BED FRAME FABRICATION FOR HEAVY DUTY MACHINE TOOLS [627788]

BED FRAME FABRICATION FOR HEAVY DUTY MACHINE TOOLS
OR UNIQUE OF HIGH STRENGHT MATERIALS QUEND 700
Claudiu Ioan RUSAN , Cornel CIUPAN
Technical University of Cluj -Napoca, Faculty of Machine Building, Cluj -Napoca, Romania
e-mail: [anonimizat] , [anonimizat]

ABSTRACT

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KEYWORDS: high strength steel, cold bending, hot bend ing, metal rolling,

1. Introduction
This theme falls into the field of engineering
sciences and materials sciences, aiming to identify
new technologies and solutions for the construction of
specific machine tool parts, such as base of structure s,
bed fr ames, columns , etc and unique large size parts.
The purpose pursued by this work is to provide
solutions to reduc ing the masses , reducing material
consumption, reduc ing costs and manufacturing time
by using high strength steel products on the market.
Each machine tool has a certain constructive
form, dictated by the size and configuration of the
workpieces, the size of the stresses produced by the
cutting forces and several requir ements: functional,
ergonomic, and aesthetic .
The most important part, which m ostly ensures
the shape of the machine tool is the frame, because the
parts or component subassemblies of the machine
tools are mounted on the frame, with their freedom to
perfor m relative or fixed movements.
The materials used in the construction of the
frames must ensure good thermal conductivity, high
corrosion resistance and adequate mechanical
strength. The frames can be made in various variants,
such as the following materia ls: gray cast iron,
malleable cast iron, globular cast iron, alloy cast iron
and steel, but they can also be made of welded
construction of sheet metal, laminated profiles , etc.
Steel, in the construction of frames, is recommended
for those who work with h igh cutting forces , shocks
and vibrations .

The resistance conditions inf luence the
constructive form of the bed frames by the idea that it
must ensure:
– high rigidity to exclude elastic deformations
that occur during machining process but also to ensure
the part , a dimensional accuracy according to the
requirements ;
– adequat e resistance to vibration to ensure
higher quality surfaces.

Fig. 1. Rectangular profile bed frame with
circular section
2. Bed frame elements made from
fabricated steel -sheet products for welded
construction
Regarding the realization of the bed frame
elements by bending thick sheet metals, we can
highlight several possible methods, for example : cold
deformation , hot deformation, cold deformation after
soft annealing.

The methods presented above have been applied
experimentally, in turn to study and define an optimal
technology for manufacturing the flat plates curved
bed frame elements of high -strength materials such as
Quend 700.
The following figure illustrates the cylindrical
frame element made of sheet metal with a wall
thickn ess of 50 mm and the quality of the material
being Quend 700. Thus, during the development of the
part, it is necessary to have an addition of material that
will later be used making samples for mechanical tests
and to study the behaviour of the material d uring the
processes.

Fig. 2. Execution drawing a nd development of
the part
Cylindrical and conical sheet metals rolling
are obtained by bending between the rollers of rolling
machines and welded along the generating line, so that
the laminating fibre o f the sheet obtained by rolling is
in the annular direction (maximum load direction in
the case of bed frames).
2.1. Cold deformation method
Cold deformation of sheet metal is done with
the help of bending presses (“abkant”) and rolling
machines. Bending presses are used for pre -bending
the ends of the sheet metal, this is mainly necessary
when inserting it between the bending roller of the
rolling machine.
The cold pre -bending of the Quend 700 sheet
metal on bending presses required a very high pressing
force, because we need to overcome the mechanical
properties of the material. If the pressing force does
not overcome the me chanical properties of the
material will result the appearance of the springback
phenomenon and the inability to achieve th e pre –
bending.
According to this method was tried cold pre-
bending of Quend 700 on an Ermaksan Power -Bend
which develops a pressing force of 1000 tons over a
length of 7100 mm . A punch with a radius of 50 mm
and a lower die with an opening of 500 mm were used
on the press machine , setting the properties of the
material and the bending length of the p art at 1376
mm, result the maximum force developed by the
machine are around 300 -350 tons /meter .

Fig. 3. Press machine, Ermaksan Power -Bend
7100×1000 Ton
Conseq uently cold pre-bending of Quend 700
has failed due to the fact that this material has a very
high yield strength of at least 700 M Pa and t ensile
strength around 780-930 MPa, but mainly due to the
inability of the equipment to develop a sufficiently
high pressing force .

