Indian Joual of Fibre & Textile Research Vol. 24, June 1 999, pp. 93-98 Wear characteristi cs and performance of spinning rings G D Batwal, T L Paradkar & A N Desai The Bombay Textile Research Association, L B S Marg, Ghatkopar est), Mumbai (0 086, India Received 18 May 1 998; revised received and accepted 16 July 1 998 The physical, geometrical and metallurgical properties such hardness, elemental composition, grain structure, nature of hardness, surface smoothness and geometrical profile of the various makes of imported and indigenous spinning rings have been critically analysed to study the performance of these rings in terms of end breakage rate, traveller damage and ya quality. The occurrence of micro-welding is also studied in these rings. Imported rings show relatively less variation in their properties and are smoother in surface finish when compar to their indigenous counterparts. Hardness decreases for all the rings after usage. A marginally higher ring ovality helps the traveller to change its point of contact with rings and thus avoids the localized heating of traveller. A smaller off-set web results in reduced point of contact with the traveller d consequently higher buing rate and traveller weight loss. In the case of larger ring diameter, higher spindle speed and coarser count, the wearout of ring is faster. Performance study shows identical y quality for all makes of rings. Keywords : Flange width, Micro-welding, Ring hardness, Ring ovality, Spinning ring 1 Intruction The travel ler speed in a ring frame is the main limitat ion in achieving higher spindle s peed because of the frictional resistance of traveller over the ring flange. The design, metallurgy, surface finish and breaking-in of the rings decide the speed at which a ring frame can be run without excessive end breaks. For minimizing f riction so as to attain higher traveller speed, many surface finishes have been suggested , , 2 and larger area of contact is provided by the ring and tnvel ler manufacturers. During ring spinning, both ycm tension and ring/traveller friction play an important role fr om the wear point of view and def'end mainly upon ring diameter, spindle speed, count and frictional resistance of traveller with ring. Micro-welding/pit formation takes place on ring surface near travel ler bearing area due to theal damage caused by friction between ring and traveller. In this study, an attempt has been made to investigate geometrical properties (flange width, ovality and web thickness), metallurgical properties (hardnes5, grain structure, chemical composition and nature of hardns s) and physical wearout of various !lnpoed and indigenous spinning rings and to relate them wi th the perfonnance of these rings in tes of end breakage rate, travel ler damage and yam quality. 2 Materials and Methods 2.1 Materials Eight different makes of rings, coded as A, B, C, 0, E, F, G and H, were chosen for the study. Among these rings, five were indigenous (B, 0, E, G and H) and three imported (A, C and F). 2.2 Methods Geometrical and metallurgical properties of all the rings were tested in accordance with the following standard test methods: Hardness (HRC) Ovality (mm) Flange width (mm) Web thicess (mm) Inner diameter (mm) IS 3078-1989 IS 3078-19 89 IS 3078-1989 IS 3078-1989 IS 3078-1989 Elemental analyses of the rings were carried out as per the chemica] wet analysis method. Grain structure was checked after polishing and etching the ring samples with 2% nital solution and observed at x4 magnification. Surface smoothness was observed with roughnss tester (Hommel-T2000). ' The nature of wearout and micro-welding/pit foation were studied with scanning electrcn r rucro- scope (JEOL JSM 5400). Indigenous ring samples
Transcript
Indian Journal of Fibre & Textile Research Vol. 24, June 1 999, pp. 93-98
Wear characteristics and performance of spinning rings
G D Batwal, T L Paradkar & A N Desai
The Bombay Textile Research Association, L B S Marg, Ghatkopar (West), Mumbai 400 086, India
Received 18 May 1 998; revised received and accepted 16 July 1 998
The physical, geometrical and metallurgical properties such as hardness, elemental composition, grain structure, nature of hardness, surface smoothness and geometrical profile of the various makes of imported and indigenous spinning rings have been critically analysed to study the performance of these rings in terms of end breakage rate, traveller damage and yarn quality. The occurrence of micro-welding is also studied in these rings. Imported rings show relatively less variation in their properties and are smoother in surface finish when compared to their indigenous counterparts. Hardness decreases for all the rings after usage. A marginally higher ring ovality helps the traveller to change its point of contact with rings and thus avoids the localized heating of traveller. A smaller off-set web results in reduced point of contact with the traveller and consequently higher burning rate and traveller weight loss. In the case of larger ring diameter, higher spindle speed and coarser count, the wearout of ring is faster. Performance study shows identical yarn quality for all makes of rings.
