Measures to reduce quenching deformation of ferrul

2022-07-24
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Measures to reduce the quenching deformation of ferrule

measures to reduce the quenching deformation of ferrule Abstract: Discussion on the passivation technology of the cutting edge of the cutting tool in the Chinese electronic disk operating system sicp/al multiphase material cutting research on the chip deformation in the high-speed milling of titanium alloy in different media during the 11th Five Year Plan period, the development prospect of China's CNC machine tools the status quo of NC teaching in machining groove parts programming source program technical schools is the same as the improvement of advanced friction stir welding technology Analysis and treatment of brushless excitation fault of step motor classification of CNC machine tools what are the classification and main properties of guide oil? Understanding the common terms of VDI tool holder numerical control technology by looking at the pictures the application of diamond materials to high-performance cutting tools five axis linkage numerical control machining technology for large-scale axial-flow turbine blades (II) Realization of serial communication between microcomputer and multiple machining centers maintenance and repair techniques of CNC machine tools fault repair of inaccurate turntable return to zero a new tool material ceramic metal 98.07 cladding tool material multi-body dynamics simulation based on RecurDyn deformation variable diameter control heating temperature size organization speed bearing heat treatment deformation is roughly divided into one kind of diameter change VPE second average diameter change VDMP third plane change ape deformation is often The change of overlapping diameter is easy to produce momentum controlled quenching deformation. The main measures are to reduce the deformation factor of diameter momentum quenching. The original structure defect of bearing is caused by uneven distribution of carbide size caused by annealing

the deformation of the bearing ring after heat treatment can be roughly divided into three categories: the first category is diameter change (VPE), the second category is average diameter change (VDMP), and the third category is flatness change (APE). These three types of deformation often overlap each other, of which the diameter change is the most likely to occur, and the variation is also large. Therefore, to control the quenching deformation, we mainly try to reduce the diameter variation of the ring

I. factors of ring quenching deformation

a. the original structure defects in bearing steel and the uneven size and distribution of carbides in the structure after annealing will lead to quenching deformation

b. the greater the thermal stress and structural stress during quenching, the greater the quenching deformation. Thermal stress and organizational stress include: heating temperature, flow rate, reverse heating speed and uniformity, cooling speed and uniformity, cooling medium temperature, etc

c. the magnitude of residual stress during ring turning and the magnitude of diameter change after turning are related to the magnitude of change after quenching, and the direction is basically the same

II. Measures to reduce quenching deformation of ferrule

a. strictly control the cooling speed and improve the annealing quality. The cooling rate of spheroidizing annealing has a direct impact on the shape, size and dispersion of carbides, thus affecting the formulation of quenching and tempering processes, diameter variation and final mechanical properties. Therefore, while correctly formulating the annealing process, the cooling rate shall be strictly controlled at 10~25 ℃/h to prepare for the final heat treatment

b. strictly control the change of turning ferrule. It can be seen from the table that the diameter change after turning is closely related to quenching deformation. Therefore, generally, lower transformation rate is used. The larger the turning diameter variation, the larger the diameter variation after quenching, and the direction is basically the same. Therefore, in order to control the diameter change of quenching heating, we must first strictly control the diameter change of turning process

c. on the premise of meeting the hardness and mutual organization, the lower limit temperature shall be adopted for quenching heating as far as possible. For the crawler type furnace with three zone control furnace temperature, the temperature of the first zone shall be appropriately reduced and the heating time shall be extended to slow down the heating speed, ensure uniform heating of the ferrule and reduce the change of quenching diameter

table the relationship between lathe operator's variable momentum and quenching variable momentum

lathe operator's qualified rate of diameter variable momentum/% diameter variable momentum after quenching/mm average diameter variable momentum/mm exceeds the specified diameter variable rate/%

%980.08~0.350.134.23

750.08~0.480.2222.70

500.08~0.560.3045.00

table the influence of furnace temperature in the third zone on the service life of ferrule

No. furnace temperature in the third zone/℃ service life L50 damage ratio of circle/%

1790~ 5

2805~. 00

3815~. 00

the 2016 wards auto interiors conference held in Detroit showed the relationship between temperature and quenching variation

oil temperature/℃ diameter variation after quenching/mm out of tolerance%

450.03~0.358.3

600.03~0.282.5

750.03~0.191.2

d. precooling quenching was adopted, i.e. the first zone (heating zone) and the second zone (insulation zone) of the crawler furnace.Normal quenching temperature, Only reduce the furnace temperature in the third zone to 790~800 ℃, and then discharge the material into the oil tank for quenching. Ensure that the ferrule is heated more evenly on the furnace, left and right, which can not only reduce the change of ferrule diameter, but also improve the service life and other mechanical properties of the bearing (see table)

e. properly raising the temperature of quenching oil is conducive to controlling the quenching variation of general light series and ultra light series ferrules, and the quenching oil temperature should be controlled between 60~90 ℃. The table shows the measurement results of 7309/01, from which it can be seen that hot oil quenching has an obvious effect on reducing the change of ferrule diameter. In order to ensure the dimensional stability of the bearing, the ring after hot oil quenching shall be washed with cold antirust water to minimize the content of residual austenite in the ring

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