Fig. 4. Abkant lower die with opening of
500 mm
According to the input data, the thickness and
bending length of the part, bending tools, we can
estimate the effective pressing force F max required to
achieve the pre -bending with the formu la below.
𝐹𝑚𝑎𝑥 =1,6 𝑅𝑚 𝑡2 𝛼
10 𝑉 [𝑡𝑜𝑛𝑠
𝑚] (1)
Where, R m is tensile strength in N/mm2, t is
sheet thickness in mm, α are angle coefficient in
degrees (for 900 →1; 300 →1,6; 600 →1,6; 1200 →1,6;
1500 →0.7) and V is die opening in mm.
𝐹𝑚𝑎𝑥=1,6 𝑥 930 𝑥 502 𝑥 0.7
10 𝑥 500=520 ,8 [𝑡𝑜𝑛𝑠
𝑚] (2)
addition for
samples

2.2. Hot deformation method
Hot deformation method consists in pre-
bending and rolling the flat plat e according to the
following steps :
– heatin g the flat plate to 750⁰ C in the electric
oven and performing the pre -bending operation on
bending press;
– after the pre -bending on the flat plate follows the
rolling on rolling machine 80×3500 up to a curvature
value of R700;

Fig. 5. Rolling machine 80×3500
– reheating the semi -finished product to 750° C and
transported to another rolling machine, AKYAPAK
Type AHS 25/35, capable of achievin g the radius of
curvature below R700 to close the cylindrical product
with the addition of pre -bent material;
– the next operation is to cut the pre -bend addition
(2×250 mm) and make the chamfers on the generators;
– then a final heating is done at 750° C to complete
the closing of the shell at a radius of R370 and spot
welding on rolling machine, AKYAPAK Type AHS
25/35 before the release forces of rollers.

Fig. 6. Closing of the shell at a radius of R370
and spot welding on rolling machine AKYAPAK
Type A HS 25/35
This method of manufacturing cylindrical
frame elements from Quend 700 has been successfully
developed but has some disadvantages that are no t
suitable for mass production , such as: the energy
consumed by the electric oven is high for many
heating and preheating , the mechanical properties of
the material decrease and after the tests show, the
tensile strength around 550 MPa and yield strength
around 5 00 MPa .
Due to the results obtained from this method
will arise a third method shown below .
2.3. Cold deformation method after soft
annealing
Cold deformation method after soft annealing is
characterized of cold pre -bending and rolling after a
single heating at 750° C and cooling in air of the flat
plate product.
This method follows the phases of operations
from the previous variant only this time the semi –
finished product does not have to be heated during t he
pre-bending and rolling operations :
– performing the pre -bending operation on bending
press
– after the pre -bending on the flat plate follows the
rolling on rolling machine 80×3500 up to a curvature
value of R700;
– transported to another rolling machi ne,
AKYAPAK Type AHS 25/35, capable of achieving
the radius of curvature below R700 to close the
cylindrical product with the addition of pre -bent
material;
– cutting the pre -bend addition (2×250 mm) and
make the chamfers on the genera tors;
– after which a last a final closing operation of the
shell at a radius of R370 and spot welding on rolling
machine, AKYAPAK Type AHS 25/35 before the
release forces of rollers.
According to the input data, the thickness and
bending length of the par t, bending tools, knowing the
tensile strength after soft annealing , according to the
table 7, we can estimate the effective pressing force
Fmax required to achieve the pre -bending with the
formula below.
𝐹𝑚𝑎𝑥 =1,6 𝑥 550 𝑥 502 𝑥 0.7
10 𝑥 500=308 [𝑡𝑜𝑛𝑠
𝑚] (3)
In conclusion, the heat treatment applied to
this method aims at improving the plasticity properties
of the material and is applied as a preliminary heat
treatment before cold de formatio n, the temperature of
the operation being approximately 750 ° C, it being
adopted depending on the chemical composition of the
steel and the allotted time being between 1 -2 hours ,
followed by a cooling in the air . At the same time, at
the end of the fabrication of the cylindrical frame
element, an improvement treatment must be applied
according to table 9, to raise its mechanical properties
at least close to the initial state.

