JPS5857006A - Regeneration of turbine blade - Google Patents

Abstract

PURPOSE:To permit easy regeneration of a turbine blade at a low cost by removing the part which is secularly deteriorated on the surface of a turbine blade and cleaning the removed part and forming the built-up layer by applying specific powder and performing molding work and reheating processing. CONSTITUTION:The secular deterioration such as creep deformation, corrosion, hole formation etc. can be generated on the effective part 1 of a turbine blade or the stud part 2 installed onto a rotor 3, especially the first hook part 2a in said stud part 2. When the turbine blade is regenerated, the secularly deteriorated part on the surface at least in the vicinity of the first hook part 2a of the stud part 2 of the turbine blade is removed, and surface treatment is applied onto the removed part for cleaning. Martensite co-material alloy powder is applied onto the removed part described the above to form a regenerative built- up layer 4, which is formed into the turbine blade shape having an allowable thickness, and then reheated to form a worked surface 5, and thus regenerative work is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for regenerating a Cr turbine blade that has suffered aging deterioration such as creep, corrosion, and pitting, and particularly relates to a method for regenerating a Cr turbine blade that performs thermal spray overlay using a common material powder. .

Conventional turbine blades are known for their strength, corrosion resistance and vibration resistance.

Considering the damped heavy ring, Cr-Me-V, /Or
-M.

- Manufactured by V-W or the like, the forged material is subjected to tempering heat treatment to ensure necessary mechanical properties, and then machined into a blade shape to produce a product blade.

However, turbine blades are constantly used under harsh conditions, resulting in creep and fatigue.

Stress concentration, I., erosion, etc. occur over time.

In particular, since the turbine true implantation part is used in a high temperature region, various types of deterioration occur over time, including creep, stress concentration, corrosion, and continuous changes in fatigue.

For example, near the final stage of low temperature, an extremely large centrifugal stress acts and the implanted part stress tends to reach its limit state, and not only the centrifugal stress but also the influence of the added vibration stress etc. are superimposed. As shown in the figure, the effective part L of the blade or the implanted part of the blade that is attached to the rotor JK, and the implanted part in 4I.
Creep deformation such as side deformation and footing deformation occurs in the first stage hook portion Ja.

Furthermore, if there is segregation of metal-containing components or nonmetallic inclusions in the material, %KI deterioration occurs in one year, and decarburization tends to occur in the deteriorated region.

Furthermore, in the turbine blades of power plants that utilize geothermal energy, the steam and hot water that serve as the heat source contain a wide variety of impurities, especially corrosive impurities, and as a result, the turbine blades are exposed to harsh corrosive environments. If it is placed in a high temperature environment, it will become K and cause full surface corrosion and pitting corrosion.

These deteriorations over time are outside the allowable wall thickness limits, and the original durability including the creep deformation mentioned above is not as expected. Therefore, new products must be replaced during periodic inspections, and if there are many This is extremely uneconomical, and countermeasures are required due to resource issues such as Cr.

The present invention has been made in view of the current situation, and its purpose is to easily and inexpensively regenerate turbine blades that have deteriorated over time to create a turbine that can obtain almost the same characteristic values as newly manufactured blades. To provide a method for regenerating wings.

In the present invention, the aged portion of the turbine blade surface is removed, surface treatment is performed to clean the removed portion, and martensitic co-material alloy powder is then sprayed to form a fleshy layer. 4I involves forming the material into a shape with an allowable thickness and then subjecting it to reheat treatment.

The present invention will be explained below with reference to an embodiment shown in FIGS. 3 and 4.

In Fig. 1, l is the effective part of the blade, and ko is the implanted part of the blade, which is implanted in the implanted part Jij El-ta J. In the vicinity of the first stage hook part Ja of the implanted part A, a regenerated sensuous layer is formed by the method described later, as shown in FIG. Processed surface 3 after finishing and reheat treatment
is being formed.

Next, the reproduction method will be explained.

(1) Partial Removal Step 1 - The parts of the Cr blade that have deteriorated over time are cut into a curved surface with a radius of curvature or greater, and surface scale etc. are completely removed and degreased with F clean.

(2) Surface treatment process for areas to be overlaid The parts of the turbine blade that need to be overlaid require sufficient surface treatment, so pre-treatment is performed using a sandblasting method.
Clean the foreign matter such as carborundum to make the uneven surface clean.

