CN1322892A

CN1322892A - Laser cladding process for crown damping surface of crowned gas turbine blade

Info

Publication number: CN1322892A
Application number: CN 00110392
Authority: CN
Inventors: 王茂才; 吴维; 白林祥; 华伟刚; 张峻巍
Original assignee: Institute of Metal Research of CAS
Current assignee: Institute of Metal Research of CAS
Priority date: 2000-05-10
Filing date: 2000-05-10
Publication date: 2001-11-21
Anticipated expiration: 2020-05-10
Also published as: CN1175954C

Abstract

The present invention relates to laser repair of metal surface. Onto one external mold in the shape corresponding to the shape of blade, special alloy powder is placed and radiated reciprocally and in vibrating scanning mode by laser beam to make heat treatment. The technological process is simple and needs no special equipment, and the repaired blade in high in strength and high in wear resistance.

Description

Laser cladding process for crown damping surface of crowned gas turbine blade

The invention belongs to a kind of metal covering table laser repair method.

At present, gas turbine is widely used on the devices such as space shuttle and terrestrial power generation, the high speed rotating shrouded blade, prevent blade leaf tenon that swing causes and stretch the big flexural stress of root segment by pushing against mutually between the hat, but because under high-temperature fuel gas and big centrifugal action, causing the surface of contact between the integral shroud is that damping area produces corrosion and fretting, make the blade of the initial assembling that closely cooperates take place loosening so that swing, the blade root fracture is had an accident, bring very big loss to personal safety and maintenance.

For solving above technical barrier, purpose of the present invention provides a kind of laser cladding process for crown damping surface of crowned gas turbine blade, can be used for the blade crown damping area is carried out stiff dough coating enhancement process, also can carry out the reparation that physical dimension is recovered, to reach long-lived purpose to the back wearing and tearing blade damping area reduced in size of being on active service.

Technological scheme of the present invention is achieved in that the integral shroud geometrical construction of turbine blade of gas turbine is varied, parallel hat, flexuose hat are arranged, be with the comb dentation hat of obturaging, the length width of damping area and inclination angle etc. are different mutually, the invention is characterized in can be to the blade of Any shape, the coating height can reach 2mm, hardness HRC38～60; The uniform metallurgy combination of coating and base material, how much of growths of coating and damping area are with shape and may command, and lay-up materials can be Co base corrosive wear resistant alloys and Ni base alloy; Can also the Co base or the ceramic particle or the fibre-reinforced composite material of Ni base, and rare earth modified Co base mixes gold copper-base alloy with Ni base height; The material of blade can be contain (At+Ti)＞＞the Ni base superalloy of %, realize the flawless coating, basic material of blade heated body in the laser cladding process is very little, filter layer only is several microns, composition dilution≤5% of coating, laser cladding processing throughput can reach 200 blade/skies, and product percent of pass is 100%, no waste product, its technological method is:

1. according to blade crown damping area geometrical shapes, adopt corresponding magnetic film mold to constitute static powder and protection blade by it; The material of mantle mold is refractory materials such as Cu, Co alloy, graphite, pottery and adopts water cooling; On static powder bed, be added with simultaneously rare earth modified self-fluxing alloyed powder and heat-resisting not with the mold of alloy powder reaction, and the positive burnt irradiation of photodissociation and the controlled cooling of mold wait and realize less irradiance power density, obtains the heat effect of the light of higher coating and coating to growth and base material minimum;

2. powder modes of emplacement: gluing connection, inspergation, briquet presets method, feeds powder diffraction method automatically, feeds a silk method;

3. alloy powder kind: Co base that rare earth or rare-earth oxide modified or ceramic particle/ceramic fiber strengthens or Ni base are from molten and non-self-fluxing alloy powder;

4. laser exposure: 0.5～5KW Co ₂Laser, 20～500,000 solid pulse and continuous lasers, sweep rate 2.5～8mm/s light beam comes and goes irradiation and oscillating scanning irradiation;

5. front and back heat treatment: 0～500 ℃ of pretreatment, 500～900 ℃ of reprocessings.

Advantage of the present invention: technological method is simple, and experimental implementation is easy, does not need what special equipment, uses on three kinds of new work engine blades, and intensity is good, and wear resistance is good, and wear-corrosion resistance has prolonged engine life greatly, and cost is low, has very big economic benefit.

The present invention's embodiment: use on the aeroengine on low-pressure turbine two grade blades; blade is the sawtooth hat; adopt yttrium modification Co base self-fluxing alloy powder; copper loose tool tackling; 500～800W laser beam irradiation; 100～350 ℃ of preheatings and 700 ℃ are with after annealing, and powdered compact presets, 2～5mm/s sweep rate; hydrogen shield; obtain even coating of thick 0.5～1.0mm and base material metallurgy combination, flawless, imporosity; nothing is mingled with; base material heat effect district is 3 μ m, and coating hardness HRC 48～50 is through the blade of the method reparation; by the flight of evaluation Heaven; flight test detected in 50 hours, and the new blade that the wear resistance of the blade after the laser cladding reparation is strengthened than plasma spraying coating has improved 1.5～2.0 times, and laser repairing has improved the life-span and the safety reliability of airplane engine significantly.

Claims

1. laser cladding process for crown damping surface of crowned gas turbine blade is characterized in that technological method is:

(1), adopt corresponding magnetic film mold to constitute static powder and protection blade by it according to blade crown damping area geometrical shapes; The material of mantle mold is refractory materials such as Cu, Co alloy, graphite, pottery and adopts water cooling; On static powder bed, be added with simultaneously rare earth modified self-fluxing alloyed powder and heat-resisting not with the mold of alloy powder reaction, and the positive burnt irradiation of photodissociation and the controlled cooling of mold wait and realize less irradiance power density, obtains the heat effect of the light of higher coating and coating to growth and base material minimum;

(2) powder modes of emplacement: gluing connection, inspergation, briquet presets method, feeds powder diffraction method automatically, feeds the silk method;

(3) alloy powder kind: Co base that rare earth or rare-earth oxide modified or ceramic particle/ceramic fiber strengthens or Ni base are from molten and non-self-fluxing alloy powder;

(4) laser exposure: 0.5～5KW Co ₂Laser, 20～500,000 solid pulse and continuous lasers, sweep rate 2.5～8mm/s light beam comes and goes irradiation and oscillating scanning irradiation;

(5) heat treatment before and after: 0～500 ℃ of pretreatment, 500～900 ℃ of reprocessings.