(PDF) Propagation of Surface Defects at Cold Pilger Rolling of Tubes and Pipes
(PDF) Propagation of Surface Defects at Cold Pilger Rolling of Tubes and Pipes
(PDF) Propagation of Surface Defects at Cold Pilger Rolling of Tubes and Pipes
rydin +1
ersität Paderborn
eiev
tional Metallurgical Academy of Ukraine
of defects transformation during cold rolling the parameter “defect’s relative depth” (RdH) was proposed,
part of wall thickness occupied by defect. It was determined that reduction of outer tube diameter in
s RdH only in case of inclined defects, which are situated on the external surface and oriented
lling direction. In all other cases the reduction of outer tube diameter increases RdH. In contrary, RdH of
efects remains constant or increases after cold pilger rolling. Inner longitudinal folds exhibit the maximal
d probably lead to the propagation of cracks. The change of dimensions of external longitudinal defects
pe of defect`s cross section and such parameter as a part of diameter reduction in contraction of the
hese defects can be partially eliminated at cold pilger rolling. For prediction of defect`s evolution it has
e the DAP index that considers the relationship between strain parameters of cold pilger rolling and initial
research
bers
cations
rojects
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 1/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
Rolling
Iaroslav Frolov
Mirko Schaper
Ol d G di
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 2/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
Vitalii Andreiev*
Rolling
Andrii Tereschenko
Abstract
In present study the propagation and transformation of longitudinal as well as transversal su
defects placed on both external and inner surfaces of cold rolled seamless steel tubes (SST) and
has been experimentally analyzed. Cold pilger rolling of tubes was carried out through diff
rolling routes with variable cross section contractions as well as wall thickness and dia
reductions. For characterization of defects transformation during cold rolling the parameter “de
relative depth” (RdH) was proposed, which is dened as a part of wall thickness occupied by d
It was determined that reduction of outer tube diameter in rolling route decreases RdH on
case of inclined defects, which are situated on the external surface and oriented transversally
rolling direction. In all other cases the reduction of outer tube diameter increases RdH. In con
RdH of internal longitudinal defects remains constant or increases after cold pilger rolling.
longitudinal folds exhibit the maximal intensity of RdH’s and probably lead to the propagati
cracks The change of dimensions of external longitudinal defects depends on both shape of de
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 3/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
cracks. The change of dimensions of external longitudinal defects depends on both shape of de
See all
cross ›
section See all
and such ›
parameter as a part of diameter reduction in contraction of the cross se
Thus, these defects4 Figures Download
can be partially eliminated at cold pilger citation
rolling. Share
For prediction of de Download full-text PDF
12 References
evolution it has been proposed to use the DAP index that considers the relationship between
parameters of cold pilger rolling and initial defect’s shape.
Key words: MANUFACTURING DEFECTS, TUBES AND PIPES, SURFACE, COLD PIL
ROLLING
Rolling
leads to the decreasing of difference between deformation parameters [11].
strength and yield strength of deformed me- All surface defects, which were ob
s is valid for all methods and modes of cold lets, were classied based on their
ation as well as after heat treatment. [4] (RdW0) (equations 1 and 2) as peak (F
intensity of this decreasing depends on strain gular (Fig. 2b) and round (Fig. 2c) def
hnological parameters of cold pilgering. The
mportant of them are the strain distribution
e deformation zone, the thermal condition of
as well as equipment parameters like a length
e or feed volume [5]. The main feature of cold
olling is consequent ovalization of cross sec-
ide working cone. It continuously alternates
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 4/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
See all ›
ss directions See all › and thus, provides
and values Download citation Share Download full-text PDF
d ductility of metal 4even
12 References at high level of accu-
Figures
strain [6].
ever, stress and strain history at cold pilger
can be responsible for surface defects. These
deteriorate the outside view of nished tube
ve as a stress- and corrosion concentrators,
ly under tangential load [7].
he other hand, the quality of surface of cold
d tube is limited by quality of previous hot
billets [8].
mical composition of metal, heat treatment as
deformation mode at hot extrusion determines
metal properties and can provoke surface de-
.
ious investigations of formation of surface
show that there are no consistent opinion
ing the transformation mechanism of these
at cold pilger rolling of tubes. Schulze et al. Figure 2. Examples of initial defect`s cro
0] concluded that control operations in tech- destination of their dimensions: a – pe
al process chain should prevent a formation rectangular defect; c – round defect; h – d
erous defects. However, it is well known that r – radius of defect`s curvature
e defects with small depth can be transformed
cks.
