Of skin of stainless steel oxidation principal form

1, the property of oxidation skin stainless steel
Cent of skin of stainless steel oxidation is hot-rolling oxidation skin and anneal oxidation skin. Darkly is normally lubricious, show sometimes glaucous, density 3.5-5.21g/cm3, mohs hardness is worth 7.5-8.5, ply of hot-rolling oxidation skin is 5-7 μ M, ply of anneal oxidation skin is 15-25 μ M. The property of skin of stainless steel oxidation that gives priority to with Cr2O3 is tectonic and smooth and steady, close, adherent and as strong as matrix, 80 ℃ also not dissolve oxidizes at H2S04, HCI, HNO3 the inorganic such as the skin is acerbity, be necessary to choose richer aggressivity confuse sick at heart (HNO3+HF or H2SO4+HNO3+HCI) pickling ability is eradicated. But matrix of the pickling that confuse sick at heart is missing bigger, hold to misgivings crosses pickling easily or nod corrode, and even produce useless defective goods. Consequently, for speed of ascensive take out, ensure product quality, undertake alkaline dip before pickling more.

2, of skin of stainless steel oxidation eradicate

Of skin of stainless steel oxidation eradicate cent to eliminate phosphorous doctrine for chemical pickling law and machinery two kinds big, sometimes thrust deep into the enemy forces of two kinds of methods is complex use. Machinery has except phosphorous law throw ball, repeat labyrinthian, light Lapopi to wait. Fact of chemical pickling law gives priority to body with some kind of acid, add appropriate additive, wait by agent of mist of oxidizer, activator, corrosion inhibiter, bleeding agent, curb match pickle. Chemical pickling law has normally pickling law, alkaline - law of acerbity compound pickling, electroanalysis pickling law. Wide now for what use alkaline - law of acerbity compound pickling is divided again for alkaline dip and pickling two paces.

Technology of stainless steel pickling includes alkaline dip and pickling two systems, call alkaline - acerbity compound pickling. Alkaline dip chooses NaOH/NaNO3 oxidation magic art generally; Pickling chooses HNO3/HF to mix acerbity pickling law. The typical technological process of skin of oxidation of stainless steel of domestic take out is as follows: → of bath of → of hardening of → of warm-up → oxidation alkaline dip beforehand → of pickling → bath mixes water of high pressure of acerbity pickling → to erode → of bath of → passivation → is counteracted.

3, alkaline dip system

Alkaline dip system includes normally: Bath of → of hardening of → of warm-up → alkaline dip 4 working procedure.

① warm-up: The wire rod that waits for processing or fastener use the hot flue gas that alkaline dip heating furnace discharges, heat to be controlled to 300 ℃ beforehand, not only shorten alkaline dip hour, and energy-saving, still can prevent moisture to take alkaline chamfer to cause vapour to burst forth together, take alkaline mist to pollute an environment.

② alkaline dip: Alkaline dip oxidize skin. Medium Cr2O3 produces a series of chemical reaction in the fluid of caustic soda frit that contains a lot ofoxidizer or reducer, cause component decay, structural damage, benefit at pickling.

③ hardening: Through urgent cold stimulative oxidation Pi Shusong, drop, create a condition for pickling.

④ bath: The cleanness before pickling, in cutting down incomplete alkaline belt to enter pickle.

4, pickling system

Pickling system includes: Beforehand → of pickling → bath mixes water of high pressure of acerbity pickling → to erode → of bath of → of passivation of → nitric acid is counteracted wait for working procedure.

① beforehand pickling: Wash but of dissolve inferior chromic acerbity natrium and ferrous acid natrium, counteract outside incomplete alkaline. Prevent take to lye in confusing sick at heart, reduce acerbity fluid concentration.

② bath: Scour off beforehand the black ash that appearance of the stainless steel after pickling produces is residual.

③ mixes acerbity pickling: Choose the pickling that confuse sick at heart to undertake enforcing dissolving, skin of take out oxidation.

Water of ④ high pressure erodes: Fall the black ash that the stainless steel after pickling expresses affectation is residual and complete erode clean.

Passivation of ⑤ nitric acid: Residual and appearance black ash, will abluent blanch, become silvery white or silver-colored gray, make chromium steel accelerates passivation, progress is able to bear or endure corrode function.

⑥ bath: The incomplete after scour off passivation is handled is acerbity, prevent to be taken counteract fluid.

⑦ counteracts: Counteract incomplete acid with Ca(OH)2 or Na2CO3 aqueous solution, prevent rustily.

5, the property of oxidation skin stainless steel

Cent of skin of stainless steel oxidation is hot-rolling oxidation skin and anneal oxidation skin. Darkly is normally lubricious, show sometimes glaucous, density 3.5-5.21g/cm3, mohs hardness is worth 7.5-8.5, ply of hot-rolling oxidation skin is 5-7 μ M, ply of anneal oxidation skin is 15-25 μ M. The property of skin of stainless steel oxidation that gives priority to with Cr2O3 is tectonic and smooth and steady, close, adherent and as strong as matrix, 80 ℃ also not dissolve oxidizes at H2S04, HCI, HNO3 the inorganic such as the skin is acerbity, be necessary to choose richer aggressivity confuse sick at heart (HNO3+HF or H2SO4+HNO3+HCI) pickling ability is eradicated. But matrix of the pickling that confuse sick at heart is missing bigger, hold to misgivings crosses pickling easily or nod corrode, and even produce useless defective goods. Consequently, for speed of ascensive take out, ensure product quality, undertake alkaline dip before pickling more.

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