FIELD OF THE INVENTION:
This invention relates to a method for analyzing welding fumes.
This invention further relates to a method of analyzing particulate matter in
welding fumes, generated from different welding consumables and welding
process i.e., which welding with coated/uncoated welding rods/material and
also from SMAW, SAW and GMAW process.
BACKGROUND OF THE INVENTION:
In Industries, although it is almost impossible to consume enough iron oxide to
cause a toxic effect, steels contain alloying elements that, in their pure forms
as found in other industries, could be hazardous to worker health if inhaled or
ingested. All steels contain manganese while stainless steels also contain
chromium and nickel. Although essential for health in small doses, pure
manganese is a neurotoxin that can cause manganese poisoning in large doses.
Chromium and nickel can be carcinogenic. Welders are exposed to these
elements if they inhale welding fume. Welding fume consists of metal oxide
particles that form during welding. These particles are small enough to become
and remain airborne and are easily inhaled. Chromium, nickel, and manganese
are not found as pure elements in welding fume. They are present as impure
compounds, which do not present the same toxic risk as pure elements. The
oxidation state of chromium and manganese also affects their toxicity. Trivalent
chromium is inert, whereas hexavalent chromium can be carcinogenic. There is
evidence that the oxidation state of welding fume manganese is less toxic than
that used to set manganese exposure limits. Therefore both the elemental and

chemical composition of welding fume must be considered when assessing
fume toxicity. Information about the chemistry of mild steel welding fume can
be used to compare the predicted toxicity of welding fume to that of elements
found in other industries. It can also be used as an example of the methods
used to study particle chemistry in general. When analysing airborne particles
like those in welding fume, the most important factor to consider is particle
size. This is because a given characterization technique only provides accurate
data for a specific size range. Many previous studies of particle chemistry do
not take this fact into account when reporting chemical composition, and thus
some of these studies present misleading conclusions.
However, no analysis technique is able to measure every element with the same
accuracy, so inconsistencies exist when comparing the results of different
techniques. When this happens, conversion between weight and atomic
percentages is only approximate, because the entire mass is not equally
characterized. Therefore, the elemental data from multiple techniques cannot
be compared, except within the two major groupings presented herein.
EP 2292367 Al, describes about a method and device for welding or soldering
in a protective gas atmosphere, Welding or soldering under an inert gas
atmosphere by a welding- or a soldering device, comprises exhausting the
resulting exhaust gases by at least one suction device, where the suction is
controlled depending on the process parameters of the welding- or the
soldering process. The process parameters include burner feeding speed, wire
feeding speed, wire diameter, wire material, current and/or current-direction,
where at least one parameter is determined and evaluated in a data processing
unit. Also described is a device for the welding or the soldering under an inert

gas atmosphere, comprising the suction device for exhausting the resulting
exhaust gases, where the suction device exhibits a control unit and a data
processing unit. The control unit is coupled with an energy source for the
welding- or the soldering process via a data line for the process parameters of
the welding- or the soldering process. The data processing unit operates the
process parameters.
US 4482246 A, discloses Inductively coupled plasma discharge in flowing non-
argon gas at atmospheric pressure for spectrochemical analysis. This invention
discloses a novel apparatus for the production of a sustained inductively
coupled non-argon plasma discharge in flowing gas in a 13-25 mm (analytical
size) containment tube at atmospheric pressure. The apparatus is developed for
elemental analysis of injected aerosol or powdered samples, and particularly for
air monitoring applications.
US 20100282728 Al, describes a power source with fume extractor for
welding. A power source for welding includes electrical components that
generate heat during a welding operation, a fume extractor for removing
welding fumes from a welding site during a welding operation, and a filtration
device for filtering the welding fumes to produce filtered air such that the
filtered air helps cool the electrical components.
US 20120193334 Al, developed a fume extractor for welding applications. A
welding system having a welding power supply coupled to a fume extractor is
provided. The fume extractor may be coupled to control circuitry configured to
operate the welding power supply. The control circuitry may be configured to
begin, terminate or modify the operation of the fume extractor prior to the
establishment of a welding arc, after the termination of the welding arc, or
both. The control circuitry may be further configured to modify the operation of
the fume extractor based upon a type of welding process used.

