Be beneficial to the laser cladding repair technique of the gear that improves hardness and wear resistance
The application divides an application, the application number of original application: 201210351302.4, the applying date: 2012-09-20, the laser cladding repair technique > > of invention and created name < < gear.
technical field
The present invention relates to a kind of laser cladding method, especially a kind of laser melting coating restorative procedure of gear.
Background technology
The application of gear in all trades and professions is extremely extensive.Due to the performance characteristics of gear, when requiring its centre to guarantee toughness, the flank of tooth can reach hardness requirement, the requirement of strength while using to meet.The occlusal surface of gear requires high, and operation labor intensity is large, so can occur at first wearing and tearing and peel off at flank of tooth occlusal area, causes gear failure to be scrapped.Laser melting coating refers to that with different adding material modes, place selecteed coated material 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 extent of dilution, become the top coat of metallurgical binding with matrix, significantly improve the processing method of wear-resisting, anti-corrosion, heat-resisting, the anti-oxidant and electrical specification of substrate surface, thereby reach the object of surface modification or reparation.With built-up welding, spraying, plating and gas phase sediment-filled phase ratio, laser melting coating has that extent of dilution 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.How laser melting and coating technique being effectively applied to gear reparation, is the problem that those skilled in the art need to solve.
Chinese patent literature CN100557082C discloses a kind of carburization-like overloading tooth component tooth surface laser cladding powdered material and restorative procedure, powdered material comprises the material of following mass percent: 0.80-1.10%C, 7.50-9.00%Mn, 0.90-1.30%Cr, 0.20-0.35%Mo, 2.00-3.50%B, 2.50-3.50%Si, impurity P≤0.06%, impurity S≤0.04%, all the other are Fe, and granularity is-140 orders~+ 260 orders.The powdered material C too high levels that the method is selected, although weldability is better, easily cracks, and Cr, Mn, Mo content are lower in addition, although there is certain alloy strengthening effect, effect is still not obvious.
Chinese patent literature CN102021568A discloses a kind of method of laser hardening gear part, comprises the following steps: 1) according to prior art machining gears part, require the little 1.5mm of gear teeth Thickness Ratio design load; 2) gear is packed on laser reinforcing equipment, and gear is preheated to 400-500 ℃; 3) laser scanning is carried out in gear member surface, laser output power is 5kw, sweep velocity is 480mm/min, powder feeding rate is 18g/min, in a work step, powder feeding is synchronizeed and is carried out with laser melting coating, the metal-powder cladding that contains high-abrasive material, to gear surface, is formed to Laser Strengthening Layer the reserved polishing surplus of cladding thickness 3mm, and laser beam is 15 * 2.5 broadband rectangular light spots; Adopt minute three layers of mode that scans respectively cladding to carry out cladding.The method divides the powder of three kinds of heterogeneities of three layers of use to carry out cladding, and excess enthalpy is loaded down with trivial details, and its preheating temperature is higher, and laser output power is higher, can make whole gear excess Temperature produce thermal distortion.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind ofly carries out laser melting coating to gear surface, makes its size restoration to service requirements, and the hardness after repairing and wear resistance surpass the laser cladding repair technique of the gear of original performance.
In order to solve the problems of the technologies described above, the invention provides a kind of laser repairing process of gear, comprise the following steps:
A. gear surface is processed, gear is carried out to failure analysis;
B. gear is carried out the whole preheating of 80 ℃ to 120 ℃, gear position to be repaired is carried out the partial preheating of 180 ℃ to 220 ℃ simultaneously;
As the embodiment of optimizing, gear is carried out to the whole preheating of 100 ℃, gear position to be repaired is carried out the partial preheating of 200 ℃ simultaneously;
C. according to the failure analysis result of gear, Optimizing Process Parameters, carry out successively laser melting coating, lower-most point in teeth groove starts laser melting coating, the thickness of every layer of cladding layer is less than or equal to 0.4mm, later layer cladding layer covers on front one deck cladding layer, and the in the past edge of one deck cladding layer 4 mm to 6mm that stretch out of the edge of later layer cladding layer;
Adopt the mode of preset powder feeding, the fast-transverse-flow CO2 laser of take carries out lap connection scanning to gear as light source; Laser power is 1500W to 1900W, and absolute altitude is 260mm to 275mm, and spot size is 10mm * 1.8mm, and sweep velocity is 110mm/min to 130mm/min, and amount of lap is 6.5mm, and powder sending quantity is 12g/min to 18g/min; The component of the powdered alloy adopting and weight percent content are C≤0.5%, Cr:38% to 52%, and B:1.5% to 2.5%, Si:0.5% to 1.5%, all the other are Fe;
As the embodiment of optimizing, according to the failure analysis result of gear, Optimizing Process Parameters, carry out successively laser melting coating, lower-most point in teeth groove starts laser melting coating, the thickness of every layer of cladding layer is 0.4mm, and later layer cladding layer covers on front one deck cladding layer, and the in the past edge of one deck cladding layer 5mm that stretches out of the edge of later layer cladding layer;
Adopt the mode of preset powder feeding, the fast-transverse-flow CO2 laser of take carries out lap connection scanning to gear as light source; Laser power is 1700W, and absolute altitude is 270mm, and spot size is 10mm * 1.8mm, and sweep velocity is 120mm/min, and amount of lap is 6.5mm, and powder sending quantity is 15g/min; The component of the powdered alloy adopting and weight percent content are C:0.5%, Cr:45%, and B:2%, Si:1%, all the other are Fe;
