Surface Treatment Services

Mechanical Polishing

• OMC offers Grinding, Polishing and Buffing services in our workshops in Limerick and we can also provide trained polishers to carry out polishing on vessels and pipe work on sites. These processes improve the surface conditions of a product for decorative or functional purposes. The various techniques are abrading operations although some plastic working of the surfaces may occur, particularly during buffing. The stages in this process include: Grinding Polishing Buffing The stages in the process follow the order in which they do for the reasoning that Grinding permits a far more aggressive a brading action compared to Polishing. The same applies to Polishing being a more aggressive brading action compared to Buffing. These services require highly skilled workers with many years of experience and a thorough knowledge of the art of their craft. OMC Technologies provide their staff with the necessary training needed on an on-going basis. Polishing is required for Electropolishing: The basic mill plate and sheet metal finishes for stainless steel include five grades that have finishes that are produced mechanically by using abrasive compositions and buffing wheels. Special mechanical polishing procedures are required for preparing metal surfaces, such as stainless steel, for electropolishing. What does Polishing do: Polishing is an intermediate step used to improve the surface finish from the grinding step, such as found on a common household stainless steel sink - lustrous, but not mirror-like. Polishing uses abrasives firmly attached to a flexible backing, such as a wheel, belt or orbital motion tool. Mechanical stainless steel polishing is an abrading operation used to remove or smooth grinding lines, scratches, pits, mold marks, parting lines, tool marks, stretcher strains, and surface defects that adversely affect the appearance or function of the part. The process causes some plastic working of the surface as metal is removed. A mechanically polished surface yields an abundance of scratches, strains, metal debris and embedded abrasives, and always distorts the metal surface. Burnishing metal by lapping or buffing decreases the micro-inch roughness and improves the image-defining quality of a surface, but it never completely removes the debris and damage metal caused by mechanical polishing. Mechanical Polishing vs. Electropolishing Mechanical polishing and buffing cannot be viewed as an adequate substitute for electropolishing. The reasoning for this is due to most applications having embedded abrasives, compounds, exposed grain structure of the metal, the lack of the non-particulating, non-contaminating, and non-outgassing characteristics of an electropolished surface. Key point: Any mechanically produced surface (ground, polished, buffed, lapped, honed, etc.) produces a work hardened, disturbed and damaged grain layer approximately 0.001 inch thick. This is accompanied by a scratched, sheared, and torn surface contaminated with embedded abrasives and compounds. Its importance depends on its application. From a cosmetic appearance standpoint, these effects may be unimportant. For high purity applications, e.g., semiconductor or pharmaceutical, particles and contaminants can be of utmost importance affecting purity of product and yield. Often it takes a SEM photomicrograph at very, very high magnification to show these effects - but it is there. A desirable alternative to be considered is electropolishing. OMC Technologies provide a full range of Mechanical Polishing services both in our Limerick work shop and onsite as required. For a specific query or quotation please contact us.

Chemical Cleaning Services

• Initially OMC begin by carrying out an onsite assessment in order to be able to recommend the chemical treatment service best suited to each specific client’s site situation. OMC provide the following cleaning services: Flushing OMC provide a full pre-clean service for new pipe work installations. This Flushing service aims to remove grease, swarf and debris typically found in new pipe work. Degreasing OMC provide a range of different alkaline degreasing solutions to remove the presence of grease from pipe work. All solutions are tested and certified for concentration prior to being used on site. The most suitable solution will be chosen from the onsite assessment carried out by project managers. OMC are committed to Safety and the Environment Safety: OMC regard providing safe working conditions for its employees and any personnel interfacing with our service crucial. Each project receives the following: Experienced site crews who are trained and retrained extensively Full time Health and Safety Officer in our company Safety Statement prepared in advance of each site assignment Track record of zero on site accidents to date over 10 years Environment: At OMC we are committed to environmental compliance by ensuring that the following steps are in place at all times. Significant investment in pumps, rigs, hoses and fittings to ensure no chemical spills Use of non toxic, non corrosive and biodegradable chemicals where possible Significant training in environmental compliance for all employees Certified treatment and disposal of waste solutions by waste OMC is independent of all chemical suppliers and prides itself on offering all customers the broadest range of chemical surface treatment services. For a specific query or quotation please contact us.