WO 2016085575 Al, lists out systems for and method of estimating the
amount and content of fumes with reporting of the results. A system includes a
fume collection system that collects fumes from a welding operation, multiple
data sources that detect operational data of the fume collection system and/or
of the welding operation indicative of at least two of arc on time, operator
factor, electrode feed speed, electrode size, and electrode type, an analysis
system that analyzes the operational data and estimates fume data indicative
of amount and content of the fumes, and a reporting system configured to
populate at least a system comprising: a fume collection system configured to
collect fumes from a welding operation;
US9468958 B2, relates to airborne component extractor with adjustable flow
rates. An extraction system is designed for metal working and other
applications. The system may comprise a cart-type base or may be
incorporated into a fixed or semi-fixed installation. A blower delivers a positive
pressure airflow to a hood that creates an air region by directing the air
through an annular space between inner and outer shrouds, impacting the air
against a single generally perpendicular flange. Return air from the operation
may be mixed with fresh air, both of which may be filtered, to supply the
positive pressure air. Both air streams to and from the hood may be adjusted
to optimize operation. Adjustments may be made at the base unit or remotely.
US 20140278243 Al, describes welding resource tracking and analysis system
and method. Metal fabrication systems, such as welding systems and related
equipment may be monitored and parameters sensed or calculated during
metal fabrication operations. The parameter values arex stored and transmitted
to a web based analysis system. Sampled values of the parameters are used to
generate graphical presentations that are used to populate user viewable
pages. The pages may be configured by users, and systems and parameters of
interest selected.

US 20100231394 Al provides a carbon monoxide detection and dissipation
apparatus. The apparatus includes a carbon monoxide detector adapted to
detect air-entrained carbon monoxide above a predetermined threshold within
an enclosure in detection communication with the carbon monoxide detector,
an alarm responsively associated with the carbon monoxide detector for
providing an audible signal indicating that the carbon monoxide detector has
detected carbon monoxide above the predetermined threshold, and a fan
responsively associated with the carbon monoxide detector for exhausting air
from the enclosure sufficient to reduce the carbon monoxide to below the
predetermined threshold.
In US 9272237 B2, three-phase portable airborne component extractor with
rotational direction control is described. An extraction system is designed for
metal working and other applications. The system may include a blower that
delivers a positive pressure airflow to a hood that creates an air region for
removal of airborne components from a work area. The blower is driven by a
three-phase motor in a portable base unit that may be plugged into a source of
three-phase power. A rotational direction reversing switch is provided between
the motor and a three-phase plug to permit reversal of the rotational direction
of the motor when the motor is determined not to rotation in the intended
direction when the plug is connected to a receptacle. The switch may be
manual or automatic.
In US 5069197 A, Fume hood is designed. A hood adapted to remove
contaminants from incoming airflow comprising a housing member having top,
front, back and side walls, and defining a lower liquid sump, and an upper

exhaust opening in the top wall, an inlet opening defined in the front wall of
the housing member the front wall is inclined inwardly and downwardly, a
partition extends between the side walls downwardly from the front wall and
has a free end defining an air passage with the back wall leading to a large
volume upper portion of the housing, a screen having openings therein extends
between the side walls and downwardly from the free end of the partition into
the sump, the partition has a dam on the free end thereof having a horizontal
upper edge, liquid will overflow the dam on the partition and move across the
openings in the screen to the sump, whereby air passing into the inlet opening
passes through the liquid moving across the screen and then through the
liquid moving across the screen and then through an agglomeration of liquid in
the upper housing, a removable liquid header is mounted to an extends across
the top wall and has a plurality of spaced apart nozzles extending through
openings in the top wall into the housing member above the front wall liquid
introduced into the header exits through the nozzles into the upper part of the
housing and is agglomerated as the airflow enters the upper part of the
housing.
US 4016398 A, provided fume extraction control for welding gun. A welding
gun is provided having vacuum fume extraction means wherein the level of
vacuum exerted at the arc welding zone is regulated to avoid extracting
shielding gas supplied to the welding zone. The vacuum level is regulated by
admitting sufficient air to a fume extracting passage provided within the gun to
reduce the vacuum to the desired level.

In US 3886344 A, Welding fume extractor is developed. A welding gun is
provided with an integral device for withdrawing smoke and hot gases
generated during the arc welding process, including means for cooling portions
of the gun that the operator normally holds during the course of his work.
US3798409 A, describes fume extracting welding gun nozzle, a welding gun
nozzle including a first passageway through which welding wire may be fed into
a weld and a second passageway through which shielding gas may be directed
over the weld to protect the molten metal from contamination. The nozzle also
includes a fume extracting passageway having an inlet orifice so located with
respect to the outlet end of the nozzle that the fumes are drawn into the nozzle
from a region laterally outward from the nozzle, and thus from an area removed
from the weld, so the shielding gas is relatively unaffected by the operation of
the fume extracting feature of the invention.
US 3909586 A, developed a method and means for removing smoke from open
arc welding operations. Apparatus for removing the smoke and fumes
generated by an electric welding arc wherein an exhaust tube is placed in the
vicinity of the source and a shield is placed between the arc and the exhaust
tube, intake port, nozzle and contact tip, so designed that the smoke and
fumes will be efficiently collected without undue heating or a rapid build-up of
weld spatter on the exhaust tube, intake port, nozzle and contact tip surfaces.
US 4057705 A, provides fume extracting welding gun. It describes about a
compact, flexible, lightweight welding gun, including a single outer tubular
casing substantially containing all the weld gun components. Concentric
disposition of annular fume evacuating passageways between the outer tubular
casing and component electrical transmitter elements insulates the external

