Pub Date : 2019-06-01DOI: 10.31399/asm.fach.rail.c0046238
Within about one month, several knuckle pins (AMS 6470 steel failed, and required to have a minimum case hardness of 92 h15N, a case depth of 0.4 to 0.5 mm (0.017 to 0.022 in.), and a core hardness of 285 to 341 HRB) used in engines failed over a range of 218 to 463 h in operation. Visual examination revealed beach marks typical of fatigue cracks that had nucleated at the base of the longitudinal oil hole. Micrographs of sections revealed a remelt zone and an area of untempered martensite within the region of the cracks. However, review of inspection procedures disclosed the pins had been magnetic-particle inspected by inserting a probe into the longitudinal hole. Evidence found supports the conclusions that the knuckle pins failed by fatigue fracture. The circular cracks at the longitudinal holes were the result of improper technique in magnetic-particle inspection. Thermal transformation of the metal also causes a stress concentration that may lead to fatigue failure. Recommendations included insulating the conductor to prevent arc burning at the base of the longitudinal oil hole. Also, a borescope or metal monitor could be used to inspect the hole for evidence of arc burning from magnetic-particle inspection.
{"title":"Fatigue Fracture of AMS 6470 Steel Knuckle Pins","authors":"","doi":"10.31399/asm.fach.rail.c0046238","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c0046238","url":null,"abstract":"\u0000 Within about one month, several knuckle pins (AMS 6470 steel failed, and required to have a minimum case hardness of 92 h15N, a case depth of 0.4 to 0.5 mm (0.017 to 0.022 in.), and a core hardness of 285 to 341 HRB) used in engines failed over a range of 218 to 463 h in operation. Visual examination revealed beach marks typical of fatigue cracks that had nucleated at the base of the longitudinal oil hole. Micrographs of sections revealed a remelt zone and an area of untempered martensite within the region of the cracks. However, review of inspection procedures disclosed the pins had been magnetic-particle inspected by inserting a probe into the longitudinal hole. Evidence found supports the conclusions that the knuckle pins failed by fatigue fracture. The circular cracks at the longitudinal holes were the result of improper technique in magnetic-particle inspection. Thermal transformation of the metal also causes a stress concentration that may lead to fatigue failure. Recommendations included insulating the conductor to prevent arc burning at the base of the longitudinal oil hole. Also, a borescope or metal monitor could be used to inspect the hole for evidence of arc burning from magnetic-particle inspection.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126818945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.31399/asm.fach.rail.c9001585
On 15 March 2000, a National Railroad Passenger Corporation (Amtrak) train traveling from Chicago to Los Angeles derailed in Carbondale, KS. After the initial on-scene investigation, 12 pieces of rail were sent to the materials laboratory for examination. Ten of them were from the point of derailment (POD). A vertical crack was observed in the head of the rail (vertical split head). The crack was at least 233 in. (591 cm) long, continuing through the entire lengths of most pieces recovered from the POD. The vertical fracture surface had features consistent with overstress fracture with short-term exposure to an oxygen-rich environment. Fracture features emanated from longitudinally-aligned inclusions rich in aluminum.
{"title":"Fracture of a Railroad Rail Related to a Train Derailment","authors":"","doi":"10.31399/asm.fach.rail.c9001585","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c9001585","url":null,"abstract":"\u0000 On 15 March 2000, a National Railroad Passenger Corporation (Amtrak) train traveling from Chicago to Los Angeles derailed in Carbondale, KS. After the initial on-scene investigation, 12 pieces of rail were sent to the materials laboratory for examination. Ten of them were from the point of derailment (POD). A vertical crack was observed in the head of the rail (vertical split head). The crack was at least 233 in. (591 cm) long, continuing through the entire lengths of most pieces recovered from the POD. The vertical fracture surface had features consistent with overstress fracture with short-term exposure to an oxygen-rich environment. Fracture features emanated from longitudinally-aligned inclusions rich in aluminum.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130039469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.31399/asm.fach.rail.c9001450
A locomotive type boiler was fitted with a copper firebox of orthodox construction. Flanged tube- and firehole-plates were attached to a wrapper plate by means of copper rivets. Shortly after it was put into service the fireside heads of a number of rivets broke off at different parts of the seams. By the time the investigation was begun a total of fifty heads had broken off. Repairs had been effected from time to time by fitting screwed rivets, none of which gave trouble in service. Microscopic examination confirmed the fracture path to be wholly intergranular. In the region of the fracture the grain boundaries were delineated as a near-continuous network of cavities and films of oxide. It was evident that the failure of the rivets in service was attributable to intergranular weakness in the material due to gassing.