3. Technological stages
The technological stages follow step by step th e
process regarding the realization of the cylindrica l and
conical sheet metals rolling , from the dimensioning
phase of the flat sheet metal until its complete closing,
these st ages are presented in more detail below .
3.1. Dimensioning the development
Calculat ion the length of the cylindrical sheet metal
development:
𝐿=𝜋∗ሺ𝐷𝑖+𝑠ሻ [𝑚𝑚 ] (4)
Where, Di is inside diameter in mm, s is sheet
thickness in mm, H are height of cylindrical part in
mm.

Fig. 7. Cylindrical sheet metal development
For calculating the development of a conical
part, it is necessary t o determine several geometric
parameters highlighted in the formulas below :
𝐷𝑚=𝐷𝑖+𝑠
cos𝛼[𝑚𝑚 ] (5)
𝑑𝑚=𝑑𝑖+𝑠
cos𝛼 [𝑚𝑚 ] (6)
𝐺=𝐻
cos𝛼 [𝑚𝑚 ] (7)
𝑡𝑔 𝛼=𝐷𝑖−𝑑𝑖
2𝐻=𝐷𝑚−𝑑𝑚
2𝐻[0] (8)
𝛽=2𝜋sin𝛼[𝑟𝑎𝑑 ] (9)
𝑅𝑝=𝜋𝐷𝑚−𝑏
𝛽 [𝑚𝑚 ] (10)
𝑟𝑝=𝜋𝑑𝑚−𝑏
𝛽 [𝑚𝑚 ] (11)

Where, is sheet thickness in mm , Di is
maximum inside diameter in mm, di is minimum
inside diameter in mm, Dm is maximum average
diameter in mm, H are height of conical part in mm, G
is side length of development in mm, b is the loft of
conical sheet metal in mm, Rp is external radius of
developm ent in mm, rp is internal radius of
development in mm.

Fig. 8. Geometric parameters of conical par t
and development
3.2. The pre -bending process
According to figures 8 it is necessary to leave an
addition at both ends to the length of the initial
development since cutting , in order to be able to
achieve the pre -bending on the press machine, this
addition is necessary to have support on the lower die
and the grip the pre -bend sheet metal on rolling
machine.

Fig. 9. Development with pre -bending line

The length of the development without the
addition of pre -bending on the ends is 2479.7 mm, see
figure 2 . With help of x-axis limiters of the press
machine will be press on the line according to the
dimensions on the development with pre -bending line
drawi ng, figure 9, and respecting the bending angles.
The bending start from the length of 869.3 mm and
will continue to the edge to a length 250.8 mm, with
several bends equal to 14 and the size of step is equal
to 47,6 mm.

Fig. 10. Pre-bending on press mach ine of the
sheet metal ends at a radius R370
At the end of the bending process, a radius check
will be p erformed using a template with R370 mm on
the entire width of the pre-bending sheet metal . The
same will be done for bending the other end.
3.3. Rolling process of pre -bending plate
After pre -bending on press machine, it follows
rolling on AKYAPAK Type AHS 25/35, capable of
achieving the radius of curvature below R700 to close
the cylindrical product with the addition of pre -bent
material .

Fig. 11. Curving the pre -bending plate on
rolling machine
3.4. Debitare exces de material
After pre -bending and rolli ng process, the
addition left to the pre -bending process will be cut and
then chamfers will be made for welding process.
Cutting and chamfering will be performed in this case
using manual plasma cutting device, followed by
adjustment of the chamfer with an angle grinder acc.
to the WPS (Welding Procedure Specification )
documentation .

Fig. 12. Manual plasma cutting of the pre -bend
addition

Fig. 13. Chamfering at both
ends of the cut addition

3.5. Final rolling process
After cutting the pre -bend addi tion and making
the chamfers in the longitudinal direction , next is final
closing operation of the shell at a radius of R370 and
spot welding on rolling machine, AKYAPAK Type
AHS 25/35 before the release forces of rollers.

Fig. 14. Final closing operatio n of the shell at a
radius of R370 and spot welding on rolling
machine
3.6. Welding process and cutting addition
Welding process is a very important stage, it
consists in the complete welding of the longitudinal
loft according to the technology presented i n chapter
four, finishing it by grinding and removing of spit .
Also, in this stage, the addition of 200 mm kept for
mechanical test shall be cut from the length of metal

shell and the weld will be checked by the personnel
responsible for performing the n on-destructive and
quality control.