surfaces of the casing from the electrical heat sources within the gun, while
cooling gases circulating in the gas passageways promote dissipation of
accumulating heat. The improved cooling properties of the gun permit relatively
higher levels of current and therefore increased speed of weld bead deposition,
while the single conduit structure of the welding apparatus renders it more
compact, flexible and lightweight, as well as more vulnerable due to the
relatively clean exterior of the gun.
US 20080020479 Al, describes a method and device for determining the
Smoke Point of Hydrocarbons. The invention relates to a method for
determining the smoke point of a hydrocarbon, comprising, among the different
steps defined in the ASTM D 1322 standard or equivalents thereof, the
identification, among different aspects of the flame according to the position of
the burner in the lamp, of a particular aspect of the flame and the reading of
the height of this flame on a graduated scale in mm. The invention is
characterized by the fact that a series of digital images of the flame is taken
and recorded with the aid of a digital camera or the like at intervals sufficiently
close for permitting, by analyzing these digital images, the detection of a
sudden change in the shape of the flame, and that the height of this flame is
measured at the moment of this sudden change in its shape, said height being
considered as the smoke point of the tested hydrocarbon.
WO 2013177480 Al, entitled systems and methods for low-manganese welding
wire. The invention relates generally to welding and, more specifically, to
welding wires for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux

Core Arc Welding (FCAW). In one embodiment, a tubular welding wire includes
a sheath and a core. The tubular welding wire includes less than approximately
0.4% manganese metal or alloy by weight, and the tubular welding wire is
configured to form a weld deposit having less than approximately 0.5%
manganese by weight.
US 6242711 Bl, Arc welding monitoring system, describes about an apparatus
for monitoring manual arc welding procedures for providing to the welder real-
time monitoring of the welding characteristics to achieve optimum welds. The
voltage and current conditions of the welding arc are instantly transferred
within the visual range of the helmet wearing operator by the use of lights,
illuminated bar graphs, light projections, illuminated see-through displays, or
the like, located in proximity to the helmet viewing window wherein, through
such monitoring, the operator is constantly aware of the arc conditions during
welding.
US 20160148098 Al elaborates out the system for estimating the amount and
content of fumes. A system includes a fume collection system that collects
fumes from a welding operation, multiple data sources that detect operational
data of the fume collection system and/or of the welding operation indicative of
at least two of arc on time, operator factor, electrode feed speed, electrode size,
and electrode type, an analysis system that analyzes the operational data and
estimates fume data indicative of amount and content of the fumes, and a
reporting system configured to populate at least one user viewable electronic
report based upon the fume data.

OBJECTS OF THE INVENTION;
It is therefore an object of this invention to provide a method for analyzing
welding fumes.
It is a further object of this invention to provide a method for analyzing welding
fumes, which can collect and analyse the fume gases with good accuracy.
Another object of this invention is to provide a method for analyzing welding
fumes, which can find that the fume concentration from different welding
processes.
Yet another object of this invention is to provide a method for analyzing welding
fumes, which can find the fume concentration from different welding processes
with shielding gases.
A still further object of this invention is to provide a method for analyzing
welding fumes, which can find fume particle morphology of the fume particles
generated from different welding processes with shielding gases.
These and other objects and advantages of the invention will be apparent from
the ensuing description, when read in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 - Shows flow chart of the methodology for evaluation of welding fumes
concentration and morphology
Figure 2 - Setting up of fume hood and methodology of collection of welding
fumes particles

