.05%, Si: 0.05 percent; ti: 0.05 percent; cr: 13.0 percent; and (C) Sc: 0.15 percent; mg: 0.15%, Al: 0.5% and the balance Ni.

The production method of the ferrochrome alloy comprises the following steps:

step 1, preparing materials, namely preparing raw materials according to the weight percentage of each component in the ferrochrome alloy;

step 2, melting, namely pouring Fe, Cr and Ni into a melting furnace, heating to be melted at 1550-;

step 3, deslagging and degassing for the first time, controlling the furnace temperature to 1350-;

step 4, standing: standing the refined chromium-nickel-iron alloy melt until the temperature of the chromium-nickel-iron alloy melt is reduced to 1250 ℃;

step 5, primary refining, namely heating the temperature in the vacuum induction furnace to 1450-;

step 6, deslagging and degassing for the second time, controlling the temperature of the vacuum induction furnace to 1250-;

step 7, secondary refining, namely heating the temperature in the vacuum induction furnace to 1500-;

step 8, deslagging and degassing for the third time, controlling the furnace temperature to 1300-;

and 9, refining, namely controlling the furnace temperature to 1600-1610 ℃, adding P, uniformly discharging liquid nitrogen into a vacuum induction furnace, and preserving the temperature for 20min to obtain the smelted and melted chromium-nickel-iron alloy.

Example 2

The material of the impeller is an inconel, and the inconel comprises the following components in percentage by mass: cu: 5.7 percent; zr: 0.1 percent; mn: 0.3 percent; v: 0.08 percent; fe: 13 percent; cd: 0.2 percent; w: 0.2 percent; p: 0.08%, Si: 0.1 percent; ti: 0.7 percent; cr: 14 percent; and (C) Sc: 0.2 percent; mg: 0.2%, Al: 0.8 percent and the balance of Ni.

The production method of the ferrochrome alloy comprises the following steps:

step 1, preparing materials, namely preparing raw materials according to the weight percentage of each component in the ferrochrome alloy;

step 2, melting, namely pouring Fe, Cr and Ni into a melting furnace, heating to be melted at 1570-;

step 3, deslagging and degassing for the first time, controlling the furnace temperature to 1370-1380 ℃, uniformly discharging CaCO3 and liquid nitrogen into a vacuum induction furnace by using a refiner, keeping for 18min, and then removing scum;

step 4, standing: standing the refined chromium-nickel-iron alloy melt until the temperature of the chromium-nickel-iron alloy melt is reduced to 1250 ℃;

step 5, primary refining, namely heating the temperature in the vacuum induction furnace to 1470-;

step 6, deslagging and degassing for the second time, controlling the temperature of the vacuum induction furnace to 1270-;

step 7, secondary refining, namely heating the temperature in the vacuum induction furnace to 1520-;

step 8, deslagging and degassing for the third time, controlling the furnace temperature to 1320-;

and 9, refining, namely controlling the furnace temperature to 1610 and 1620 ℃, adding P, uniformly discharging liquid nitrogen into a vacuum induction furnace, and preserving the temperature for 25min to obtain the smelted and melted inconel.

Example 3

The material of the impeller is an inconel, and the inconel comprises the following components in percentage by mass: cu: 6.0 percent; zr: 0.2 percent; mn: 0.4 percent; v: 0.10 percent; fe: 15.0 percent; cd: 0.25 percent; w: 0.25 percent; p: 0.1%, Si: 0.2 percent; ti: 0.1 percent; cr: 13.0 to 16.0 percent; and (C) Sc: 0.25 percent; mg: 0.25%, Al: 1.0% and the balance Ni.

