free - cutting steel
sulphur in steel
machinability

h o m e
p r i c e   l i s t
o r d e r
r e f e r e n c e s
c o n t a c t

 

 

 

 

Ferosíra (ferrosulphur) is a trademark for an original product enabling the production of free-cutting steels in an efficient and environmentally satisfactory way.
A new alloy product was launched after series of investigations by the group Feralloy, výrobní sdružení. Already 500 kt steels alloyed with ferrosulphur were produced in czech steelworks and abroad.

It is well known that the machinability of many steel grades are considerably improved by the addition of sulphur. Due to the high vapour pressure of sulphur is the addition of elemental sulphur to molten steel accompanied by the strong enviromental pollution by SO2 which requires the adequate exhaust system. Uneven sulphur recovery brings about a bigger dispersion of final sulphur content in steel. Ecological methodes of sulphur addition (wire filled with sulphur or the pyrite ) are too expensive. 

The mentioned problems are solved by a new product – ferrosulphur – developed and commercialized by the Feralloy, výrobní sdružení.

The  F e r r o s u l p h u r  is a sintered mixture of iron powder and sulphur which contains 40 wt % S.  

It is added to molten steel in ladle at tap in the same way as pure sulphur. The higher density of ferrosulphur keeps down the evaporation of the sulphur.

1. substantial reduction of sulphur dioxide generation (80-90 %) by better recovery of sulphur. Most of sulphur loss is neutralised in slag which decreases the enviromental pollution.
2. improved consistency of steel composition
3. better machinability due to the content of oxygen in ferrosulphur
4. dustless transport and less risky manipulation
5. lower costs to alloying by pyrite or filled wire ( 3 to 4 times ).

The ferrosulphur initialy tailored for the production of free-cutting steels with 0,3 % S is suitable also for other grades (structural and stainless steel).

The ferrosulphur has a great advantage of being handleable and much less friable than the elemental sulphur. Thus the dust generation and moisture contamination during handling can be significantly reduced. It reduces also the chance of sulphur dust explosion.