The laser cladding repair technique of the valve seat that hardness is high and deflection is little
The application is divisional application, the application number of original application: 201210351281.6, and the applying date: 2012-09-20, invention and created name " laser cladding repair technique of valve seat ".
Technical field
The present invention relates to a kind of laser cladding method, especially a kind of laser melting coating restorative procedure of valve seat.
Background technology
The valve seat using in petroleum chemical industry, due to its operating characteristic, requires higher to anti-corrosion, wearability. At present, the equipment great majority of domestic petrochemical enterprise are import equipments, will drop into very large cost and go abroad and order goods or maintenance when wearing and tearing, burn into when vaporization appears in valve seat, have increased burden economically to enterprise.
Laser melting coating refers to that place selecteed coating material with different adding material modes on by cladding matrix surface makes it to melt with matrix surface skim through laser irradiation simultaneously, and it is extremely low after rapid solidification, to form dilution factor, become the face coat of metallurgical binding with matrix, significantly improve the process of wear-resisting, anti-corrosion, heat-resisting, the anti-oxidant and electrical characteristic of substrate surface, thereby reach the object of surface modification or reparation. With built-up welding, spraying, plating and gas phase sedimentary facies ratio, laser melting coating has that dilution factor is little, dense structure, coating and matrix is combined, be applicable to that cladding material is many, granularity and the feature such as content is large.
Owing to repairing the valve seat of petroleum chemical industry, the wettability to cladding layer, wearability, corrosion resistance all require high, so how laser melting and coating technique is effectively applied to valve seat reparation, are the problems that those skilled in the art need to solve.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of carries out laser melting coating to valve base surface, makes its size restoration to instructions for use, and corrosion resistance after repairing and wearability all exceed the laser cladding repair technique of the valve seat of original performance.
In order to solve the problems of the technologies described above, the invention provides a kind of laser repairing process of valve seat, comprise the following steps:
A. valve base surface is processed, valve seat is carried out to failure analysis;
B. according to the failure analysis result of valve seat, Optimizing Process Parameters, carries out laser melting coating;
Adopt the mode of preset powder feeding, taking fast-transverse-flow CO2 laser as light source, valve seat is carried out to lap connection scanning, laser power is 1700W to 2100W, absolute altitude is 260mm to 275mm, spot size is 10mm × 1.8mm, sweep speed is 110mm/min to 130mm/min, and amount of lap is 6.5mm, and powder sending quantity is 10g/min to 15g/min; The component of the alloy powder adopting and weight percent content are C:0.5% to 1%, Cr:19% to 23%, and B:1.5% to 2%, Si:1% to 3%, Mo:0.05% to 0.5%, Mn:0.05% to 0.5%, W:7% to 9%, Ni:2.5% to 4%, all the other are Co;
As the embodiment of optimizing, adopt the mode of preset powder feeding, taking fast-transverse-flow CO2 laser as light source, valve seat is carried out to lap connection scanning, laser power is 1900W, absolute altitude is 270mm, and spot size is 10mm × 1.8mm, and sweep speed is 120mm/min, amount of lap is 6.5mm, and powder sending quantity is 12g/min; The component of the alloy powder adopting and weight percent content are C:1%, Cr:21%, and B:2%, Si:2%, Mo:0.2%, Mn:0.2%, W:8%, Ni:3%, all the other are Co;
C. detect.
For valve seat to be repaired is repaired successfully in the process of laser melting coating, and obtain better repairing effect, a kind of preferred technical scheme is: above-mentioned steps A removes the dust on valve seat, greasy dirt, corrosion; Detect the size at the each position of valve seat, determine failure site and wear extent thereof, determine valve seat deflection; Remove the fatigue layer 0.5mm to 2mm of valve seat failure site, and clean.
In order to ensure the quality of the valve seat after reparation, a kind of preferred technical scheme is: above-mentioned steps C detects valve base surface hardness; Detect valve seat deflection; Valve base surface is carried out to machining; Detect a flaw, verification.
Technique scheme of the present invention has the following advantages compared to existing technology:
(1) in the laser repairing process of valve seat of the present invention, adopt homemade Co-based alloy powder, in the composition of alloy powder, by the strict content of controlling C, make it have good wetability, in cladding process, crack and pore preventing; In alloy powder, by adding appropriate B, Si, alloy is formed taking austenite as main matrix after solidifying simultaneously, to meet its hardness requirement, and make alloy powder there is good self-fluxing nature; Appropriate Cr, Mo, Mn, W, Ni element have carried out alloy strengthening to cobalt-base alloys in addition, do not affecting under the prerequisite of weldability, can make valve seat corrosion resistance and wearability after repairing greatly improve, and hardness can reach 50HRC to 55HRC and meet instructions for use.
(2) laser repairing process of valve seat of the present invention adopts broad band laser bundle, and efficiency is higher; Adopt the mode of preset powder feeding, strictly control powder sending quantity, and laser power, sweep speed, amount of lap etc. are optimized, make the structural homogenity of cladding layer good, thickness and hardness even. This technique make the fusion rate of matrix of cladding layer and valve seat failure site high, in conjunction with closely, valve seat deflection is little, valve base surface does not have crackle and pore, hardness is high, has fabulous wearability.
(3) laser repairing process of valve seat of the present invention is because adopted alloy powder weldability is good, and the technological parameter of laser melting coating is optimized, laser melting coating is before without preheating, laser melting coating is afterwards without being incubated, more without annealing, ensureing that under the prerequisite of repairing quality, technological process is relatively succinct.
Detailed description of the invention
The concrete steps of the laser repairing process of the valve seat of the present embodiment are as follows:
A. valve base surface to be repaired is processed, valve seat is carried out to failure analysis.
By removings such as the dust on valve seat, greasy dirt, corrosions; Detect the size at the each position of valve seat, determine failure site and wear extent thereof, whether inspection valve seat has metaboly; Remove the fatigue layer 0.5mm of valve seat failure site by polishing, and clean.
B. according to the failure analysis result of valve seat, Optimizing Process Parameters, carries out laser melting coating.
Adopt the mode of preset powder feeding, lap connection scanning is carried out at position to be repaired taking fast-transverse-flow CO2 laser as light source to valve seat, laser power is 1900W, absolute altitude (is that laser instrument is from the distance between agent, absolute altitude=focal length+defocusing amount) be 270mm, spot size is 10mm × 1.8mm, sweep speed is 120mm/min, amount of lap is 6.5mm, and powder sending quantity is 12g/min. The component of the alloy powder adopting and weight percent content are C:1%, Cr:21%, and B:2%, Si:2%, Mo:0.2%, Mn:0.2%, W:8%, Ni:3%, all the other are Co.
C., after reparation finishes, detect.
Detect case hardness; Detect deflection; Valve base surface is carried out to machining; Detect a flaw, detect and whether have pore, slag inclusion, slight crack etc. to affect the defect of valve seat mechanical performance; Carry out verification, whether quality inspection is qualified.
Obviously, above-described embodiment is only for example of the present invention is clearly described, and is not the restriction to embodiments of the present invention. For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description. Here without also giving exhaustive to all embodiments. And these belong to apparent variation that spirit of the present invention extended out or variation still among protection scope of the present invention.