Effect of Strain History on Steel Tube Umbilical

2007 ◽  
Author(s):  
Alan Dobson
Keyword(s):  
Mechanical Properties ◽  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Steel Tube ◽  
Fatigue Properties ◽  
Strain History ◽  
Stress Cracking ◽  
Induced Stress ◽  
The Impact ◽  
Strain Cycling

The effect of repeated plastic strain on the mechanical properties of reeled super duplex tube used in the construction of umbilical riser systems is assessed. The impact of typical plastic strain cycles on the fatigue properties of tubing, mechanical properties of the tubing and the susceptibility of hydrogen embrittlement of the tubing has been investigated. There is evidence that plastic strain cycles have an effect upon the fatigue life of the tube; which can be attributed to a low cycle fatigue mechanism. There is no evidence that plastic strain cycling to specified limits has an effect upon the susceptibility of the material to Hydrogen Induced Stress Cracking (HISC) and typical plastic strain cycles have no degenerative effect upon the mechanical properties of super duplex tube and radial welds.

scholarly journals Crack Healing and Mechanical Properties Recovery in SA 508–3 Steel

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 890 ◽  
Author(s):  
Yao Qiu ◽  
Ruishan Xin ◽  
Jianbin Luo ◽  
Qingxian Ma
Keyword(s):  
Mechanical Properties ◽  
Low Cycle Fatigue ◽  
Optical Microscope ◽  
Reduction Ratio ◽  
Fatigue Properties ◽  
Crack Healing ◽  
Hot Plastic Deformation ◽  
Crack Zone ◽  
Healing Temperature ◽  
The Impact

Internal cracks could be healed under the process of hot plastic deformation. In this study, mechanical properties recovery after crack healing in SA 508–3 steel were investigated. Microstructures of the crack healing zones were observed using an optical microscope (OM) and electron back scattered diffraction (EBSD) technology, and the recovery degrees of mechanical properties in the crack healing zones with the healing temperature and a reduction ratio were tested systematically. The results showed that the internal cracks in SA 508–3 steel disappeared and were replaced by newly formed grains, achieved by recrystallization and abnormal grain growth. The tensile properties of crack healing zones could be fully restored, while their impact and low cycle fatigue properties could only be partially achieved. The recovery degrees of mechanical properties in crack healing zones increased with increasing the healing temperature and reduction ratio in the temperature range of 950–1050 °C. When the temperature was above 1150 °C, the impact properties began to deteriorate because of grain coarsening and larger MA (martensite–austenite) constituents. The microstructural evolution of the crack zone in the SA 508–3 steel was sketched.

Mechanical Properties of Equal-Channel Angular Extrusion-Processed Al-20Zn Alloy

2012 ◽  
Vol 445 ◽  
pp. 195-200
Author(s):  
Murat Aydin ◽  
Yakup Heyal
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Equal Channel Angular Extrusion ◽  
Considerable Change ◽  
Fatigue Properties ◽  
Dendritic Microstructure ◽  
Two Phase ◽  
Angular Extrusion ◽  
Alloy Increase ◽  
The Impact

The mechanical properties mainly tensile properties, impact toughness and high-cycle fatigue properties, of two-phase Al-20Zn alloy subjected to severe plastic deformation (SPD) via equal-channel angular extrusion (ECAE) using route A up to 2 passes were studied. The ECAE almost completely eliminated as-cast dendritic microstructure including casting defects such as micro porosities. A refined microstructure consisting of elongated micro constituents, α and α+η eutectic phases, formed after ECAE via route A. As a result of this microstructural change, mechanical properties mainly the impact toughness and fatigue performance of the as-cast Al-20Zn alloy increased significantly through the ECAE. The rates of increase in fatigue endurance limit are approximately 74 % after one pass and 89 % after two passes while the increase in impact toughness is 122 %. Also the yield and tensile strengths of the alloy increase with ECAE. However, no considerable change occurred in hardness and percentage elongation of the alloy. It was also observed that the ECAE changed the nature of the fatigue fracture characteristics of the as-cast Al-20Zn alloy.

