Thehigh content of manganese played desulfurization
Manganesecontent is between 11.0% and 14.0%, and generally should not be less than 13%. Thehigh manganese steel is no international standard, manganese content should begreater than 18%. The level of the silicon content, to countersunk head chipboard screw Suppliers the impact of toughness isgreater, it should be taken as the lower limit, not more than 0.5% isappropriate. Hypophosphatemia low sulfur is a basic requirement, due to thehigh content of manganese played desulfurization, lowering phosphorus is themost important thing, and try to make the phosphorus less than 0.07%. Chromiumis to improve the abrasion resistance, usually in about 2.0%.The main charge is a high-quality carbonsteel (or ingot), high-carbon ferromanganese, medium carbon ferromanganese,high-carbon ferrochrome and high manganese steel scrap. Not only high-manganesesteel, any metal castings must not be excessive use of scrap, scrap should notexceed 25%. Then how to deal with the excess back charge? Back charge as longas the waste to a minimum, not to excess. Both intermediate frequency furnace,electric arc furnace melting, always first melting carbon steel, various typesof ferromanganese and other precious alloy material, several little at a timeinto the furnace, precious elements added at the last, in order to reduce theburning .
Material block should be as small as possible, the 50-80mm is appropriate. Melting clear, thefurnace temperature is 1580-1600 , deoxidation, dehydrogenation,denitrification, available aluminum wire, Si-Ca alloy or SiC material can alsobe used. Deoxidizer certain pressure deep into the furnace. The molten metallevel the cover agent Gaiyan partition outside air. But also calm for some time,so that the oxide inclusions have enough time to go up. However, manycompanies, only sprinkle the aluminum wire and even aluminum shavings on themolten metal level, do not coverage, it is wasted! During this period, use thecarbon ferromanganese to adjust the content of manganese and carbon in time.Add a small amount of boron powder inthe steel can significantly increase the hardenability of steel resistance, andtherefore, improve the ability of the hardenability of the boron in thequenched and tempered steel is what other alloying elements could notcomparable. Use add aluminum and given nitrogen method, to control theacid-soluble boron content of the steel. Carbon silico-manganese steel quenchedand tempered before rolling state. In the regulated quality processed steel, thedistribution of boron and impact properties of the different heat treatment orthermal processing.
The results show that the different thermal processingcourse, reversed the impact properties of boron carbide steel after temperingtreatment at Grain Boundaries poly precipitation and steel have varying degreesof impact. To improve the degree of uniformity of the boron in the steel, onthe one hand to the extent permitted by the process to select a higher thermalprocessing temperature, on the other hand, oil-cooled fast cold quenching canbe avoided along the grain of the boron carbide segregation precipitated .In carbon silicon manganese steel containingboron swapped tempering treatment, when the nitrogen content in steel is 0.005wt%, aluminum added in an amount of 800g/ t, the acid-soluble boron content of the steel can be controlled close to thetotal boron content. Boron steel thermal processing or heat treatmenttemperature is higher than 900 ° C, most of the boron carbide steeldissolution, the subsequent cooling rate has a great influence on thedeposition of boron carbide, the cooling is slower, the more the number ofprecipitated along the grain, resulting in the precipitation of grain boundarygrew up in blocks (such as stacking cooling after hot rolling). Before the heattreatment of quenching and tempering treatment, the thermal processingtemperature and the cooling rate can affect the distribution of boron in thesteel after quenching and tempering treatment, and impact properties. After 1180 thermal processing, quenched and tempering temperature range of 450 ~ 550 ,tempering temperature on the impact properties of boron distribution is notobvious.Source:
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