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Optimum design of internal upset geometry of drill pipe for longer fatigue life
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This section contains abstracts of selected articles, technical reports, dissertations and patents concerned with fatigue. The abstracts are prepared in collaboration with Materials Information, a joint service of The Institute of Metals and ASM International. Readers wishing to obtain the full text of articles abstracted here should contact either: The Institute of Metals, 1 Carlton House Terrace, London S W l Y 5DB, UK, or: ASM International, Metals Park, OH 44073, USA (not Internationa/Journa/of Fatigue). The fees charged for photocopying articles are £7.00 for the first ten pages and £3.00 per additional ten pages (UK office), or $10.00 for the first ten pages and $4.00 per additional ten pages (US office).
General T h e m e c h a n i s m s o f dispersion s t r e n g t h e n i n g and fracture in s l u m i n i u m based X D alloys. Aikin, R.M. Jr.
Martin Marietta Laboratories, NASA Langley Research Center, Report No NASA CR-4365 1991 140pp
The influence of reinforcement size, volume fraction, and matrix deformation bahaviour on room and elevated temperature strength; the fracture toughness; and the fatigue crack growth rate of metal matrix composites of Ai-4Cu-I.SMg with TiB2 have been examined. The influence of reinforcement volume fraction has also been examined for pure AI with TiB2. The interperticle spacing appears to be the factor that controls the strength of these alloys, with the exact nature of the dependence relying on the nature of dislocetion slip in the matrix (planar or diffuse). The isothermal ageing response of the precipitation-strangthened AI-4Cu-l.5Mg alloys was not accelerated by the presence of TiB2. Cold work prior to artificial ageing created additional geometrically necessary dislocations that sewed as heterogeneous nucleation sites leading to accelerated ageing, a finer precipitate size and an increase in the strength of the alloy. Graphs, photomicrographs, diffraction patterns, spectra. 91 refs. Effect o f a h i g h - t e m p e r a t u r e cycle on t h e mechanical properties o f silicon c e r b i d e / t i t a n i u m m e t a l m a t r i x composites. Neik, R.A., Pollock,
W.D. and Johnson, W.S. J. Mater. ScL J u n e 1991 26, (11), 2913-2920 The effects of fibra/mstrix interface strength and thermal residual stresses on the mechanical properties of a silicon cerbide/Ti composite were investigated. A threeply (0°/900/0°) composite SiCf/Ti-15V-3Cr-3AI-3Sn was subjected to a simulated superplastic forming/diffusion bonding (SPF/DB) temperature cycle which changed the fibre/matrix interfecial strength and thermal residual stresses in the composite. The (0~/90°/0°) composite subjected to the SPF/DB process showed a 25% decrease in ultimate tensile strength (UTS) and a 30% decrease in failure strain compared to the es-fabriceted (ABF) material. The fatigue life for the SPF/DB specimens was approximately 50% lower than that for the ASF specimens. The fracture surface of the ABF specimens was very irregular accompanied by substantial fibre pull-out as compared to the planar fracture surface of the SPF/DB-cycled specimens that showed negligible fibre pull-out. The large changes in the tensile strength and fatigue life due to the SPF/DB cycle are explained by a difference in the failure mechanisms occurring as a result of the SPF/DB-induced changes in the strength of the fibre/matrix interface and higher thermal residual stresses. Unreinforced Ti was also tested to study the effect of the SPF/DB cycle on the matrix static properties. Fibres were etched from the composite and then individually tested for modulus and strength. Finally, a microscopic examination of the fibre/matrix interface was performed to study the effects of the SPF/DB cycle on the interface. Graphs, photomicrographs. 9 refs.
O p t i m u m design of internal upset g e o m e t r y o f d r i l l p i p e f o r longer f a t i g u e life. Tsukano, Y., Miyoshi, H., Sogo, Y., Nishi, S. and Takeuchi,
E. Nippon Steel Technical Report Jan. 1990 (44), 3 7 - 4 2 The fatigue failure of a drill pipe originating in the transition area of an internal upset is a serious problem in oil well drilling. A procedure is described for optimizing the internal upset geometry to prevent this type of failure. The optimum geometry of internal upset was defined such that the stress developed in the transition area of an internal upset under a bending load does not exceed the stress developed in the external surface of the pipe body. The optimum internal upset geometry that satisfies this requirement was specifically determined by finite-element analysis. The accuracy of the optimum internal upset geometry obtained by the finite-element analysis was successfully validated by rotary-bending fatigue tests made of full-size drill pipe specimens. These results led to the optimization of the internal upset geometry in all the drill pipe production by Nippon Steel corporation. Graphs. 6 refs. Axial-fatigue-life prediction of structural cables f r o m first principles.
