RatchetStrap.com's Coatings & Finishes
In order to impart qualities necessary for safe operation, Industrial Coatings & Finishes are applied to Heavy Duty Tie Down Hardware that impart corrosion resistance, wear resistance and abrasion resistance.
- Zinc Plating (Galvanizing) is a process invented as early as the 4th Century and involves applying zinc to steel to prevent rust. In hot dip galvanizing, parts are immersed in molten zinc (think silver garbage can). The zinc forms a coating, preventing corrosive materials from reaching the core and further, the zinc serves as a sacrificial coating meaning if the zinc coating is compromised, the bare steel will be protected by remaining zinc. Most cargo control or load restraint hardware is zinc plated.
- Cadmium plating is toxic but is excellent because it is sacrificial like zinc, offers excellent corrosion in salt, it’s malleable and offers freedom of stick-slip, allowing reliable torquing of plated threads.
- Nickel is used to plate steel requiring a shiny appearance but opposite of zinc, if a scratch occurs, the steel corrodes to protect the nickel. Nickel plating can be additive and correct under-dimension products or cover flaws. Electroless nickel plating does not use electrical power but requires extensive pretreatments.
- Thermal Aluminum Zinc ‘TAZ’ - an alloy thermally sprayed onto steel that imparts the best characteristics of both metals for optimal corrosion protection. Products protected by this alloy have shown maximum protection from magnesium chloride and granular sodium chloride, both commonly used for Road Salt or Rock Salt. [in 1940 Detroit, MI was the first city in the world to spread salt on its roads to lower the freezing point of water on the road.]
- Hexavalent Chromium is a toxic, chemical compound (Yellow Dichromate is the pigment color of the inexpensive lead base) commonly used in anti-corrosion coatings on tie down strap hardware shipped to the United States from China. Chromic acid is electroplated onto metal parts and if welded to, ground or around high heat, oxidation converts chromium to a hexavalent state. This inhaled hexavalent chromium is recognized as a human carcinogen and is prohibited in the European Union. Hexavalent Chromium was also the contaminant blamed for polluting the drinking water of Hinkley, California in the famed movie, Erin Brockovich. Many imported tie downs warn consumers to wear gloves or wash their hands immediately after use, no doubt concerned about contaminants resulting from the manufacturing process. Click here for further information.
- Trivalent Chromium is a safer, non-toxic alternative chromate conversion becoming more common on hardware, recognized by bluish-green or greenish-yellow hues.
- Hydrogen Embrittlement is a process that renders steel brittle and is caused by improper controls during manufacturing, finishing or use, when the metal comes into contact with molecular hydrogen. Tests are available (ASTM STP 962 "Hydrogen Embrittlement: Prevention and Control") as are counteractions.
- Type 304 Stainless Steel, with its chromium-nickel content and low carbon, is the most versatile and widely used of the austenitic stainless steels. Type 304 alloys are all modifications of the 18% chromium, 8% nickel austenitic alloy. Type 316 is an austenitic chromium-nickel stainless and heat-resisting steel with superior corrosion resistance as compared to other chromium-nickel steels when exposed to many types of chemical corrodents such as sea water, brine solutions, and the like. This is due to the +2% molybdenum found in 316. NEVER use any chemicals that contain chlorine near any stainless. This includes any cleaners, acids to clean quarry tile or brick, and some detergents. Even the vapors can attack stainless steel. The only inorganic acid that is friendly to stainless is nitric and it is used to remove any iron particles left on the surface from manufacturing or machining. Never use steel wool to clean stainless. Particles of the steel wool will get trapped in the grain of the stainless and these steel particles will rust. Halogen salts, especially chlorides easily penetrate this passive film and will allow corrosive attack to occur. The halogens are easy to recognize because they end in the letters "ine". WARNING: Do Not Use plated steel bolts to attach stainless steel hooks, hangers or parts. The plating/stainless areas are subject to a process called galvanic corrosion, which occurs when two different materials swap ions and degrade.
- Electrophoretic Painting (E-Paint, E-Coat) is an automated industrial paint process for metal products that are electrically conductive. The result is a uniform thickness, coats within cavities, is quick and the liquid nature means there is little waste and little mess or overspray.
- Powder Coating is applied as a free-flowing powder and does not require a solvent as does conventional liquid paint. Typically applied electrostatic ally then heated to cure, the finish is harder than standard paint.
- Galvanic Corrosion occurs when two different metals, like steel & aluminum are placed in contact. When aluminum track is added to steel flat bed trailers, a gasket must be added the entire length to create separation. Another possibility is to add a cadmium plating because cadmium and aluminum offer galvanic compatibility. However, a better solution is to match steel flat bed trailers with steel track & steel cargo tie down fittings - and - match aluminum flat bed trailers with aluminum track & aluminum cargo tie down fittings.
www.metallurgist.com - J.E.I. Metallurgical, Inc.