efore, present study is devoted to the analysis
ts behavior at cold pilger rolling with variable
for peak and rectangular defects (Fig. 2
ations of cross section contraction as well as
ckness and diameter reductions. The follow-
e types of defects have been investigated:
ernal longitudinal defects;
ernal longitudinal defects; for rounded defects (Fig. 2c)
ernal transversal defects. where b0 and h0 – initial width and d
erimental procedure and methods of re- respectively (mm);
r0 - radius of curvature of round def
esent study, hot extruded tubes made of steel Further the defects with RdW0 ≥ 1, or R
NS 30400 have been investigated. They have dened as gentle defects and defects w
ected as defect tubes at quality control due to or RdW0R < 0,5 - as sharp defects.
ace defects and then prepared to experimen- All defects were also classied ac
edure. The initial dimensions of defects were relationship between their length (a) an
ed and then these tubes were cold pilger rolled - a ≤ 3b - surface cavity;
ng to the specied rolling routes with variable - 3b≤a≤10b - fold;
Rolling
0b – notch; If the value of IF is less than 0,7, it
→0 – crack. current rolling route take place substan
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 5/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
determination of both
See allstrain parameters at ness reduction. If it equals 0,7 or mo
ger See all ›
rolling and
12 References
propagation›
4 Figures
of defects, the fol- route is Download
characterized
citation by Share
substantial d Download full-text PDF
parameters were used: tion.
in parameters at cold pilger rolling Parameters of defects propagatio
e elongation factor: Relative defect’s depth (RdH) is de
of wall thickness that is occupied by de
, (3) Relative defect’s depth of billet:
s section contraction:
Change of RdH at cold pilgering:
, (4)
Deformation parameters of cold pilger rolling, initial and nal sizes of tubes as well as character
igated ELD
D0 t0 D1 t1 ε Σ, b0 h0 h1 RdH0 R
of defect Route IF RdW0
mm mm mm mm % mm mm mm % %
1a 50 5,5 28 3,5 64,96 0,68 0,28 0,11 2,52 0,10 2,02 2
notches
1b 50 5,5 28 3,5 64,96 0,68 0,33 0,11 2,95 0,08 2,04 2
ngular 2a 57 3,2 32 1,8 68,42 0,64 0,55 0,31 1,79 0,25 9,63 1
es 2a 57 3,2 45 1,5 62,10 0,34 0,81 0,45 1,80 0,19 14,06 1
3a 57 6 28 4 68,63 0,74 0,15 0,38 0,39 0,77 6,33 1
3b 57 6 28 4 68,63 0,74 5,00 1,30 3,85 0,35 21,67 8
ded defects
3c 57 9 31 6,8 61,91 0,74 7,00 0,90 7,78 0,15 10,00 2
3d 57 9 31 6,8 61,91 0,74 6,00 2,50 2,40 1,70 27,78 2
. External defects. Inuence of initial relative defect`s width RdW0 (a) and part of diameter re
ontraction IF (b) at cold pilgering on change of relative defect`s depth Rd
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 6/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
Rolling
ording to the analysis of propagation of exter- in near surface layers and thus, its w
cts the following observations were made: reduced after rolling. Hence, the presen
ernal peak defects. The relative depth of this characterize the transformation of such
ncreases in both researched cases, especially very useful.
of sharper defect (Route 1a, Table 1). This - External rounded defects. For ana
hat for such shape of cross section of defect ior of these defects the rolling routes ha
wed RdH0 should be more than 3. Therefore, values of IF. In these conditions thresho
s with such defects should be rolled through crease and decrease of relative defect’s
with IF≤ 0,7. at values of relative defect’s width abo
ternal rectangular defects. Such type of de- Internal longitudinal defects (ILD
more sensitive to the rolling route. The anal- Deformation parameters of cold pilg
these defects revealed that decreasing of IF tial and nal sizes of tubes as well as ch
n provide good mechanical properties as well mensions of investigated ILD are presen
ce RdH1 below one. On the other hand, such Relationship between calculated va
tend to close at cold rolling stage and develop RdW0 as well as Rd and IF are present
Deformation parameters of cold pilger rolling, initial and nal sizes of tubes as well as character
igated ILD
D0 t0 D1 t1 εΣ, h0 h1 RdH0 R
of defect Route IF b0 mm RdW0
mm mm mm mm % mm mm % %
notch 4a 50 5,5 25 2,35 78,25 0,64 0,04 0,06 0,67 0,08 1,09 3
5a 57 8 32 6 60,20 0,73 1,00 0,80 1,25 0,60 10,00
angular
5b 57 8 40 6 47,96 0,62 1,00 1,00 1,00 0,70 12,50
ts
5c 57 3,2 32 1,8 68,42 0,64 1,00 0,56 1,80 0,47 17,38 2
6a 50 5 28 3,5 61,89 0,71 0,00 0,06 0,00 0,20 1,12 5
6b 57 9 32 4 74,07 0,59 0,00 0,07 0,00 0,05 0,72
4. Internal defects. Inuence of initial relative defect`s width RdW0 (a) and part of diameter red
section contraction IF (b) at cold pilgering on change of relative defect`s depth Rd
are more sharp compare to ELD that corre- inuenced by investigated parameters
with practical experience. That is the reason they tend to close their edges and tra
absence of rounded defects in these experi- undersurface folds that is the same to t
The propagation of ILD at cold pilger rolling external rectangular defects.
