The role of technology in treating surfaces has always been meeting the requirements for following operations expected by a specific production process. In this phase, the efforts of system manufacturers used to focus on designing solutions able to offer high productivity, consistency of results, reduced consumption (water, energy and treatment products), low installation costs, simplifying maintenance and contained and intelligent use of the space. Nowadays, it is no longer only the case. The rules imposed by modern industry have changed and the surface treatment sector is undergoing a significant phase of transformation. The current situation actually sees strong growth in the demand for technologies with features increasingly more driven in terms of quality, efficiency, automation and sophistication and, at the same time, system manufacturers are required to deal with strict regulations regarding the environment and workplace health and safety. It is no longer just a system, but a system that, in addition to performing its primary function as well as possible, must be able to integrate into a production cycle, characterised by a predefined work management and advanced technologies that respect the environment and operator safety. TRITON has accepted the challenge, investing in research, design and production of solutions which help keep operators of the sector attentive to the importance of complying with regulations and, most importantly, respecting the environment.
With the term "washing", we refer to a process comprising one or more operations to remove and eliminate from the surface of industrial products, and with the required degree of cleaning, the contaminant substances of an organic and inorganic nature, through operations of a chemical and physical (mechanical, thermal and electrical) nature combined in different ways. The washing process is generally understood to be constituted by several operations, each of which has its own precise function. In principle, the phases can be broken down into: pre-washing, washing, rinsing and drying. More and more, today, the role of washing is to satisfy the cleaning requirements of the components, as defined by the parameters of industrial processes. Manufacturers must be able to wash parts with high-precision, with different characteristics and with different quality levels, depending on their intended use, and sometimes even depending on the work area of the part. In some sectors, such requirements are extremely stringent, actually setting quantitatively and dimensionally the level of residual contaminant particles. This is the case with automotive, aeronautical, hydraulic and general engineering manufacturing sector components that operate with high production volumes, where TRITON has successfully supplied systems to resolve cleaning problems of difficult parts and those increasingly more complex shapes.
Protection is a process designed to slow or completely prevent the corrosion reaction of metals. This phenomenon consists of the formation of a thin film that adheres perfectly to the part of the piece surface in contact with the aggressive environment (for example water or air). For this protection to take place, this film must hinder the spread of oxidising agents (usually oxygen), therefore it must be "compact", in other words, dense and not very porous. It must be also applied to metals that have undergone a previous treatment, such as degreasing or pickling.
The range includes a variety of protections for metals suitable for any situation, either wet or marine atmospheres. The protections are divided into oil, fluid and without residues, waxy, covering, peelable and water-based products.
Passivation is the phenomenon of a chemical nature capable of rendering metal surfaces less susceptible (precisely that, passive) to environmental factors such as air or water and in particular to their corrosive effect. It consists of the formation of a thin corrosion protective outer layer (even to the order of a few nanometres), which can be obtained by applying a micro coating. In this way, the metal surfaces avoid structural damage due to deep oxidation and preserve the external appearance.
Surface preparation is a process that leads to the modification of the chemical composition of a metal's surface, with resulting connected modification of its chemical-physical properties. It is also called surface conversion process. Phosphating processes belong to surface conversion; chroming, phosphochroming, fluorination and fluoride glass processing. Phosphating is a chemical conversion process applicable on different metal substrates, such as iron, steel, coated steel and aluminium, characterised by the reaction between phosphoric acid and the metal surface in question. Phosphating has a great practical importance because it is widely used in the preparation of metal surfaces for painting, although there is an interesting, albeit limited, application for the temporary passivation of ferrous surfaces, both as an end in itself and followed by subsequent oiling. We can mention: iron phosphating, zinc/manganese phosphating, alkaline phosphating, degreasing phosphating: with reference to double phosphating and degreasing action of the solution.
Aluminium chroming, phosphochroming, fluorination and fluoride glass processing: as aluminium is an amphoteric metal, therefore capable of being solubilised with hydrogen formation in either alkaline or acidic conditions, it is possible to deposit coatings on it in both conditions.
Phosphate coatings are nearly always a re-treatment depending on the intended application; two of these, rinsing with demineralised water and passivation, although used in practice almost only in pre-painting, however, nevertheless have a general character.
Treatment with demineralised water is carried out when it is deemed appropriate to remove all traces of water soluble salts from the coating, such as, for example, chlorides that are particularly harmful because they have a high affinity with iron and are oxidation catalysts.
Passivation consists of a post-treatment capable of sealing the residual porosity of the coating, thereby increasing the resistance to corrosion of the system.
Before performing a galvanic treatment or a chemical conversion, before painting or even as a simple finishing operation of a metallic product before final assembly or sale. The removal of greasy, fatty and dirty particulates is commonly called "degreasing"; while the removal of oxides is called "pickling".
Degreasing and pickling are often associated or contiguous in industrial activities, however, when these are "chemically" performed, the two processes are very different. In the former, removal takes place in most cases through physical mechanisms (emulsification, use of thermal or mechanical energy); in the latter actual chemical reactions involved to dissolve oxides and the corrosion of the basic metal. Often in practice, the term "degreasing" is used in place of "cleaning" or "decontamination" which, while not entirely accurate, conveys well the fundamental purpose of the process: to eliminate from the surface of the metal, mineral and/or natural oils and fats sometimes present in large quantities. By way of example, here are some of the most common surface pollutants of metals, usually encountered in workshop activities, however it must be underlined that their variability is almost infinite.
- Oxides: these are removed by pickling; oxides can be inconsistent: rust on carbon steel, white oxide on aluminium etc., oxides from thermal treatment: calamine on carbon steel, welding oxides, thermal oxides on stainless steels etc ...
- Special lubricants: these can be combinations of substances and are sometimes difficult to remove; they can be lubricants for cold deformation, pigmented oils, animal fats, chlorinated or sulphur oils, soaps, phosphate coating (on bolts), lubricating greases with varying levels of enriching with graphite or carbon residues, whole oils from cutting, protective oils, coolant emulsions, protective oils (often on carbon steel sheets), whole or emulsifiable, cleaning pastes: these are present on various metals such as aluminium, stainless steel, copper alloys, zinc alloys and are especially used for polishing surfaces.
In industrial activities, the metals which are most commonly subjected to chemical pickling are carbon steel, stainless steels, brass, copper and aluminium. Ferrous metals and copper alloys are usually pickled to remove thermal oxide; for aluminium the purpose of pickling (called "etching") is not so much the removal of oxides but the removal of material from the surface, generally for aesthetic purposes (matting or satinising).