Download Title - My FIT

Title: Impact behavior of different stainless steel weldments at low temperatures
Authors: Ibrahim,O.H.^; Ibrahim,I.S.^; Khalifa,T.A.F.^
Source: Eng.Failure Anal., 2010, 17, 5, 1069-1076
Abstract: A comparative study was made of the fracture behavior of austenitic and
duplex stainless steel weldments at cryogenic temperatures by impact testing. The
investigated materials were two austenitic (304L and 316L) and one duplex (2505)
stainless steel weldments. Shielded metal arc welding (SMAW) and tungsten inert gas
welding (TIG) were employed as joining techniques. Instrumented impact testing was
performed between room and liquid nitrogen (−196°C) test temperatures. The results
showed a slight decrease in the impact energy of the 304L and 316L base metals with
decreasing test temperature. However, their corresponding SMAW and TIG weld
metals displayed much greater drop in their impact energy values. A remarkable
decrease (higher than 95%) was observed for the duplex stainless steel base and weld
metals impact energy with apparent ductile to brittle transition behavior. Examination
of fracture surface of tested specimens revealed complete ductile fracture morphology
for the austenitic base and weld metals characterized by wide and narrow deep and
shallow dimples. On the contrary, the duplex stainless steel base and weld metals
fracture surface displayed complete brittle fracture morphology with extended large
and small stepped cleavage facets. The ductile and brittle fracture behavior of both
austenitic and duplex stainless steels was supplemented by the instrumented
load–time traces. The distinct variation in the behavior of the two stainless steel
categories was discussed in light of the main parameters that control the deformation
mechanisms of stainless steels at low temperatures; stacking fault energy, strain
induced martensite transformation and delta ferrite phase deformation.
Summary:
stainless steel base
duplex stainless steel base
and weld metals
impact energy
a slight decrease
A remarkable decrease
(higher than 95%)
fracture surface
complete ductile fracture
morphology with wide
and narrow deep and
shallow dimples
complete brittle fracture
morphology with
extended large and small
stepped cleavage facets
Title: Properties of Cr-Ni and Cr-Ni-Mn steels and alloy 36NKhTYu at low
temperatures
Authors: Koshelev,P.F.; Nikitin,P.N.; Katkova,V.V.
Source: Metal Science and Heat Treatment, 1976, 18, 10, 866-869
Abstract:1.Precipitation-hardened alloy 36NKhT Yu has high strength, good ductility,
a stable structure, low sensitivity to stress concentrations at low temperatures, and can
be used for highly stressed components of cryogenic apparatus.2.Austenitic-ferritic
steels 15Kh18N12S4T Yu and 12Kh21N5T are characterized by satisfactory strength,
ductility, and toughness at temperatures down to 4°K.3.Steel 0Kh20N4AG10 has
low ductility and is sensitive to stress concentrations at temperatures below 77°K.
Title: Low-temperature properties of strain-hardened austenitic stainless steels
containing nitrogen
Authors: Kvasnevskii,O.G.; Yushchenko,K.A.; Mon'ko, G. G.
Source: Strength of Materials, 1978, 10, 7, 843-846
Abstract: 1.Low-carbon austenitic steels containing nitrogen are strengthened
considerably by deformation at normal and low temperatures. The yield strength of
stable austenitic steel 03Kh20N16AG6 at 77°K depends only on the preliminary
deformation and is prctically independent of the temperature.2.To ensure high
strength of stable austenitic steels containing nitrogen the deformation can be
conducted at room temperature. The absolute values of the strength characteristics of
stable austenitic steel 03Kh20N16AG6 deformed 30% at room temperature and
metastable steels 03Kh18N11 and 03Kh19AN12 deformed at low temperature are
almost identical.3.The ductility of stable austenitic steel 03Kh20N16AG6
strengthened by deformation at room temperature is quite adequate and the steel can
be used for cryogenic equipment. Its yeild strength increases to 190 kgf/mm2 at
77°K and to 110 kgf/mm2 at room temperature.4.The change in the fracture
toughness of steel 03Kh19AN12 at 77°K after small preliminary deformations (up
to 5%) depends mainly on the reduction of the work of crack initiation. The reduction
of the work of crack propagation with increasing preliminary deformation is due
mainly to inhibition of the formation of strain martensite. With over 30% martensite
the initiation of fracture is facilitated.