Keywords : Flange width, Micro-welding, Ring hardness, Ring ovality, Spinning ring
1 Introduction
The traveller speed in a ring frame i s the main limitation in achieving higher spindle speed because of the frictional resistance of traveller over the ring flange. The design, metallurgy, surface finish and breaking-in of the rings decide the speed at which a ring frame can be run without excessive end breaks. For minimizing friction so as to attain higher traveller speed, many surface finishes have been suggested , ,2
and larger area of contact is provided by the ring and tnveller manufacturers . During ring spinning, both ycm tension and ring/traveller friction play an important role from the wear point of view and def'end mainly upon ring diameter, spindle speed, count and frictional resistance of traveller with ring. Micro-welding/pit formation takes place on ring surface near traveller bearing area due to thennal damage caused by friction between ring and traveller.
In this study, an attempt has been made to investigate geometrical properties (flange width, ovality and web thickness), metallurgical properties (hardnes5, grain structure, chemical composition and nature of hardnt'ss) and physical wearout of various ! l nported and indigenous spinning rings and to relate them with the perfonnance of these rings in tenns of end breakage rate, traveller damage and yam quality.
2 Materials and Methods 2.1 Materials
Eight different makes of rings, coded as A, B, C, 0, E, F, G and H, were chosen for the study. Among these rings, five were indigenous (B, 0, E, G and H) and three imported (A, C and F).
2.2 Methods
Geometrical and metallurgical properties of all the rings were tested in accordance with the following standard test methods:
IS 3078-1 989 IS 3078-1989 IS 3078- 1989 IS 3078-1989 IS 3078- 1989
Elemental analyses of the rings were carried out as per the chemica] wet analysis method.
Grain structure was checked after polishing and etching the ring samples with 2% nital solution and observed at x400 magnification.
Surface smoothness was observed with roughnotss tester (Hommel-T2000) .
'
The nature of wearout and micro-welding/pit fonnation were studied with scanning electrcn rrucroscope (JEOL JSM 5400). Indigenous ring samples
94 INDIAN J. FIBRE TEXT. RES., JUNE 1 999
were collected directly from the running machine in mi lls and classified as ' ] �year, 2-year, 3-year and 4-year old.
Geometrical profile of the flange for different rings was studied with the help of scanning electron mIcroscope.
Out of the eight makes of rings, four rings (A, C, E and F) were studied for working perfonnance at mill level after 'carrying out proper running-in, using the fol lowing spinn ing conditions:
Count
M i xing
Ring diameter Fiange No Spindle speed Travelier No. and type
3 Results and Discussion
40s combed warp 1 00% S-40 mm
1 7800 rpm 6/0 VI VL UDR
3.1 Physical Properties of Different Makes or Rings
Table I shows the physical properties of the new and old (after J 4 months of use) spinning rings. The new i mported rings show a coefficient of variation of 0.3-0 .5% for hardness as compared to 0.2-0.8% for new indigenous rings (except for ring D which shows a CV% of 5 . 1 ) . Simi larly, a higher level of variation is observed for flange width, web thickness and inner diameter of indigenous rings when compared to
imported rings. Surprisingly, for one of the imported rings (ring C), the oVality values are on the higher side but still within the Indian Standards ( 1 989) of 0.2 mrn.
It is also observed from Table 1 that the hardness values decrease for all the makes of rings after usage, since hardness of metal decreases with the increase in temperature during use. The CV% values for hardness and web thickness increase in rings A, C, E and F due to ·wear which could be uneven along the surface .
It is also observed that deterioration in flange width and web thic�ness of ring F is higher than that in any other ring. This could be due to the smalle;' off-set web from the centre of ring (Table 2 and Fig.
1 ). The smaHer off-set web results in smaller travel lc: point of contact with the ring, which, in turn, causes poor heat dissipation, leading to increase in temperature of the system, and at higher temperature the material becomes softer and hence a higher wearout.
3.2 Elemental Analysis and Nature of Hardness AHoy material is used for manufacturing rings to
attain desirable characteristics. As can be seen from Table 3, all the rings have identical composition except the rings D and H which have carbon and chromium contents respectively as 0.86% and 0.05% (ring D) and 0.66% and 0. 1 3% (ri.ng H).