scholarly journals Physico-Mechanical Properties of the Poly(oxymethylene) Composites Reinforced with Glass Fibers under Dynamical Loading

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2064 ◽  
Author(s):  
Stanisław Kuciel ◽  
Patrycja Bazan ◽  
Aneta Liber-Kneć ◽  
Aneta Gądek-Moszczak
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Fiber Diameter ◽  
Glass Fibers ◽  
Fiber Reinforced Composites ◽  
Dynamic Loads ◽  
Fatigue Properties ◽  
Reinforced Composites ◽  
The Impact ◽  
Microscopy Images

The paper evaluated the possibility of potential reinforcing of poly(oxymethylene) (POM) by glass fiber and the influence of fiberglass addition on mechanical properties under dynamic load. Four types of composites with glass fiber and another four with carbon fiber were produced. The fiber content ranged from 5% to 40% by weight. In the experimental part, the basic mechanical and fatigue properties of POM-based composites were determined. The impact of water absorption was also investigated. The influence of fiber geometry on the mechanical behavior of fiber-reinforced composites of various diameters was determined. To refer to the effects of reinforcement and determine the features of the structure scanning electron microscopy images were taken. The results showed that the addition of up to 10 wt %. fiberglass increases the tensile properties and impact strength more than twice, the ability to absorb energy also increases in relation to neat poly(oxymethylene). Fiber geometry also has a significant impact on the mechanical properties. The study of the mechanical properties at dynamic loads over time suggests that composites filled with a smaller fiber diameter have better fatigue properties.

The Effect of Morphology and Distribution of Sulfides on Mechanical Properties and Fatigue Life of Non-Quenched and Tempered Steel

2008 ◽  
Vol 51 ◽  
pp. 11-20
Author(s):  
Ming Tu Ma ◽  
Guo Zhong Li ◽  
Zhi Gang Li ◽  
Hong Zhou Lu
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Fracture ◽  
Rolling Direction ◽  
Impact Fracture ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Quenched And Tempered Steel ◽  
The Impact ◽  
Tempered Steel

The effect of morphology and distribution of sulfides on tensile, impact and bending fatigue properties of non-quenched and tempered steel 49MnVS3 has been investigated in this paper. Microscopic structure and morphology of sulfides are observed, and impact fracture and fatigue fracture have been analyzed by SEM. The results show that the morphology of sulfides is mostly strip and distributes in ferrite, which affects mechanical properties and fatigue life. The length direction of sulfide strip is parallel to the rolling direction of steel. When the length of sulfide is short relatively and is approximate to the shape of particles. The impact properties and bending fatigue performance of 49MnVS3 are higher. Under those conditions, there are more ductile characteristics in their impact fracture and the fatigue fracture. The reasons for the effect of sulfide morphology on the mechanical and fatigue properties are explained.

Mechanical Properties and Environmental Stress Cracking Resistance of Rubber Toughened Polyester/Clay Composite

2012 ◽  
Vol 576 ◽  
pp. 318-321 ◽  
Author(s):  
Bonnia Noor Najmi ◽  
Sahrim Haji Ahmad ◽  
Surip Siti Norasmah ◽  
S.S. Nurul ◽  
Noor Azlina Hassan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Natural Rubber ◽  
Stress Cracking ◽  
Rubber Toughened ◽  
Environmental Stress Cracking ◽  
Liquid Natural Rubber ◽  
Polyester Composite ◽  
Polyester Matrix ◽  
The Impact

