Innovative Stainless Steel Applications in transport ... - Euro Inox

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Table 31. Tensile strength test results for arc-brazed and laser-brazed butt joints in various austenitic grades (DOLTRAC). Welding Filler metal Tensile strength (N/mm 2 ) 304SP 1.4318 2B C850 C1000 BM - 682 956 1008 arc brazing CuSi3 721 897 arc brazing CuAl5Ni2 710 783 laser brazing CuAl5Ni2 710 783 arc brazing CuNi10Fe 714 801 laser brazing CuNi10Fe 714 778 The results indicate that for 304SP, nominal tensile strength values higher than the base material can be reached. This is probably due to the test arrangements and sample geometry, etc. but it is still a very promising result. It is also worthy of note that the measured strength values remain more or less constant regardless of the filler metal or heat source used. Furthermore, the values are always higher than those for laser or MAG welding – but this may also be due to differences in experiment arrangements, since the results originate from different projects. For the high-strength cold-rolled 1.4318 material, the brazed samples show about 10 - 20 % lower tensile strength values than the base material, as might be expected. Also, here, the differences between brazing methods or filler materials are negligible. Unfortunately, no results directly comparable to arc-welded or laser-welded joints were available for this material. 5.1.2 Fatigue and corrosion fatigue strength Comparable fatigue and corrosion-fatigue data is available from a recent Finnish national project (Huhtala 2008). These tests were carried out using transverse test coupons of 3 mm austenitic stainless sheets, in various grades. The coupons were designed to fulfil the requirements of ASTM E 466-96, especially with regard to curvature radius. The joints were welded from one side, using matching flux-cored 308L-type filler metal for 1.4301 and 1.4318 grades. Exceptions were obviously the reference experiments made using CuSi3 solid-wire arc-brazing filler metal. Furthermore, some post-weld mechanical treatments were tested using ultrasonic peening and grit blasting. The International Institute of Welding (IIW) Commission XIII “Fatigue of welded components and structures” (a globally recognised authority in fatigue assessment and design of welded structures) commonly uses the term FAT to describe the fatigue 94
performance of a weld-joint detail (Hobbacher 2007). To simplify, FAT is the fatigue strength at 2 million cycles. Both mean FAT50% (i.e. 50 % confidence) and characteristic FAT95% (i.e. 95 % confidence) values are used. FAT values are listed for a number of joint-type cases made of C-Mn steel or aluminium. No direct data is given for stainless steel, but C-Mn steel cases are often also used for stainless. For the joint type tested by Huhtala (2008), IIW cases nos. 214 or 215 can be used. According to Hobbacher (2007), the characteristic FAT95% is 80 and 71 N/mm 2 for cases 214 and 215 respectively. The results from Huihtala (2008) are shown in Table 32. Apart from conventional fatigue testing in air, further reference tests were carried out in both air and NaCl-environments for ferritic stainless steel 1.4003 welded with 308L filler material. Table 32. Fatigue and corrosion-fatigue test results for 3 mm stainless steel base materials and their butt joints (Huhtala 2008). B = arc brazing, U = ultrasonic treatment, G = grit blasting, BM = base material. Material & Environment FAT Remarks BM MAG Laser FAT50 % FAT95 % FAT50 % FAT95 % FAT50 % FAT95 % 1.4301 air 261 200 154 105 180 108 NaCl - - 147 71 152 52 1.4318 air 311 280 137 92 - - NaCl - - - - - - 1.4318B air - - 127 114 - - arc brazed 1.4318 air - - 131 105 - - all samples 1.4318U - - 138 98 - - UT root 1.4318G - - 124 110 - - grit blast root 1.4003 air 281 261 152 131 - - NaCl - - 161 105 - - It can be concluded from the results that the IIW recommendations are easily exceeded with all the tested materials, welding methods and filler materials, including the silicon bronze CuSi3 used for arc brazing. The ultrasonic or grit blasting post-weld treatments increased fatigue performance slightly but the highest FAT value for 1.4318 material was achieved with arc brazing. This was probably due to the smooth top and root reinforcement geometry typical of an arc-brazed joint, which is favourable from a fatigue point of view. A limited number of corrosion-fatigue tests were carried out for these materials but it does appear that the NaCl environment has a negative effect on fatigue strength. Nevertheless, according to these results, the joints (except perhaps the laser-welded joints) still meet the IIW requirements. 95
Page 1 and 2:
Preface This publication is the mai
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Contents Preface ..................
Page 5:
List of symbols Mechanical properti
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Figure 1. Rear view of El Capitan.
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In Japan and the Asia-Pacific areas
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12 Figure 13. Delhi metro coach (Go
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1.3 Bus and coach applications 14 A
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1.4 Future potential Future prospec
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2. Materials By definition, stainle
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use higher nitrogen contents in aus
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Grade 1.4318 stainless steel was su
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MPa). Table 7 shows the format and
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1. Design using minimum specified v
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Table 9. The most common stainless
Page 31 and 32:
Table 10. Physical properties of so
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for example, in the case of lap joi
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to develop new de-icing chemicals,
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(a) (b) Figure 30. Photograph from
Page 39 and 40:
Austenitic CrNi and CrNiMo stainles
Page 41 and 42:
Figure 33 shows the behaviour of fe
Page 43 and 44: (a) (b) Figure 35. Localised corros
Page 45 and 46: visual and not detrimental to struc
Page 47 and 48: Reduction factor 1 0.9 0.8 0.7 0.6
Page 49 and 50: It is typical of cold-worked stainl
Page 51 and 52: Thermomechanical treatments can be
Page 53 and 54: Table 17. The minimum values for co
Page 55 and 56: 3. Lightweight structures and desig
Page 57 and 58: K joints The requirements for K joi
Page 59 and 60: Figure 42. Overlapping joint (Yrjö
Page 61 and 62: Another typical way to join a hollo
Page 63 and 64: There are some disadvantages with a
Page 65 and 66: New challenges have to be met in bo
Page 67 and 68: Stiffness parameters Despite the li
Page 69 and 70: Figure 52. An experimental, sandwic
Page 71: 71 Figure 53. Stainless steel sandw
Page 74 and 75: values are shown in Table 20. A com
Page 76 and 77: Springback was determined by measur
Page 78 and 79: A “three-roll” (pyramid-type) b
Page 80 and 81: angle of 180 °. Figure 58 shows th
Page 82 and 83: design and the manufacture of the t
Page 84 and 85: Combined with modern pulsing techni
Page 86 and 87: possibility of transferring the bea
Page 89 and 90: 5. Properties of lightweight struct
Page 91 and 92: Table 28. Fusion welding results fo
Page 93: welding mechanical treatments. Howe
Page 97 and 98: 2400 N. Thus, the specified fatigue
Page 99 and 100: limited number of static bending te
Page 101 and 102: material strengths or manufacturing
Page 103 and 104: section at a velocity of 3.0 m/s. F
Page 105 and 106: (a) (b) (c) Figure 65. (a) Deflecti
Page 107 and 108: Figure 67. Panel sections after lon
Page 109 and 110: 6. Life cycle issues The transporti
Page 111 and 112: and services, occurring throughout
Page 113 and 114: 100 % 80 % 60 % 40 % 20 % 0 % Mater
Page 115 and 116: (especially in the case of lower-al
Page 117 and 118: Acknowledgements The following orga
Page 119 and 120: References Ala-Outinen, T. 1996. Fi
Page 121 and 122: DIN 6935. 1975. Kaltbiegen von Flac
Page 123 and 124: Federation of metals industries. ME
Page 125: UNEP 2002. Industry as a partner fo
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