The production method of the ferrochrome alloy comprises the following steps:

step 1, preparing materials, namely preparing raw materials according to the weight percentage of each component in the ferrochrome alloy;

step 2, melting, namely pouring Fe, Cr and Ni into a melting furnace, heating to melt at 1580-;

step 3, deslagging and degassing for the first time, controlling the furnace temperature to 1360-1380 ℃, uniformly discharging CaCO3 and liquid nitrogen into a vacuum induction furnace by using a refiner, keeping for 20min, and then removing scum;

step 4, standing: standing the refined chromium-nickel-iron alloy melt until the temperature of the chromium-nickel-iron alloy melt is reduced to 1250 ℃;

step 5, primary refining, namely heating the temperature in the vacuum induction furnace to 1480-;

step 6, deslagging and degassing for the second time, controlling the temperature of the vacuum induction furnace to 1280-1300 ℃, uniformly discharging a degassing agent Cl2 and liquid nitrogen into the vacuum induction furnace by using a refiner, keeping for 20min, and then skimming scum;

step 7, secondary refining, namely heating the temperature in the vacuum induction furnace to 1530-;

step 8, deslagging and degassing for the third time, controlling the furnace temperature to 1330-1350 ℃, uniformly discharging liquid nitrogen into the vacuum induction furnace by using a refiner, keeping for 20min, and skimming scum;

and 9, refining, namely controlling the furnace temperature to 1620-1630 ℃, adding P, uniformly discharging liquid nitrogen into a vacuum induction furnace, and preserving the temperature for 30min to obtain the smelted and melted inconel.

Example 4

The material of the impeller is an inconel, and the inconel comprises the following components in percentage by mass: cu: 6.0 percent; zr: 0.05 percent; mn: 0.2 percent; v: 0.10 percent; fe: 10.0 percent; cd: 0.25 percent; w: 0.15 percent; p: 0.05%, Si: 0.2 percent; ti: 0.06 percent; cr: 16.0 percent; and (C) Sc: 0.15 percent; mg: 0.25%, Al: 0.5% and the balance Ni.

The production method of the ferrochrome alloy comprises the following steps:

step 1, preparing materials, namely preparing raw materials according to the weight percentage of each component in the ferrochrome alloy;

step 2, melting, namely pouring Fe, Cr and Ni into a melting furnace, heating to melt at 1590-;

step 3, deslagging and degassing for the first time, controlling the furnace temperature to 1350-;

step 4, standing: standing the refined chromium-nickel-iron alloy melt until the temperature of the chromium-nickel-iron alloy melt is reduced to 1250 ℃;

step 5, primary refining, namely heating the temperature in the vacuum induction furnace to 1470-;

step 6, deslagging and degassing for the second time, controlling the temperature of the vacuum induction furnace to 1280-1290 ℃, uniformly discharging a degassing agent Cl2 and liquid nitrogen into the vacuum induction furnace by using a refiner, keeping for 19min, and skimming scum;

step 7, secondary refining, namely heating the temperature in the vacuum induction furnace to 1510-;

step 8, deslagging and degassing for the third time, wherein the furnace temperature is controlled to 1330-1340 ℃, liquid nitrogen is uniformly discharged into a vacuum induction furnace by using a refiner, and scum is removed after the liquid nitrogen is kept for 15-20 min;

and 9, refining, namely controlling the furnace temperature to 1605-.

Comparative example 1

Proceeding according to example 2, the compositions are identical; the operation of the steps S3-S9 in the production method is that all alloy components are directly added into a vacuum induction furnace together for melting treatment at the temperature of 1600-1650 for 1-1.5 h;

comparative example 2

Commercially available inconel;

comparative example 3

Commercially available titanium alloys;

example 5

Producing an impeller by using the melted inconel prepared in example 2;

a production process of the small-displacement turbocharger impeller comprises the following steps: the method comprises the following steps of raw material acceptance, wax mold manufacturing, assembly welding, shell manufacturing, roasting, pouring, shell vibrating and shot blasting, primary sand blasting, cutting, secondary sand blasting, primary inspection, grinding, tertiary sand blasting, fluorescent flaw detection and final inspection; the closed impeller mould shell is placed into a roasting furnace to be roasted for 1.5h at 1050 ℃ under the temperature of 1000-; and in the pouring step, the melted chromium-nickel-iron alloy is poured into the roasted closed impeller mould shell, the pouring temperature is 1570-.

