Background technology
TRANSIENT HIGH TEMPERATURE when grinding burn refers to due to grinding changes the workpiece surface local organization, makes the lower hardness of piece surface, and the phenomenon of oxidation stain occurs in some part of surface of the work.The grinding burn meeting reduces wearability, corrosion resistance and the fatigue strength of material.
The basic reason of grinding burn is the Grinding superheat of grinding moment generation, and the principal element of grinding burn is the generation of grinding heat and spreading out of of grinding heat, and the generation of grinding heat is emery wheel and grinding parameter, and spreading out of of grinding heat is by cutting fluid and cooling control.
Before improvement, the control of grinding burn is by frequent replacing cutting fluid, improves the cooling effectiveness of carburized gears.This control method can not be eliminated grinding burn fully, cause the carburized gears performance reduce and repeat to reprocess, more seriously cause carburized gears to be scrapped, extended the manufacturing cycle, increased manufacturing cost, the development work of restriction aero-engine model, affect production payment task.
Summary of the invention
The control method that the purpose of this invention is to provide the grinding burn of a kind of aero-engine carburized gears, overcome prior art and have the deficiency that properties of product are unstable, qualification rate is low and the workpiece manufacturing cycle is long, manufacturing cost is high.
The mechanism that at first the present invention analyzes aero-engine carburized gears grinding burn generation is as follows:
When the grinding area temperature significantly surpasses the temperature of steel, but still during lower than phase transition temperature, secondary troostite or tempered sorbite softening tissue appear in workpiece surface; When the grinding area temperature surpasses the phase transition temperature AC1 of steel, the workpiece surface regional area will become austenite, be subject to subsequently the cooling effect rapidly of cooling fluid and workpiece self heat conduction and secondary quenching martensite occurs in workpiece surface, tempered sorbite appears in inferior top layer.
To sum up, the present invention considers that the temperature that grinding produces is to cause the main cause of gear grinding burn, determines that the key of the new control method of aero-engine carburized gears grinding burn is: in gear manufacturing processes, rationally control the grinding thermal source.
Therefore, technical scheme of the present invention is: the control method of a kind of aero-engine carburized gears grinding burn specifically comprises the steps:
Step 1: corase grind, parameter is set to: grinding modification amount 0.02mm/ time, positive stroke mill amount 0.008mm, positive stroke feed rate 1800mm/min, revesal mill amount 0.008mm, revesal feed rate 1800mm/min, grinding speed 25m/min, every grinding 1 time, emery wheel is carried out to balance and throwing is repaiied, and cooling fluid is Castrol 600HC;
Step 2: half fine grinding, parameter is set to: grinding modification amount 0.01mm/ time, positive stroke mill amount 0.008mm, positive stroke feed rate 1800mm/min, revesal mill amount 0.008mm, revesal feed rate 1800mm/min, grinding speed 25m/min, every grinding 1 time, emery wheel is carried out to balance and throwing is repaiied, and cooling fluid is Castrol 600HC;
Step 3: fine grinding, parameter is set to: grinding modification amount 0.01mm/ time, positive stroke mill amount 0.008mm, positive stroke feed rate 1200mm/min, revesal mill amount 0.008mm, revesal feed rate 1200mm/min, grinding speed 25m/min, every grinding 1 time, emery wheel is carried out to balance and throwing is repaiied, and cooling fluid is Castrol 600HC;
Step 4: super grinding, parameter is set to: grinding modification amount 0.005mm/ time, positive stroke mill amount 0.005mm, positive stroke feed rate 600mm/min, revesal mill amount 0.005mm, revesal feed rate 1200mm/min, grinding speed 25m/min, every grinding 1 time, emery wheel is carried out to balance and throwing is repaiied, and cooling fluid is Castrol 600HC.
Beneficial effect of the present invention: use new control method, aero-engine carburized gears surface has no grinding burn.With former control method, compare: the positive revesal mill amount in the present invention reduces, and is difficult for producing a large amount of grinding heats; The cooling fluid viscosity reduces, and it is cooling and developing result is better.
The specific embodiment:
In the present embodiment by before improving and the method for grinding after improving contrasted, embody the validity of the method proposed in the present invention.
Grinding parameter before improving is in Table 1, and the grinding parameter after improvement is in Table 2, and the cooling fluid parameter before and after improving is in Table 3.
Grinding parameter before table 1 improves
Grinding parameter after table 2 improves
Cooling fluid parameter before and after table 3 improves
After improvement, from grinding parameter and cooling fluid two aspects, carry out contrast test, determine that the method for the present embodiment can effectively be controlled the carburized gears grinding burn.