l th ELD I l f ld Th i l ti t
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 7/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
mogenously
See allin
than ELD. all ›
› current See
Internal folds. Their evolution at c
k defect study according to above ing conrms a well-known
Download citation opinion: int
Share Download full-text PDF
ed 12 References can
classication 4 Figures
be arranged to the sharp most dangerous defects of tubes. Intens
These type of defects presents threefold in- ness reduction at investigated rolling ro
f RdH1 compare to RdH0 at cold pilger rolling any effect on propagation of RdH1 of
atively small IF value (less than 0,7). Growth of IF index on 20% (from 0,5
nal rectangular defects. These defects are not vokes 2,9 times increase of Rd value.
Rolling
rnal transversal defects (ETD) mensions of investigated ELD are presen
rmation parameters of cold pilger rolling, ini- Relationship between calculated va
nal sizes of tubes as well as characteristic di- RdW0 as well as Rd and IF are present
. Deformation parameters of cold pilger rolling, initial and nal sizes of tubes as well a
ons of investigated ETD
D0 t0 D1 εΣ, t1 b0 h0 h1 RdH0
f defect Route IF RdW0
mm mm Mm mm % mm mm mm %
4a 57 3,2 32 1,8 68,42 0,64 6,70 0,82 8,17 0,39 25,63
ersal peak 5a 57 3,2 32 1,8 68,42 0,64 4,30 0,82 5,24 0,44 25,63
5b 57 3,2 25 1,6 78,25 0,72 6,70 0,82 8,17 0,12 25,63
5c 57 3,2 25 1,6 78,25 0,72 4,30 1,20 3,58 0,32 37,50
e 5. External transversal peal defects. Inuence of initial relative defect`s width RdW0 (a) and pa
reduction in cross section contraction IF (b) at cold pilgering on change of relative defect`s dep
defects. In all researched cases these defects Figure 6 illustrates the dependence
ecrease of their RdH1. In comparison with initial relative defect’s depth at cold
LD, growth of diameter reduction decreases on the index DAP (11). Rd values
Therefore, it can be concluded that for such gated defects continuously decrease w
ype the rolling routes with primarily reduction DAP values.
eter are favorable. However, stress concentra-
these defects is dangerous and can provoke
of tube at rolling.
performed observations demonstrate that lon-
Rolling
illustration could help to predict defect’s defects and planned deformation para
basing on previous identied initial dimen- pilgering.
defects and planned deformation parameters References
pilgering. 1. Hilbert, Lisbeth R, Dorthe Bag
instance, route 1a (Table 1) has IF of 0,68. Kold, Lone Gram (2003). Inu
ak defect exhibits RdW0 of 2,52. DAP index roughness of stainless steel on
ase is 3,7 that is less than 4,5. Therefore this hesion and corrosion resistance
t such rolling route has a high possibility to Biodeterioration & Biodegrad
rther at cold rolling. After rolling the value of 52, Issue 3, pp. 175-185, ISS
as increased from 2,02% to 2,86%. Index Rd Available at: http://dx.doi.org/1
case equals 1,42. Thus, the part of damaged 8305(03)00104-5.
ckness has increased and this billet cannot be 2. Surfaces of stainless steel tube
hrough this rolling route. tps-technitube röhrenwerke gm
efore, this billet can be further rolled, for ex- at: http://www.tpsd.de/downloa
in tube 28x2 mm instead of 28x3,5 (see rout osindt_surfaces_en_27.pdf
le 1) with other deformation parameters. In 3. Brensing, K.-H., Sommer B., S
e, IF index is 0,56 and DAP index is 4,51 that pipe manufacturing processes
ue of DAP index corresponds to the minimal http://www.mrw.de/download
engl.pdf
ity of defect growth and thus, suggested roll-
4. Frolov Ya. V. (2010). Effect o
e is appropriate for billet with such defect.
