This document discusses de-oxidation, desulphurization, and dephosphorization processes in steelmaking. It explains that desulphurization requires basic slag and reducing conditions. Dephosphorization requires oxidizing conditions, high slag basicity, and a relatively low temperature. It notes various options for dephosphorization in oxygen steelmaking by controlling temperature, slag volume, and basicity.

1. De-oxidation

2. Desulphurization And Dephosphoriser
What do we need for good desulphurisation?
Basic slag, reducing conditions
Ladle desulphurisation uses CaO-rich slag,
with Al deoxidation (low hO)
Reaction: [S]steel + (O2-) slag = (S2-) slag + [O]steel
How can [Si] affect desulphurisation?
[Si] can control the oxygen potential in Al-killed steel
if
- Steel equilibrates with the slag
- Low SiO2 activity in slag (relative to Al2O3 activity)
Dephosphorisation requires:
oxidising conditions (higher [O] or higher po2)
high slag basicity
Relatively low temperature
pO2 (O2-) T
Blast furnace hearth (10-16 atm)
Lower
Oxygen steelmaking / EAF (10-9 atm) higher
Ladle (deoxidised steel) (10-14 atm) higher
Dephosphorisation options
Oxygen steelmaking:
- Limit tapping temperature
- control slag volume
- maximize basicity (ensure CaO dissolves)
- enhance kinetics (e.g. bottom stirring)
Note: steelmaking involves oxidising
C (~4%), Si (~0.5-1%) and P (~0.1%)
Out of hot metal

3. Aluminium based Master Alloys
A master alloy is a base metal such as aluminium, copper or nickel combined with a relatively high percentage of
one or two other elements. An example is AlTi10 - a binary alloy consisting of 10% titanium in aluminium. A
master alloy is a semi-finished product. It is manufactured for use as a raw material by the metals industry.
Master alloys are produced in various shapes. Examples are: ingot, waffle plate, rod in coils, etc.
Master alloys are used worldwide. Invariably they are found in plants where metal is melted, alloyed with various
elements and then cast into shapes. This can be aluminium, iron, steel or even a precious metal such as gold.
There are various reasons for adding master alloys to a melt. One of the main applications is composition
Adjustment,
i.e. changing the composition of the liquid metal to achieve the desired chemical specification. Another important
Application is structure control - influencing the microstructure of a metal during casting and solidification in order
to change its properties. Such properties include mechanical strength, ductility, electrical conductivity, castability or surface
appearance. A master alloy is sometimes also referred to as "hardener", "grain refiner" or "modifier"
Depending on its application.
Reasons for using a master alloy instead of a pure metal can be economical, technical or both. Some elements
Show high losses - or poor yield - when added in pure form. Others will not dissolve at all at the furnace
Temperature prevailing in a cast house. A master alloy often provides the solution, as it dissolves much quicker at
Lower temperatures, saving valuable energy and production time.
The master alloy industry uses specialized equipment such as high temperature induction furnaces to produce the
alloy composition suitable for use by the regular metals industry.
Master alloy fabrication is a truly specialized field.

4. Aluminium based Grain Refiners :
Grain Refinement is a process used for grain boundary strengthening of casting material.
Aluminum alloys with ultra fine grain structure has received Objectives
Aluminum alloys with ultra fine grain structure has received tremendous increase in research interest in
various disciplines specially in automotive and aerospace industries for properties like low density and good
castability.
Grain refinement of Al and its alloys improve the mechanical properties of casting along with surface
finish, soundness etc.
Methods of Grain Refinement
Methods of grain refinements used in casting process are mainly classified into following three
groups
Thermal method i.e. cooling rate control Methods of Grain Refinement
Chemical method i.e. Grain size refiners addition
Mechanical method i.e. agitation of melt during solidification

5. Aluminium MIG and TIG Welding wire:
MUL 4047
Automotive components
Body panels
Heat exchangers
MUL 4043 MIG
For welding 6XXX alloys, and most
casting alloys
Automotive components such as
frame and drive shafts
Bicycle frames
MUL 5554
Automotive wheels
Transportation applications such as
over-the-road trailers and rail tank cars
Chemical storage tanks
MUL 5183
5XXX alloys
Marine fabrication and repair
Cryogenic tanks
Shipbuilding and other high strength structural
aluminum applications
MUL 5356 Bicycle frames
High speed groove welds on formed truck
panels
Multi-pass fillet and lap welds on 6XXX series
base materials
Robotic fillet welds on trailer tanks requiring
minimal post-weld clean up
MUL 5356 MIG
Automotive bumpers and supports
Structural frames in the shipbuilding
industry
Bicycle frames
Formed truck panels