In the goods manufacture and repair, the use of the ecologically harmful and dangerous for the man´s health technologies is inevitable. This negative influence manifests in the form of the manufacturing industry wastes (metal chips at grinding, metal dust at grinding and drilling out repaired goods to achieve repairing dimension, etc.) Besides, being in up-to-date use methods of the goods are not ecological themselves manufacturing and repairing.
In modern mechanical engineering cyanidation (nitro - cementation) widely used for details working surfaces hardening. The essence of this treatment method includes details surface layer saturation by carbon and nitrogen compounds. The nitro - cementation disadvantage is the higher cost of the process as compared with other types of the chemical - thermal treatment. It´s caused by the necessity of the strict industrial safety rules observance because of cyanic salts (NaCN and KCN) or gas (CH4 + NH3 ) high toxicity. Also, expensive equipment for performing this process is necessary needed (hermetic containers, atmosphere - harmful matter content control gages, an isolated ventilation system, a special harmful matter protection for workers, etc.)
It is necessary to emphasis especially the negative influence of this method, on the environment on in thee other words, the low ecological safety of it. This influence manifests in such important goods life cycle phases as the manufacture, the repair, the maintenance and the utilization. Owing to this there is the necessity of such new technologies working out to provide and support the goods (machines, in particular) life cycle with ecological safety.
In Volgograd state architectural-building university the methods of contacting machines parts surfaces hardening with laser technologies application were worked out. The following laser treatment advantages were brought to light during the investigation:
1. High energy concentration gives the opportunity to treat (according to the special program, id needed) only small volume of undersurface zone without the other volume heating and its structure and properties breaking. This minimizes details war ping owing to residual tension.
2. High speeds of treated material heating and cooling down. This enables to create different structures of the surface working layer from usual tempered structure to high dispersion and even amorphous structure.
3. Possibility of the massive and large - scale details treatment.
4. Absence of the mechanical forces applied to the details during the treatment. This enables to treat thin and breakable details.
5. Respective process automation simplicity and harmful wastes absence.
In addition, it is necessary to mention the more hardened zone depth at the laser treatment (h=1-1,5 mm) as compared with the cyanidation (h=0.6-1,0 mm).
The surface laser treatment technology gives an opportunity to modify the active surface layer properties. Such working condition of the thermal treatment are selected that surface hardening is performed without deep material melting. This technology was named the selective laser hardening because there wasn´t done the complete treatment of entire surface, but only the thermal-treatment "tracks"were performed. Depending on the direction and configuration of these "tracks" it is possible to increase (immovable junctions, for example) or to reduce (journal bearings and machine - tools slides, for example) the friction coefficient.
The experimental results affirmed these technologies effectiveness. It is determined that the life cycle of the machine treated with this mode use increases at the expense of the phase of the application and the utilization extension. The service life in this way increases on 30-40% depending on the working conditions.
For example, the main service life criterion for the bolt junction is the resistance to shear and deformation. Fig.1 reveals the laser treatment influence on the tangential stiffness of junction and the resistance to shear. The tangential safeness is a function of maximum shear strain 
before sliding initiates. The tangential stiffness is a reverse function of the asperities presliding shear deformation. The harmful matter atmosphere apportionment is 8 times lower as compared with the cyanidation.
Figure 1. Presliding deformation ε versus shear strain τ for various volumes of normal pressures (plane contact of metal parts)
_________ no laser treatment;
- - - - - - - - after laser hardening;
1 - σ = 1 MPa; 2 - σ = 2 MPa; 3 - σ = 3 MPa.
These technologies application gives the opportunity of the more through realization of the life cycle control main functions: the quality guaranteeing (the phases of the goods manufacture, the application, the utilization), the making (the goods technical preparation and the manufacture), the maintenance (the application and the utilization phase), etc.
Thus, the investigations witness that the laser technologies can become one of the links in the measures system for ecological safety providing not only in the engineering industry, but also in all industry branches associated with the goods life cycle support.
Библиографическая ссылка
Burlachenko O. ECOLOGICALLY SAFE TECHNOLOGIES FOR GOODS LIFE CYCLE SUPPORT // European Journal of Natural History. – 2010. – № 3. – С. 11-13;URL: https://world-science.ru/ru/article/view?id=20996 (дата обращения: 22.11.2024).