1 Introduction
The laser surface modification technology is rapidly developed in the 1970s after the emergence of the high power laser,
an optical, mechanical, electrical integration, high-tech. This process has a hardening effect, the high degree of
automation, simple operation, low energy consumption, high efficiency and minimal deformation of the workpiece, the basic
waste such as a number of advantages. The use of laser processed parts of the surface can change the physical structure,
chemical composition and microstructure of the part surface, thus changing the physical, chemical and mechanical properties
of the surface of the part, such as wear resistance, corrosion resistance and fatigue resistance, effectively solved Many
conventional heat treatment is still difficult to solve or resolve the bad parts of the surface properties of Therefore, in
countries around the world and achieved rapid development. Surface hardening treatment such as gray iron camshaft AVCOEVETT
Institute for Ford, the maximum deformation of <0.13mm. The same time, the diesel of nodular cast iron crankshaft journal and
the Po neck heat treatment, hardness 55 ~ 62HRC, without straightening treatment of the crankshaft, so that the crankshaft
heat treatment costs fell by 20%, and achieved good effect.
Laser surface hardening technology in China in recent years, before entering the use stage, but in certain areas or blank
paper describes the multi-function laser machine and its control system of Qingdao in hair laser technology Co., Ltd. jointly
developed in the automobile engine cylinder, cylinder liner, crankshaft, the laser surface hardening in the application.
Laser surface hardening principle
Laser surface hardening is also known as laser heat treatment. The principle is irradiated with a laser beam as heat
source engine to be to strengthen the surface, the surface is heated rapidly to metal phase transition temperature, when the
leave of the laser, the high-temperature surface heat quickly to the conductivity of metal matrix and the formation of self-
quenching, so that after treatment the surface layers of the formation of cryptocrystalline martensite with a hardness high,
thereby increasing the surface hardness, wear resistance and service life of parts.
Laser equipment and technology
3.1 The laser equipment
Laser surface hardening equipment includes three parts: 1.5kW CO2 laser generator, multi-function laser processing
machine and the computer control system.
Conventional methods and defects of the 3.2 car engine overhaul
Engine overhaul, primarily through the cylinder boring, grinding axes handle, the cylinder wall after repeated grinding,
surface hardness and reduced; crankshaft journal grinding round loss, the general need to re-grinding axes, for bearing.
Crankshaft journal surface hardness after several grinding lower, can not meet the requirements. Therefore, the conventional
approach of engine overhaul cycle is shorter.
3.3 car engine overhaul laser process
Laser processing of car engine overhaul process is conventional overhaul process with laser treatment. Laser heat
treatment is generally arranged in a semi-finished. Metal up to the reflectivity of the CO2 laser wavelength 10.6μm due to
room temperature for more than 80%, higher grinding machine smooth surface reflectivity, the reflection of the laser will
cause a lot of energy loss, therefore, before the laser heat treatment using pre-deposited absorbance Tu layer approach to
improve the absorption rate of the part surface of the laser. The coating can absorb electromagnetic COSCO infrared part of
the variety of metal or non-metallic oxides, graphite, carbon ink, phosphate is a better coating material.
没有评论:
发表评论