Passivation

• OMC Technologies provide both Two Stage and Three Stage passivation alternatives. According to ASTM A 380, passivation is “the removal of exogenous iron or iron compounds from the surface of a stainless steel by means of a chemical dissolution most typically by a treatment with an acid solution that will remove the surface contamination but will not significantly affect the stainless steel itself.” If left untreated, the result will be premature corrosion and ultimately result in deterioration of the component. Passivation removes all traces of iron present in stainless steel and in addition facilitates the formation of a very thin, transparent oxide film, which protects the stainless steel from “selective” oxidation (corrosion). TWO STAGE PASSIVATION consists of the following activities: Stage 1: De-Greasing with a Caustic based degreaser at 60 - 80 degrees centigrade for 2 - 4 hours. The waste is usually held for certified disposal. The system is then rinsed to a neutral pH. Stage 2: Passivation with either Citric or Nitric Acid at 10% for 2 hours at 30 – 40 degrees centigrade. The waste is removed for certified disposal The system is then rinsed using D.I. water until the conductivity of the effluent is below 10 microsiemens THREE STAGE PASSIVATION consists of the following activities: Stage 1: Alkaline Chelation Stage 2: Acidic Chelation with Applied Reductants Stage 3: Passivation with Chelating Agent (Proprietary Product) Testing: The following tests are usually carried out after all passivations carried out by OMC teams: pH Conductivity Verification of chemical concentrations Temperature measurement Some facilities also require a Ferroxile test for free iron OMC Technologies provide both Two-Stage and Three Stage passivation alternatives. For a specific query or quotation please contact us.

Water Treatment Services

• OMC provide specialised Water Treatment services to assist clients comply with the Health & Safety at Work Act and associated Regulations and Codes of Practice. OMC Technologies are committed to assisting companies to adopt a systemic approach to their legislative and maintenance requirements. Our specialised services have been developed to initially assess the onsite requirements of our client, to recommend the most suitable service and to provide the necessary procedures for our customers. The following services are provided by OMC: Risk Assessments Chlorination and Disinfection Legionella Controls Corrosion Treatments Cooling Tower Treatments Chemical Cleaning Speciality/Problem Cleaning OMC Technologies provide specific Water Treatment Services tailored to meet clients requirements. For a specific query or quotation please contact us.

Electropolishing

• Electropolishing, also known as electrochemical polishing or electrolytic polishing (especially in the metallography field), is an electrochemical process that removes material from a metallic workpiece. It is used to polish, passivate, and deburr metal parts. It is often described as the reverse of electroplating. It may be used in lieu of abrasive fine polishing in microstructural preparation. Typically, the workpiece is immersed in a temperature controlled bath of electrolyte and serves as the anode as it is connected to the positive terminal of a DC power supply, the negative terminal being attached to the cathode. A current passes from the anode, where metal on the surface is oxidized and dissolved in the electrolyte, to the cathode. At the cathode, a reduction reaction occurs, which normally produces hydrogen. Electrolytes used for electropolishing are most often concentrated acid solutions having a high viscosity, such as mixtures of sulfuric acid and phosphoric acid. Electropolishing has many applications in the metal finishing industry because of its simplicity and it can be applied to objects of complex shape. Typical examples are electropolished stainless steel drums of washing machines and stainless steel surgical devices. OMC Technologies offer a competitive contract electropolishing service from our facility in Ballysimon Road, Limerick. We have the capapility to electropolish a wide array of parts from the smallest size right up to large tanks and vessels. For a specific query or quotation please contact us.

Derougeing

• Rouge is a by product of corrosion and occurs on stainless steel surfaces when exposed to a corrosive environment either from an external source or from the destruction of the passive layer. The primary constitutes of rouge are iron oxides (ferric oxide FE203, or ferrous oxide FE304), but may include iron, chromium, nickel and other elements. Initially, rouge may slough off, but eventually it will adhere to the surface as a glossy coating that is not removed by wiping. The surface corrosion may eventually contribute to increased microbial contamination and further deterioration of the stainless surface. In high purity water systems, rouge can be classified in three types: Type 1 Rouge This type originates from external sources, usually by erosion of impellers or pump surfaces due to cavitation. The surface composition of the stainless steel passive layer is unchanged from that of the originally installed system. The rouge particles usually have the same composition as the material from which the particles came and, in early stages, can easily be wiped off. The colour is orange to red-orange due to the presence of various iron oxide and hydroxides. Type 2 Rouge This type originates as a result of the dissolution of the chromium oxide passive layer and the subsequent oxidation of the role in the substrate. It often times develops on unpassivated or mechanically polished surfaces. The type presence of chlorides in a high purity water system would accelerate type two rouge formation. Chloride reacts with the chromium to form a hypochlorous acid as a by product that in turn oxidizes the iron to form more chloride. The rouge can only be removed by grinding, polishing or by using an acid solution. Citric acid is a cleaning, as well as a re-passivation agent, that is often used for type two rouge. Type 3 Rouge Type three originates from exposure of stainless steel to high temperatures found in steam systems. The rouge is the product of the reaction of stream with the iron in the stainless steel forming magnetite. Some of the iron oxide may be replaced with nickel oxide, but the iron sesquioxide will control the colour of the film. When the rouge first forms it is blue, then turns black as it grows to a thickness that prevents further diffusion of oxygen. It can only be removed chemically or by grinding. After chemical cleaning, the surface must be passivated. OMC offer customers a range of proprietary chemical solutions which have been effective in addressing all three forms of rouge in various sites across Europe. For a specific query or quotation please contact us.