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

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(a) (b) (c) d) Figure 31. Localised corrosion and staining of powder plasma arc welded (PPAW) and weldbonded (WB) EN 1.4003 2B after 500-hour salt-spray test in CaCl2 at 20 °C. (a) PPAW before and after 500-hour test, not pickled, (b) PPAW before and after 500-hour test, pickled, (c) WB before and after 500-hour test, not pickled, (d) WB before and after 500-hour test, pickled (BUS). 38
Austenitic CrNi and CrNiMo stainless steels Austenitic grades EN 1.4301 with a minimum of 17.5 % Cr and 8 % Ni and EN 1.4401 (minimum 16.5 % Cr, 10 % Ni and 2 % Mo) have good atmospheric corrosion resistance and have been successfully used for decades in various architectural applications. According to laboratory tests, field tests and practical experience, EN 1.4301 grade should provide adequate atmospheric corrosion resistance in most vehicle applications (Figure 32, Figure 33 and Table 12). Apart from remaining intact in urban atmospheres, it should also remain practically intact in marine atmospheres and even, when properly treated, in urban atmospheres in the presence of de-icing salts (Figure 33(d)). Welding reduces corrosion resistance and can lead to pitting corrosion and staining in the presence of chlorides, originating from sources such as seawater mist, rainwater, de-icing salts or dust-control chemicals. Laser welding gives better corrosion resistance than arc or spot welding. Excessive heat input is detrimental. Corrosion resistance can be restored by post-weld surface treatments – again pickling provides the best results. Molybdenum and nitrogen alloying improve pitting-corrosion and crevice-corrosion resistance. This was clearly seen both in the salt-spray and field tests, where grade 304SP, with 0.8 % Mo and 0.1 % N, was superior to standard grade EN 1.4301, both in as-welded condition and after pickling (Figure 34 and Table 12). Based on the nitrogen content, the corrosion resistance of grade EN 1.4318, with minimum 17 % Cr, 6 % Ni and 0.1 % N, should be equal to or even slightly better than that of standard grade EN 1.4301. This assumption is supported by salt-spray tests on sandwich panels. Grade EN 1.4310 has also been successfully used in railway cars and truck trailers. In building applications, grade EN 1.4310 is reported to suffer from rust staining in the presence de-icing salts. The risk of crevice corrosion can be minimised by careful design. Butt joints should be preferred to lap joints and, if lap joints are used, weld bonding should be preferred to spot welds. Although weld bonding itself can prevent crevice corrosion, pickling is still required to restore the corrosion resistance of the outer surfaces, as shown in Figure 32(c) and (d). Pickling must be performed with care, to avoid deterioration of the adhesive in the joint. Surface finish has a major effect on localised-corrosion resistance in atmospheric applications. Smoother surfaces retain less dirt and deposits and provide better resistance against pitting corrosion, surface staining and tarnishing than do rough surfaces. This was clearly seen in the salt-spray tests, where the colourisation of both 1D and brushed surfaces was more intense than that of the smoother 2B finish (BUS p. 199). 39
Page 1 and 2: Preface This publication is the mai
Page 3 and 4: Contents Preface ..................
Page 5: List of symbols Mechanical properti
Page 8 and 9: Figure 1. Rear view of El Capitan.
Page 10 and 11: In Japan and the Asia-Pacific areas
Page 12 and 13: 12 Figure 13. Delhi metro coach (Go
Page 14 and 15: 1.3 Bus and coach applications 14 A
Page 16 and 17: 1.4 Future potential Future prospec
Page 19 and 20: 2. Materials By definition, stainle
Page 21 and 22: use higher nitrogen contents in aus
Page 23 and 24: Grade 1.4318 stainless steel was su
Page 25 and 26: MPa). Table 7 shows the format and
Page 27 and 28: 1. Design using minimum specified v
Page 29 and 30: Table 9. The most common stainless
Page 31 and 32: Table 10. Physical properties of so
Page 33 and 34: for example, in the case of lap joi
Page 35 and 36: to develop new de-icing chemicals,
Page 37: (a) (b) Figure 30. Photograph from
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 and 94:
welding mechanical treatments. Howe
Page 95 and 96:
performance of a weld-joint detail
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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