1Proposal of the problem The SH78Z drive shaft has five internal gears with internal splines, and the wall thickness of the gear ends is uneven. After the carburizing and quenching, the deformation of the upper and lower ends of the splines is inconsistent, the taper of the inner hole is serious, and the gear tooth direction changes. The amount is also large and the parts cannot be assembled. To this end, the method of reducing the spline distortion in the gear by improving the carburizing and quenching process is explored, and the above problems are well solved.
2 parts heat treatment technology requirements parts material is 16MnCr5, structure such as 1. surface hardness is 680780HV30 or 80.782.8HRA, core hardness is 3548HRC, effective hardened layer (550HV1) is 0.650.95mm deep, metallographic structure is evaluated according to QC/T262-1999 The surface hardness after grinding surface grinding is ≥ 680HV10, and the effective hardened layer (550HV1) after grinding is ≥0.5mm deep.
3 Process control and improvement 3.1 The original process is carburized and quenched by the German Aichelin multi-purpose furnace, and the product is placed in the furnace. The heat treatment process (for example) is: carburizing at 900±5°C, quenching at 855±5°C, using Humdenton 355 graded quenching oil, oil temperature 120°C. As a result of the process, the gear tooth direction variation is large, and the internal spline taper is severe, resulting in a product pass rate of only about 50.
3.2 Analysis of the cause of distortion The gear has an internal spline structure, and the effective thickness dimensions of the upper and lower ends of the aperture are quite different, resulting in a large difference in the deformation of each part of the gear.
During the quenching process, the end of the internal spline wall thickness increases, the unequal time of the inner and outer martensite transformation increases, the tissue stress increases, the thermal stress is relatively small, and the tissue stress predominates. Due to the volume expansion of the martensite structure, the core of the workpiece is compressed and the surface is pulled, which shows that the pore diameter increases. The thermal stress at the end of the thin wall is dominant, the core of the workpiece is pulled, the surface is pressed, and the pore diameter is expressed. Zoom out, so the inner spline is severely tapped up and down. At the same time, the uneven stress and strain caused by the uneven wall thickness also causes the tooth direction variation to be too large, which makes the adjustment of the heat front shaving process difficult.
3.3 After the improvement of the process, the process is as follows: the furnace is still installed by hanging method, carburized at 900±5°C, quenched at 845±5°C, and still graded quenching oil of Houghton 355, the oil temperature is 160°C. The test results and spline deformation after process improvement are listed.
After the improvement, the deformation of the process product is well controlled, and the pass rate is over 95.
3.4 Analysis of improvement measures Compared with the two heat treatment processes before and after improvement, it can be seen that two aspects have been improved. a. reduce the quenching temperature to relatively reduce the temperature difference of the parts cooled from high temperature, thereby reducing the distortion caused by the thermal stress of the carburized and quenched parts; b. increasing the temperature of the quenching oil to reduce the deformation, because the temperature of the oil increases, the fluidity The improvement makes it easier to evenly circulate the flow up and down, so as to facilitate uniform cooling of the parts and reduce deformation. After the process improves carburizing and quenching and tempering, the heat treatment quality of the gear as a whole is significantly improved.
4 Summary After the process improvement, the main technical parameters of the main five-speed gear are all met the technical requirements, and the heat treatment distortion becomes effective control. The distortion control of the carburizing and quenching heat treatment of the in-band spline and the effective thickness difference and the complicated structure of the gear can be achieved by appropriately reducing the carburizing and quenching temperature of the part and appropriately increasing the temperature of the quenching oil. As a popular application, the same process is used for the driven three-gear and the driven four-gear to solve the problem of deformation over-conversion, and good results have been achieved.
In daily maintenance, you often encounter replacement hardware equipment, some software for upgrading the machine tool, and equipment modification. In order to ensure that the machine can quickly recover after a fault occurs, effective and timely backup of the machine data is necessary. Moreover, the newer the backup of the machine tool, the more it can restore the original state of the machine tool, and win valuable time for the production to resume as soon as possible. Therefore, in actual production, it is necessary to regularly and regularly update the machine data.
