Pradeep Vaidya explains some critical points on use of pickling and passivation for SS fabrications
How to select SS pickling and passivation products for use?Primary considerations are the grades of stainless steel being used and the size of the parts. Most commonly used products for pickling and passivation of 304 and 316L grade SS fabrications are available. The important criteria of selection are cost per hg, cleaning efficiency, consumption, consistency and stability.
Can outdoors on-site passivation be performed during the winter months?Pickling and passivation chemicals are used at room temperature. These contain ionisable acids and hence not recommended to be used in rainy seasons or in open areas.
Can I handle and use Britoss range of products using bare hand? No. SS pickling products contain strong acids and oxidising chemicals. These products must be handled after wearing the required safety gears. Nitrous oxide and hydrofluoric acid gases are toxic, cause severe irritation to throat and respiratory track. Therefore adequate safety measures should be taken while performing the process.
Which tools or means of applications are recommended for use of SS pickling and passivation products during cleaning? Any plastic spray bottle available for spraying spray-type product can be used. Use face-shield during the spray. For application by brushing, use 1-inch or 3-inch brush with nylon bristles. Always dip the brush in water after application is complete. It will increase the utility performance life of brush.
Are the SS pickling range products water soluble and water washable? Yes, all SS pickling range products are completely water washable.
Any dilutions recommended for SS pickling products?SS pickling products are to be used as supplied without any dilutions.
Are SS pickling products RoHS compliant?Yes, all SS pickling products must be essentially RoHS compliant and free from halides and sulphur.
To which standards are Britoss range products conforming?SS pickling products must conform to requirements of ASTM A 380 and IS 10117.
How do I know that my parts are passivated?The appearance of the parts is not changed by passivation. Accepted passivation test methods are given in ASTM A 967 and other specifications. The copper sulphate test is the most common quick and easy method for grades with high chromium content.
Do fabricated equipment parts need to be pre-cleaned?It is utmost necessary to remove light oils or dirt on the parts. Britoss products are excellent cleaners and can handle light grease and oils. However, stainless steel alloys high in sulphur or carbon usually require a pre-treatment in an alkaline bath such as Cleenol SS degreaser. Wiping with 7-10 per cent solution of Cleenol SS will remove surface oil and grease.
Should I heat my Britoss dip bath for cleaning of small SS parts by dipping?The passivation requires less time at higher temperatures, so we recommend heating when available, but room temperature is usually sufficient as well.
Is it required to use only deionised or de-mineralised water with Britoss range products?No, any type of water can be chosen for washing and rinsing. Certain industries have purity concerns and choose to only use DI or another type of purified water. For this reason Britoss range is produced using DI water. However using tap water has no negative effect on the passivation process. Using purified water for the final rinse bath can help avoid water-spotting issues.
Can Britoss range of products be used on metals other than stainless steel?Britoss range may be used to remove surface iron from nearly any metal including titanium, aluminium, hastalloy, inconel, cobalt chrome etc. It also works as a good brightener for copper, brass, and bronze when used as a flash cleaner.
Are Britoss range products safe for rubber, plastic, soldering and brazings?Britoss range of products is manufactured with nitric acid in its formulation. Hence prolonged exposure for rubbers, plastics, HDPE, PVC and synthetic rubber is not recommended. Use of PTFE materials and to some extent HDPE  or PP can be done.
Authored by__
Pradeep Vaidya, CEO, Promtech Consultancy Group
Contact:Pradeep Vaidya: +91- 9820181738 Sonia Vaidya: +91-9819813015Email: puvpromtech@gmail.com, soniavaidya30@gmail.com www.promtechaerosol.com

 
How do I know which SS pickling and passivation product to use?Please contact us for assistance in selecting a Britoss range product that is best for your application. Primary considerations are the grades of stainless steel being used and the size of the parts. Most commonly used products for pickling and passivation of 304 and 316L grade SS fabrications are Britoss normal range. For all other grades the product formulation should be developed.
Most important points to be noted before undertaking pickling and passivation of SS 304 316L : Perform the process in areas open to sky or well ventilated areas. Nitrous oxide & hydrofluoric acid gases generated are toxic, cause severe irritation to throat and respiratory tract. Operators must avoid direct breathing of acidic vapours. Never ever use any products formulated with sulphuric acid and hydrochloric acid. These acids if used for cleaning of weld joints or for pickling and passivation of any grade of steel, will lead to post cleaning corrosion within 15 days to 3 months. More-over both these acids will also cause hydrogen embrittlement and will create porosity on SS surface. This will lead to rusting of SS fabrications. Rusting is a sub-surface phenomenon will lead to creeping corrosion. Once the metal or fabrication starts rusting due to these factors, recovery becomes impossible and most expensive.
Can outdoors on-site passivation be performed during the winter months?Britoss gel and Britoss spray are used at room temperature. These contain ionisable acids and hence not recommended to be used in rainy seasons, in open areas. Room temperature or higher is preferred, but outdoor passivation in cold seasons may be done if the exposure time is extended beyond the recommended timings, due to slower pace of chemical action in Damp weathers.Can I touch, handle and use BRITOSS RANGE Products by hand? No,  Britoss range products contain strong acids and oxidising chemicals. These products must be handled after wearing all the safety equipments. Which tools or means of application are recommended for use of Britoss range products during cleaning? Use any plastic spray bottle available for spraying Britoss spray. Use face-shield during the spray. For application by brushing, use 1 or 3 brush with nylon bristles. Always dip the brush in water; this will increase the utility performance life of brush.
