Laser melting quenching process capable of greatly increasing RuT300 surface hardness

A laser fusion and surface hardness technology, applied in the field of metal surface modification, can solve the problems of inability to meet the high performance requirements of vermicular graphite cast iron parts, low surface hardness, short service life, etc., to facilitate process control and adjustment, workpiece deformation, etc. Small, the effect of improving the service life

Active Publication Date: 2013-04-03
北方材料科学与工程研究院有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, with the continuous improvement of domestic and foreign automobiles, ships and their engines for assemblies and components, for key components working under severe impact wear, thermal alternating load and corrosive medium conditions, vermicular graphite cast iron and other cast iron The material also has the problems of low surface hardness, poor wea...

Method used

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  • Laser melting quenching process capable of greatly increasing RuT300 surface hardness
  • Laser melting quenching process capable of greatly increasing RuT300 surface hardness

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] (A) Take three RuT300 samples, 1-1, 1-2 and 1-3, and smooth the surface of the sample at the same time: the surface is machined, and the roughness Ra requires 3.2.

[0028] (B) Surface pretreatment: The surface of the RuT300 parts treated in (a) is first polished with sandpaper to remove surface rust, and then cleaned with acetone.

[0029] (C) Set the angle between the laser beam and the normal of the workpiece surface. The experimental material specification is: 30×80×10 (mm) plate, the workpiece is fixed, the machine tool is linearly scanned, and the normal angle is set to 0°.

[0030] (D) Set the quenching process parameters:

[0031] The laser power rise time is 0s, the laser power is 900W, and the decay time is 3s; the laser beam scanning speed is 150mm / min; the defocus is +15mm; the protective gas is Ar 2 , The air flow is: 5L / min.

[0032] (E), laser melting and quenching.

[0033] (F) After laser melting and quenching, the workpiece is cooled to room temperature and then ...

Embodiment 2

[0037] (A) Take the other three RuT300 samples 2-1, 2-2 and 2-3, and flatten the surface of the RuT300 sample: the surface is machined, and the roughness Ra requires 4.8.

[0038] (B) Surface pretreatment: first polish the surface of RuT300 parts treated with (a) with sandpaper to remove surface rust, and then wipe it with acetone.

[0039] (C) Set the angle between the laser beam and the normal of the workpiece surface. The experimental material specification is: Φ36 ring, the processing surface is 45° inclined plane, adjust the processing surface to be perpendicular to the beam, the beam does not move, and the workpiece rotates with the spindle at a constant speed. The normal angle is 15°.

[0040] (D) Set the quenching process parameters:

[0041] The laser power rise time is 3s, the laser power is 1300W, the decay time is 1s, and the overlap amount is 1.5s; the scanning speed of the laser beam is 300mm / min; the defocus is +35mm; the shielding gas is N 2 , The air flow is 10L / min. ...

Embodiment 3

[0047] (A) The surface of the three RuT300 parts with sample numbers 3-1, 3-2 and 3-3 is flattened: the surface is machined, and the roughness Ra requires 5.6.

[0048] (B) Surface pretreatment: first polish the surface of RuT300 parts treated with (a) with sandpaper to remove surface rust, and then wipe it with acetone.

[0049] (C) Set the angle between the laser beam and the normal of the surface of the workpiece according to the surface form of the part to be processed. After the workpiece is clamped, the surface to be processed cannot be adjusted to the position perpendicular to the beam. During the experiment, the workpiece does not move and the machine tool moves. The angle between the straight line and the normal is set to 30°.

[0050] (D) Set the quenching process parameters as required:

[0051] The laser power rise time is 3s, the laser power is 2200W, and the decay time is 4s; the scanning speed of the laser beam is 480mm / min; the defocusing amount is: +75mm; the shieldin...

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Abstract

The invention relates to a laser melting quenching process capable of greatly increasing the RuT300 surface hardness. The laser melting quenching process is characterized by comprising the following steps of carrying out flattening treatment and surface pretreatment on the surface of a to-be-treated RuT300 workpiece, setting the included angle of the transmitting direction of a laser beam and the normal of the treated surface of the workpiece at 0-45 DEG, carrying out laser melting quenching and carrying out liquid penetrant test immediately after the workpiece is cooled to the room temperature after the laser melting quenching. Compared with the prior art, the process disclosed by the invention has advantages that the operation is simple, the efficiency is high and the corresponding surface blackening treatment is not needed, so that the processing efficiency is increased; the workpiece deformation is little, so that the application of high-precision parts or dies can be satisfied; and the repeatability is good, the crater crack problem is well solved and a laser quenching zone with no crack or air hole on the surface is obtained, so that the surface fatigue resistance of the parts can be greatly increased and the service life of the parts is prolonged.

Description

Technical field [0001] The invention relates to the technical field of metal surface modification, and specifically refers to a laser melting and quenching process that can greatly improve the surface hardness of RuT300. Background technique [0002] Vermicular graphite cast iron has high room temperature strength, high temperature strength, good casting performance, fatigue reliability, weldability and low production cost, and it has low environmental pollution during the production process and has good comprehensive performance. Has achieved rapid development at home and abroad. Compared with ordinary gray cast iron, vermicular graphite cast iron has higher hardness and can produce thinner and lighter engine parts such as cylinder heads and valve seats; in addition, it can effectively improve engine efficiency and reduce engine emissions. , The use of higher hardness vermicular graphite cast iron valve seat in the manufacture of cylinder head can withstand higher combustion ch...

Claims

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Application Information

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IPC IPC(8): C21D1/09C21D5/00
Inventor 马冰郑子云冯胜强刘光潘力平刘红伟刘琴石磊马志华
Owner 北方材料科学与工程研究院有限公司
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