Sulphur Cored Wires - Minex

Sulphur Cored Wires
SULPHUR ADDITION IN STEEL
Many steel specifications require significant alloying quantities of sulphur, primarily for its ability to improve
machinability of the final product. Indeed, in some applications such as forging dies, the product may be
ordered to any one of a number of machinability ratings as well as hardenability and other factors.
Sulphur is used as an alloying addition to improve machinability. Increasing the sulphur content from nominal
say 0.008% to 0.060% lowers the charpy upper shelf level, thereby raising the transition temperature as fixed by
a given impact energy.
ADDITION PRACTICE
The addition of sulphur, and close control over the degree of addition, is an important step in the steelmaking
process. There is various ways to add sulphur into steel melt. Usually the sulphur is added in steel melt
(temperature 1500 - 1600°C) the form of stick sulphur which is, essentially, elemental sulphur. From experience
it has been determined that recovery of about 40 - 50% can be expected from stick sulphur. The
non-recovered sulphur easily ignites in air to form sulphur dioxide, a noxious gas with a strong, pungent
objectionable odor. Since the density of the stick sulphur (2.08 gm/cc) is low and the boiling point (444.72°C)
is also low, this sulphur vapor generation, and subsequent sulphur dioxide fume generation, occurs before
molten steel reactions involving sulphur can reach completion. As those skilled in the art will appreciate, the
steel reactions are essentially the formation of Mn S in the steel which is non-odorous coupled with the
vaporization of uncombined sulphur, which vaporization causes environmental conditions to become very
objectionable.
Whereas in cored wire Injection system the recovery
of sulphur is 60 – 70% with precise control of
composition. In sulphur cored wire, sulphur is
encapsulated in steel sheath, when injected into
steel it can go in depth of steel melt as shown in
figure, where due to sufficient ferrostatic pressure,
sulphur bubbles slowly raise to surface and react
efficiently in steel melt and also control of wire
feeding with help of wire feeder at desired speed
ensures high recovery, precise composition control
and less fumes generation. Thus the cored wire
injection into the steel is environmental friendly due to
less fumes generation and economical due to high
recovery and less heat rejection.
Selenium Cored Wire Specification
Chemical composition of Sulphur Cored Wire
Grade S (Min) Si (Max) Moist (Max)
S 98 98 0.2 0.3
Pouring Reliability Into Your Melt - Alloying Solution in Foundry Industry