Stainless Steel Casting Difference
Stainless steel: chromium content of more than 12% of the iron-based alloy known as stainless steel, stainless steel and acid-resistant steel in general. Stainless steel is resistant to atmospheric, steam and water and other weak corrosive media of steel, Stainless Steel Casting and acid-resistant steel is resistant to acid, alkali, salt and other chemical corrosive media corrosion of steel, stainless steel and acid-resistant steel in the degree of alloying are quite different , Stainless steel, although it has a stainless, but not necessarily acid; and acid-resistant steel are generally rusty, in the air or chemical corrosion medium can resist corrosion of a high alloy steel, stainless steel is a beautiful surface and Corrosion resistance, good, Stainless Steel Casting do not have to wait through the surface treatment of color, and play the inherent surface properties of stainless steel, used in a wide range of steel, usually called stainless steel. At present, stainless steel castings in the market has also been widely used, today Xiaobian for everyone to explain the four categories of stainless steel casting:
Classification of chemical composition Stainless steel Cr stainless steel and Cr, Ni stainless steel two categories. The corrosion resistance of stainless steel is mainly C content and precipitation of carbides, so corrosion-resistant stainless steel containing C as low as possible, Stainless Steel Casting usually C ≤ 0.08%, but the high temperature mechanical properties of heat-resistant steel is determined by its organization stability Of the carbide precipitation phase, so the heat-resistant steel containing C are higher, generally carbon content of 0.20% or more.
With chromium as the main alloying element, Stainless Steel Casting the amount of Cr is generally between 13% and 30%. Has a good resistance to oxidative media corrosion and the ability to withstand air oxidation at high temperatures, can also be used as heat-resistant steel. The welding performance of this kind of steel is poor. When the chromium content is more than 16%, the as-cast structure is coarse, Stainless Steel Casting and long-term insulation between 400-525 ℃ and 550-700 ℃, there will be "475 ℃" brittle phase and σ phase, so that steel brittle. The brittleness at 475 ° C is related to the ordering of Cr-containing ferrite. 475 ℃ brittle phase and σ phase brittleness, can be heated to 475 ℃ above and then fast to improve. The brittleness at room temperature and the brittleness of the post-weld heat affected zone are also one of the basic problems of ferritic stainless steel. Stainless Steel Casting Vacuum refining can be used to add trace elements such as boron, rare earth and calcium, or austenite forming elements such as Ni, Mu, N, Cu, etc.) approach to be improved. In order to improve the mechanical properties of the weld zone and the heat affected zone, a small amount of Ti and Nb are usually added to prevent grain growth in the heat affected zone. Commonly used ferrite steel ZGCr17 and ZGCr28. The impact toughness of this type of steel is low, Stainless Steel Casting in many cases by high nickel austenitic stainless steel replaced. Ni content of more than 2%, containing more than 0.15% of the amount of ferrite steel has a good impact performance.
The microstructure of the composite steel is usually containing 5% -40% ferrite to improve the weldability of the alloy, increase the strength and improve the resistance to stress corrosion. For example, Cr28% -Ni10% -C0.30% high-carbon high-chromium alloy steel, with good resistance to sulfuric acid corrosion, Stainless Steel Casting can be used to manufacture castings. On this basis, the development of controllable ferrite steels, Stainless Steel Casting with high strength, and in the sulfate have good resistance to stress corrosion, commonly used in the oil industry equipment.