THE METHODOLOGY OF CALCULATION OF THE GEOMETRIC SIZES
OF THE WELDS ON THE PARAMETERS OF THE MODE OF AUTOMATIC ARC
WELDING UNDER A LAYER OF FLUX
Assoc. Prof. Ivanov M.A., Eng. Ulanov A.M.,
Faculty of Metallurgy – South Ural State University, Russia
Abstract: The article is devoted to approaches to the calculation of mode of arc welding under flux, there are considered and systematized
modern techniques. As a result of the analysis there was presented a new methodology for parameters' calculation of the mode of arc
welding under flux. There was implemented a new automated complex for calculation of mode of arc welding under flux. The tests were
conducted.
KEYWORDS: WELDING, GEOMETRIC SIZES OF THE WELDS, MODE OF WELDING, WELDING UNDER A LAYER OF FLUX
Specification 8713-79. According to the geometry of the weld (wall
thickness, height, width of seam, gap between parts) the area of
deposited metal Fn is determined (Fig. 1).
1. Introduction
Russia's accession to the world trade organization requires
from Russian producers of welded metal structures to reduce the
cost price and to increase the speed of development of new parts
and products in order to meet the demand on the world market.
Production of the machine-building sector of Russia requires
to obtain complex welded metal structures with long stretches of
welded seams. To improve the productivity and reduce the cost
price of the welding process there is used modern automated
complexes, which include welding tractor, power supply and
control unit. Of all types of arc welding the most qualitative welded
connection is provided by the welding under a layer of flux.
For the guaranteed reception of qualitative welded
connection, it is necessary to set the operation mode of welding,
which defines the structure and the properties of the weld seam and
the heat affected zone. Calculation of an optimum mode of arc
welding under a layer of flux, as well as cooling rates for each steel
grade is relevant and determines the time of carrying out of
starting-up and adjustment works for the manufacture of new parts
or products, which, in turn, increases the productivity of labor.
In order to accelerate the design of welding technology and
the formation of technological basis for calculation of arc welding
under a layer of flux, the analysis and development of the existing
approaches in this direction it is necessary to systematize the
modern techniques and to create a new high-performance
automated complex for calculation of mode of arc welding under
flux.
а)
b)
Fig. 1 Contact connection without edge preparation (a);
with groove edges (b)
If the total area of deposited metal is more than 0.5 cm2, then
the welding is not performed in one pass. Number of passes is
calculated by the following formula [1]:
F
(1)
n= n ,
F
1
where n is a number of passes; F1= (6 .. 8) del / 100 is a square of
the first deposited weld, cm2; el is a diameter of electrode wire, mm.
The welding current value Isv (A) is determined by the
empirical dependence with the account of number of passes:
(2)
(80..100)  h
I
sv
=
p .
n
Let's calculate the current density j (A/mm2) by the formula:
I ,
(3)
j = sv
F
el
where Fel = πd2el/4 is an area of electrode wire, mm2.
Let us check the conformity of electrode diameter with the
permissible current density according to table 1 for welding under
flux.
Table 1. The dependence of electrode wire diameter on the
density of a current in the welding under flux
2,0
3,0
4,0
5,0
6,0
del , mm
j, А/mm2
65 – 200 45 – 90
35 – 60
30 – 50
25 – 45
2. Prerequisites and solution of the problem
Now in Russian Federation there is a large number of
normative-technical documents, scientific works considering the
calculation of arc welding regime. The variety of approaches
requires the systematization of accumulated material and their
comparison.
Calculation of arc welding mode is an important component
of the process of designing and producing welded metal
constructions.
Obtaining the optimal technological parameters of the
welding process, such as the strength of a current, the voltage on
the arc, welding speed directly determines the quality of the
finished welded product and its performance.
The analysis of different methods of calculating the modes
of arc welding under a layer of flux showed that in the most details
it is described in the writings of Demyantzevich V.P. [1],
Shahmatov M.V. [2].
The calculation is based on the fundamental tenets of the
theory of welding processes [7], developed by the leading scientists
of Russia and CIS countries – Rykalin N.N. [3], Paton E.O. [4],
Demyantzevich V.P. [1], Shahmatov M.V. [2].
In calculating the modes of welding under a layer of flux it
is necessary to follow the recommendation of State Standard
The value of the voltage on the arc Ud (V) of the count under
the formula:
5I
sv  1 ,
(4)
U  20 
d
100  d
el
Speed of welding under flux Vsv (cm/s) is calculated by the
formula:
α I
(5)
н sv ,
V 
sv
.