Raoof, M. Proc. Inst. Civil Eng. 2 Mar. 1991 91 1 9 - 3 8 Using the results from previously reported sheet theory, an insight is given into the pattern of normal (Hertzian) stresses throughout realistic end muitilayered spiral
138
strands. Based on such information in conjunction with the available axial-fatigue data on single-component wires, an analytical model is developed that is capable of predicting the cable axial-fatigue life away from terminations from first principles. The model is capable of throwing some light on various cable characteristics of practical importance. The match between experimental date on some substantial 51 mm o.d. strands and theoretical predictions is very encouraging. The theory also provides a useful upper bound to the fatigue life of cables whose component wires have failed at the end terminations; it is shown that the types of end termination employed at present can lead to very significant reductions in the observed fatigue life (compared with the free-field situation). Wire failures can be both internal and/or external: the theory is capable of predicting internal wire failures end highlights the shortcomings of the methods of discard criteria based on the number of vieuel (outer layer) wire fractures that are employed at present. The axial-fatigue characteristics of sheathed spiral stands employed at present for deep water applications are also considered. It is shown that the external water pressure on such 'sealed' strands can lead to significant reductions in the cable fatigue life. The corrosion fatigue of steel spiral strands in seawater is also addressed: the analytical model employs empirical data in respect of fretting corrosion fatigue of single wires in contact to estimate cable fatigue life in seawater. The theory offers an explanation for the previously published observations that there did not seem to be a marked difference between the experimentally obtained cable fatigue life in seawater and in air over the ranges of test frequencies and imposed environmental conditions investigated. Graphs. 39 rsfs. Effect o f p h o s p h a t e coatings on f a t i g u e crack initiation in quenched and t a m p e r e d l o w - a l l o y steel. Technical report. Farrara, R.A. and Ritter, J.C. Materials Research Laboratories (Australia) Report No AD-A230 871/6/XAB Dec. 1990 22 pp Fatigue testing was performed on small notched-bend specimens of the highstrength steel AISI 4335 used for cannon barrels, breech rings and blocks. The effect of surface coatings of Zn and manganese phosphate on the fatigue life to crack initiation was determined at two levels of applied stress, selected to cause failures in the range of 103-104 cycles appropriate to cannon breech mechanisms. Both types of coating dresticelly decreased life to crack initiation compared with that of tmcoated samp~s, the degradation being attributed to surface pitting and crevice attack by the phospheting process.
Improvement o f surface i n t e g r i t y and materiel f a t i g u e strength b y CBN g r i n d i n g wheels. Yokogawa, M. and Yokogawa, K. Werkstatt Betrieb Mar. 1991 124, (3), 187-190 (in G e r m a n ) Grinding with cubic boron nitride produces smooth surfaces with closely finished dimensions. A comparison was made of the surface quality of 34CrMo4 with tensile and yield strengths of 932 and 785 MPa, respectively, ground with CBN type (550)80/100Wl 200VN4 or AI203 ceramic type SA80J7V75S. Results showed that compared to AI203 material surfaces ground with CBN had lower surface roughness and residual stresses, better fatigue properties and caused less wear on the grinding wheels. These test results have been confirmed in production runs. Graphs, photomicrographs. 5 refs.
The corrosion f a t i g u e of t h e o u t l e t pipes in t h e firet-stage ammonium c a r b e m e t e p u m p s . Huang, Y. Huagong Jixie (Chem. Eng. Mach.) 1991 18, (1), 5 3 - 5 6 (in Chinese) A fracture investigation was made of the corrosion fatigue cracking of austenitic stainless steel in a high-pressure ammonium carbamate solution and the cause of corrosion fatigue was analysed in solution, stress and fatigue source. Finally a reference solution was put forward. 6 refs.
Corrosion fatigue process of 12Cr stainless steel. Ebara, R., Yamada, T. and Kawano, H. ISIJ Int. J u l y 1990 30, (7), 5 3 5 - 5 3 9 Microfractographicel features of the corrosion fatigue process of 12Cr stainless-steel turbine blade material are described. The emphasis is focused upon the initiation and growth of corrosion pits in the corrosion fatigue crack initiation process. A quantitative example of corrosion pitting examined by use of recently developed image analysing technology is also discussed in brief. Graphs, photomicrographs. 13 refs.