Fig. 15. Preparation of metal shell for welding
process

Fig. 16. Completion of the welding operation
3.8. Calibration process
Calibration is the technological operation by
which the deviations from the circularity of the
sections are eliminated of cross sections in our case a
cylindrical and conical sheet metals . Calibration
applies only to rigid cylindrical and conical sheet
metals, characterized by a ratio between the wall
thickness (s) and the inside diameter ( Di), which meets
the criterion in the equation below .
𝑠
𝐷𝑖>0.01 (12)
The calibration is also performed on the rolling
machines and involves the following steps:
– checking the shape deviations of the cylindrical
sheet metal to be calibrated and establ ishing the r c
calibration radius (the radius at which the rolling
machine is adjusted);
– preparing the cylindrical sheet metal , usually
consisting in grinding the longitudinal increased
height of weld;
– tightening the cylindrical sheet metal between
the upper roller of the machine and the side rollers to
ensure th e calibration radius
– checking the quality (shape accuracy) of the
calibrated cylindrical sheet metal.
4. Custom w elding procedure
specification
Welding of Quend 700 can be performed using
any o f the conventional welding methods available
both as manual and robotic welding. In the thickness
range up to 30 mm, if a heat input of 1,7 kJ/mm is
used, preheating prior to welding is not needed.
Welding of Quend 700 is recommended to be
performed at amb ient temperature not lower than
+5°C. Subsequent to welding, let the welded parts
slowly cool down to room temperature. Do never
accelerate the cooling process of the weld. It is always
recommended to use low hydrogen electrodes when
welding Quend 700. []
Table 1. Welding Procedure Specification
(EN ISO 15609)
Transfer mode dip + spray + globular
Welding process 135(MAG; GMAW)
Joint type BW
Weld preparation
details (sketch)
Method of
preparation and
cleaning grinding
Parental material
specification S690 QL
QUEND 700
Material thickness t1 =50 [mm]
t2 =50 [mm]
Welding position PA (Flat Position)
Filler metal EN ISO 16834 -A: G 69 4 M
Mn3Ni1CrMo / AWS A5.28:
ER100S -G
Classification and
trade name FILCORD 100
Gas (Shielding) EN ISO 14175:
M21 – Arc – 18
Gas flow rate
(Shielding) 15÷18 [l/min]
Gas Nozzle
(diameter) Ø16 [mm] inside diameter
Details of back
gouging/backing bs (both sided welding;
root grinding and backing
run)
Preheating
temperature Tp = +150 [șC]
Interpass
temperature +150 oC ≤ T ≤ +185 oC
Post-weld heat
treatment NA
Heating and cooling
rates NA
Weaving (maximum
width of run) string beads
Stand -off distance 15 ÷ 22 [mm]
Torch angle Lead angle = 10°- 20°

Table 2. Welding details
Run Tack+1 2÷8 9÷n
Process 135 135 135
Size of
filler metal Ø1,2
[mm] Ø1,2
[mm] Ø1,2
[mm]
Current 180÷190
[A] 260÷280
[A] 250÷270
[A]
Voltage 21÷23 27÷29 25÷27
Type of current/
polarity DC+ DC+ DC+
Wire feed
speed 5÷6
[m/min] 9÷10
[m/min] 7÷8
[m/min]
Travel
speed 13÷17
[cm/min] 26÷37
[cm/min] 22÷31
[cm/min]
Heat input
Max. 10672
÷
16135
[J/cm] 9107
÷
14990
[J/cm] 9677
÷
15905
[J/cm]
Transfer
mode dip spray globular

Fig. 1 7. Joint design sketch

Fig. 18. Welding sequences
5. Properties of high strength material
QUEND 700
The foll owing Quend product mix is
currently available of thickness 4 -64 mm and width
1500 -3100 mm. []
3.1. Properties in laminated state

Table 3. Mechanical properties []
Yield strength
Rp 0.2
[MPa] Tensile
strength Rm
[MPa] Elongation
A5
700 min 780-930 14% m in

Ultrasonic testing (UT) is used to identify
such discontinuities as inclusions, cracks, and
porosity. In thickness from 8 mm and higher, all plates
are UT tested and controlled against class S2, E2 in
accordance with EN 10160. []
Table 4. Impact tough ness
Minimum values at
0⁰ C -20⁰ C -40⁰ C
35 J 30 J 27 J

Table 5. Carbon equivalent, typical value, %
Plate thickness [mm] CEV(1) CET(2)
4 – 15 0.45 0.29
15.01 – 25 0.44 0.30
25.01 – 40 0.45 0.30
40.01 – 64 0.54 0.33

