blued steel - a chemical process used to produce on the surface of the steel parts with a thin protective film of iron oxides Fe3O4.The name derives from the characteristic color of the items after treatment (blue-black, raven), also known as "blackening" or "sinenie" in general, regardless of color - "oxidation".The resulting film passivate the surface and protect the part from atmospheric corrosion and other harsh environments.
Before making burnishing steel detail previously prepared, cleaned of rust mechanically polished, degreased and etched in an acidic solution.You can defat solvent or alcohol.Etch need to remove from the surface all the extra oxides, leaving bare metal.
easiest way - burnishing steel oil.There are different methods, but the point is simple: in the detail of a thin layer of oil, then it must be heated to 300-350 ° C.Oil obgorite leaves on the surface of the oxide film.From the first time a uniform coating is impossible, so the process is repeated until the desired result.It is important to achieve uniform heating, otherwise the film goes spots, and do not overheat the item, as it may deform or release.Many people make the mistake and drop the item into a preheated oil, it is wrong.It should be exactly the other way around: first smear, then warming.Use any oil from sunflower to the transmission or engine.Such bluing coating has a low strength.It is suitable only in decorative and protective purposes.
blued steel with ferrous sulfate, ferric chloride and nitric acid
To do this, a liter of water to dissolve 15 grams of iron sulfate 30 g and 10 g of acid.In the solution is lowered in the product will form a rusty plaque, it is necessary to periodically remove the brush and continue to dip until the desired color of the oxide film.Now almost every city there is a store that sells chemicals, so get them is relatively easy.
blued steel with bichromate (potassium dichromate).For that per liter of water 200 grams of diluted potassium bichromate and was immersed in the solution for 20-30 minutes item.After removal from the solution, it must be dried at a high temperature (in the oven or over the coals).The process is repeated until a uniform blue-black.Then wipe with an oily rag detail.Chrompick - reagent is very common, it is used in the leather industry.
for blueing of gun barrels were mixed by heating 1 part by weight of antimony trichloride with 3 parts olive oil.The mixture was then applied to the item and leave at night.The process is repeated 10-12 times, then the trunk is washed, dried and polished.Color turns greenish-brown.
As can be seen from the above, burnishing steel at home - it is feasible and simple process.It can be applied to any products made of steel in cases where other methods of corrosion protection, such as paint, are not applicable.