The first sand blasting is to use a sand blasting machine to spray quartz sand to the surface of the rough product of the impeller die casting; the second sand blasting is to use a sand blasting machine to spray iron sand to the surface of the crude product of the impeller die casting; and the third sand blasting is to spray carborundum on the surface of the crude product of the impeller die casting by using a sand blasting machine.

Example 6

Producing an impeller by using the melted inconel prepared in the comparative example 1;

a production process of the small-displacement turbocharger impeller comprises the following steps: raw material acceptance, wax mold manufacturing, assembly welding, shell manufacturing, roasting, pouring, shell vibrating and shot blasting, primary sand blasting, cutting, primary inspection, grinding, fluorescent flaw detection and final inspection; the closed impeller mould shell is placed into a roasting furnace to be roasted for 1.5h at 1050 ℃ under the temperature of 1000-; and in the pouring step, the melted chromium-nickel-iron alloy is poured into the roasted closed impeller mould shell, the pouring temperature is 1570-.

And the first sand blasting is to use a sand blasting machine to spray quartz sand to the surface of the rough product of the impeller die casting.

Example 7

The commercially available inconel of comparative example 2 was melted and added to the casting process, and the other operations were carried out as in example 5;

example 8

The commercially available titanium alloy of comparative example 3 was melted and added to the casting process, and the other operations were carried out as in example 5;

test 1 Performance testing of the Material

(1) The strength and toughness of the inconel, the inconel and the titanium alloy obtained in the examples 1 to 4 and the comparative examples 1 to 3 are tested according to the GB/T16865 standard, and the test result is obtained; (2) the ferrochrome, inconel and titanium alloys obtained in examples 1 to 4 and comparative examples 1 to 4 were tested according to the IS04628-1 rating method, the temperature of the tank was kept at 35 + -2 deg.C, the brine concentration was 50g/L + -10 g/L, and the spray amount was 1-2mL/(80 cm)²H); (3) the ferrochrome alloys, commercially available inconel alloys and commercially available titanium alloys obtained in examples 1 to 4 and comparative examples 1 to 4 were tested under the impact of high-temperature air flow at 1150 ℃ (20 hours); the above test results are summarized in the following table 1:

TABLE 1 results of testing the Properties of the materials

Wherein: examples 1-4, comparative example 1 was a molten inconel alloy prepared directly, and the molten inconel alloy was die cast into an alloy according to a conventional process, and the material was tested for properties.

(1) Mechanical Property test

As can be seen from Table 1, the CrNi-Fe alloys prepared in examples 1-4 of the present invention have tensile strength of 679-; comparative example 1 lacks steps 3-9, resulting in different degrees of reduction in tensile strength, yield strength, elongation, and hardness, affecting the performance of inconel.

(2) Test of Corrosion resistance

As can be seen from Table 1, the ferrochromium alloys prepared in examples 1 to 4 of the present invention have corrosion resistance rates of 0.04 to 0.06 mg/cm. d, which is better than that of comparative example 4 of titanium alloy, i.e., 0.15 mg/cm. d, and also better than that of comparative example 3 of commercial ferrochromium alloy, i.e., 0.55 mg/cm. d; comparative example 1 is 0.65 mg/cm. d, which shows that the lack of steps 3 to 9, respectively, causes a decrease in the performance of the inconel, and a decrease in the corrosion resistance, affects the performance of the inconel.

(3) High temperature impact test

As can be seen from Table 1, the CrNiFe alloy prepared in the embodiments 1-4 of the invention has no obvious change under the impact of high-temperature airflow at 1150 ℃, and micro holes appear on the surface after the impact of airflow for 15 hours according to the proportion of 3 to the titanium alloy; after the commercially available ferrochrome comparative example 2 is impacted for 6 hours, holes appear on the surface, and the high-temperature resistance is poor; comparative example 1 lacks steps 3-9, and holes appear on the surface after 8h of impact, which shows that the lack of steps 3-9 in the production method can reduce the high temperature impact resistance of the product.

Experiment 2 impeller Performance testing

The impellers prepared in examples 5 to 8 were subjected to erosion wear tests under the following erosion conditions: the erosion rate was 10m/s, the erosion angle was 70 degrees, and the erosion time was 96 hours continuously, and then the surface condition of the impeller was observed to see whether or not the peeling phenomenon occurred.

