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File: 1.9.1.2-95MXCIssue: P11205Supercedes: N10810
Material Review:
Made exclusively for arc spraying. This material produces a
hard, abrasive and corrosion resistant coating. Thiswire has the
unique property of increasing hardness in service. A service
environment of up to 1700F ispossible. Conventional grinding and
lapping techniques provide high chrome like finishes.
CAUTION: All Praxair and TAFA wires have been optimized for arc
spraying. Use of alternate wires usuallycause problems such as
excessive tip wear, spitting and feeding problems. We only
recommend Praxair andTAFA certified wires.
Application Review:
Praxair and TAFA 95XC wire is used primarily as a hard corrosion
resistant interface. When applied 0.010 inchesthick, the material
exhibits impressive elasticity for a coating this hard. Typical
applications use coatingthicknesses up to 0.060 inch.
After application, the coating can be ground using aluminum
oxide and subsequently polished to under a 10 RMSsurface finish.
This, coupled with good bond strength, high deposit efficiency, low
coefficient of friction, highdeposition rates, and ease of
application, allows 95MXC coatings to compete with processes that
require platingor plasma technologies.
This material also offers the added advantage of increasing
coating hardness to as high as 1180 DPH (Vickers)after abrasive
load is applied.
Praxair and TAFA 95MXC coating application procedures are the
same as other Praxair and TAFA hardfacingwires, and can be applied
using the same process parameters.
MXC is a registered trademark of TAFA Incorporated, Concord,
NHUltraHard is a registered trademark of TAFA Incorporated,
Concord, NH
Praxair and TAFA 95MXC UltraHard Wire
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Composition:
ELEMENTS WEIGHT %1
Silicon 1.6
Chromium 29.0
Manganese 1.65
Boron 3.75
Iron Balance
Coating Physical Properties:
Wire Size 1/16" (1.6 mm)
Deposit Efficiency 70 Percent*
Melting Point 2200F (1204C) (approx.)
Bond Strength 5775 psi (39.82 MPa noiminal) @ 20 mils thick
Coating Texture Variable**
Microhardness As sprayed: 595 DPH Rc55After abrasive load: 1180
DPH
Coating Density 6.7 gm/cc***
Finish - ground Excellent
Spraying:
Spray Rate 8 lbs/hr/100 amps (3.64 kg/hr/100 amps)
Coverage (wire consumption) 1.0 oz/ft2/0.001" (1.2 kg/m2/100
microns)
Spray Pattern****(approximate 3-5" standoff) Cross
Nozzle/Positioner - 3" (7.6 cm)
Length of wire per lb 102 ft. (1/16")
1 Compositions are nominal unless otherwise specified
* Depends on air pressure, standoff, nozzle cap and target
size.** 5" standoff, 60 psi - 8830, depends on air pressure - fine
with high psi, average with medium psi, and
rough with low psi.*** Depends on atomizing air pressure.****
Higher air pressures, smaller wire (1/16), and lower amperage with
red nozzle cap gives smallest
diameter pattern.
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Coating TypeNormal8830/8835
Arc Jet8830/8835
Arc Jet9000
9000
Atomizing Air Pressure:Primary Secondary
50c
---50c
40 c60c
60c60c
Nozzle Cap Blue * Blue BlueNozzle/Positioner (Cross=C; Slot=S)
Short C ** Short C Short C
Arc Load Voltsa 33-34 33-34 33-34 33-34Ampsb 100-200 100-200
100-200 100-200Standoff Inches 3-5 3-5 3-5 3-5Coating
Thickness/Pass-mils 5 5 5 5Coating Texture-microinches aa 200-350
150-250 150-250 200-350
Using excessive voltage reduces quality of coating. Voltage
should be adjusted to give minimum noiseand smooth arc operation.
Excessive voltage causes larger particles and poor spray pattern.
Too low avoltage will cause popping.
Be sure not to overheat substrate even if this means stopping to
allow cooling, use air jet cooling ifgreater speed is required.
Note that on some applications where preheating is tolerable,
preheating workto 300F can improve bond and deposit efficiency.
Note: Standard air caps and positioners can be used in 8830 or
9000 systems.
* P/N 450729 8830 Arc Jet Air Cap** P/N 620074 Arc Jet Modified
Short Cross (8830 & 9000)
--------------------------a When using power lead extensions
other than the normal 12 foot furnished, the voltage must be
increased by approximately 3.4 volts per 50 foot extension; i.e.
add 3.4 volts to the recommendedvoltage setting for a given wire if
the extension is increased to a 50 foot length.
b Can vary between 50-300 depending on size of workpiece and
traverse speed.c For finer finish, raise air pressure at point of
finish.
Spraying Procedure
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Finishing:
Praxair and TAFA 95MXC coatings are usually finished by grinding
with an aluminum oxide wheel. Subsequentpolishing can produce a
surface finish approaching 10 microinches (RMS). Refer to Bulletin
2.1.4.5 for finishinginformation.
Hazards:
Observe normal spraying practices, respiratory protection and
proper air flow pattern advised. For general spraypractices, see
AWS Publications AWS C2.1-73, "Recommended Safe Practices for
Thermal Spraying" and AWSTSS-85, "Thermal Spraying, Practice,
Theory and Application." Thermal spraying is a completely safe
processwhen performed in accordance with proper safety measures.
Become familiar with local safety regulations beforestarting spray
operations. DO NOT operate your spraying equipment or use the spray
material supplied beforeyou have thoroughly read the Praxair and
TAFA Instruction Manual.
A Material Safety Data Sheet will be sent with each initial
purchase and updated as required.
DISREGARDING THESE INSTRUCTIONS MAY BE DANGEROUS TO YOUR
HEALTH.
The Information provided herein is believed to be accurate and
reliable; however, results may vary withworkpiece preparation and
operator technique. Praxair and TAFA warrants only that the wires
are free ofdefects in material and workmanship. No other warranty
is expressed or implied.
Copyright 2000 Praxair Technology, Inc. All rights reserved
[email protected]
Telephone: 1-317-240-2650
Fax: 1-317-240-2596
Praxair, the Flowing Airstream design and Making our planet
moreproductive are trademarks or registered trademarks of
PraxairTechnology, Inc. in the United States and/or other
countries.
Other trademarks used herein are trademarks or
registeredtrademarks of their respective owners.
Printed in the United States of America 05-2000
[email protected]
Telephone: 603-224-9585
Fax: 603-225-4342
TAFA is constantly improving its products, therefore
specifications aresubject to change without notice
TAFA Incorporated is a Praxair Surface Technologies company.
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