Table I-Physical properties and wearout of spinning rings
C
E
F
B D G H
Ring"
New n ng
Old ring
% Deterioration New ring Old ring
% Deterioratton New ring Old Tlng
% DeterioratIOn New ring Old ring
% Deterioration New ring New ring New ring
New ring
Hardness Ovality HRCJCV% mmlCVO/c
63.7/0.4 0.04/4 U;
6 1 . 1/0.7 O.OS/48.2
62.210.5 O. I 4/54."
61 .8/0.8 0. 1 3/45.6
6 1 .010.7 O.OS/44,9
58.9/ 1 .2 0.04/48. 5
63. 1 10.3 0.07/43.7
62.010.9 O.06i42.7
64.210.2 0.06/65.9
63. 1 /5 . 1 0.06/3 1 .2
65.7/0.2 0. 1 3/23 . 1
63.7/0.8 0.08/5:4.4
"A, C and F-Imported rings and B, D, E, G and H-Indigenous rings
BA 1W AL et al.: WEAR CHARAcrnRISnCS & PERFORMANCE OF SPINNING RINGS 95
3.3 Grain Structure in Various Rings Finer grain structure offers advantages like quick
heat dissipation, better surface finish, uniform wear, better toughness, stronger material and much better
a -..................... s.;;-
Fig l-GeometricaI profile of flange
wear life. It is observed that most of the rings are with fine grain structure except the rings D and H which are with coarse grain structure. Scanning electron micrographs of grain structure for rings A, C, D and H are shown in Fig. 2.
.
3.4 Surface Smoothness of Rings Smoother surface finish helps to develop uniform
wear of traveller path on the rings. At the same time,
Table 2-GeometricaI profile of flange in various rings
Ring Angle at Off-set Outer Flange Flange top crown flange flange width height of flange
All the rings are thorough hardened except ring D which is case hardened with case depth of 0.375 mrn.
Fig 2-SEM photographs of grain structure of rings A. C, D and H
96 INDIAN J. ABRE 'TEXT. RES., JUNE 1999
running-in period can be reduced substantially due to the lesser number of micro-irregularities over the travel ler path' and this reduces friction between ring and travel ler. Table 1 shows that the surface smoothness of imported rings is lower compared to that of indigenous rings .
It is further observed from Table 1 that after 14 months of use the surface smoothness deteriorates in case of rings A. C and F, possibly due to the increase in micro-irregularities beca�se of the friction between ring and travel ler, particularly near traveller bearing area. In the case of ring E, the surface smoothness is already high and remains unaltered after use. 3.5 Micro-welding/Pit Formation in Rings
To confinn the above observations on surface smoothness, SEM studies were carried out for microwelding/pit formation phenomenon.
The heat generated due to friction between ring and travel ler must be dissipated into atmosphere through the travel ler or into the ring. But due to prolonged working of travel ler or smaller contact of traveller with ring or exceptionally high traveller speed, the travel ler reaches the temperature at which bluing occurs in early stage. Since traveller has lower hardness than ring, the oxidised material from the travel ler is deposited on the ring flange. To study the phenomenon of micro-welding, . ring G with different age groups (new ring, 3-year old and 4-year old) was col lected and SEM photographs were taken at point where the travel ler continuously touches the ring flange (Fig. 3) . All the photographs show the occurrence of micro-welding on ring flange where the traveller touches the ring.
Similarly. the SEM photographs for the new and 14 months old A, C, E and F rings were taken near traveller bearing area and the results are shown in Figs 4 and 5 respectively. All the photographs confirm the occurrence of micro-welding/pit formation onto rings. But the quantum of microwelding varies from one make to another; the ring with smoother surface shows minimum micro-welding and vice-versa. This is also reflected from surface smoothness values. This clearly shows that for better perfonnance of ring and traveller, smoother surface finish is very essential apart from the physical and metallurgical properties.