Conditions on Mechanical Prop
clusions
During Tube Cold Pilger Rollin
old pilger rolling due to their favorable defor-
cal and Mining Industry, Vol
conditions allows to decrease the depth of
36-38. Open access: http://meta
pes of defects. Mostly it is right for transver-
images/statti/frolov/mechanic
le defects on external surface. In this case re-
ties%20at%20cold%20pilger%2
of diameter in rolling route plays a positive
5. Frolov Ya. V., Danchenko V. N
eferences (12)
(2012). Defects introduced into Metals during Fabrication and Service. Materials science Vol. ІІІ, UK
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 10/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
quality. Metallurgical Technology. Seninar Plastic deformation of metals at National metallurgical academy of
cess: http://metal-forming.org/images/statti/frolov/client-oriented-quality-en.pdf
ufacturing processes
r
B., Steel tube and pipe manufacturing processes. Available at: http://www.mrw.de/downloads/stahlrohre_
le
anchenko
ysis on the initiation and propagation of circumferential and longitudinal cracks in straight pipes and
ES
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 11/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
R · ESee
BODMANN
all › See all ›
Download citation Share Download full-text PDF
12 References 4 Figures
Show more
Recommendations
Project
View project
Project
View project
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 12/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
View project
Project
Development of multi- scale model of recrystallization, that occurs in fine wires from biocompatible Mg alloys during drawing at
elevated temperature for diameters of wires, comparable with the siz ... [more]
View project
Article
THE INVESTIGATION OF THE MAXIMUM POSITION IN CONTACT NORMAL STRESSES RELATIVE TO THE NEUTRAL
PLANE B...
March 2015 · Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya
Ya. D. Vasilev · M. I. Zavgorodniy · D. N. Samokish
Ascertained data as to the character of the contact stresses distribution have been obtained thanks to the application of the
ascertained solution for the differential equation of longitudinal forces’ balance by the cold rolling. The mentioned solution takes
into account the kinematics particularities of a deformation zone. These data have been used to determine the position of the
maximum in ... [Show full abstract]
Read more
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 13/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
Experimental pressure histories, axial and circumferential strains, and crack-opening shapes were compared with the predictions
of a simplified model of a fracturing pipe. This model, based upon previous analytical and numerical studies, assumed that the
axial strains were negligible. The comparison showed that this assumption was valid only for relatively thickwalled pipes. An
analytical energy ... [Show full abstract]
Read more
Article
COLD STRENGTH AND FRACTURE RESISTANCE OF WELDED JOINTS IN GAS TRANSMISSION PIPES.
November 1984
V.N. Goritskii · A.S. Bolotov
A method of full-scale testing was developed for comparative evaluation of the cold strength and resistance of welded joints in
gas transmission pipes to fracture propagation. It is based on the simultaneous initiation of a crack in the welded joint and parent
metal of a pneumatically loaded pipe followed by determination of the fracture characteristics used in the standard methods. The
results ... [Show full abstract]
Read more
Comparison of strip deformation between the contour roll forming (CORF) process and cage roll formin...
January 2012
Mohammad Mehdi Kasaei · H. Moslemi Naeini
One of the most important applications of cold roll forming process is the manufacturing of high frequency welded (HFW) pipes.
Two of the most commonly used methods to produce HFW pipes are Contour roll forming (CORF) and cage roll forming (CARF)
processes. Main objective of this paper is scientific comparison of strip deformation between CORF and CARF processes. So, the
CORF and CARF process are ... [Show full abstract]
View full-text
Discover more
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 14/15
4/3/2020 (PDF) Propagation of surface defects at cold pilger rolling of tubes and pipes
Company
See all › SeeSupport
all › Business
solutions Download citation Share Download full-text PDF
12 References 4 Figures
About us Help
News Center Advertising
Careers Recruiting
© 2008-2020 ResearchGate GmbH. All rights reserved. Terms · Privacy · Copyright · Imprint
https://www.researchgate.net/publication/310465276_Propagation_of_surface_defects_at_cold_pilger_rolling_of_tubes_and_pipes 15/15