Beijing's imports of stainless steel manufacturers the 440C high precision stainless steel plate imports of stainless steel sheet trillion Connaught wholesale imports of stainless steel SUS303 Stainless Steel SUS440C SUS440C stainless steel plate stainless steel round bar SUS301 stainless steel SUS301 stainless steel round bar SUS303 stainless steel round bar trillion Connaught wholesale domestic 440C stainless steel plate made of 440C stainless steel round bar imports Price of high temperature stainless steel stainless steel prices domestic stainless steel prices stainless steel line trillion promise full hard stainless steel wire high elastic stainless steel with bent stainless steel with high hardness stainless steel with stainless steel sheet megabytes promise stainless spring steel wire, stainless steel the flat line trillion Connaught stainless steel flat bar resistance stamping stainless sheet corrosion-resistant stainless steel rods trillion Connaught durable stainless steel pipe the mirror stainless steel plate http://bjzhaonuo.com.cn the Beijing trillion Connaught wholesale imports of stainless steel SUS303, SUS440C SUS440C stainless steel plate, stainless steel, stainless steel round bar SUS301 stainless steel SUS301 stainless steel round bar SUS303 stainless steel round bar Beijing trillion domestic 440C the Connaught wholesale domestic 440C stainless steel plate stainless steel stainless steel round bar imports of stainless steel prices domestic stainless steel prices Price of high temperature stainless steel line trillion promise high elasticity of full-hard stainless steel wire stainless steel band bending stainless steel with high hardness stainless steel with stainless steel sheet Siu promise stainless steel spring steel wire stainless steel flat wire stainless steel flat the strip resistance stamping stainless steel sheet corrosion-resistant stainless steel rods trillion promise wear-resistant stainless steel tube stainless steel mirror stainless steel: SUS440C ● Features and Scope: production of bearing rings and rolling with high carbon chromium stainless steel. ● Chemical Composition: Carbon C: from 0.95 ~~ 1.10 Si Si: ≤ 0.80 Manganese Mn: ≤ 0.80 SS: ≤ 0.030 PP: ≤ 0.035 Chromium Cr: 16.00 ~~ 18.00 Ni-Ni: May contain ≤ 0.60 Mo Mo: 0.40 ~~ 0.70 ● Mechanical Properties: Hardness: annealing, ≤ 269HB; quenching and tempering, ≥ 55HV ● heat treatment specification and metallurgical structure: heat treatment specifications: 1) annealing, 800 ~ 900 ℃ slow cooling; 2) quenching, 1000 ~ 1050 ℃ oil cooling; 3 ), 200 ~ 300 ℃ air cooling of the tempering. Microstructure: Organizing for the martensite type. ● Delivery status: generally heat treatment delivery, the treatment types specified in the contract; not indicated, by not heat treatment delivery. Stainless role: Stainless steel does not produce corrosion, pitting, corrosion or wear. Stainless steel or building with one of the highest material strength metallic materials. Because the stainless steel has a good corrosion resistance, so it enables the structural member to permanently maintain the integrity of the engineering design. Chromium-containing stainless steel also set the mechanical strength and high ductility in an easy-to-parts manufacturing, to meet the needs of architects and structural designers. 2, stainless steel the grades grouped precipitation hardening stainless steel. Good formability and weldability, as ultra-high-strength material applications in the nuclear industry, aviation and aerospace industries. The ingredients can be divided into the Cr series (400 series), Cr-Ni system (Series 300), a Cr-Mn-Ni (200 series) and precipitation hardening system (600 series). 200 Series - chromium - nickel - manganese austenitic stainless steel 300 series - chromium - nickel austenitic stainless steel 301 - malleable for a molding product. Can also be rapidly hardened by machining it. Good weldability. Abrasion resistance and fatigue strength than 304 stainless steel. 302 - corrosion resistance with the 304, due to the carbon content relative higher strength better. 303 - by adding a small amount of sulfur, phosphorus and make it the than 304 easier cutting. 304 - 18/8 stainless steel. GB grades 0Cr18Ni9. 309 - better temperature resistance compared to 304. 316 - after following the 304, the second most widely used kinds of steel, mainly used in the food industry, the pharmaceutical industry, and surgical equipment, add molybdenum to the special structure of an anti-corrosion. As compared to 304 has better resistance to chloride corrosion thus also for marine steel. SS316 is often used for nuclear fuel recovery unit. 18/10 stainless steel usually meet the application level. [1] Model 321 - In addition to the added titanium element to reduce the risk of material weld corrosion performance similar to the 304. 400 Series - ferritic and martensitic stainless steel. 408 - good heat resistance, weak resistance to corrosion, the 11% Cr, 8% Ni. 409 - the cheapest models (Anglo-American), usually as an automobile exhaust pipe of ferritic stainless steel (chrome steel). 410 - martensite (high strength chromium steel), good wear resistance, corrosion resistance is poor. 416 - sulfur is added to improve the processing performance of the material. 420 - "cutlery grade martensitic steel, high chromium steel of similar Brinell this the first stainless steel. Also used for the surgical tool, you can do very bright. 