Weldability The requirements for welding performance vary depending on the purpose of the product. A class of tableware on the welding performance is generally not required, even including part of the pot enterprises.
But the vast majority of products need raw materials welding performance is good, such as two types of tableware, insulation cup, steel pipe, water heater, water dispenser and so on.
Stainless steel sculpture
Corrosion resistance The vast majority of stainless steel products require good corrosion resistance, such as one or two types of tableware, kitchenware, water heaters, water dispensers, some foreign businessmen on the product also do corrosion resistance test: With NACL aqueous solution heating to boiling, after a period of time to pour out the solution, wash and dry, said weight loss, to determine the degree of corrosion (note: Product polishing,
The presence of Fe in Sandcloth or sandpaper can lead to rust on the surface during testing)
Polishing performance Today's social stainless steel products in the production of generally polished this process, only a few products such as water heaters, water dispensers and so on do not need polishing. Therefore, this requires the polishing performance of raw materials is very good.
The main factors affecting the polishing performance are as follows: ① raw material surface defects.
Such as scratches, hemp spots, over pickling and so on. ② raw material material problems. Hardness is too low, polishing is not easy to throw on (BQ is not good), and the hardness is too low, in the deep stretch of the surface is prone to orange peel phenomenon, thus affecting the BQ.
The BQ of high hardness is relatively good.
③ after deep stretching of the product, the deformation of the area surface will also be small black spots and RIDGING, thus affecting the BQ.
Heat Resistant properties
Thermal resistance means that stainless steel can still maintain its excellent physical and mechanical properties at high temperatures. Carbon impact: Carbon is strongly formed and stabilized in austenitic stainless steel. The elements of the austenitic region are determined by the austenitic body. The ability of carbon to form austenite is about 30 times times that of nickel, carbon is a gap element, and the strength of austenitic stainless steel can be significantly improved by solid dissolution enhancement.
Carbon also improves the stress-resistant corrosion resistance of austenitic stainless steel in highly concentrated chloride, such as 42%MgCl2 boiling solution. However, carbon is often considered a harmful element in austenitic stainless steel, mainly due to the fact that carbon can form high chromium Cr23C6 carbon compounds with chromium in steel as a result of some conditions in the corrosion resistance of stainless steel (e.g. welding or 450~850℃ heating), resulting in the dilution of local chromium, The corrosion resistance of steel, especially the resistance between crystals, is reduced. So. Since the 60 's, the new development of chromium nickel austenitic stainless steel is mostly carbon content of less than 0.03% or 0.02% ultra-low carbon type, we can know that with the decrease of carbon content, steel intergranular corrosion sensitivity is reduced, when the carbon content is less than 0.02% has the most obvious effect, some experiments also pointed out that Carbon will also increase the point corrosion tendency of chrome austenitic stainless steel.
Due to the harmful effects of carbon, not only in the austenitic stainless steel smelting process should be controlled as low as possible carbon content, but also in the subsequent heat, cold processing and heat treatment and other processes to prevent the stainless steel surface to increase carbon, to avoid chromium carbide precipitation.
Corrosion resistance When the number of chromium atoms in steel is not less than 12.5%, the electrode potential of the steel can be mutated and the negative position rise to the positive electrode potential. Prevents electrochemical corrosion.