D. detect.
For gear 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 gear, greasy dirt, corrosion; The size at each position of detection of gear, determines failure site and abrasion loss thereof, determines gear shifting quadrant texturing amount; Remove the fatigue layer 0.5mm to 2mm at gear failure position, and clean.
In order to guarantee the quality of the gear after reparation, a kind of preferred technical scheme is: above-mentioned steps D is detection of gear surface hardness; Detection of gear deflection; Gear surface is carried out to mechanical workout; 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 gear of the present invention, adopt homemade powdered alloy, in the composition of powdered alloy, by the strict content of controlling C, make it have good wettability, in cladding process, crack preventing; By adding appropriate B, Si, alloy to be formed after solidifying take austenite be main matrix, to meet its hardness requirement, and makes powdered alloy have good self-fluxing nature; Only utilize Cr element to carry out element strengthening to ferrous alloy, and in powdered alloy, the content of Cr element, apparently higher than prior art, is not affecting under the prerequisite of weldability, can significantly improve so that repair hardness and the wear resistance on backgear surface.
(2) laser repairing process of gear 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 velocity, amount of lap etc. are optimized, make the homogeneity of structure of cladding layer good, thickness and hardness even.This technique make the fusion rate of matrix at cladding layer and gear failure position high, in conjunction with closely, gear shifting quadrant texturing amount is little, gear surface does not have crackle and pore, hardness is high, has fabulous wear resistance.
(3) laser repairing process of gear of the present invention adopts gear to carry out whole preheating in 100 ℃ of left and right of low temperature, the flank of tooth carries out partial preheating in 200 ℃ of left and right of middle temperature, can avoid integral high-temperature preheating to make gear produce thermal distortion, the thermograde that has effectively reduced local surfacing, has reduced the stress in laser cladding process simultaneously.In addition, this process using is the method for laser melting coating successively, and the thickness of every layer of cladding layer is no more than 0.4mm, and later layer cladding layer covers front one deck cladding layer completely, and both edges are not overlapping, also can effectively prevent concentrating of stress.The gear that adopts this technique to repair, after laser melting coating without being incubated, more without annealing.
Embodiment
The concrete steps of the laser repairing process of the gear of the present embodiment are as follows:
A. gear surface to be repaired is processed, gear is carried out to failure analysis.
By removings such as the dust on gear, greasy dirt, corrosions; The size at each position of detection of gear, determines failure site and abrasion loss thereof, and whether check gear has metamorphism; By polishing, remove the fatigue layer 0.5mm at gear failure position, and clean.
B. gear is carried out to whole preheating, whole preheating temperature is 100 ℃, partial preheating is carried out in the position to be repaired of gear simultaneously, and local preheat temperature is 200 ℃.
C. according to the failure analysis result of gear, Optimizing Process Parameters, carry out successively laser melting coating, lower-most point in teeth groove starts laser melting coating, the thickness of every layer of cladding layer is 0.4mm, later layer cladding layer covers on front one deck cladding layer, and the edge of later layer cladding layer stretches out at the edge of one deck cladding layer in the past, and the distance of extension is 5mm.
Adopt the mode of preset powder feeding, the fast-transverse-flow CO2 laser of take carries out lap connection scanning to the position to be repaired of gear as light source.Laser power is 1700W, and absolute altitude (being that laser apparatus is from the distance between Substrate, absolute altitude=focal length+defocusing amount) is 270mm, and spot size is 10mm * 1.8mm, and sweep velocity is 120 mm/min, and amount of lap is 6.5mm, and powder sending quantity is 15g/min.The component of the powdered alloy adopting and weight percent content are C:0.5%, Cr:45%, and B:2%, Si:1%, all the other are Fe.
D., after reparation finishes, detect.
Detect surface hardness; Detect deflection; Gear surface is carried out to mechanical workout; Detect a flaw, detect and whether have pore, slag inclusion, slight crack etc. to affect the defect of gear mechanism 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 exhaustive without also giving all embodiments.And these belong to apparent variation that spirit of the present invention extended out or change still among protection scope of the present invention.