Effect of Yield Strength and Crack Depth on COD-Decrease-Parameter m

2000 ◽  
Vol 183-187 ◽  
pp. 589-594
Author(s):  
Qing Fen Li ◽  
Huocai Ni ◽  
Sang Lin Yang ◽  
Maoyuan Ma ◽  
Ping Long ◽  
...  
Keyword(s):  
Author(s):  
Fred V. Ellis ◽  
Sebastian Tordonato

A metallurgical failure analysis and life prediction was performed for an economizer tube. The tube failed after approximately nine years of service. The failure was a pin hole leak, elliptically shaped with the long axis in the circumferential direction. On the inside surface of the tube, there were several circumferential cracks and numerous oxygen pits on the top half. The cracks were transgranular and initiated at pits. The failure mechanism is corrosion fatigue and is believed to be due to a cyclic applied bending moment. Life predictions were performed using two crack geometries and zero-tension loading cycle. The geometries were a thumbnail shaped ID crack with an a/c of 0.2 and a 360° ID cracked cylinder. A parametric approach was used with two initial crack depths based on the measured pit depths and three remote stresses centered around the minimum yield strength of the SA-178-A tube material. The failure criteria was the reference stress equal to the flow stress. For the thumbnail crack geometry at a remote load of 179 MPa (equal to minimum specified yield strength), the calculated lives were 15,960 cycles for an initial crack depth of 5% and 3,450 cycles for an initial crack depth of 10%. The cyclic lives of the 360° crack geometry were approximately half of those for the thumbnail crack geometry. The slope of the log life-log stress curve was approximately −5.8.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Wang Hui-li ◽  
Qin Si-feng

The corrosion fatigue performance of high-strength bolt was studied. Based on the fracture mechanics theory and the Gerberich-Chen formula, the high-strength bolt corrosion fracture crack model and the fatigue life model were established. The high-strength bolt crack depth and the fatigue life under corrosion environment were quantitatively analyzed. The factors affecting high-strength bolt corrosion fatigue life were discussed. The result showed that the high-strength bolt corrosion fracture biggest crack depth reduces along with the material yield strength and the applied stress increases. The material yield strength was the major factor. And the high-strength bolt corrosion fatigue life reduced along with the increase of material strength, the applied stress or stress amplitude. The stress amplitude influenced the most, and the material yield strength influenced the least. Low bolt strength and a low stress amplitude level could extend high-strength bolt corrosion fatigue life.


2019 ◽  
Author(s):  
Chelsey Henry ◽  
Keith Rupel ◽  
Charles Park ◽  
Joseph Costanzo ◽  
Cary Kaczowka ◽  
...  

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.


2020 ◽  
Vol 86 (5) ◽  
pp. 43-51
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
P. V. Volkov ◽  
D. A. Zhgut

The history of appearance and the current state of instrumented indentation are briefly described. It is noted that the materials instrumented indentation methods using a pyramid and ball indenters are actively developing and are currently regulated by several Russian and international standards. These standards provide formulas for calculating the Young’s modulus and hardness at maximum indentation load. Instrumented indentation diagrams «load F – displacement α» of a ball indenter for metallic materials were investigated. The special points on the instrumented indentation diagrams «F – α» loading curves in the area of elastic into elastoplastic deformation transition, and in the area of stable elastoplastic deformation are revealed. A loading curve area with the load above which the dF/dα begins to decrease is analyzed. A technique is proposed for converting «F – α» diagrams to «unrestored Brinell hardness HBt – relative unrestored indent depth t/R» diagrams. The elastic and elastoplastic areas of «HBt – t/R» diagrams are described by equations obtained analytically and experimentally. The materials strain hardening parameters during ball indentation in the area of elastoplastic and plastic deformation are proposed. The similarity of «HBt – t/R» indentation diagram with the «stress σ – strain δ» tensile diagrams containing common zones and points is shown. Methods have been developed for determining hardness at the elastic limit, hardness at the yield strength, and hardness at the ultimate strength by instrumented indentation with the equations for their calculation. Experiments on structural materials with different mechanical properties were carried out by instrumented indentation. The values of hardness at the elastic limit, hardness at the yield strength and hardness at the ultimate strength are determined. It is concluded that the correlations between the elastic limit and hardness at the elastic limit, yield strength and hardness at the yield strength, ultimate tensile strength and hardness at the ultimate strength is more justified, since the listed mechanical characteristics are determined by the common special points of indentation diagrams and tensile tests diagrams.


Alloy Digest ◽  
2007 ◽  
Vol 56 (2) ◽  

Abstract Durimphy is a maraging steel with 1724 MPa (250 ksi) tensile strength and a very high yield strength due to precipitation hardening. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: FE-140. Producer or source: Metalimphy Precision Alloys.


Alloy Digest ◽  
2011 ◽  
Vol 60 (10) ◽  

Abstract Dogal 300 LAD, 340 LAD, 380 LAD, 420 LAD, 460 LAD and 500 LAD are high-strength low alloyed steels intended for pressing. The designation in the name is the guaranteed minimum yield strength. Dogal steels can be zinc coated. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on surface qualities as well as forming, heat treating, joining, and surface treatment. Filing Code: CS-167. Producer or source: SSAB Swedish Steel Inc..


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