Cladding is the application of a material that
provides a corrosion-resistant surface. Buildup welds are
made to restore worn parts to original dimensions or to
apply the surfacing material.
Base Materials
Cast irons, low- and high-alloy steels, stainless
steels, and manganese steels are the most common mate-
rials surfaced with the FCAW process.
The mining, steelmaking, railroad, and construction
industries use many types of base materials for the manu-
facture of their products and equipment. Many have been
specially developed or modified for use in a specific
industry application.
Filler Materials
Some filler materials fit into an AWS specification
for a particular material. However, many of the surfacing
materials have been developed by electrode manufac-
turers for specific applications and are not classified by
AWS. These proprietary electrodes are listed by a
number or a trade name.
An electrode may be designed for buildup, impact
resistance, hardfacing, or corrosion- and heat-protection.
The various electrode and chemical elements used in
their manufacture are described next.
Buildup Electrodes
Buildup electrodes may or may not match the parent
metal chemical analysis and mechanical values devel-
oped as a base for the final surfacing material.
Carbon-steel electrodes consists of the following
elements:
• Iron-base core.
• Carbon.
• Manganese.
• Silicon.
• Chromium.
• Molybdenum.
Total alloy content is low and has good impact
strength and machinability for application of the final
surfacing material. Carbon-steel electrodes are used for
buildup that may require multiple layers. Buildup layers
should be made within one or two layers of the final
dimension. The actual surfacing material is then applied
for the final surfacing operation. These electrodes are
designed for welds on all weldable carbon and low-alloy
steels. The welds have a high resistance to deformation.
Manganese steel electrodes consists of:
• Iron base core.
• Carbon.
• Manganese.
• Nickel.
Total alloy content is high due to the increased
strength level of the base material. The electrode may be
used to join manganese steels, repair worn areas, and
build up for surfacing. The deposit work-hardens to a
high tensile strength and has good impact properties.
Buildup electrodes for welding on cast iron are
limited to the steel electrodes in some areas and the iron-
nickel electrodes listed in Chapter 10. The use of steel for
a buildup electrode creates extreme hardness in the weld
area due to carbon pickup from the cast iron. The mate-
rial then cracks along or across the weld, leaving a poor
base for applying the surfacing material. Iron-nickel-
manganese steel electrodes are strongly recommended
for this application.
Surfacing Electrodes
Surfacing materials can usually be applied to any of
the buildup materials and many base materials. The main
objective is to retain the values of the surfacing material
after the welding operation. This is accomplished by
using the correct procedures to minimize the depth of
penetration on all buildup and surfacing welds, and by
properly adding the final surfacing material. Incorrect
procedures or excessive dilution will nullify the weld
quality and lower the surfacing protection desired.
Contact the surfacing material manufacturer for the
proper welding procedure.
During surfacing operations on construction equip-
ment using extremely high-alloy-content electrodes, the
weld may have a tendency to crack either across or in line
with the weld. This is caused by rapid cooling of the weld
and extreme hardness of the deposited metal. In most
cases, these cracks do not have an adverse effect on the
usability of the completed weld.
Surfacing electrode composition
Through experience and physical testing, each
manufacturer has established the chemical values of
surfacing electrodes and the procedures for applying
them. The electrodes and chemical requirements in
Figure 12-2 are general and serve only as a guide for
selection of the desired electrode. The manufacturer has
thoroughly tested the welding material and found the
recommended electrode works very satisfactorily for the
intended application.
Material Preparation
The weld area should be cleaned and any dirt, rust,
scale, or grease removed before welding. Such contami-
nates will affect the deposition of the weld metal and may
cause defects in the weld or weld interface. Castings with
surface scale should be ground and the scale removed.
Thermal-cut materials have oxidized metal on the face of
102 Flux Cored Arc Welding Handbook