Below, various cases involving damage are illustrated, causes described and solutions suggested.

	Delayed fracture in galvanized bolts  Grade 10.9 galvanized bolts installed in a steel supply bridge failed relatively soon after installation. The individual bolts fractured spontaneously. Macroscopic analysis showed only slight deformation at the fracture sites.  Delayed fracture in galvanized bolts    Corrosion damage to copper pipes  Damage caused by leaks in the copper piping supplying cold drinking water in a residential building was the reason for preparing a court opinion. The piping diameter was 18 and/or 22 mm.   Corrosion damage to copper pipes    Corrosion damage to a wash basin mixer tap  The mixer tap of a wash basin in a hotel room failed and caused water damage. The tap, to which drinking water satisfying the quality requirements of the drinking water regulation was supplied, had been in service for approximately one year. The tap was cleaned with commercial cleaning agents.  Corrosion damage to a wash basin mixer tap    Erosion-corrosion damage to the heat exchanger tubes of a steam superheater  In a refinery, boiler feedwater is heated in an exhaust-heat boiler and the steam thus generated returned to the process via a steam superheater. The heat-exchanger tubes of the steam superheater had been damaged during operation to such an extent as to even cause bursting.  Erosion-corrosion damage to the heat exchanger tubes of a steam superheater    Damage due to frost  Leaks have occurred on the 180º bends of a heat exchanger provided with cooling gills and having coiled cooling pipes (Fig. 1). Water was conveyed within the pipes and a cooling fluid was acting upon the outer face of the pipes. In the damaged area, the outer surfaces have shown corrosion damage.  Damage due to frost    Material damage through thermal shock stress  Leakage was detected at the welding seam of a main-steam collector outlet. Metallographic analysis of the fracture surface identified thermal cycling as the cause of failure. However, neither manufacturer nor operator could provide an explanation.   Material damage through thermal shock stress    Natural-frequency piping vibrations  In an austenitic control line for a main-steam valve of a power plant, a poorly executed welding seam began to leak after approx. three operating years. The plant had to be shut down as a result.   Natural-frequency piping vibrations    Weld seam optimization  After some years of operation, cracks formed in the perpendicular longitudinal weld on the vertical column guides of a roller-guided rack feeder.  Weld seam optimization    Vibration reduction  On a pleasure steamer, strong vibrations which passengers perceived as unpleasant occurred under certain conditions on the rear sun-deck benches.  Vibration reduction    Pitting corrosion  Approximately two months after fitting, a gutter made of aluminum plate surrounding the foyer of a building was leaking at various locations (cf. Fig. 1), resulting in water intrusion into the entrance hall of the building. The foyer was provided with a grass cover on its roof structure.   Pitting corrosion    Damage caused by start/stop operation  Large parts broke from the die-cast bearing rollers of a large, drum-type rotating drying stove for wood shavings. Operation had to be stopped and, at the same time, there was the risk of the cylinder-shaped stove falling onto the operating premises.  Damage caused by start/stop operation    Remaining lifetime assessment based on creep strain  After two years of operation, cracks were detected on the circumferential welds of a combustion chamber for powdered coal. An even surface was restored by grinding and operation was resumed. As creep cracking could not be ruled out as the failure cause, creep strain measurements were performed.  Remaining lifetime assessment based on creep strain    Defects in material  Rectangular copper profile sections are welded together and formed to rings having various different radii. In these processing steps, brittle fractures will occur within the heat affected zone of the weld seams (Fig. 1).   Defects in material    Defects in welding  Rectangular copper profile sections are welded together and formed to rings having various different radii. In these processing steps, brittle fractures will occur within the heat affected zone of the weld seams (Fig. 1).   Defects in welding    Vibration fatigue failures on a compressed gas bottle   Premature cracks have occurred in alternating load tests on a compressed natural gas bottle used as fuel tank for a motor vehicle, in the area of the cylindrical shell.   Vibration fatigue failures on a compressed gas bottle     Stress/strain reduction  Stress/strain reduction by modifying design or mode of operation  Stress/strain reduction    Tank vehicle with strain gauge measuring points  To reduce dead weight and/or increase payload, strain gauge measurements were to provide experimental evidence of sufficient and safe tank-vehicle dimensions.  Tank vehicle with strain gauge measuring points    Fatigue failure at the welds of nested tubes  An already existing municipal heating and power station was supplemented by a water-tube boiler fueled with natural gas and light oil. After only 28 hours of operation, fatigue failure occurred at 2 welds of the nested tubes of a new cylindrical boiler shell.   Fatigue failure at the welds of nested tubes    Laugeninduzierte Spannungsrisskorrosion  In einer mit Dampf beaufschlagten Rohrleitung aus dem Werkstoff St 35.8 III sind während des Betriebes Risse quer zu Rundschweißnähten aufgetreten (Abb. 1). Die Überprüfung der chemischen Zusammensetzung der Rohrleitungswerkstoffe und des Schweißgutes ergab keine Hinweise auf die Schadensursache.  Laugeninduzierte Spannungsrisskorrosion    Zahnriemenscheibe eines Kraftfahrzeuges  Die Zahnriemenscheibe eines Kraftfahrzeuges versagte, wobei ein Segment der Riemenscheiben aus dem Bauteil ausgebrochen ist.  Zahnriemenscheibe eines Kraftfahrzeuges    Autositzbefestigung: Schaden an einem Bauteil  Im Versuch (Crash Test) versagte ein aus ferritischem Werkstoff kaltgebogenes Bauteil, das zur Befestigung von Autositzen eingesetzt wird. Das Bauteil hat bei vorangegangenen gleichen Versuchen den jeweils dabei aufgetretenen Beanspruchungen standgehalten.  Autositzbefestigung: Schaden an einem Bauteil

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