Stainless Steel CNC Machining

Yes! Stainless steel will rust, there are three main factors that affect the rusting of stainless steel.

The content of alloying elements

Generally speaking, the content of chromium in 10.5% steel is not easy to rust. The higher the content of chromium and nickel, the better the corrosion resistance, such as 304 material nickel to the content of 8-10%, chromium content of 18-20%, such stainless steel in general is not rusty.

Smelting Process

Smelting technology is good, advanced equipment, advanced technology of the large stainless steel plant both in the control of alloying elements, impurity removal, billet cooling temperature control can be guaranteed, so the product quality is stable and reliable, good inherent quality, not easy to rust. On the contrary, some small steel mills are backward in equipment, technology, smelting process, impurities can not be removed, the production of products will inevitably rust.

External Environment

The climate is dry and well ventilated environment is not easy to rust, while the air humidity, continuous rainy weather, or the air contains acidity and alkalinity of the environment area will be easy to rust. 304 stainless steel, if the surrounding environment is too poor is also rusty.

Chemical method

Use pickling paste or spray to assist its rusted parts to re-passivate the formation of chromium oxide film so that it regains corrosion resistance, after pickling, in order to remove all the contaminants and acid residues, it is very important to use water for proper rinsing. After all treatment, repolish with polishing equipment and close with polishing wax. For local slight rust spots can also be used 1:1 gasoline, engine oil mixture with a clean rag to wipe away the rust spots.

Mechanical Method

Sandblasting, cleaning with glass or ceramic particles, annihilation, brushing and polishing. It is possible to wipe away the contamination caused by previously removed materials, polishing materials or obliterated materials by mechanical methods. All kinds of contamination, especially foreign iron particles, can be a source of corrosion, especially in wet environments. Therefore, mechanical cleaning of the surface should preferably be carried out under dry conditions for formal cleaning. The use of mechanical methods can only clean its surface, can not change the material itself corrosion resistance. Therefore, it is recommended to re-polish with polishing equipment after mechanical cleaning, closed with polishing wax.

904L Stainless Steel

Super complete austenitic stainless steel, its nickel mass fraction is 24% a 26%, carbon mass fraction is less than 0.02%, excellent corrosion resistance, while having good resistance to crevice corrosion and stress corrosion resistance. The original standard ASMESB-625 classifies it as a nickel alloy, and the new standard classifies it as stainless steel. China only has a similar grade 015Cr19Ni26Mo5Cu2 steel, a few European instrument manufacturers use 904L stainless steel for key materials, such as E + H mass flowmeter measuring tube is the use of 904L stainless steel, Rolex watch cases also use 904L stainless steel.

440C Stainless Steel

Martensitic stainless steel, hardenable stainless steel, stainless steel in the highest hardness, hardness of HRC57. mainly used for making nozzles, bearings, valve spool, valve seat, sleeve, valve stem, etc..