Title: Hydrogen environment embrittlement of type 316 series austenitic stainless
steels at low temperatures (study on low temperature materials used in WE-NET 18).
Authors: Fukuyama,S.; Sun,D.; Yokogawa,K.
Source: Hydrogen Planet, World Hydrogen Energy Conf., 14th, 2003, 1063-1070
Abstrat: H environment embrittlement (HEE) of 316 series austenitic stainless steels
was studied at 300-80 K. H had an effect on the tensile properties of 316, 316L,
316LN and F316LN stainless steels, and no effect on those of type 310S stainless
steel. HEE of the materials increased with decreasing temp., reached a max.
at .apprx.200 K and decreased rapidly with decreasing temp. down to 80 K. HEE of
the materials also increased with increasing H pressure. Sensitization of type 316
stainless steel increased HEE and decreased the min. HEE temp. HEE of the materials
from room temp. to the max. HEE temp. depended on the transformation of
strain-induced martensite. The behavior below the max. HEE temp. depended on the
diffusion of H.
Title: Strengthening mechanism of 316LN stainless steel at cryogenic temperatures
Authors: Li,L.F.; Yang,K.; Rong,L.J.
Source: AIP Conference Proceedings, 2002, 614, 1, 165
Abstract: Using vacuum metallurgical technique, we have fabricated the metastable
austenitic stainless steel, 316LN which is aimed to be used as structural materials for
superconducting magnets in Tokamak equipment in China. We have studied the basic
properties of due materials at cryogenic temperatures, such as tensile strength, yield
strength and Young's modulus. The effects of various elements on mechanical
behaviors are discussed.
Title: Recent developments in stainless steels
Authors: Lo,K.H.^; Shek,C.H.^; Lai,J.K.L.^
Source: Materials Science & Engineering: R, 2009, 65, 4-6, 39-104
Abstract: This article presents an overview of the developments in stainless steels
made since the 1990s. Some of the new applications that involve the use of stainless
steel are also introduced. A brief introduction to the various classes of stainless steels,
their precipitate phases and the status quo of their production around the globe is
given first. The advances in a variety of subject areas that have been made recently
will then be presented. These recent advances include (1) new findings on the various
precipitate phases (the new J phase, new orientation relationships, new phase diagram
for the Fe–Cr system, etc.); (2) new suggestions for the prevention/mitigation of the
different problems and new methods for their detection/measurement and (3) new
techniques for surface/bulk property enhancement (such as laser shot peening, grain
boundary engineering and grain refinement). Recent developments in topics like
phase prediction, stacking fault energy, superplasticity, metadynamic recrystallisation
and the calculation of mechanical properties are introduced, too. In the end of this
article, several new applications that involve the use of stainless steels are presented.
Some of these are the use of austenitic stainless steels for signature authentication
(magnetic recording), the utilisation of the cryogenic magnetic transition of the sigma
phase for hot spot detection (the Sigmaplugs), the new Pt-enhanced radiopaque
stainless steel (PERSS) coronary stents and stainless steel stents that may be used for
magnetic drug targeting. Besides recent developments in conventional stainless steels,
those in the high-nitrogen, low-Ni (or Ni-free) varieties are also introduced. These
recent developments include new methods for attaining very high nitrogen contents,
new guidelines for alloy design, the merits/demerits associated with high nitrogen
contents, etc.
