ASM Failure Analysis Case Histories: Processing Errors and Defects最新文献_第3页

Some Manufacturing Defects in Copper Conductors 铜导体的一些制造缺陷

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c9001443

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Fatigue Fracture of a 4140 Steel Forged Crankshaft Resulting From Stress Raisers Created During Hot Trimming 热切边过程中产生的应力引起的4140钢锻造曲轴疲劳断裂

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c0047830

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Failure During Fabrication of an Armature Because of Lamellar Tearing 电枢制造过程中由于片层撕裂造成的失效

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c0089793

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Fatigue Fracture of a Carbon Steel Wiper Spring Because of Stress Concentration at a Sharp Corner 碳钢雨刮器弹簧尖角应力集中导致疲劳断裂

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c0048150

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Failure of a Welded Boiler Tube During a Bending Operation 焊接锅炉管在弯曲操作过程中的失效

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c9001433

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Fracture of Welds in a Pressure Vessel Because of Atmospheric Contamination 压力容器中由于大气污染导致的焊缝断裂

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c0047641

{"title":"Fracture of Welds in a Pressure Vessel Because of Atmospheric Contamination","authors":"","doi":"10.31399/asm.fach.process.c0047641","DOIUrl":"https://doi.org/10.31399/asm.fach.process.c0047641","url":null,"abstract":"\u0000 A Ti-6Al-4V alloy pressure vessel failed during a proof-pressure test, fracturing along the center girth weld. The girth joints were welded with the automatic gas tungsten arc process utilizing an auxiliary trailing shield attached to the welding torch to provide inert-gas shielding for the exterior surface of the weld. A segmented backup ring with a gas channel was used inside the vessel to shield the weld root. The pressure vessel failed due to contamination of the fusion zone by oxygen, which resulted when the gas shielding the root face of the weld was diluted by air that leaked into the gas channel. Thermal stresses cracked the embrittled weld, exposing the crack surfaces to oxidation before cooling. One of these cracks caused a stress concentration so severe that failure of the vessel wall during the proof test was inevitable. A sealing system at the split-line region of the segmented backup ring was provided, and a fine-mesh stainless steel screen diffuser was incorporated in the channel section of the backup ring to prevent air from leaking in. A titanium alloy color chart was furnished to permit correlation of weld-zone discoloration with the degree of atmospheric contamination.","PeriodicalId":294593,"journal":{"name":"ASM Failure Analysis Case Histories: Processing Errors and Defects","volume":"90 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":"122839807","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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Leaky Socket Pipe from the Safety Return Circuit of a Heating Installation 加热装置安全回路的承插管漏水

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c9001211

Egon Kauczor

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Failure by Blowout of Aluminum Alloy 6061-T6 Connector Tubes From a Water-Cooling System 水冷系统6061-T6铝合金接头管爆裂故障

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c0047080

{"title":"Failure by Blowout of Aluminum Alloy 6061-T6 Connector Tubes From a Water-Cooling System","authors":"","doi":"10.31399/asm.fach.process.c0047080","DOIUrl":"https://doi.org/10.31399/asm.fach.process.c0047080","url":null,"abstract":"\u0000 Several of the aluminum alloy 6061-T6 drawn seamless tubes (ASTM B 234, 2.5 cm (1.0 in.) OD with wall thickness of 1.7 mm (0.065 in.)) connecting an array of headers to a system of water-cooling pipes failed. The tubes were supplied in the O temper. They were bent to the desired curvature, preheated, then solution treated, water quenched, and then aged for 8 to 10 h. Analysis (visual inspection, slow-bend testing, 65x macrographic analysis, macroetching, spectrographic analysis, hardness tests, microhardness tests, tension tests, and microscopic examination) supported the conclusions that bending of the connector tubes in the annealed condition induced critical strain near the neutral axis of the tube, which resulted in excessive growth of individual grains during the subsequent solution treatment. Recommendations included bending the connector tubes in the T4 temper as early as possible after being quenched from the solution temperature. The tubes should be stored in dry ice after the quench until bending can be done. The tubes should be aged immediately after being formed. Flattening and slow-bend tests should be specified to ensure that the connector tubes had satisfactory ductility.","PeriodicalId":294593,"journal":{"name":"ASM Failure Analysis Case Histories: Processing Errors and Defects","volume":"93 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":"121196428","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}

引用次数: 0

Fracturing of Gray Iron Door-Closer Cylinder Castings Caused by Lack of Foundry Control Over Chemistry 灰铸铁闭门筒铸件化学控制不足导致的断裂

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c0047297

{"title":"Fracturing of Gray Iron Door-Closer Cylinder Castings Caused by Lack of Foundry Control Over Chemistry","authors":"","doi":"10.31399/asm.fach.process.c0047297","DOIUrl":"https://doi.org/10.31399/asm.fach.process.c0047297","url":null,"abstract":"\u0000 Door-closer cylinder castings manufactured of class 30 gray iron were breaking during machining. The manufacturing source reported that a random sampling of castings from this lot had hardnesses from 180 to 210 HRB. Based on the color of the components, heat treatment of these castings was suspected. Metallurgical examination on two representative castings supported the conclusions that the cracks in these gray iron door closers that were present either before or during the heat treatment were attributed to a substandard microstructure of the wrong type of graphite combined with excessive ferrite. This anomalous structure is caused by shortcomings in the foundry practice of chemical composition, solidification, and inoculation control. Judging from the microstructure, the strength of the material was lower than desired for class 30 gray iron, and the suspected heat treatment further reduced the strength. Recommendations included that the chemistry and inoculation should be controlled to produce type A graphite structure. The chemistry control should aim for a carbon equivalent close to 4.3% to achieve adequate fluidity for thin sections and to alleviate gas defects.","PeriodicalId":294593,"journal":{"name":"ASM Failure Analysis Case Histories: Processing Errors and Defects","volume":"61 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":"115208502","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}

引用次数: 0

Ductile Overload Fracture of an Extension Ladder Made From 6061-T6 Aluminum Alloy Extrusions 6061-T6铝合金拉伸梯的延性过载断裂

ASM Failure Analysis Case Histories: Processing Errors and Defects Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.process.c0046015

{"title":"Ductile Overload Fracture of an Extension Ladder Made From 6061-T6 Aluminum Alloy Extrusions","authors":"","doi":"10.31399/asm.fach.process.c0046015","DOIUrl":"https://doi.org/10.31399/asm.fach.process.c0046015","url":null,"abstract":"\u0000 A two-section extension ladder, made from 6061-T6 aluminum alloy extrusions and stampings that were riveted together at each rung location and at the ends of side rails, broke in service after having been used at the sites of several fires by the fire department of a large city. The fracture surfaces were examined visually and by optical (light) stereomicroscopy. Material testing showed a sample to be within the specified material limits for aluminum alloy 6061. Microscopic examination showed no significant differences in microstructure or grain size among the four T-sections, and thickness measurements at various locations indicated that thicknesses were well within standard industry tolerances for aluminum extrusions in this size range. However, hardness testing of the four T-sections showed that in two, hardness was considerably lower than the acceptable hardness for the T6 temper and were within the range for 6061-T4 (acceptable hardness, 19 to 45 HRB). This indicated they had been naturally aged at room temperature after solution heat treatment instead of artificially aged as per specs. Edge cracking in two of the T-sections was the result of improper conditions during extrusion of the T-sections; however, this condition was not a primary cause of failure.","PeriodicalId":294593,"journal":{"name":"ASM Failure Analysis Case Histories: Processing Errors and Defects","volume":"20 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":"125601142","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}

引用次数: 0