Figure 3 - Shows the methodology for evaluation of fume particulates-
gravimetric estimation, fume particles-individual concentration and fume
particle morphology.
SUMMARY OF THE INVENTION:
A fume hood chamber is made with the arrangements to collect the fume from
the top of the fume hood. A small glass window is made for the welder to see
the welding arc or the welding spot. The chamber covers both the work piece
and the electrode holder. An extraction pump system is used to extract fume
from the fume hood through the wire mesh fixed with a collector, which is a
filter paper, preferably a Whatman GF/A glass fiber filter and collected. The
mass of fume collected is measured by weighing the filter paper before and
after fume collection. The welding is performed at different current ranges for
different shielding gas flow rates. The welding is performed without shielding
gas also. The weight of the filter paper is measured before and after sampling
using a sensitive balance (accuracy±0.01mg). The total fume concentration is
calculated from the following equation: Where Wa and Wb are the
weights of the filter paper in mg, before and after sampling, Ts is the sampling
time in min and f is the flow rate in 1/min. Welding fume samples are collected
at different experimental conditions. The filter paper samples are digested
using aqua regia(lHN03:3HCl) and diluted 25 ml using 5% aqua regia solution.
The concentration of metallic particles in the fumes was analyzed using
Inductively Coupled Plasma method. The fume samples are analyzed solely for
oxides of iron, aluminium, calcium, manganese, nickel and chromium
particulates. The solution concentration for the sample, Cs (ng/ml), is obtained
from the instrument. The concentration of the metallic particles is calculated
using the following equation. Where CM is the concentration of metal
in the work atmosphere (mg/m3) and Vs volume of the sample (ml)

The morphology of the particulates is studied using SEM-EDAX analytical
technique for examining particle size of metals. The Filter paper which adsorbs
the fume particles, 1 cm2 is prepared and fixed in a stub and taken for gold
sputter coating. Gold particles from the source get coated on the surface of the
fume particle surface and make the surface conductive, so to analyse the particle
morphology of fume particles in SEM, keeping the KV lower. The EDAX analysis
of the fume particles is done. Depending upon the electrodes used, current used,
shielding gas used, the fume particles concentration and the morphology also
varies. The particles shape, size and concentration are analysed.
DETAILED DESCRIPTION OF THE INVENTION:
Thus according to this invention a method for analyzing welding fumes is
provided.
In accordance with this invention a method for analyzing the concentration of
welding fumes and morphology of particles involves several steps as highlighted
in the flow diagram (Fig 1) and the set-up of the fume hood is shown in Fig. 2.
A methodology for finding fume concentration including particulate content is
developed. This has been fairly common in welding fume literature, particularly
with regard to studies involving energy dispersive spectroscopy with scanning
electron microscopes (SEM-EDS). For example, it is inaccurate to report
compositional gradients measured with SEM-EDS across fume particles that are
smaller than half a micrometer, because the SEM beam penetrates and samples
the volume of such small particles rather than just their surface. Welding fume
particles range in size from 0.005 to 20 um, although less than 10-30%

(depending on the welding process) of the fume mass is larger than 1 um.
Therefore, it is important to carefully consider the techniques for analysing
welding fume. Various analysis techniques that can be used to characterize
welding fume (and other particulate matter). The information provided and the
particle size ranges for which these techniques are applicable vary considerably.
These contain reviews of the various techniques used to chemically characterize
particles. In practice, there are two types of elemental characterization
techniques: those that measure proportional to the atomic number and those that
measure proportional to the atomic mass. The former produce data easily
transformed into molar/atomic fractions, whereas the latter create data reported
as weight percentages. If one has reliable values for each element present in the
specimen being analyzed, then one can convert from atomic fraction to weight
percent and back.
Due to Environmental awareness of welding fume from both welding consumables
as well as welding process, Present Method Welding fume samples were collected
at ambient condition as well as at breathing zone. At the zone of 5m, 10m and
15m were analysed. Then fume samples were analysed. By gravimetric method
the particulate matter were analysed. From the weight loss, the amount of
particulate were calculated. The gaseous constituents were analysed thru each
individual gas such as C02, CO, NOx, S02 and Ozone gas sensors. Report was
prepared and sent. Here the problem is the total welding fume samples could not
be collected fully. In the sense, the fumes once forms gets diluted with air. The
fume samples what collected is the diluted one. Major problem is the collection of
welding fumes.

New fume hood has been designed and developed. The total volume of fume gases
and particulates has been collected and analyzed with good accuracy. A data base
on fume particulates has been created with each Welding consumables were
tested for their welding fumes and particulates with good accuracy.
A fume hood chamber was made with the arrangements to collect the fume from
the top of the fume hood. The chamber covers both the work piece and the
electrode holder. An extraction pump system was used to extract fume from the
fume hood and collected on a Whatman GF/A glass fiber filter. The mass of fume
collected was measured by weighing the filter before and after fume collection.
The experiments were carried out for the data set of current ranging from 100 to
250 A for flow rates with 20, 25 and 30 1/min. The welding was performed at
different current ranges for different shielding gas flow rates, which varied
according to the manufacturer's recommendations. The welding was performed
without shielding gas also.
SAMPLING OF FUME PARTICULATES
The weight of the filter paper was measured before and after sampling using a
sensitive balance (accuracy+O.Olmg). The total fume concentration was calculated
from the following equation: Where Wa and Wb are the weights of the
filter paper in mg, before and after sampling, Ts is the sampling time in min and f
is the flow rate in 1/min. Welding fume samples collected at different experimental
conditions.
ANALYSIS OF METALLIC CONSTITUENTS
The filter paper samples were digested using aqua regia (1HN03:3HC1) and diluted