Title: Mechanical properties of 32Mn-7Cr-0.6Mo-0.3N austenitic steel for cryogenic
applications
Authors: Ruidong,Fu; Yangzeng,Zheng; Yibin,Ren
Source: Journal of Materials Engineering and Performance, 2001, 10, 4, 456-459
Abstract: The tensile, impact, and fracture toughness tests from ambient temperature
to 77 K were carried out on 32Mn-7Cr-0.6Mo-0.3N austenitic steel. The fracture
surfaces and the phase constitution were analyzed using scanning electron microscopy
and x-ray diffraction. The results show that the relation between yield strength and
temperature is σ0.2 � 300 + 1392.4 exp (−0.0106T). The 77 K yield strength is
883 MPa � m1/2 and the K J0.05 value is about 236 MPa � m1/2. The cryogenic
intergranular fracture is fully suppressed. The 77 K fracture surfaces exhibit a tough
character composed of many dimples and few small quasi-cleavage facets. The results
of x-ray analysis show that the austenite phase of the steel is stable even under
cryogenic deformation conditions.
Title: Primary:Trends and Advances in Cryogenic Materials
Authors: Primary:Reed,R.P.
Source: Cryogenic Engineering, 2007, 52-83
Abstract: Increased emphasis has been placed on research and development of
specialized materials for use in low-temperature applications. Most research has been
driven by (1) the construction of large superconducting coils, (2) requirements for
transport and storage of liquefied natural gas, and (3) the discovery of
superconductors with critical temperatures Tc as high as 90 K. The integration
between structural design and material properties for critical low-temperature
applications has been facilitated by the incorporation of fracture mechanics concepts.
This development has led to measurement of an entirely new set of mechanical
properties at low temperatures, to increased nondestructive inspection to measure
in-situ flaw sizes, and to the development of fracture control practices for a number of
cryogenic applications.
Title: Cryogenic CVN impact study of high nitrogen stainless steels.
Authors: Yuan,Zhi-zhong; Dai,Qi-xun; Cheng,Xiao-nong; Chen,Kang-min;
Xu,Wen-wei
Source: Jiangsu Daxue Xuebao, Ziran Kexueban, 2004, 25, 3, 247-251
Abstract: The Charpy (v notch) (CVN) impact properties of two kinds of high
nitrogen stainless steels, Fe-24Mn-13Cr-1Ni-0.44N and Fe-24Mn-18Cr-3Ni-0.62N
under low temps., were tested. Results show that with the concn. of nitrogen
increasing, the ductile property at low temp. decreases rapidly while the DBTT
increases, which are at 140 K and 210 K resp.; one feature of brittle fracture is peeled
off layers in high nitrogen austenitic stainless steels when impacted at 83 K. The
change of fracture modes of high nitrogen austenitic stainless steels with temp.
decreasing is prolonged/equiaxial dimple->shallow dimple->mixt. of brittle facet and
ductile dimple->peeled off layers within dominated brittle facets.
Title: Temperature Dependence of Tensile Behaviors of Nitrogen-Alloyed Austenitic
Stainless Steels
Authors: Wang,Wei; Yan,Wei; Yang,Ke; Shan,Yiyin; Jiang,ZhouhuaSource:Journal of
Materials Engineering and Performance
Abstract: The temperature dependence of tensile behaviors of two nitrogen-alloyed
austenitic stainless steels, an annealed 316LN steel and a high-nitrogen austenitic
stainless steel (Fe-Cr-Mn-0.66% N), was investigated by tensile test at different
temperatures from 293 K down to 77 K. It was found that strength of the two steels
increased with decrease of temperature. With a decrease in temperature, the uniform
elongation increased for the 316LN steel, whereas it increased followed by a decrease
for the high-nitrogen steel. A three-stage hardening behavior occurred in the 316LN
steel, but not in the high-nitrogen steel, with decrease of temperature. The
strain-induced martensite transformation in the 316LN steel could retard void
nucleation and increase the strain-hardening rate, resulting in much higher tensile
stress and higher uniform elongation of 316LN steel. It was analyzed that stacking
fault energy of the high-nitrogen steel decreased with decrease of temperature, which
promoted the twinning and planar slipping in the steel, and resulted in brittle fracture
at cryogenic temperatures.