{"title":"Failure of Copper Rivets Due to “Gassing”","authors":"","doi":"10.31399/asm.fach.rail.c9001450","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c9001450","url":null,"abstract":"\u0000 A locomotive type boiler was fitted with a copper firebox of orthodox construction. Flanged tube- and firehole-plates were attached to a wrapper plate by means of copper rivets. Shortly after it was put into service the fireside heads of a number of rivets broke off at different parts of the seams. By the time the investigation was begun a total of fifty heads had broken off. Repairs had been effected from time to time by fitting screwed rivets, none of which gave trouble in service. Microscopic examination confirmed the fracture path to be wholly intergranular. In the region of the fracture the grain boundaries were delineated as a near-continuous network of cavities and films of oxide. It was evident that the failure of the rivets in service was attributable to intergranular weakness in the material due to gassing.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"54 65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133150240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.31399/asm.fach.rail.c9001659
R. Rungta, R. Rice, Richard D. Buchheit, D. Broek
A failure analysis case study on railroad rails is presented. The work, performed under the sponsorship of the Department of Transportation, addresses the problem of shell and detail fracture formation in standard rails. Fractographic and metallographic results coupled with hardness and residual stress measurements are presented. These results suggest that the shell fractures form on the plane of maximum residual tensile stresses. The formation of the shells is aided by the presence of defects in the material in these planes of maximum residual stress. The detail fracture forms as a perturbation from the shell crack under cyclic loading and is constrained to develop as an embedded flaw in the early stages of growth because the crack is impeded at the gage side and surface of the rail head by compressive longitudinal stresses.
{"title":"An Investigation of Shell and Detail Cracking in Railroad Rails","authors":"R. Rungta, R. Rice, Richard D. Buchheit, D. Broek","doi":"10.31399/asm.fach.rail.c9001659","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c9001659","url":null,"abstract":"\u0000 A failure analysis case study on railroad rails is presented. The work, performed under the sponsorship of the Department of Transportation, addresses the problem of shell and detail fracture formation in standard rails. Fractographic and metallographic results coupled with hardness and residual stress measurements are presented. These results suggest that the shell fractures form on the plane of maximum residual tensile stresses. The formation of the shells is aided by the presence of defects in the material in these planes of maximum residual stress. The detail fracture forms as a perturbation from the shell crack under cyclic loading and is constrained to develop as an embedded flaw in the early stages of growth because the crack is impeded at the gage side and surface of the rail head by compressive longitudinal stresses.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134290649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.31399/asm.fach.rail.c9001138
M. P. Kaplan
A hi-rail device is a vehicle designed to travel both on roads and on rails. In this case, a truck was modified to accept the wheels for rail locomotion. The rear wheel/axle set was attached to the truck frame. Both the front and rear wheel/axle sets were raised by means of a hydraulic cylinder driven off the PTO of the truck. The wheel/axle set was rigidly fixed into an up or down position by the use of locking pins. It was assumed by the manufacturer that there would be no load on the cylinder once the wheel/axle set was in its locked position. However, as the cylinder pivoted about its mounting trunnion and extended during its motion, it interfered with a frame member. This caused both a bending load and a rotational movement. These effects caused a combination of fretting, galling, and fatigue to the internal thread structure of the clevis. As a result of these deleterious effects, failure of the thread structure of the clevis occurred. The failure occurred where the cylinder rod screws into the clevis. The rod was manufactured from 1045 steel.
{"title":"Failure of a Hi-Rail Device","authors":"M. P. Kaplan","doi":"10.31399/asm.fach.rail.c9001138","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c9001138","url":null,"abstract":"\u0000 A hi-rail device is a vehicle designed to travel both on roads and on rails. In this case, a truck was modified to accept the wheels for rail locomotion. The rear wheel/axle set was attached to the truck frame. Both the front and rear wheel/axle sets were raised by means of a hydraulic cylinder driven off the PTO of the truck. The wheel/axle set was rigidly fixed into an up or down position by the use of locking pins. It was assumed by the manufacturer that there would be no load on the cylinder once the wheel/axle set was in its locked position. However, as the cylinder pivoted about its mounting trunnion and extended during its motion, it interfered with a frame member. This caused both a bending load and a rotational movement. These effects caused a combination of fretting, galling, and fatigue to the internal thread structure of the clevis. As a result of these deleterious effects, failure of the thread structure of the clevis occurred. The failure occurred where the cylinder rod screws into the clevis. The rod was manufactured from 1045 steel.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114715027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.31399/asm.fach.rail.c0047328
Cracks formed on cylinder inserts from a water-cooled locomotive diesel engine, on the water side in the neck between the cylindrical part and the collar. Cracks were revealed by magnetic-particle inspection. As a rule, several parallel cracks had appeared, some of which were very fine. The part played by corrosion in the formation of the cracks was demonstrated with the help of metallographic techniques. The surface regions of the cracks widened into funnel form, which is a result of the corrosive influence of the cooling water. Actual corrosion pits could not be found indicating that the vibrational stresses had a greater share in the damage than the corrosive influence. Cracks appeared initially only in those engines in which no corrosion inhibitor had been added to the cooling water. The cracking was caused by corrosion fatigue. The combined presence of a corrosive medium and cyclical operating stress was needed to cause cracks. No cracks appeared when corrosion inhibitor was added to the cooling water.
