Method for thermally spraying molybdenum coating on axial surface of crank shaft

A technology of thermal spraying and molybdenum coating, which is applied in coating, metal material coating process, fusion spraying, etc., can solve the problems of insufficient oxidation, decreased performance of Mo coating, low hardness of Mo coating, etc.

Active Publication Date: 2013-04-03
GUANGDONG INST OF NEW MATERIALS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the spraying parameters do not match, the oxidation process will be insufficient, the hardness of the Mo coating will be lower, and the porosity will be lower, which will inevitably lead to a decline in the performance of the Mo coating.

Method used

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  • Method for thermally spraying molybdenum coating on axial surface of crank shaft

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] GTV MF-P-1500 high-energy plasma spraying equipment was used to spray Mo coating on the crankshaft with a diameter of φ500mm.

[0040] The spray parameters are:

[0041] Spraying distance: 130(mm).

[0042] Spray gun nozzle: Laval nozzle

[0043] Current: 650 (A)

[0044] Ar gas: 47 (l / min)

[0045] Hydrogen: 10(l / min)

[0046] Powder feeding volume: 40±3(g / min)

[0047] Cooling air pressure: 3MPa

[0048] After spraying, the porosity of the coating reaches 8.3%. The pulling force reaches 41MPa. The oxide content is 13.8%, and it is MoO 2 . In the normal temperature friction and wear test of the Mo coating under the pressure of 80N and oil immersion, the friction coefficient is 0.164. Microhardness is Hv 0.3 561. The coated workpiece has good performance, and its service life is more than 3 times that of the unsprayed Mo coating.

Embodiment 2

[0050] The flame spraying equipment is used to spray the Mo coating with the Mo wire spray gun, and the diameter of the crankshaft is φ500mm.

[0051] The spray parameters are:

[0052] Spray gun: gas wire spray gun

[0053] Oxygen: 0.8m 3 / h

[0054] Acetylene: 0.5m 3 / h

[0055] Compressed air: 5Kg / cm3

[0056] Spray distance: 90-110mm

[0057] After spraying, the porosity of the coating is 10%, the tensile stress of the coating is 34MPa, and the microhardness of the coating is Hv 0.3 581. The coating has good performance, and the service life of the workpiece is increased by 3 times compared with that before treatment.

Embodiment 3

[0059] Use GTV MF-P-1500 high-energy plasma spraying equipment to spray Mo coating on the crankshaft with a diameter of φ360mm.

[0060] The spray parameters are:

[0061] Spraying distance: 130(mm).

[0062] Spray gun nozzle: Laval nozzle

[0063] Current: 600 (A)

[0064] Ar gas: 45(l / min)

[0065] Hydrogen: 8(l / min)

[0066] Powder feeding volume: 40±3(g / min)

[0067] Cooling air pressure: 4MPa

[0068] After spraying the coating, the porosity reaches 9%. The pulling force reaches 43MPa. The oxide content is 15.2%, and it is MoO 2 . In the normal temperature friction and wear test of the Mo coating under the pressure of 80N and oil immersion, the friction coefficient is 0.168. Microhardness is Hv 0.3 544. The coated workpiece has good performance, and its service life is more than 3 times that of the unsprayed Mo coating.

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Abstract

The invention discloses a method for thermally spraying a molybdenum coating on axial surface of a crank shaft. The method comprises the steps of firstly, cleaning and protecting the spraying position of the crank shaft so as to carry out surface sandblasting treatment, installing and balancing according to the specification of the crank shaft, and checking and adjusting technological parameters to carry out thermal spraying on the axial surface of a hydraulic crank shaft. A method for rigidly controlling the thermal spraying technological parameters so as to control the process oxidization degree is adopted, so that the sprayed molybdenum (Mo) coating has better texture structure and performance. Process oxidization in the spraying process can be reasonably controlled by controlling the technological parameters in the spraying process; the oxide in the Mo coating can be controlled within the range of 13-19%; the hardness of the Mo coating is more than Hv0.3500; the porosity of the Mo coating can be up to 7-10%; the normal-temperature abrasion coefficient of the Mo coating under the condition of 80N of immersion oil is smaller than 0.2, and the utilization rate of the Mo powder can be up to over 80% in the spraying process. Therefore, efficient utilization is achieved.

Description

technical field [0001] The invention relates to a method for thermally spraying a molybdenum coating on the shaft surface of a crankshaft, in particular to a method for thermally spraying a molybdenum coating on the crankshaft surface of a hydraulic motor. Background technique [0002] Molybdenum (Mo) is a refractory metal with low metal activity. It has a high melting point and boiling point. It has good corrosion resistance to acids, alkalis and molten metals, and has good thermal and electrical conductivity. Molybdenum is also a good anti-friction material, which can effectively reduce the friction coefficient. In the case where it is difficult to use liquid lubrication, thermal spraying molybdenum coating can reduce friction and prolong life. [0003] The crankshaft shaft surfaces used in the market such as hydraulic motors are basically not treated or only simply electroplated, which has poor wear resistance and corrosion resistance, which is not conducive to the normal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C4/02C23C4/08C23C4/12C23C4/134
Inventor 刘自敬朱晖朝陈志坤谢少阳叶春浓黄芳珍张忠诚黄建王枫朱霞高倪伟邦雷运生
Owner GUANGDONG INST OF NEW MATERIALS
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