MetFab - Welding Fume Handbook - Flipbook - Page 18
7 Emission Rates: general factors
Current and voltage
Of the process parameters, welding current and arc voltage
have the largest effect on fume emission rate. Often the
effects of other parameters, such as shielding gas and flux
type, stem from the changes they confer in arc voltage.
Generally, emission rates of both particulate fume and
pollutant gases increase with both welding current and arc
voltage. For most processes, the relationship is roughly linear
(Figure 5).
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Fume emission rate mg/s
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6
5
4
3
2
1
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20
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40
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60
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80
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100
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120
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140
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160
Welding Current Amps
Figure 5: The effect of current on fume emission rate during MMA welding of mild steel
Average exposure to ozone PPM
0.35
0.30
0.25
0.20
0.15
0.10
0.05
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27
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29
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30
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31
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32
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Voltage
Figure 6: The effect of voltage on exposure to ozone during MAG welding of mild steel
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