CEV = C+Mn/6+(Ni+Cu)/15+(Cr +Mo+V)/5 (1 3)
CET = C+(Mn+Mo)/10+Ni/40+(Cr+Cu)/20 (14)

3.2. Properties after partial or total after
soft annealing
Table 7. Mechanical properties after tempering
Material: plate 50 [mm]
Quality: QUEND 700
Sample
number 1 2 3
The heating
temp. of
sampl e [⁰C] 25
(laminated
state) 750 750
The force [N]
obtained in
the test d 0= 10
[mm] 70000 44500 44000
Rm [M Pa] 891 566 506
Rp [M Pa] 853 501 506
A5 [%] 15 19 20
Z [%] 62.6 71.3 70.7
Impact
toughness
KV ( -40⁰ C)
[J] 162 44; 60; 82 →
transversal

104; 10 6; 86 →
longitudinal

Table 6. Chemical composition
C Si Mn P S Nb Cr V Ti Ni Al Mo N B
0.20 0.60 1.50 0.02 0.01 0.04 0.60 0.07 0.04 1.00 0.07 0.50 0.014 0.005

Table 8. Mechanical properties when the material are heated
Material: plate 50 [mm] , Quality: QUEND 700
Sample
number The heated
temp. of
sample [⁰C] Temperature of
testing sample
[⁰C] The force [N]
obtained in the
test d 0= 10 [mm] Rm
[Mpa] Rp
[Mpa] A5 [%] Z
[%]
1 950 550 17500 220 – 40 94
2 950 510 19000 242 – 38 91
3 950 450 24500 312 – 44 87
4 780 400 37500 477 – 26.4 86.5
5 510 350 46500 592 – 15.3 84.8
6 460 300 61000 777 – 15.3 84
7 430 250 63500 808 – 15.3 68.6
8 350 200 66000 840 – 16.7 67.5

Table 9. Mechanical properties after improvement treatments in water and oil
Material: plate 50 [mm] , Quality: QUEND 700
Sample
number The kind of
improvement
treatments The force [N]
obtained in
the test d 0=
10 [mm] Rm
[MPa] Rp
[MPa] A5
[%] Z
[%] Impact
toughness
KV ( -40⁰ C)
[J]
1 25 (laminated state) 70000 891 853 15 62.6 162
170
2 The quenching in
water at 900˚C and
tempering at 580˚C
with an hour's
keeping with air
cooling 63500
64750 808
824.8 745
789.8 14
14 69
68 36; 30; 1 8 →
transversal
102; 120; 116 →
longitudinal
3 The quenching in
oil at 900˚C and
tempering at 580˚C
with an hour's
keeping with air
cooling 55000
51000 700
719 630
635 18
15 72.9
66 22; 18; 34 →
transversal
94; 42; 102 →
longitudinal

Concluzii
Nașterea variantei 3 s -a datorat faptului efectuari diferitelor incercari facute la varianta 2 in care s-a
observat scaderea considerabila a proprietatilor mecanice asupra materialului supus la temperaturi de peste 550
°C .

Table 10. The final improvement treatments in water
Material: plate 50 [mm], Quality: QUEND 700
Sample number 1 2
Outside
of the
piece 3
Inside
of the
piece 4
Middle
of the
piece
Improvement treatments 25 (laminated
state) The quenching in water at
900˚C and tempering at 580˚C
with an hour's keeping
The force [N] obtained in the
test
d0= 10 [mm] 70000
70000 62000
64000 60000
59500 56000
56500
Rm [M Pa] 891
891 789
815 706
700 713.4
719.7
Rp [M Pa] 828
834 739
738 677
616 649
662.4
A5 [%] 15
15 19
17 24
24 26
26
Z [%] 62.6
71.8 71.2
67.5 68
72 70.8
69.7
Impact
toughness
KV
[J] -40 [⁰ C] 162
170 260
220 286
240 106
80
-20 [⁰ C] 178
184 280
272 205
192 218
206
0 [⁰ C] 174 276 280 212
+20 [⁰ C] 187 274 184 240

Concluzia rezultată a fost aceea că
preîndoirea și virolarea să se realizeze la cald,
astfel s -a realizat o prima serie de epruvete de
tracțiune și reziliență pentru a vedea in special
cum este afectată Rm in funcție de temperatură .