Int J Fatigue March 1992
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This section contains abstracts of selected articles, technical reports, dissertations and patents concerned with fatigue. The abstracts are prepared in collaboration with Materials Information, a joint service of The Institute of Metals and ASM International. Readers wishing to obtain the full text of articles abstracted here should contact either: The Institute of Metals, 1 Carlton House Terrace, London S W l Y 5DB, UK, or: ASM International, Metals Park, OH 44073, USA (not Internationa/Journa/of Fatigue). The fees charged for photocopying articles are £7.00 for the first ten pages and £3.00 per additional ten pages (UK office), or $10.00 for the first ten pages and $4.00 per additional ten pages (US office).
General T h e m e c h a n i s m s o f dispersion s t r e n g t h e n i n g and fracture in s l u m i n i u m based X D alloys. Aikin, R.M. Jr.
Martin Marietta Laboratories, NASA Langley Research Center, Report No NASA CR-4365 1991 140pp
The influence of reinforcement size, volume fraction, and matrix deformation bahaviour on room and elevated temperature strength; the fracture toughness; and the fatigue crack growth rate of metal matrix composites of Ai-4Cu-I.SMg with TiB2 have been examined. The influence of reinforcement volume fraction has also been examined for pure AI with TiB2. The interperticle spacing appears to be the factor that controls the strength of these alloys, with the exact nature of the dependence relying on the nature of dislocetion slip in the matrix (planar or diffuse). The isothermal ageing response of the precipitation-strangthened AI-4Cu-l.5Mg alloys was not accelerated by the presence of TiB2. Cold work prior to artificial ageing created additional geometrically necessary dislocations that sewed as heterogeneous nucleation sites leading to accelerated ageing, a finer precipitate size and an increase in the strength of the alloy. Graphs, photomicrographs, diffraction patterns, spectra. 91 refs. Effect o f a h i g h - t e m p e r a t u r e cycle on t h e mechanical properties o f silicon c e r b i d e / t i t a n i u m m e t a l m a t r i x composites. Neik, R.A., Pollock,
W.D. and Johnson, W.S. J. Mater. ScL J u n e 1991 26, (11), 2913-2920 The effects of fibra/mstrix interface strength and thermal residual stresses on the mechanical properties of a silicon cerbide/Ti composite were investigated. A threeply (0°/900/0°) composite SiCf/Ti-15V-3Cr-3AI-3Sn was subjected to a simulated superplastic forming/diffusion bonding (SPF/DB) temperature cycle which changed the fibre/matrix interfecial strength and thermal residual stresses in the composite. The (0~/90°/0°) composite subjected to the SPF/DB process showed a 25% decrease in ultimate tensile strength (UTS) and a 30% decrease in failure strain compared to the es-fabriceted (ABF) material. The fatigue life for the SPF/DB specimens was approximately 50% lower than that for the ASF specimens. The fracture surface of the ABF specimens was very irregular accompanied by substantial fibre pull-out as compared to the planar fracture surface of the SPF/DB-cycled specimens that showed negligible fibre pull-out. The large changes in the tensile strength and fatigue life due to the SPF/DB cycle are explained by a difference in the failure mechanisms occurring as a result of the SPF/DB-induced changes in the strength of the fibre/matrix interface and higher thermal residual stresses. Unreinforced Ti was also tested to study the effect of the SPF/DB cycle on the matrix static properties. Fibres were etched from the composite and then individually tested for modulus and strength. Finally, a microscopic examination of the fibre/matrix interface was performed to study the effects of the SPF/DB cycle on the interface. Graphs, photomicrographs. 9 refs.
O p t i m u m design of internal upset g e o m e t r y o f d r i l l p i p e f o r longer f a t i g u e life. Tsukano, Y., Miyoshi, H., Sogo, Y., Nishi, S. and Takeuchi,
E. Nippon Steel Technical Report Jan. 1990 (44), 3 7 - 4 2 The fatigue failure of a drill pipe originating in the transition area of an internal upset is a serious problem in oil well drilling. A procedure is described for optimizing the internal upset geometry to prevent this type of failure. The optimum geometry of internal upset was defined such that the stress developed in the transition area of an internal upset under a bending load does not exceed the stress developed in the external surface of the pipe body. The optimum internal upset geometry that satisfies this requirement was specifically determined by finite-element analysis. The accuracy of the optimum internal upset geometry obtained by the finite-element analysis was successfully validated by rotary-bending fatigue tests made of full-size drill pipe specimens. These results led to the optimization of the internal upset geometry in all the drill pipe production by Nippon Steel corporation. Graphs. 6 refs. Axial-fatigue-life prediction of structural cables f r o m first principles.
