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Fabrication Addendum January
05
Welding, Hard-facing of Edges, and Bending
Introduction:
Welding via mild steel wire and rod is covered in "Installation/Studding/Bolting/Welding
Guidelines". This addendum covers new recommendations
for:
- Welding CRODON Plus (AR400 steel backing)
and CRODON Standard (mild steel backing) Wear Plate
- Protect exposed edges with hard-facing
wire.
- Rolling and Press Break Bending of CRODON
Plus and CRODON Standard Wear Plate.
These are recommendations based on field experience
and bench testing. Individual trial applications by the operators
are strongly recommended before applying to finished products.
1. Welding
Previous information discussed the need to control heat input
to the CRODON surface. Heating the surface above 750°
F will have a significant detrimental impact on the CRODON
Surface making it much less abrasive resistant and impairing
its bond with the base metal. Heat sinks or welding gel is
always advisable.
Via Welding Rod:
We generally recommend MIG (wire) welding with .045"
mild steel, flux cored wire, keeping amperage at 67 or minimum
possible. When this is not an option, we recommend the following
rod and procedures.
Manufacturer:
X-Ergon
P. O. Box 152102
Irving, TX 75015
(800) 527-9916
(972) 721-6870 (fax)
Fabrication Addendum
January 2005
Product:
Impact-A-Wear SD
Code 173-4-000
Diameter: 1/8"
Procedure:
Use minimal Amperage. The manufacturer recommends minimum
90 amps. Reverse polarity (positive electrode), short to no
arc, and thin beads, 1/8" to 3/16" wide. Recommend
filet weld from the back or skip welding using multiple passes
as needed. Heat sink or cooling gel recommended.
Other:
Per manufacturer, weld surface will work-harden under impact
but not recommended by Chromium Corporation as abrasion resistant
surface to protect exposed edges. Use lower amperage to prevent
overheating if welding from front side - max of 62 amps. Additional
information on X-Ergon Web Page.
Skip & Pulse Welding
As discussed in other locations, Chromium does not recommend
continuous welding to join sections. Tack welds, 2" long,
are preferred. When large areas must be joined we recommend
skip welds 2" long with 4" between welds before
returning to fill the welds in 2" increments.
Pulse welding can also be used. Weld in 1
second intervals allowing enough time between pulses for weld
color to drop below a dull red. Only MIG welding is recommended
for pulse welding applications.
Fabrication Addendum
January 2005
2. Edge and Weld Protection of CRODON Wear
Plate
When "CRODON Edge Protection" is
impractical or base welds need to be protected, a welded hardfacing
surface is indicated. Chromium Corporation developed the following
procedures below to apply a hard-facing wire and rod with
little or no measurable heat induced deterioration of the
CRODON surface. Note that neither of these applications are
recommended as alternative methods for joining pieces. They
are exclusively for protection of exposed edges or base welds.
Via Hard-Facing Wire:
Manufacturer:
Postle Industries
P. O. Box 42037
Cleveland, OH 44142
Contact: Chris Postle
(216) 265-9000
Product:
Postle 2829-SPL hard-facing wire, 0.035" diameter
Hardness - 65Rc
Procedure:
Amps - 150 - 170
Volts - 18
Feed Rate - 220 inches per minute
Skip and pulse welding strongly recommended. Apply with a
weave or 1/8" straight bead. Do not overlap to CRODON
surface. Use heat sink or cooling gel when possible.
Fabrication Addendum
January 2005
Via Hardfacing Rod:
Manufacturer:
X-Ergon
P. O. Box 152102
Irving, TX 75015
(800) 527-9916
(972) 721-6870 (fax)
Product:
MAX-ABRADETM SD
Code 176-1-0250
Diameter: 1/4"
Procedure:
Use minimal Amperage. The manufacturer recommends minimum
80 amps. Chromium testing showed acceptable results with 60
amps. AC or DC current. Can be applied in two passes. Strongly
recommend welding in pulses in 1 to 2 second intervals. Heat
sink or cooling gel recommended.
Other:
As applied hardness 62 to 64 Rc. Additional information on
X-Ergon Web Page.
Fabrication Addendum
January 2005
3. Rolling and Bending of CRODON Standard
and CRODON Plus Wear Plate
General Information:
CRODON Standard and Plus Wear Plate can be formed in one direction
on the internal or external diameter. CRODON Plus with base
steel greater than ¼" thick is not recommended
for forming. We do not recommend forming CRODON Premier (AR500
steel backing) at this time.
Because the CRODON wear surface does not stretch,
forming on the external diameter will create a fine network
of horizontal cracks across the plate opposite the direction
of forming. Adhesion is not compromised but the fine crack
pattern can allow fine abrasive materials or corrosives to
propagate wear under the CRODON surface.
Formed pieces need to be in a generally rectangular
shape without internal angles. Never try to create a "cupped"
shape or bend a section in more than one direction.
Radius
Always form CRODON on a radius, not a sharp angle. Chromium
Corporation recommends a bending ratio of 32 to 1 of the formed
angle to the thickness of the base steel.
Base Steel Thickness Minimum Radius
1/8" (11 gauge) 4"
¼" 8"
3/8" 12"
½" 16"
Press Break and Roll Forming
CRODON Standard can be press break rolled using a mandrel
no smaller than 3" in diameter. CRODON Plus should be
formed by rolling only and not subjected to press breaking.
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