Gear coupling induction heating quenching process

2019 - gear coupling induction heating quenching process research 11 - 23 m palin ningxia bull-running industrial group co. , LTD. Heaven and earth gear coupling is a key components in coal mine with scraper conveyor equipment, conveyor is transmission of power from the reducer is passed to the sprocket wheel is an important part. The effect of gear coupling is a torque; Secondly, the release can be carried out when dividing, make the driving shaft and driven shaft transmission phase Angle. In order to improve the tooth contact conditions, improve the bearing capacity of the gear coupling, increase the allowable relative angular displacement of two axis, using drum tooth. Drum gear coupling is widely used in high speed, heavy machinery, has no axial channeling dynamic balance, transmission, shock vibration and noise characteristics of the machining process is more complex, the original spline using nitriding heat treatment processing, technical requirements for the nitriding hardness 550 ~ 650 hv, infiltration depth 0. 4 to 0. 6 mm, in order to improve the production efficiency, reduce production cost, on the premise of guarantee the quality of products, the gear coupling has carried on the induction heating quenching process. 1. Materials and methods ( 1) Test object selection as shown in figure 1 gear coupling structure, technical requirements for the tooth of 46 ~ 53 HRC hardness, the depth of hardening layer> 1 mm. Figure 1 gear coupling structure ( 2) Experiment process (1) the use of equipment: this test is nc vertical quenching machine tool and equipment parameters of the transformer quenching speed 1 ~ 10 mm/s, the workpiece rotation speed 0 ~ 100 r/min infinitely variable speed, 3 ~ 380 v power supply voltage, frequency 50 hz, using the spline sensor structure as shown in figure 2, the outer drum tooth the conventional structure, the heating coil is separated from water circle. (2) the internal spline, drum gear quenching process parameters: uniform clearance between sensors and artifacts, scanning quenching method, the heating frequency 7 ~ 10 KHZ, 80 ~ 120 kw power. The test results and analysis ( 1) Workpiece surface hardness after quenching using portable hardness tester on the Richter scale, the workpiece random parking three tooth addendum hardness, the result is shown in figure 3. Figure 3 gear coupling addendum surface hardness after quenching from test results, the workpiece quenching after internal spline, drum gear hardness are conform to technical requirements, internal spline, the outer drum gear crack detection, found no crack. （ 2) Deformation situation of induction hardening process after internal spline gear coupling, drum gear tooth deformation test, internal spline detection method from top to bottom for 3 points, the results are shown in figure 4. Outside the drum teeth detection method to detect the middle part, the result is shown in figure 5. Figure 4 internal spline quenching deformation figure 5 the drum gear quenching deformation from the test results, the internal spline deformation law for the inner hole shrinkage, shrinkage in 0. 25 ~ 0. 35 mm, and the tooth top big shrinkage, large deformation, the main reason is the internal spline of thin wall in order to make the depth of hardening layer meet technical requirements, when heated in the preheating process, so the deformation is larger, but overall is relatively uniform, according to the experience in front of the gear shaper will reserve deformation, after induction heating quenching size conform to the requirements of the design technology; Outside the drum gear change rule to bulk up 0. 04 ~ 0. 6 mm, small deformation, conform to the technical requirements. （ 3) Hardening layer depth detection figure 6 for the gear coupling with 4% nitric acid alcohol solution after induction hardening after etching the macro picture, the left side as the outer drum gear, right for internal spline, hardness testing for corrosion black areas, including addendum applying the rockwell hardness tester, hardness testing of hardness is 52 addendum 5 mm. 5 HRC, detect contour line near quenching area parts hardness of 40. 9 HRC, the black part as the hardened area. For outer drum gear, the tooth position basic hardening, for internal spline, due to the large modulus, tooth parts not hardening. In order to more accurate measurement of tooth root part of the effective depth of hardening layer, according to GB/T5617 - to root positions After the induction hardening or flame hardening of 2005 steel testing method for determination of the effective depth of hardening layer, the results are shown in figure 7. From figure 7 analysis, internal spline tooth root parts effective hardening layer depth of 1. 25 mm, outside the drum tooth effective hardening layer depth of 1. 18 mm, meet the technical requirements. Figure 6 gear coupling induction heating quenching after the macro picture tooth root position microhardness trend (figure 7 4) Microstructure of the inspection according to JB/T9204 - induction quenching organization 2008 steel induction quenching test metallographic examination standard method, according to GB/T13320 - matrix organization 2007 the microstructure of the steel die forgings ratings figure and assessment method for inspection. Metallographic organization as shown in figure 8, shown in figure 9. Figure 8 quenching parts organization evaluation level for level 5, belong to the fine martensite, organizational accord with a standard to ask. Figure 9 for tempering sorbite organization level for level 1, is the normal tissue after tempering treatment. Figure 8 parts of the hardening layer microstructure figure 9 matrix was 3. Epilogue ( 1) On gear coupling by induction heating quenching process instead of the original nitriding process method is feasible, the induction heating quenching hardness, effective hardening layer depth and deformation after satisfies the requirement of drawing technology, microstructure in accordance with JB/T9204 - 2008 steel induction hardening metallographic examination standard requirements. （ 2) Compared with the original nitriding process, the production cycle shorten 60 h and production efficiency increased by 30%, reduce production costs $300 per piece. Source: the metal processing ( Hot working) 13, 2016