JPS60228676A - Treatment for smoothing surface of rotor and stator vanes - Google Patents

Abstract

PURPOSE:To prevent sticking of foreign matter such as soot and dust on the surface of the rotor and stator vanes of an axial flow compressor or the like by forming a TiN-TiC layer on the vane surfaces by chemical vapor deposition under the same heat treating conditions as in the ordinary practice. CONSTITUTION:The rotor and stator vanes of the axial flow compressor consisting of, for example, a 12% Cr steel are cleaned for 3-10min according to the degree of contamination by an aq. 10-15% Na2CO3 soln. and are further cleaned by an alkali then washed. The vanes after washing are dried and are subjected to steam cleaning by a comercially marketed fluorine solvent. The cleaned vanes are then subjected to composite TiN-TiC coating to 10mum film thickness as target. The CVD conditions for TiN-TiC in this case are set at 900 deg.CX4hr. Gaseous N2 is sucked into the coating layer to cool the coated vanes down to about 100 deg.C, then the temp. in the vessel is increased to 650-750 deg.C and the vanes are subjected to a tempering treatment. The tempered vanes are cooled and the vane surfaces are lightly buffed to remove the deposits from the surface, by which the surfaces are finished.

Description

[Detailed Description of the Invention] (Summary of the Prior Art) Axial flow compressors, such as compressors, are used in many devices and plants, but their efficiency is closely related to the blade surface roughness. It is known that the smoother the material, the more preferable it is.

For this reason, the surface of each blade is smoothed using various methods such as machining and hand polishing, but these processes require a large number of man-hours, which has the disadvantage of increasing the cost of the blade.

In addition, if an axial flow blower is used in an environment containing a large amount of impurities such as suspended dust, these substances will adhere to the blade surface and not only reduce the efficiency of the turbine, but in extreme cases, it will become impossible to operate. Although it is desirable to have a material that is difficult to adhere to and accumulate, there are currently no adequate countermeasures because the adhesion mechanism itself is complex.

(Object of the present invention) An object of the present invention is to provide a method for smoothing the surfaces of movable and stationary blades of an axial flow compressor, etc., to prevent the adhesion of foreign matter such as soot and dust. .

(Findings of the present invention) The present invention provides a method for preparing a blade after mechanical processing using a mixture of TiN and TiC at 0VD (Chemical) under appropriate temperature conditions depending on the blade material.
This method was developed based on the fact that a smooth surface that is resistant to deposits can be obtained by coating by cal vapor deposition (chemical vapor deposition (hereinafter referred to as OVD)) and then simple polishing.

(Structure of the present invention) The present invention is based on heat treatment conditions (temperature 9
Composite C of TiN and TiC under the same temperature and 1 hour conditions as
The blade is characterized by VD coating, and then tempered and then simply polished to smooth the blade surface and prevent foreign matter from adhering to it.

(Effects of the present invention) The present invention has the following effects.

(1) Compared to conventional manual polishing, smoothing can be achieved in a shorter time and at a lower cost.

(2) The blade surface is covered with a smooth and hard TiC and TiN mixture, which prevents erosion and adhesion caused by foreign substances in the atmosphere.

(3) As a result of (1) and (2), compressor efficiency improved;
We can expect retention.

(4) Under the heat treatment conditions of the blade material (temperature 2 hours), CV
Since D-coating is performed, there is no need for additional heat treatment.

(5) Since the hardness of this treated layer is extremely high, occurrence of erosion etc. can be prevented.

(Detailed Description of the Present Invention) Since 12XOr steel is often used in axial flow compressors and moving/stationary blades, a specific embodiment using this material as a workpiece will be described below.

The movable and stationary blades to be treated are 10 to 15 X Ha, C
Wash with o3 aqueous solution for 3 to 10 minutes depending on the degree of contamination,
After the alkali cleaning, the moving and stationary blades were further washed with water for 3 to 5 minutes to remove the alkali on the blade surface.

Next, expose the wing to warm air at 100-120℃ for 1-3 minutes,
Dry. After drying, the blade was steam-cleaned for 6 to 5 minutes using chlorocene Nu (fluorinated solvent: trade name of The Dow Chemical Company, USA).

After cleaning, the movable and stationary blades were placed in a TiN-TiC coating bath, and a Tin-TiC composite coating was applied with a target film thickness of 10 μm. Ti, N'-Tie's OV
The D reaction formula is as follows.

2TiOL4+ Hz + 5 horses 10H4 → 2TiON
-1-8HOL4-Bird The reaction conditions were set as follows.

Since the material of the dynamic and stationary blades is 12XOr steel, considering the quenching conditions, the OVD conditions for TiN-TiC are 900
℃×4 hours.

In and\, the reaction temperature and time were determined as above, but the relationship between reaction temperature and time was based on the quenching conditions of 950°C and 0.5 hours, and 850 to 1050°C for 12 hours to α5 hours. can be determined by the following formula.

(T1+273)(20+10g t+)=(T*
+273) (20+1og ta) However, in the above formula, T
, , tl are the temperature and time of the standard quenching conditions (i.e.,
T,:950℃+tl+=Q,5Hr)'r
, t tt is the temperature under OVD conditions of TiN-TiC.

It's time.

After TiN-TiC coating, N and gas were sucked into the coating tank, and the six blades were cooled to around 100°C.
Next, the temperature in the coating tank was raised to 650 to 750°C, and tempering treatment was performed for 1 hour.

After heating the coating tank, blow in N and gas as necessary. When the temperature of the 6 blades reaches around 200℃, take out each blade from the coating tank and lightly polish the surface of the 6 blades (1 ~2 minutes) and finishing by removing surface deposits.

The moving and stationary blades used here were machined and had a surface roughness of about 6B (4.8 to 6-6 μm).
After the above treatment, the peaks and valleys of roughness are rounded, and
It was possible to smooth the surface within 2.4 to 6 μm.

The hardness of the coating layer treated according to the present invention is 1500~
2000 mHv is shown, and the base material (200-300
mHv).

In addition, repeated heating and cooling tests were conducted in air at a room temperature of 8,500°C using an electric furnace, but no cracks or peeling were observed in the coating layer, indicating that it has excellent adhesion and heat resistance. confirmed.

To investigate the corrosion resistance of the coating layer, 10X HO
It was immersed in a L aqueous solution (room temperature) for 50 hours and its changes were investigated, but no particularly significant changes or weight loss were observed.

After confirming the above performance, the processing blade according to the present invention was incorporated into an actual general moving/stationary blade of an axial flow compressor, and after test operation for about one year, an open inspection was conducted, and the following facts were confirmed as a result. .

Conventional (untreated) blades have a considerable amount of deposits accumulated, and when the deposits are removed by washing with water, the surface becomes uneven due to corrosion, but the treated blades of the present invention have no deposits. Almost no peeling of the coating layer, cracks, or corrosion was observed on the blade surface after washing with water.

As mentioned above, conventional blades required a great deal of effort to smooth, but the process of the present invention can process a large number of blades simultaneously in a short time, reducing the cost required for smoothing after machining compared to conventional blades. It was possible to reduce the amount by about 20% compared to .

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Claims (1)

[Claims] The surface of moving and stationary blades is characterized by forming a composite TiN-T10 layer by chemically vapor depositing TiN and Tie on the blade surface under the same temperature and time conditions as the heat treatment conditions normally applied to blade materials. Smoothing processing method〇