Raoof, M. Proc. Inst. Civil Eng. 2 Mar. 1991 91 1 9 - 3 8 Using the results from previously reported sheet theory, an insight is given into the pattern of normal (Hertzian) stresses throughout realistic end muitilayered spiral
138
strands. Based on such information in conjunction with the available axial-fatigue data on single-component wires, an analytical model is developed that is capable of predicting the cable axial-fatigue life away from terminations from first principles. The model is capable of throwing some light on various cable characteristics of practical importance. The match between experimental date on some substantial 51 mm o.d. strands and theoretical predictions is very encouraging. The theory also provides a useful upper bound to the fatigue life of cables whose component wires have failed at the end terminations; it is shown that the types of end termination employed at present can lead to very significant reductions in the observed fatigue life (compared with the free-field situation). Wire failures can be both internal and/or external: the theory is capable of predicting internal wire failures end highlights the shortcomings of the methods of discard criteria based on the number of vieuel (outer layer) wire fractures that are employed at present. The axial-fatigue characteristics of sheathed spiral stands employed at present for deep water applications are also considered. It is shown that the external water pressure on such 'sealed' strands can lead to significant reductions in the cable fatigue life. The corrosion fatigue of steel spiral strands in seawater is also addressed: the analytical model employs empirical data in respect of fretting corrosion fatigue of single wires in contact to estimate cable fatigue life in seawater. The theory offers an explanation for the previously published observations that there did not seem to be a marked difference between the experimentally obtained cable fatigue life in seawater and in air over the ranges of test frequencies and imposed environmental conditions investigated. Graphs. 39 rsfs. Effect o f p h o s p h a t e coatings on f a t i g u e crack initiation in quenched and t a m p e r e d l o w - a l l o y steel. Technical report. Farrara, R.A. and Ritter, J.C. Materials Research Laboratories (Australia) Report No AD-A230 871/6/XAB Dec. 1990 22 pp Fatigue testing was performed on small notched-bend specimens of the highstrength steel AISI 4335 used for cannon barrels, breech rings and blocks. The effect of surface coatings of Zn and manganese phosphate on the fatigue life to crack initiation was determined at two levels of applied stress, selected to cause failures in the range of 103-104 cycles appropriate to cannon breech mechanisms. Both types of coating dresticelly decreased life to crack initiation compared with that of tmcoated samp~s, the degradation being attributed to surface pitting and crevice attack by the phospheting process.
Improvement o f surface i n t e g r i t y and materiel f a t i g u e strength b y CBN g r i n d i n g wheels. Yokogawa, M. and Yokogawa, K. Werkstatt Betrieb Mar. 1991 124, (3), 187-190 (in G e r m a n ) Grinding with cubic boron nitride produces smooth surfaces with closely finished dimensions. A comparison was made of the surface quality of 34CrMo4 with tensile and yield strengths of 932 and 785 MPa, respectively, ground with CBN type (550)80/100Wl 200VN4 or AI203 ceramic type SA80J7V75S. Results showed that compared to AI203 material surfaces ground with CBN had lower surface roughness and residual stresses, better fatigue properties and caused less wear on the grinding wheels. These test results have been confirmed in production runs. Graphs, photomicrographs. 5 refs.
The corrosion f a t i g u e of t h e o u t l e t pipes in t h e firet-stage ammonium c a r b e m e t e p u m p s . Huang, Y. Huagong Jixie (Chem. Eng. Mach.) 1991 18, (1), 5 3 - 5 6 (in Chinese) A fracture investigation was made of the corrosion fatigue cracking of austenitic stainless steel in a high-pressure ammonium carbamate solution and the cause of corrosion fatigue was analysed in solution, stress and fatigue source. Finally a reference solution was put forward. 6 refs.
Corrosion fatigue process of 12Cr stainless steel. Ebara, R., Yamada, T. and Kawano, H. ISIJ Int. J u l y 1990 30, (7), 5 3 5 - 5 3 9 Microfractographicel features of the corrosion fatigue process of 12Cr stainless-steel turbine blade material are described. The emphasis is focused upon the initiation and growth of corrosion pits in the corrosion fatigue crack initiation process. A quantitative example of corrosion pitting examined by use of recently developed image analysing technology is also discussed in brief. Graphs, photomicrographs. 13 refs.
Int J Fatigue March 1992