(3) In order to increase the adhesion of the coating on the overlay 1-layer overlay construction surface, it is dried in a drying oven at 50 to 10° C. using O8S for 1 hour. For the fleshy texture, a Plasmatron thermal spray machine or a Minigun thermal spray machine was used, and Ar and N were used to improve adhesion.
Approx.
Preheat to below 10°C.

The spraying conditions are maintained at a spraying distance of lIl'Po to 1jO- with a working plasma flame with a power of 00 to 100 m and an argon flow rate of y to '16'/m its. At this time, it is desirable that the thermal spraying machine collide with the construction surface at right angles, and it is best to repair the corners of the first hook core a in the x-y-z directions using a minigun thermal spraying machine. .

For a thermal spray machine, Ni-muj powder (with a particle size of 10 to 10
0 mesh) to 0.3 to o for the inner fill dimension /-,
sm thermal spraying, then reproduced fleshy layer on top of /2
Cr-martensite co-material alloy powder (particle size 200 to 3 pieces 3 mesh) is 0., 1111 from the allowable wall thickness dimension.
Sprayed to a thickness of 1M. In this case, the temperature of the construction surface should be maintained at 300 to 310℃ or less, and the coating speed should be controlled at
The surface area of the OIII angle is 0.0 and the thickness is Δ1n.

Although the thermal sprayed overlay layer differs depending on the degree of deterioration and creep deformation, it is usually 1. It is optimal because the sensual layer below j■ is firmly fixed.

(4) 0. /-The thickly built-up turbine blade is cut with a grinder or the like, and then formed into a turbine blade shape with an allowable thickness using a coining process. In addition, in the case of a turbine blade in which the implanted portion forms a fork lance, the bottle through-hole portion is formed by a four-way machining method.

Although the regenerated surface obtained through these processing steps and its vicinity exhibits a somewhat hardened state,
A quenching treatment is carried out by heating and holding at 0° C. for about 0,000 hours, followed by rapid cooling, and a tempering treatment is carried out by heating at about 340° C. for about 0,000 hours and then slowly cooling.

Therefore, in the regenerated blade obtained through the above process, the carbide is finely and densely dispersed and precipitated, and the hardness value also increases, similar to the newly manufactured blade. Therefore, the deformation resistance at high temperatures increases and sufficient strength is maintained.

The at and ig4 diagrams respectively show changes in the depth of the erosion hole and the amount of erosion depending on the test time.
and E represent the sprayed layer thickness, respectively. FIG. 7 is a comparison of the near-deterioration hardness of 1dtJCr steel and the hardness of the regenerated build-up layer. In the figure, F indicates the regenerated build-up layer region, G indicates the Cr steel region, and H indicates the deteriorated region, respectively.

As is clear from these graphs, it can be seen that almost the same characteristic values as the newly manufactured blade can be obtained by performing the regeneration overlay treatment.

Note that the technology of thermally spraying Cr-Na alloy powder has been applied to ordinary thermal turbine parts, etc., but this type of technology is aimed at preventing wear and thermal shock, etc. Therefore, the present invention Their purpose is completely different.

Further, as shown in FIG. S, the present invention can also be applied to a turbine in which the implanted portion IO is in the form of a fork. In this case, a built-up layer is formed near the base of the fork/co.

As explained above, according to the present invention, turbine blades that have deteriorated over time can be easily and inexpensively regenerated, and even in the harsh environment of power generation plants, the regenerated blades have superior performance compared to new blades. Stable strength against high-speed rotation can be obtained without damaging the properties.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the shape of a general turbine blade.
The figure is a perspective view of a turbine blade, an explanatory diagram showing one aspect of the implementation of fI developed by J. Graphs showing changes,
Figure 1 is a graph showing changes in the amount of corrosion due to test time, Figure 1 is a graph comparing near-deterioration hardness of IJ/UCR steel and regenerated flesh layer hardness, Figure 1 shows another example of the present invention. 1 is a perspective view of a turbine blade with a fork-shaped implant; FIG. l...effective part, ko...implanted part, koho...first stage 7
Kuku part, DA... Regenerated sensual layer, 5... Processed surface. Applicant's agent Kiyoshi Inomata Figure 1 Figure 2

Claims (1)

[Claims] At least the part of the surface near the first stage hook part of the implanted part of the turbine blade that has deteriorated over time is removed, and this removed part is cleaned and subjected to a surface treatment, and then martensitic co-material alloy powder is applied. In addition to thermal spraying to form a fleshy layer, it is also molded into a shape with allowable wall thickness, and then reheated.
A method for regenerating turbine blades.