Tests show that the impeller prepared by the implementation of the 5 has a perfect surface and does not have a stripping phenomenon;

the impellers prepared in the examples 6 to 7 showed a small amount of peeling after 48 hours, and showed a more significant peeling after 80 hours;

the impeller prepared in the example 8 has no peeling phenomenon within 48 hours; after 90 hours, a small amount of peeling occurred.

Therefore, the impeller prepared in the embodiment 3 is subjected to three times of sand blasting, the structure and the surface form of the surface of the crude product of the impeller die casting are shown, and meanwhile, the prepared impeller has excellent impact resistance and corrosion resistance by combining the ferrochrome alloy with excellent mechanical properties.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the design concept of the present invention should be included in the scope of the present invention.

Claims (1)

1. The material of the impeller is an inconel, and the inconel comprises the following components in percentage by mass: cu: 5.5 to 6.0 percent; zr: 0.05 to 0.2 percent; mn: 0.2 to 0.4 percent; v: 0.05-0.10%; fe: 10.0 to 15.0 percent; cd: 0.15 to 0.25 percent; w: 0.2 percent; p: 0.08%, Si: 0.05 to 0.2 percent; ti: 0.07 percent; cr: 13.0 to 16.0 percent; and (C) Sc: 0.2 percent; mg: 0.15-0.25%, Al: 0.5-1.0% and the balance of Ni;

the production process of the small-displacement turbocharger impeller is characterized by comprising the following steps of: the method comprises the following steps of raw material acceptance, wax mold manufacturing, assembly welding, shell manufacturing, roasting, pouring, shell vibrating and shot blasting, primary sand blasting, cutting, secondary sand blasting, primary inspection, grinding, tertiary sand blasting, fluorescent flaw detection and final inspection; the closed impeller mould shell is placed into a roasting furnace to be roasted for 1-1.5h at 1050 ℃ and 1000-; pouring, namely injecting the melted chromium-nickel-iron alloy into a roasted closed impeller mould shell, and cooling to obtain a crude product of the closed impeller die casting;

the first sand blasting is to use a sand blasting machine to spray quartz sand to the surface of the crude product of the impeller die casting; the second sand blasting is to use a sand blasting machine to spray iron sand to the surface of the crude product of the impeller die casting; the third sand blasting is to use a sand blasting machine to spray the diamond sand to the surface of the crude product of the impeller die casting;

the production method of the ferrochrome alloy comprises the following steps:

step 1, preparing materials, namely preparing raw materials according to the weight percentage of each component in the ferrochrome alloy;

step 2, melting, namely pouring Fe, Cr and Ni into a melting furnace, heating to melt at 1550-;

step 3, deslagging and degassing for the first time, and then placing the furnace in a furnaceThe temperature is controlled to 1350 ℃ and 1380 ℃, and a refiner is used for removing the gas agent CaCO₃Uniformly discharging the liquid nitrogen and the liquid nitrogen into a vacuum induction furnace, keeping for 15-20min, and removing scum;

step 4, standing: standing the refined chromium-nickel-iron alloy melt until the temperature of the chromium-nickel-iron alloy melt is reduced to 1250 ℃;

step 5, primary refining, namely heating the temperature in the vacuum induction furnace to 1450-;

step 6, deslagging and degassing for the second time, controlling the temperature of the vacuum induction furnace to 1250-₂Uniformly discharging the liquid nitrogen and the liquid nitrogen into a vacuum induction furnace, keeping for 15-20min, and removing scum;

step 7, secondary refining, namely heating the temperature in the vacuum induction furnace to 1500-;

step 8, deslagging and degassing for the third time, controlling the furnace temperature to 1300-;

and 9, refining, namely controlling the furnace temperature to be 1600-1630 ℃, adding P, uniformly discharging liquid nitrogen into the vacuum induction furnace, and preserving the temperature for 20-30min to obtain the smelted and melted chromium-nickel-iron alloy.