3600  F  ρ
n
where αн is a deposition rate g/А hour; ρ = 7,8 is the raft of steel,
g/cm3.
Let us carry out the calculation of the coefficient of melting
αр:
(6)
44
k ,
α н  α р  (1 
)
100
Further we define the penetration depth h1 according to the
formula:
q
pog ,
(11)
h1  0,076 
ψ
Let us define the width of a seam b1:
(12)
b1 = h1 Ψ
Determine the height of a seam A1:
a b .
(13)
a1 
where k is a coefficient of losses during the transition melting down
wire in the weld seam, %; αр is a coefficient of melting, g/А*hour.
For welding under a layer of flux the value of the losses of k
can be adopted with some uncertainty of continuing value equal to
5-7%. The smaller value of k is usually taken for the wire with a
diameter of up to 3 mm and more for the diameters of 4..6 mm.
The coefficient of melting αр for welding under a layer of
flux can be determined according to the schedule presented in Fig. 2
and depending on the diameter of welding wire and value of the
welding current.
h1  ψ
For non-standard butt welds (not according to State Standard
Specification) made by one pass the real value of the coefficient of
penetration form ψ = b1 / h1 and the coefficient of the form of roller
ψval = a1 / b1 must be in the following optimal ranges: 0,8 < ψ < 4;
7 < ψval < 10. In this case, if ψ < 0,8 then the tendency of the weld
metal to hot cracking increases (narrow seams with great depth of
penetration), when ψ > 4 the seams are large with a small depth of
penetration with the irrational usage of heat capacity of the arc. If
ψval < 7, then for the tall narrow seams, not having a smooth
interface, there is high concentration of stresses in places of
transition from the weld metal to base that under-leads to low
efficiency of welded joints, especially in the case of variable loads.
When ψval > 10. Then the seams are too broad, what is irrational
from the point of view of use of the thermal capacity of the arc.
For details with the equivalent content of carbon
Cekv > 0,45%, a preliminary heating is necessary, set according to
Fig. 3.
Fig. 2. The dependence of the coefficient of melting αр from
the diameter of the electrode wire and value of the welding current
During the welding mode calculating it is necessary to
conduct a check of satisfactory of weld formation under the
following formula:
(7)
A = Vsv . Isv . 36,
where A is a coefficient of weld formation, A·m/hour; Vsv is a
welding speed, cm/s; Isv is a welding current, A.
Let us substitute values in the formula (7); the derived values
are compared with the selected value of the diameter of table 2
(satisfactory formation of the weld).
Table 2. The dependence of the diameter of electrode wire
on the coefficient A
1,2
1,4 1,6
2,0
3,0
4,0
del , mm
А· 103,А·m/hour
2-5
3-6 5-8
8-12 12-16 16-20
Fig. 3. The temperature of the heating by Seferian’s formula
Electrode wire feed rate Vpod is defined by the formula:
(8)
V F
V

pod
To prevent the formation of hardening structures during
welding it is necessary to conduct the correspondence between the
linear energy welding and permissible cooling rate [2]. Due to the
limited volume of the article detailed nomograms are not shown.
Also, in the calculation, it is necessary to take into account the
influence of the flux at the depth of penetration of the base of the
weld metal. If necessary, it is necessary to make adjustments to the
methodology in the form of correction factors.
Thus, there presented the method of calculation of geometric
sizes of the welds on the parameters of automate arc welding under
a layer of flux.
sv n .
k
F  (1 
)
el
100
For inspection of the main parameters of the welding mode
the amount of heat input welding is calculated:
U I η ,
(9)
d sv
q
pog

V
sv
where qpog is a heat input welding, j/cm; Ud is an arc voltage, V;
ISV is a welding current, A; η is an effective coefficient of useful
action of heating the product by arc, is selected for welding under
flux η = 0,8–0,85; Vsv is a welding speed, cm/sec.
Then let us calculate the real value of the coefficient of the
penetration form ψ:
(10)
3. Results and discussion
For the automation of the calculation the mode of arc
welding under a layer of flux it was developed the computer
program [5, 6], in base of which it is the method presented above
(Fig. 4).
k1  (19  0,01  I )  d  U ,
sv
el d
ψ
I
sv
where K1 is a certain coefficient, 1/mm*V.
A certain coefficient K1 depends on the kind, polarity,
current density and is determined by the table 3.