Crosslinked polyester clay nanocomposites were prepared by dispersing originically modified montmorillonite in prepromoted polyester resin and subsequently crosslinked using methyl ethyl ketone peroxide catalyst at different clay concentration. Cure process and the mechanical properties of rubber toughened polyester clay composite have been studied. Rubber toughened thermoset polyester composite were prepared by adding 3 per hundred rubber (phr) of liquid natural rubber (LNR) was used in the mixing of producing this composite. Modification of polyester matrix was done due to the brittle problem of polyester composite. Addition of LNR will increase the toughness of composite and produce ductile polyester. Two types of composites were produced which is clay-lnr polyester composite and clay polyester composite. Addition of liquid natural rubber significantly increased the impact strength and flexural properties. Result shows that addition of 6% of clay-lnr composite give good properties on impact, strength and flexural. From the ESCR test, both composites showed good resistance to environmental.

Low Cycle Fatigue Evaluation of Inconel 713C and Waspaloy

1965 ◽  
Vol 87 (2) ◽  
pp. 275-289 ◽  
Author(s):  
JoDean Morrow ◽  
F. R. Tuler
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Strain Energy ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Plastic Strain Energy ◽  
Fatigue Evaluation ◽  
Inconel 713C

Completely reversed axial fatigue results are reported for Waspaloy and Inconel 713C at room temperature. Fatigue strength and ductility are evaluated using power functions of the fatigue life. The exponents and coefficients of these two equations are looked upon as four fatigue properties of the material. They appear in the equations which are developed to relate cyclic stress, plastic strain, total strain, plastic strain energy per cycle, total plastic strain energy to fracture, and fatigue life. These equations and the four fatigue properties permit the evaluation of the relative fatigue resistance of various metals at different fatigue lives when subjected to strain, stress, or plastic strain energy cycling. The “best” selection of material to resist fatigue is found to depend on the type of cycling and the desired life. At room temperature, the wrought Waspaloy is found to be more fatigue resistant than the cast Inconel 713C, particularly in resisting strain or plastic strain energy cycling in the low cycle fatigue region. For longer lives the difference in fatigue resistance between the two diminishes, especially for stress cycling. It is believed that the method of fatigue evaluation used here is generally applicable to the engineering problem of material selection to resist fatigue, and should in some cases replace methods based on conventional rotating bending fatigue tests which only evaluate the fatigue strength at long lives.

scholarly journals The Effect of Heat Treatment Parameters on Mechanical Characteristics of 10CrMo9-10 Steel Tube Bends / Wpływ Parametrów Obróbki Cieplnej Na Charakterystyki Mechaniczne Łuków Rurowych Ze Stali 10CrMo9-10

2015 ◽  
Vol 60 (4) ◽  
pp. 2971-2976
Author(s):  
M. Cieśla ◽  
R. Findziński ◽  
G. Junak ◽  
T. Kawała
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Characteristics ◽  
Low Cycle Fatigue ◽  
Steel Tube ◽  
Material Microstructure ◽  
Factor Conditioning ◽  
Lower Temperature ◽  
Material Durability ◽  
Tempering Time

The purpose of the paper was to analyse the effect of diverse heat treatment parameters (normalising and tempering) on mechanical characteristics of the material used to develop ϕ508x20 tube bends made of the 10CrMo9-10 steel by application of induction heating. The research conducted included tests of basic mechanical properties as well as low cycle fatigue and creep at the temperature of 500°C. With reference to the results thus obtained, it has been established that there is a relationship between mechanical properties of bends and individual features of their microstructure conditional to the heat treatment parameters. Among other conclusions drawn in the research, it has been found that the main structural factor conditioning the mechanical properties of bends was the grain size. Heat treatment parameters characterised by lower temperature and shorter tempering time triggered changes in the material microstructure, such as increased grain comminution. The effects of the said changes included improvement of strength characteristics (Rm, Rp0,2) as well as increased material durability under conditions of fatigue and creep. Main criterion-specific mechanical properties and geometric features of the bends developed conformed with the relevant requirements of reference standards (PN-EN 10216-2, PN-EN 12952).

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