{"title":"Corrosion-Fatigue Cracking of Gray Iron Cylinder Inserts From a Water-Cooled Locomotive Diesel Engine","authors":"","doi":"10.31399/asm.fach.rail.c0047328","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c0047328","url":null,"abstract":"\u0000 Cracks formed on cylinder inserts from a water-cooled locomotive diesel engine, on the water side in the neck between the cylindrical part and the collar. Cracks were revealed by magnetic-particle inspection. As a rule, several parallel cracks had appeared, some of which were very fine. The part played by corrosion in the formation of the cracks was demonstrated with the help of metallographic techniques. The surface regions of the cracks widened into funnel form, which is a result of the corrosive influence of the cooling water. Actual corrosion pits could not be found indicating that the vibrational stresses had a greater share in the damage than the corrosive influence. Cracks appeared initially only in those engines in which no corrosion inhibitor had been added to the cooling water. The cracking was caused by corrosion fatigue. The combined presence of a corrosive medium and cyclical operating stress was needed to cause cracks. No cracks appeared when corrosion inhibitor was added to the cooling water.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114731053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.31399/asm.fach.rail.c9001465
A rail section that failed due to fatigue showed a smooth surface with well-developed conchoidal markings. This indicated successive stages of crack propagation, characteristic of fatigue failure. The crack was one of several which developed in the sections of curved rail which formed the lower roller path on which the superstructure of a walking drag-line excavator slewed. The cracking, which ran horizontally, developed at the junction of the underside of the rail head with the web and originated at surface defects in the form of grooves present on the castings. It was concluded that the cracking was caused by lateral deflection of the rails under in-service loads. The web of a rail would normally be loaded in compression but, should lateral movements occur, then it would be subjected to bending stresses and fatigue cracks could break out in regions where excessive tensile components predominated.
{"title":"Failure of Roller Path Rail","authors":"","doi":"10.31399/asm.fach.rail.c9001465","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c9001465","url":null,"abstract":"\u0000 A rail section that failed due to fatigue showed a smooth surface with well-developed conchoidal markings. This indicated successive stages of crack propagation, characteristic of fatigue failure. The crack was one of several which developed in the sections of curved rail which formed the lower roller path on which the superstructure of a walking drag-line excavator slewed. The cracking, which ran horizontally, developed at the junction of the underside of the rail head with the web and originated at surface defects in the form of grooves present on the castings. It was concluded that the cracking was caused by lateral deflection of the rails under in-service loads. The web of a rail would normally be loaded in compression but, should lateral movements occur, then it would be subjected to bending stresses and fatigue cracks could break out in regions where excessive tensile components predominated.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127687448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-11-01DOI: 10.31399/asm.fach.rail.c9001607
N. Tiner
Wire ropes, pulleys, counterweights, and connecting systems are used for auto tensioning of contact wires of electric railways. A wire rope in one such auto tensioning system suffered premature failure. Failure investigation revealed fatigue cracks initiating at nonmetallic inclusions near the surface of individual wire strands in the rope. The inclusions were identified as Al-Ca-Ti silicates in a large number of stringers, and some oxide and nitride inclusions were also found. The wire used in the rope did not conform to the composition specified for AISI 316 grade steel, nor did it satisfy the minimum tensile strength requirements. Failure of the wire rope was found to be due to fatigue; however, the ultimate fracture of the rope was the result of overload that occurred after fatigue failure had reduced the number of wire strands supporting the load.
{"title":"Failure Analysis of a Wire Rope","authors":"N. Tiner","doi":"10.31399/asm.fach.rail.c9001607","DOIUrl":"https://doi.org/10.31399/asm.fach.rail.c9001607","url":null,"abstract":"\u0000 Wire ropes, pulleys, counterweights, and connecting systems are used for auto tensioning of contact wires of electric railways. A wire rope in one such auto tensioning system suffered premature failure. Failure investigation revealed fatigue cracks initiating at nonmetallic inclusions near the surface of individual wire strands in the rope. The inclusions were identified as Al-Ca-Ti silicates in a large number of stringers, and some oxide and nitride inclusions were also found. The wire used in the rope did not conform to the composition specified for AISI 316 grade steel, nor did it satisfy the minimum tensile strength requirements. Failure of the wire rope was found to be due to fatigue; however, the ultimate fracture of the rope was the result of overload that occurred after fatigue failure had reduced the number of wire strands supporting the load.","PeriodicalId":190158,"journal":{"name":"ASM Failure Analysis Case Histories: Rail and Rolling Stock","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1979-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131749324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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