Are the Britoss range products water soluble and water washable? Yes, all Britoss range products are completely water washable.
Any dilutions recommended for Britoss range products?Britoss range products are to be used as supplied without any dilutions.
Are Britoss range products ROHS compliant?Yes, all Britoss range products are rohs compliant and free from halides and sulphur.
To which standards are Britoss range products confirming?Britoss range products confirm to the requirements of astm a 380 and is 10117.
Do we need a ventilation system to use Britoss range products in our plant?Britoss range chemicals are acidic and fuming in nature. The use of these chemicals shall be done in open area or highly ventilated areas . Do not use these products in hot sunlight or beyond 45 0C.
What is the recommended shelf life of Britoss range products? For best and optimum results and performance, use Britoss products within six months from the time of purchase. Keep the containers tightly closed with inner and outer lids. Store in a cool and dry place . What are the precautions to be taken?Britoss range products are highly acidic. Avoid body contacts. Avoid spillage on floor. The products will attack tiles, stone, marble, granite, glass, wood, laminations and concrete and cement floorings. Wash the spill area with plenty of running water. Operators must use all the safety gears (viz: face shield, goggles , face mask, respiratory filters, rubber apron full size, hand-gloves , gum-boots etc), while working with these products. Call for medical attention in case of prolonged exposure to fumes or direct contact with these products.
How do I know if my parts are passivated?The appearance of the parts is not changed by passivation. Accepted passivation test methods are given in astm a 967 and other specifications. The copper sulfate test is the most common quick and easy method for grades with high chromium content. Copper sulfate test kits shall be offered by innovative coating industries.
Do I need to pre-clean my fabricated equipment parts?It is utmost necessary to remove light oils or dirt on the parts. Britoss products are excellent cleaners and can handle light grease and oils. However, stainless steel alloys high in sulfur or carbon usually require a pre-treatment in an alkaline bath such as cleenol SS degreaser. Wiping with 7-10 per cent solution of cleenol SS will remove surface oil and grease.
Should I heat my Britoss dip bath for cleaning of small SS parts by dipping?The passivation requires less time at higher temperatures, so we recommend heating when available, but room temperature is usually sufficient.
Do I have to use de-ionised / de-ineralised water with Britoss range products?No, you may use any type of water you choose for washing and rinsing. Certain industries have purity concerns and choose to only use DI or another type of purified water. For this reason Britoss range is produced using DI water. However using tap water has no negative effect on the passivation process. Using purified water for the final rinse bath can help avoid water-spotting issues.
How long does Britoss dip in a bath last?This depends on the quantity and geometry of the parts being passivated and is difficult to predict. Use bath monitoring procedures recommended by innovative to maintain the effectiveness of your bath. The best judge to decide on this parameter in the operator himself. His own experience and discretion will help in standardisation.
Will Britoss range products affect the finish of the stainless steel?Nitric acid based passivation solution will etch to SS Surface. Hence it will affect the original gloss of SS marginally.
Can Britoss range products be used on metals other than stainless steel?Britoss range may be used to remove surface iron from nearly any metal, including titanium, aluminum, hastalloy, inconel, cobalt chrome, etc. It also works as a good brightener for copper, brass and bronze.
Are Britoss range products safe for rubber, plastic, soldering and brazings?Britoss range products are manufactured with nitric acid in its formulation. Hence prolonged exposure for rubbers, plastics, HDPE, PVC, synthetic rubber are not recommended. Use of PTFE materials and to some extent HDPE and PP can be done.
Are Britoss Range products not compatible with any other metal?Britoss range products will cause damage to the surfaces of concrete, mild steel, carbon steel, zinc, and galvanised steel. Avoid exposure of these materials to Britoss range and rinse immediately if there is an inadvertent spill onto these materials. We recommend extra dilution and room temperature operation. PVC pipe and fittings made from copper, brass or bronze are not recommended for long term use with Britoss range products.
Will Britoss range products clean off heat scales, black burn marks or weld dis-coloration? Britoss gel, Britoss spray and Britoss dip are meant for total and complete removal of all black scales, burn-marks due to heat treatment and welding. The process time can be 5 min to 30 min. The surface is completely water washed for removal of residual acids, after cleaning.
Will Britoss range products remove rust from mild steel fabrications?Britoss range products are not recommended for mild steel fabrications. Innovative coating industries offer rustogel 1406, phosgel and galvaprep for derusting MS & GI fabrications. These are used as pre-treatment for MS, GI steels are especially formulated for faster rust removal. For removal of rust on SS 304 and 316 L, regular Britoss range products are the only recommended products.
My stainless steel item is a railing, sculpture or otherwise too large and unwieldy for immersion in a bath. What product can I use?Britoss gel and Britoss spray are especially made for such applications and can be used at your location or at site.
How to complete effluent treatment of wash waters and chemical spillage on work floor?Britoss range products are acidic and will etch the floor. These spillage as well as wash water shall be neutralised by sprinkling lime water or alkaline neutraliser till the final effluent pH is 7.
Contact:Pradeep Vaidya, CEO,Promtech ConsultancyMobile: 91-9820181738puvpromtech@gmail.comSonia Vaidya+91-9819813015soniavaidya30@gmail.com