Why should be RH furnace changed without chromium with fireproof material?

RH furnace follows the development of fine craft to update progress ceaselessly with fireproof material, be able to bear or endure character from inchoate tall aluminium material, it is newlier common and firing magnesian chromium is able to bear or endure character material, hand-in-hand pace is direct union magnesian chromic brick, half recombine or recombine magnesium chromic brick. Tervalent chromium issues can progressively change to be 6 price chromium in certain condition in magnesian chromic brick, pollute an environment badly, minatory person is safe in recent years, the concept with friendly environment gets increasingly aggrandizement, change technical development to get attention without chromium, accordingly, RH furnace changes material to get canal of great progress macerate, circumfluent Guan Moge changes material to basically include whole of corundum pointed spar without chromium brick of pointed spar of pouring, corundum and brick of magnesian pointed spar. Current, because brick of magnesian pointed spar is fought aggressivity and be able to bear or endure molten steel erodes, scope of application is wide.


Steel is planted main characteristic is the quantity that contain carbon inferior (0.02% ～ 0.06%) , low silicon (≤ 0.03%) , plant on behalf of steel have SPHC, SS400. Handling a characteristic is vacuum spends a requirement inferior, ordinary control controls; to handle time weak point in 6 ～ 7kPa, general processing time is less than 15min, circumfluent gas flow control is inferior. To converter the requirement controls C, n, the molten steel that converter comes over can be the steel that take oxygen or deoxidization steel, to deoxidization steel requirement carbon accords with a requirement basically. Intermediate processing mode and light processing are basic about the same, its ask component of molten steel carbon is in commonly 0.01% ～ 0.03% , the molten steel that requirement converter comes over must be the steel that take oxygen (the purpose is decarbonization) . Object steel is planted for not sensitive to H, but relatively strict; does not contain use condition Cr, of Ni be able to bear or endure the cop steel with not quite high level of intensity of; of steel of cop of low rank of Hou Gang; . Be like,plant on behalf of steel DI material (pull coal tub) easily, x65, SM490.
Mode of deep decarbonization processing is planted in the light of steel to exceed mild steel, plant on behalf of steel the steel that it is IF, namely the car that common common weighs board steel. The steel that its ask is planted carbolic content is less than 100PPm, the level that Japan reached 2019 is ≤ 13ppm, steel of our country treasure reachs this level basically also, its are right C, n, o, s has very firm demand. Craft characteristic is to ask vacuum is spent tall, achieve 65Pa the following; to ask converter molten steel is the steel that take oxygen, control of the capacity that take oxygen is between 400 ～ 800ppm, carbolic content is less than 0.05% , time of inferior; processing grows azotic content, decarbonization time is more than 15min, the control that smelt time is more than 30min; to shed gas to annulus is relatively strict.
RH furnace is intermittent operation, temperature of fine molten steel is 1600-1670 ℃ commonly, every time fine time is 18-40 minute, turnaround time is 45-120 commonly minute, however environmental temperature is 5-30 ℃ only. Macerate canal is in urgent cold urgent hot condition for a long time, macerate canal is exterior and pouring makings craze, flake serious. Not only such, get molten steel is acuteness erode, macerate canal and brick of circumfluent canal liner also are damage too fast. Accordingly, need uses magnesium (chromic) qualitative gush filling makings undertakes gush fills safeguard.
The function of RH fine law basically has: Molten steel takes off gas, the hydrogenous content that can make steel medium decreases, make the azotic content in steel decreases, molten steel to oxigenate, through the molten steel that LF+RH double couplet processes, the total oxygen content that can make steel medium achieves 1×10-5; decarbonization, undertake in RH furnace decompression decarbonization is operated, the carbolic content that can make steel medium is less than 10×10-6; to decoke, to The gush in RH furnace blows synthetic broken bits, the sulfur content that can make molten steel medium commonly is less than attune of 30×10-6; composition essence, the molten steel after be being handled through RH furnace is in good reductive position, undertake composition fine tuning can obtain accurate adjustment precision; heats: Use chemistry to heat the fine need that can satisfy sequel, satisfy the Lian Zhu requirement to molten steel temperature.