430 - ferritic stainless steel, decorative, such as for car accessories. Good moldability, heat resistance and corrosion resistance to be worse. 440 - the CUTLERY steel of high strength carbonaceous slightly higher, after appropriate heat treatment can be obtained a higher yield strength, hardness can reach 58HRC, belong to the most hard stainless steel column. Examples of the most common application is the "razor blade". There are three commonly used models: 440A, 440B, 440C, in addition to 440F (easy processing type). 500 series - heat-resistant chromium alloy steel. 600 Series - martensitic precipitation hardening stainless steel. 630 - the most commonly used models of precipitation hardening stainless steel, usually also called 17-4; 17% Cr, 4% Ni. 3, corrosion stainless Why? All metals and oxygen in the atmosphere in the reaction was carried out to form an oxide film on the surface. Unfortunately, the formation of iron oxide on the plain carbon steel to proceed with the oxidation, so that the corrosion continues to expand, the final pore formation. Paint or oxidation-resistant metal (e.g., zinc, nickel and chromium) electroplating can use to ensure that the surface of carbon steel, however, as people know, this protection is only a thin film. If the protective layer is damaged, the following steel began to rust. Stainless steel corrosion mechanism and prevention methods: 1: Corrosion Type: uniform corrosion corrosion state: general corrosion causes and institutions: stainless steel in strong acid alkali solution, mostly belonging to uniform corrosion control methods: Avoid using strong base of in the environment. selected steels corrosion environment without 2: corrosion types: the bimetallic corrosion (Shuangliu corrosion). the corrosion status: localized corrosion causes and institutions: the different metal bonding, its potential to form a closed loop, the current generated great activity for the anode, the corrosion reaction. prevention method: select potential similar to the metal. rubber or ceramic gasket between the fastener and the substrate. fastener material selection more passive than the substrate metal as anode the active metal surface area as possible zoom. 3: Corrosion species: pitting corrosion state: Local corrosion causes and institutions: solution containing halogen ion such as chloride, can break through the passivation film of the stainless steel surface, a pitting metal surface dust, iron filings, dirt and other sediments, hinder stainless steel in contact with air, resulting in hypoxia, loss of effectiveness of the passivation film, cavitation control methods: the choice of a good resistance to pitting steels, such as: 316.316 L.317.317L.329, and even nickel alloy reduces the concentration of the halogen ion, especially Cl and Br, and should be maintained in the low temperature operation, to a liquid flow. Join the pre-preparation NaOH3, can reduce the occurrence of pitting. NaOH was added to increase the PH value, pH greater than or equal to 11 does not generate pitting. Cathodic protection method. 4: corrosion types; crevice corrosion. The corrosion state: localized corrosion. The reason institutions; mainly because the solution can not clear the gap, the solution staying too long, lack of oxygen, caused by the gap-port internal and external solution concentration (ion) concentration differences. Metal ion difference, forming a metal ion battery. The differences in the oxygen content of the solution, forming a molten pool of oxygen. Control methods: reducing metal to metal or non-metallic interface gap, the regular use of alkaline detergent removal of the deposit. Avoid solution to produce a solution retention area. Accessories junction as much as possible welding, instead of screws, rivet connections. Cathodic protection method. 5: Corrosion Type; intergranular corrosion. The corrosion state: localized corrosion. Causes and institutions: stainless slowly through the range of 450-850 degrees, the carbon would chromium form carbonization chromium precipitates at the grain boundaries, thus reducing the chromium content of its collar nearly form a chromium deficiency, the corrosion resistance is greatly reduced, and this is called sensitization phenomenon. Control methods; giving high temperature solid solution treatment, the chromium carbide is dissolved, and rapidly cooled to prevent the precipitation of chromium carbide. Lower C content avoid carbide precipitation. Add stabilizer titanium (Ti) or niobium (Nb) 6: Corrosion Type; stress corrosion. The corrosion state: localized corrosion. Reason in institutions; metallic materials subjected to stress (tensile stress) and placed in a corrosive environment, caused by corrosion known as stress corrosion. Control methods; reduce harmful ions such as Cl and OH, or join NO3 pre-preparation. The machining avoid residual stress, stress, if any, should be cleared processing. The operating temperature is below 80 degrees. Cathodic protection method. 7: corrosion types; erosion. The corrosion status; localized corrosion. Reason in institutions: erosion causes of high-speed fluid and corrosive liquids can exist. Control methods; change the corrosive environment, to remove suspended solid particles, and add pre-preparation, and to reduce the corrosive fluid. Smooth flow of the solution does not produce the turbulence. Selection of better performance of anti-erosion materials. 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