smelting process:
stainless steel smelting basic principle
of carbon steel production, stainless steel containing at least 10.5% Cr, in the decarburization reaction, the reaction:
Cr3O4 +4 [C] = 3 [Cr] +4 CO
due to the molten steel of high Cr and Cr than the C preferential oxidation in normal smelting temperature, C 0.03%, the balance of Cr only about 4%; to raise the temperature can improve the balance of the Cr content but refractory unbearable. : 18% Cr steel fluid temperature above 1900 ℃, this has developed in order to reduce the partial pressure of CO smelting. Stainless steel commonly used in direct smelting method of refining methods:
Electric Arc Furnace (EF), AOD (argon oxygen decarburization France), VOD (Vacuum Oxygen the decarburization France), the converter top low combined blowing (K -the OBM-S, K-BOP method, etc.), RH-OB, which the AOD method, the VOD method dominated. , Respectively, the two-step and three-step process smelting stainless steel, can be mass-produced low-carbon, low carbon stainless steel, Cr recoveries reach a higher level.
1) several stainless steel smelting the:
one step:
the EAF EAF direct two-step production process
:
the EAF + the AOD ; the EAF + VOD
the EAF + CLU, LD-OB + the VOD
three-step method:
; the EAF + K-the OBM-S + VOD or the AOD + (LF),
the EAF and the AOD + of VOD
the EAF + LD-OB + the VOD
low investment costs and 2) the advantages and disadvantages of the AOD and VOD:
of AOD smelting decarburization speed, high production efficiency; high thermal efficiency and low cost of smelting; molten steel stirring effect, off S, O; equipment is relatively simple, easy to master technology, currently about 70 percent of the world's stainless steel AOD production. The disadvantage is that the production of low C, N steel difficulties.
The VOD smelting de C, Paul Cr effect deoxidation effect; suitable for the production of low C, N-steels. The disadvantage of high investment costs, equipment maintenance difficulties.
cold rolling:
stainless steel, high alloy steel, rolling deformation resistance, high efficiency World pipe network reported that the world's steel pipe network to provide the world's steel pipe network editor , high-precision rolling should be used in the rigidity of the mill, the general multi-roll cold rolling mill.
The mill
twenty roller ◆ Sendzimir mill ◆ eighteen roller
◆ 12-high rolling mill
; ◆ four roller the mill
◆ the cold rolling mill
which use up to Sendzimir 20-roll mill, by improving the automatic control precision thickness control, board control means, continue to meet high-quality stainless steel.
hot-rolled process:
, stainless steel products, the strip about 70%. Stainless steel hot strip by hot rolling mill, Steckel Mill production, which the hot strip mill, with a large output, low cost and good quality, are widely used, such as POSCO World Steel Pipe News . But at present the world after the Steckel mill improved the number of stainless steel are also increasing, such as AVESTA, YUSCO, and so on. The heavy plate is generally dominated by the 4-high reversing mill.