Fig. 8. Epruvete de tractiune;

Fig. 9. Rezistența mecanica influențată de
temperatura;

Conform buletinului de incercări
rezistența mecanică scade in funcție de creșterea
temperaturi conform fig uri de mai su s, ceea
ce ne ajută in continuare la realizarea preindoiri
și virolări la cald explicată in varianta 2.

Varianta 2 : Peîndoir ea și operați a de
virol are la cald
Respectand urmatorele faze:

– íncalzirea semifabricatului pana la 750
°C in cuptorul electric de detensionare si
realizarea operatiei de preindoire pe
Abkant;

– dupa realizarea preindoirii pe Abkant
urmeaza virolarea semifabricatului
preindoit p e calandrul pana la o valoare
mai mica de R700 (cat a permis valtul
superior );

– reincalzirea semifabricatului pana la 750
°C si transportarea acestu ia pana la
calandrul capabil de realizare a razei de
700 mm, pentru a realiza inchiderea
virolei cu adaosul de prelucrare;

– urmatoarea operatie este aceea de
debitare a adaosului de preindoire
(2x250mm) si realizarea sanfrenelor;

– dupa care se realizeaza o ultima incalzire
tot la 750 °C pentru a finaliza inchiderea
definitiva a virolei la raza de R370 si
puncta rea acesteia pe calandrul inainte
de eliberarea fortelor din valturi;

– in continuare se realizeaza sudarea
longitudinala completa a virolei;

– urmata de o faza de finisare a sudurilor
si suprainaltarilor;

– ultima faza fiind calibrarea acesteia pe
calandru .

v

Fig. 10. Preîndoirea pe Abkant a capetelor
tablei Quend 700 scoase din cuptor la raza de
R370;

Fig. 11. Masina de virolat tabla 80×3500;

Fig. 12. Manipularea semifabricatului preîndoit
dupa încalzirea acestuia;

Fig. 13. Realizarea haftuirii ( sudura in puncte) pentru
pastrarea zonelor apropriate in momentul eliberari fortelor
aplicare de valțuri;

Fig. 14. Sfarsirea operatiilor de virolare la cald si
evidentierea zonelor care urmeaza a fi sudate continuu;
Concluzia rezultată in urma aplicări
variantei 2 este aceea ca in urma supuneri acestei
table/semifabricat la incălziri repetate de 750 °C,
ea a inceput sa isi piarda proprietatile mecanice
considerabil de aceea in continuare a urmat o serie
de ince rcari mecanice realizate asupra unor
epruvete.

Fig. 14. Bucati din care au fost realizate epruvete
impartite dintr -o bucata din adaosul de
preindoire ;

Fig. 15. Buletin de incercări cu rezultatele incercarilor epruvetelor din materialul care a urmat
ciclul virolei ;

Fig. 1 6. Rezultatele testelor de imbunatatire ( ridicarea proprietatilor mecanice) aplicate
asupra materialului care a urmat ciclul virolei ;

Datorită scăderi proprietătilor mec anice
a virolei in urma incalzirilor care au avut loc in
continuare s -a facut teste pentru incercarea de a
ridica proprietatile mecanice cat mai apropriate
de cele din starea de livr are.
Varianta 3
Realizarea virolari la rece dupa o singura
incalzire la 75 0°C și răcire in aer a
semifabricatului plan.

Nașterea v ariantei 3 s -a datorat faptului
efectuari diferitelor incercari facute la varianta 2
in care s -a observat scaderea considerabila a
proprietatilor mecanice asupra materialului
supus la temperaturi pes te 550 °C .

Astfel dupa incalzirea semifabricatului plan
la o temp. de 750 °C si racirea acestuia in aer,
urmeaza fazele operatiilor de la varianta 2 doar
ca de ace sta data virola nu mai trebuie incalzita
pentru deformarea plastica (la rece).
Pe scurt :
-se realizeaza preindoirea capetelor
semifabricatului plan ;
-se realizeaza virolarea pentru inchiderea
acesteia cu adaosul de preindoire 2×250[mm] pe
masina de virolat table AKYAPAK Type AHS
25/35;
-virola va merge la debitare unde se
indeparteaza adaosul lasat la preîndoire si se
executa șanfrenarea acesteia pe zonele unde s -a
debitat;
-se realizeaza din nou o virolare pentru
inchiderea acesteia (dupa ce sa debitat și
șanfrenat) și haftuirea acesteia;
-se realizeaza sudura completa a
acesteia;
-merge la finisare unde se ajusteaza
sudura atat pe exterior cat si pe interior daca este
cazul;
-și in final se realizează o calibrare
pentru c are se elimină abaterile de la
circularitate;
Varianta 3 este cea mai productiva si
economica varianta deoarece are loc doar o
singura incalzire a semifabricatului plan la 750
°C iar dupa racirea acestuia se vor realiza
operatiile de deformare plastica la rece.