Data backup of the machine tool also requires the cooperation of the machine state. That is to say, the data backup of the machine tool is preferably the same as the state of the machine tool when the backup is resumed in the future, so as to minimize the artificial adjustment of the workload of the machine tool and save time. At present, the common practice is to use the machine in-situ processing state as a backup opportunity. When backing up, the machine needs to be stopped in the in-situ state until the backup is completed.
Therefore, the backup of the machine tool should minimize the production time and shorten the stoppage.
Backup is the basic need for machine tool maintenance, especially for CNC machine tools. No backup or inaccurate backup, backup damage will bring considerable damage to the repair, and even cause machine defects. Therefore, for the backups made, we must ensure that they can be applied in practice and avoid losses during the storage process.
Deep Groove Ball Bearing is the most common type among ball bearings.The basic structure of deep groove Ball Bearing include an outer ring,an inner ring, a group of steel ball and a set of cage. Deep groove ball bearing has two types: single row and double rows bearings. 6900-2RS bearing is made of Chrome Steel, 6900-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination, 6900-2RS bearing is self lubricated bearing,6900-2RS bearing is already greased.
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Model Number
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6900 Series
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Brand Name
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NMN OR OEM
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Type
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Ball Bearing
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Structure
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Deep Groove
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Number of Row
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Single Row
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Seals Type
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OPEN ZZ 2RS
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Precision Rating
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P0 P6 P5 P4
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Specification
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6900 To 6910
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Steel Ball Amount
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9-14. Depend on the ball size
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Chamfer
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0.3-0.6mm
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Application
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Machine & Rolling Mill
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Certification
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ISO9001:2008
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ODM and OEM
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To order
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MOQ
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1 sample. Please contact with us for the lastest MOQ
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Payment Terms
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L/C, T/T, Western Untion, PayPal, Bank, etc.
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Packing
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Depend on the items. We also can packing it as your request
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Bearing number
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Bore
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O.D
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Width
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Chamfer
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Load Rating
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Ball complement
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Maximum Seed
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Kg/pc
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mm
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mm
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mm
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mm
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Dynamic
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Static
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No.
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Size
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Grease
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Oil
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6900
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10
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22
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6
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0.5
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2.7
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1.27
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12
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2.381
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2500
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32000
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0.009
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6901
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12
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24
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6
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0.5
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2.89
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1.46
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9
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3.5
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20000
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28000
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0.011
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6902
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15
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28
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6
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0.5
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4.1
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2.06
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10
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3.969
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19000
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26000
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0.016
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6903
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17
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30
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7
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0.5
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4.65
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2.58
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11
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3.969
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18000
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24000
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0.018
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6904
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20
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37
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7
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0.5
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6.4
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3.7
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11
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4.763
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17000
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22000
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0.036
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6905
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25
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42
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9
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0.5
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7.05
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4.56
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13
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4.763
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14000
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18000
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0.042
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6906
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30
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47
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9
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0.6
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7.25
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5
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14
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4.763
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12000
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16000
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0.148
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6907
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35
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55
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10
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0.6
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11.2
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7.45
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14
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5.556
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10000
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14000
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0.074
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6908
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40
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62
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12
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0.6
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14.5
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10.2
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14
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6.747
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8000
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12000
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0.11
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6909
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45
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68
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12
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0.6
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15.1
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11.2
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15
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6.747
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6000
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10000
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0.128
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6910
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50
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72
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12
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0.6
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15.6
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12.2
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16
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6.747
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4000
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8000
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0.132
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Product Photo:
Packing:
1 Industry package: 200pcs/plastic bag, 2000pcs /carbon , 50 cartons/pallet ,
2 Tube Package: 10PCS/tube,then put in Carton and Pallet
3 Single Package: 1PC/single box, then put in Carton and Pallet
And also we can pack according to your requirement.
Packing Photo:
Workshop:
Shippment:
Exhibition:
6900 Series Deep Groove Ball Bearing
6900 Series Deep Groove Ball Bearing,6900 Thin-Wall Ball Bearing,Thin-Wall Bearing 6900
Hebei Naimei Bearing Co., Ltd. , http://www.nmn-bearing.com