25 ml using 5%aqua regain solution. The concentration of metallic particles in
the fumes was analyzed using Inductively Coupled Plasma method. The fume
samples were analyzed solely for oxides of iron, aluminium, calcium, manganese,
nickel and chromium particulates. The solution concentration for the sample, Cs
(|ig/ml), was obtained from the instrument. The concentration of the metallic
particles was calculated using the following equation. Where CM is the
concentration of metal in the work atmosphere (mg/m3) and Vs volume of the
sample (ml).
MORPHOLOGY OF FUMES
The morphology of the particulates was studied using SEM-EDAX analytical
technique for examining particle size of metals. The Filter paper which adsorbed
the fume particles 1 cm2 is prepared and fixed in a stub and taken for gold
sputter coating. Gold particles from the source get coated on the surface of the
fume particle surface and made the surface conductive, so to analyse the particle
morphology of fume particles in SEM, keeping the Kv lower. The EDAX analysis
of the fume particles was done. Depends upon the electrodes used, current used,
shielding gas used, the fume particles concentration and the morphology also
varied.
The fume concentration level increased with increase in shielding gas flow rate
and current in gas tungsten arc welding process. While comparing the individual
metal oxides present in the total fumes, iron oxides, aluminum oxides and
calcium oxides were predominant in concentration level for the process and the
oxides of nickel, chromium, and manganese were present in less quantity. The
EDAX spectra confirmed the presence of metallic particles and carbon in the

fume samples. It is also observed that the particles were present in crystalline
shape. The most important observation from the analysis was the size of
particles. This result clearly indicated that the size of fume particulates is in the
nano meter range, which potentially can lead to severe health issues.
The methodology for evaluation of welding fumes concentration and morphology
in figure-1. Setting up of fume hood and methodology of collection of welding
fumes particles is shown in figure-2.The methodology has 10 parts:
A fume hood is made above the welding table [10], which covers both the work
piece and the electrode holder. Arrangements, one Stainless steel wire mesh of 15
cm2 [5] fixed in a wooden stem[3] to collect the total fume from the top of the fume
hood. An extraction pump system [1], blower assembly was fixed in the out let to
extract fume from the fume hood. A preweighed Whatman GF/A glass fiber filter
paper [4] of size 15cm2 is fixed over the stainless steel mesh. Two holes [8,9] are
made in the surface of the hood to the welder side for welder left hand and right
hand. One rectangle hole [7], glass window is fixed with safe lens so that welder
could see the welding thru the hole and perform welding. Welding with different
welding consumables, different welding process and generated fume gets collected
in the filter paper. And all the fumes generated gets collected through suction [6]
or filter pump because of the extraction pump(blower assembly) connected in the
outlet [2]. Once welding is over, fume particle deposited, filter paper is carefully
removed and taken for quantitative measurements for total fume particles and
taken for individual elemental concentration measurements and for morphology
studies. Then computation of gravimetric difference, elemental concentration
and Morphology difference are made.

WE CLAIM:
1. A method for analyzing welding fumes comprising setting up a fume hood
over a welding table to cover the work-piece and electrode holder, covered with
a collector fixing a wire mesh for collecting fumes, over said fume hood,
extracting the fumes from the fume hood and allowing particles from the fume
to collect in said collector,
removing said collector and subjecting the welding fume particles collected
therein, to quantitative measurements and morphology studies.
2. The method as claimed in claim 1, wherein said collector is a filter paper,
preferably a glass fibre filter paper.
3. The method as claimed in claim 1, wherein the fumes are extracted by
means by an extraction pump system attached to the fume hood.
4. The method as claimed in claim 1, wherein the quantitative measurements
and morphology studies are conducted to compute total concentration of
particles, elemental concentration and morphology of the welding fume
particles.
5. The method as claimed in claim 1, wherein said welding is performed at
different current ranges for different shielding gas flow rates.
6. The method as claimed in claim 5, wherein said shielding gas may be same
or different and is used individually or in combination.
7. The method as claimed in claim 5, wherein said current ranges from 100 to
250A for flow rates 20,25 and 301/min.