Insa proprietatile mecanice ale piesei
rezultate scad la o valoare inferioara fata de cele
din certificatul de calitate a meterialului
QUEND 700 si anume la urmatoarele valori
conform certi ficatelor de incercari de mai sus:
rezistenta mecanica aprox. Rm= 5 63 [Mpa],
limita de curgere Rc= 503.5 [Mpa] dar in schimb
o rezilienta (KV) foarte buna la – 40 ș C in jur
de 98 (J) pe fibra longitudinala.

Datorita rezultatelor obtinute in urma
incerca rilor realizate pe epruvete si gasirii unui
tratament adecvat pentr u readucerea
proprietatior mecanice in continuare a avut loc
aplicarea tratamentului de imbunatatire (calire
900° C + revenire ≈ 550 ș C) efectiv pe virole
(piese).

Fig. 1 7. Aplicarea t ratamentului de călire;
Dupa realizarea tratamentului termic de
imbunatatire se face decuparea virolelor in
zonele indicate pe desenul de executie dupa cum
se observa in figurile alaturate.
Iar din materialul ce va cadea la decupare
se vor realiza o serie de teste si incercari fizice.

Fig.19. Rezultatele testelor de duritate ;

Fig.18. Prelevarea epruvetelor din grosimea
virolei d upa tratamentul de îmbuntatire;

Incercarile de tractiune, rezilienta si
duritate s -au realizat din materialul cazut la
decupare exemplificat mai sus (practic a urmarit
tot ciclul de realizare a virolei ) si au constat in
realizarea unor serie de epruve te atat din zona
exterioara, interioara si miez pentru a vedea
efectul tratamentului de imbunatatire in toate
zonele din masa mate rialului.
De obicei sau de cele mai multe ori cea
mai slab afectata zona in cazul unui taratament
termic de imbunatatire (calire + revenire) este
zona medie sau miezul piesei.

Fig. 20. Rezultatul incercarilor mecanice ;
5. CONCLUZII Quend is recommended for the following applications: ——truck chassis;
——lifting equipment;
——handling and charging
6. REFERINȚE

Datorită scăderi proprie tătilor mecanice a virol ei in urma incalzirilor care
au avut loc in continuare s -a facut teste pentru incercarea de a ridica
proprietatile mecanice cat mai apropriate de cele din starea de livrare.
Quenching and tempering are processes that strengthen and harden materials like steel and
other iron-based alloys. The process of quenching or quench hardening involves heating the
material and then rapidly cooling in water, oil, forced air or inert gases such as nitrogen.
Secțiune de batiu cu profil dreptunghiula r de tip cadru cu secțiuni inel are combinate

In this study, the effects of tempering thermal treatment on the microstructural and
properties behaviour of 0.22wt pct C microalloyed steel were investigated. The microalloyed steel
samples were austenitized a nd quenched to produce a lath martensite followed by annealing in
intercritical region (á+ë) and subsequently quenched to produce a dual phase of ferrite -martensite
microstructure. The specimens were subsequently tempered at temperatures of 250, 350 and 45 0
C for 1 hour . The microstructures, tensile o and impact toughness properties of these steels were
analyzed and compared with the microalloyed steel that were conventionally quenched and
tempered. The result showed that tempered dual phase microalloyed st eel samples si gnificantly
exhibited superb mechanical properties including higher tensile strength, ductility and impact
toughness as compared with that of conventionally quenched and tempered steel samples.

5. CONCLUZII
6. REFERINȚE
http://www.rasfoiesc.com/educatie/fizica/
Material: plate 50 [mm]
Quality: QUEND 700
Sample
number The heating
temp. of
sample [⁰C] The force
[N]
obtained
in the test
d0= 10
[mm] Rm
[Mpa] Rp
[Mpa] A5
[%] Z
[%] KV ( -40⁰ C)
[J]
1 25
(laminated
state) 70000 891 853 15 62.6 162
2 750 44500 566 501 19 71.3
44; 60; 82 → transversal
104; 106; 86 → longitudinal 3 750 44000 560 506 20 70.7
TEHNOLOGII -DE-PROCESARE -A-META68.php