3.6 Extent of Wearout in Used Rings
The rings are subjected to stresses and strains due to travel ler running on it, which, in turn, leads to wear
Fig 3-SEM photographs of indigenous .nng G: (a) new; (b) 3-year old, showing micro-welding; and (c) 4-year old, showing micro-welding
Table 4-Extent of wearout in used rings
Spindle speed, rpm 1 3500 1 2500 14000 1 4000 Ring diameter, mm 44 4 1 4 1 41 Count, Ne 205 1 6s 60s 60s Ring G B G B Flange width, mm 4.00 3.20 3.22 3 .25 (New ring) Flange width, mm 3.69 3 . 1 2 3.20 3.22 (4-year old ring)
% Deterioration in 7.8 2.5 0.6 0.9 flange width after 4 years
Y
BA 1W AL et at. : WEAR CHARACfERISTICS & PERFORMANCE OF SPINNING RINGS 97
Fig 4-SEM photographs of new rings A, C, E and F
Fig 5-SEM photographs of 1 4 months old rings A, C, E and F, showing micro-welding
of inner side of flange. This wearout depends upon the amount of pressure the traveller applies to the inner side of flange; the pressure depends upon ring diameter, yam count, spindle speed and traveller number.
From Table-4, it is observed that in spite of similar metallurgical properties of rings G and B, the per cent deterioration in flange width after 4 years is higher for the ring having higher spindle speed, larger ring diameter and coarser count.
91 INDIAN 1. FIBRE TEXT. RES., JUNE 1999
Table 5-Perfonnance studies of good quality rings
[Count, 40s combed; Spindle speed, 17800 rpm]
Ring Traveller changing life schedule ·
(Months) (Days)
Traveller 2 5
burning, % 4 17
8 5 ·
Traveller 2 5
weight loss, % 4 17
8 5
End breaks 2 5
per 100 spindle hour 4 17
8 5
Hairiness 2 5
index (HI) 4 17
8 5
Average imperfectionsikm
U% Thin places
Thick places
Neps
Total
3.7 Performance Studies in Mill
Four good quality rings A,C,E and F were selected after proper running-in and then taken to the mills where yarn quality, yarn breakage rate and traveller
buming/ �eight -lOSS were studied. The en<1 breakage study was carried out for more than 2000 spindle hours. Table 5 shows that in spite of similarity in hardness, grain structure and composition, ring C
shows minimum traveller burning and traveller weight loss because of the following two reasons: (i) as the ovality of ring C is slightly higher, the traveller point of contact keeps on changing and thus avoiding the
localized heating of travellers. Hence, the traveller point of contact spreads over longer length; and (ii) the smaller flange height (Table 2) provides larger yarn passage, which, in tum, helps to minimise the friction of yarn with ring.
On the other hand, in case of ring F the traveller weight loss and traveller burning are higher because the off-set web from the centre of ring is smallest amongst all the rings (Table 2) . This [educes the traveller point of contact '",ith the ring, thereby increasing the travel ler burning and traveller weight loss.
Ring A C E F
19.3 8 . 1 22.7 66.7
62. 1 58.6 69.0 86.2
67.9 40.9 59.3 88.7
1 .2 0.6 2.5 3.3 2.2 2.3 1 .5 4. 1
2.5 J .3 2.9 5.0
3.2 3.5 3.6 4.3
2.8 3.3 3.7 4.4
2.6 2. 1 2.6 4.0
4.2 4.0 4 . 1 4.0
4.2 4.2 4.2 4.1
4.2 4.2 4.2 4.2
1 1 . 1 1 1 .2 1 1 . 1 1 1 . 1
9 1 1 1 2 9
52 56 54 60
92 98 93 94
153 165 1 59 1 63
. 4 Conclusions 4.1 Imported rings show less variation in properties
and are smoother in surface finish when compared to their indigenous counterparts.
4.2 Metallurgical composition of all the rings is identical.
4.3 Hardness values decrease and their variation increases for all the makes of rings after usage.
4.4 A slightly higher ring ovality may help the
traveller keep on changing its point of contact with
the ring and thus avoiding localized heating which
could possibly lead to lower traveller burniIlg rate._ 4.5 A smaller off-set web reduces the point · of
contact with the traveller and consequently higher · burning rate and traveller weight loss.
4.6 In the case of larger ring diameter, higher spindle speed and coarser counts, wearout of the ring is faster.
4.7 Performance study shows identical yarn quality for all the makes of the rings. Even at 80-85% traveller burning rate, the yarn evenness and imperfections remain unaffected.
References
1 Nutter W & Lomax R, Text Recorder, 83 (997) ( 1 966) 52. 2 Furst H J, Text Prax Int, 48 ( 1 1 ) ( 1993) 2.