Table 3. Determination of the coefficient K1 depending on
the kind, polarity and current density
Kind and polarity
of density
Current density
Direct current of direct
polarity
Direct current of reverse
polarity
Alternating current
j ≤ 120 А/mm2
j > 120 А/mm2
к1 = 2,82 j0,1925
к1 = 1,12
к1=0,367 j0,1925
к1 = 0,92
a)
b)
Fig. 4. The appearance of the program with the completed
settlement of the welded joints without edge preparation: «Data
Source» (a); «Geometry of the seam» (b)
к1 = 1
45
The program provides performance of the following
functions:
• enter the geometrical characteristics of the cutting of the
welded product;
• choose the kind and the polarity of current, the diameter of
electrode wire;
• choose the depth of penetration;
• calculation of the strength and density of current, supply
voltage on the arc;
• calculation of coefficients of losses and melting;
• calculation of the speed of the welding electrode wire feed,
heat input welding;
• calculation of the coefficients of the form of penetration
and roller;
• check the calculated parameters and visual indication of
erroneous technological parameters, with the possibility of
adjustments;
• save results of work in the form of special file and the
output of the extended report in a text processor MS Word.
During the calculation received data are automatically
analysed with the included to the program ranges of density,
coefficients of the form of roller and the form of penetration. If the
values do not satisfy the needs-in terms of formation of the weld
geometry, they will be painted in red. The calculation cannot be
continued, if there are inconsistencies. To eliminate them the
mechanism of hints is created, which is activated when you hover
the cursor on the wrong parameter painted in red color.
To verify the compliance of calculated data we conducted an
experiment. Source data: the thickness of the plate is 11 mm; the
diameter of electrode wire is 3 mm; without edge preparation.
The results are presented in Fig. 5 and in table 4.
2. Calculation of the geometric sizes of the welds on the
parameters of the mode of automatic arc welding under a layer of
flux must be conducted with the usage of computer-aided complex.
3. The usage of recommended settings of welding
technology allows controlling the structure and quality of a weld
seam of steel metal constructions.
Literature
1. Akulov A.I. Technology and equipment of welding.
Textbook for students of higher educational institutions / A.I.
Akulov, G.A. Belchuk, V.P. Demyantzevich. - M.: Mechanical
engineering. - 1997. - 432с. Il.
2. Shahmatov M.V. Manufacturing technology and
calculation of welded shells / M.V. Shahmatov, V.V. Erofeev, V.V.
Kovalenko. - Ufa: Poligrafkombinat. - 1999. - 272 p.
3. Rykalin N.N. Calculations of thermal processes in welding
/ edited by academician A.A. Erohina - M.: MASHGIZ, 1951. 291с.
4. Paton B.E. Technology of electric welding of metals and
fusion melting / edited by academician B.E. Paton - M.: Machinery,
1974. - 768.
5. Pat. 2011613354 Russian Federation. Certificate of state
registration of the computer program «Calculation of mode of arc
welding Welding Rate Calculation» / M.A. Ivanov, A.M.. Ulanov. №2011611511; Appl. 9.03.11; registered 28.04.11.
6. Ivanov M.A. The program realization of the calculation of
arc welding mode / M.A. Ivanov, A.M. Ulanov // Science Library:
materials of the 63-th scientific conference. Section of technical
sciences: in 2 vol. - Chelyabinsk: Publishing center of SUSU, 2011.
- T. 2. С.127-130.
7. Comparison of methodological approaches to calculation
of welding mode / M.A. Ivanov, A.M. Ulanov, V.V. Rode, P.A.
Danilkin // Science Library: materials of the 63-th scientific
conference. Section of technical Sciences: in 2 vol. - Chelyabinsk:
Publishing center of SUSU, 2011. - T. 2. С.131-135.
Fig. 5 Welded joint after the experiment
Table 4. Data of calculation and experiment
Vsv, Vpod,
I sv , U d , hp ,
Source data
sm/s sm/s
В
А
mm
ec
ec
b,
mm
a,
mm
2
Experience 1
Experimental
data
Program
calculation
1,0
3,1
440
30
5,5
15
1,0
3,5
440
30
5,6
14,9
2,4
1,0
3,6
480
37
6
17
2,5
0,9
3,9
480
37
16,7
2,4
Experience 2
Experimental
data
Program
calculation
6,12
As you can be see from table 4, the values of experiment are
consistent with the estimates.
4. Conclusion
1. In order to increase competitiveness of Russian enterprises
that produce complex welded metal constructions the reduction of
terms for development of technical documentation for welding is an
urgent task.
46