scholarly journals Experimental measurement of sound velocity in the unloading wave in the 12Cr18Ni10Ti stainless steel in a longitudinal stress range of 10–88 GPa

2018 ◽  
Author(s):  
D. T. Yusupov ◽  
K. S. Sidorov ◽  
V. G. Vildanov ◽  
V. M. Slobodenyukov ◽  
A. O. Borshchevsky ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Sound Velocity ◽  
Experimental Measurement ◽  
Stress Range ◽  
Longitudinal Stress ◽  
Unloading Wave

A Study on Laser Welding of Titanium and Stainless Steel

2018 ◽  
Author(s):  
Angshuman Chattopadhyay ◽  
Gopinath Muvvala ◽  
Vikranth Racherla ◽  
Ashish Kumar Nath
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Weld Joint ◽  
Welding Speed ◽  
Fusion Process ◽  
Longitudinal Stress ◽  
Transverse Cracks ◽  
Cooling Rates ◽  
Melt Pool ◽  
Longitudinal Cracks

Joining of dissimilar metals and alloys has been envisioned since a long time with specific high end applications in various fields. One such combination is austenitic stainless steel grade SS304 and commercial grade titanium, which is very difficult to join under conventional fusion process due to extensive cracking and failure caused by mismatch in structural and thermal properties as well as formation of the extremely brittle and hard intermetallic compounds. One of the methods proposed in literature to control the formation of intermetallics is by fast cooling fusion process like laser beam welding. The present study has been done on laser welding of titanium and stainless steel AISI 304 to understand the interaction of these materials during laser welding at different laser power and welding speed which could yield different cooling rates. Two types of cracks were observed in the weld joint, namely longitudinal cracks and transverse cracks with respect to the weld direction. Longitudinal cracks could be completely eliminated at faster welding speeds, but transverse cracks were found little influenced by the welding speed. The thermal history, i.e. melt pool lifetime and cooling rate of the molten pool during laser welding was monitored and a relation between thermo-cycle with occurrence of cracks was established. It is inferred that the longitudinal cracks are mainly due to the formation of various brittle intermetallic phases of Fe and Ti, which could be minimized by providing relatively less melt pool lifetime at high welding speeds. The reason of the transverse cracks could be the generation of longitudinal stress in weld joint due to the large difference in the thermal expansion coefficient of steel and titanium. In order to mitigate the longitudinal stress laser welding was carried out with a novel experimental arrangement which ensured different cooling rates of these two metals during laser welding. With this the tendency of transverse cracks also could be minimized significantly.

Experimental measurement of residual stress and distortion in additively manufactured stainless steel components with various dimensions

2017 ◽  
Vol 707 ◽  
pp. 689-700 ◽  
Author(s):  
M. Ghasri-Khouzani ◽  
H. Peng ◽  
R. Rogge ◽  
R. Attardo ◽  
P. Ostiguy ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Experimental Measurement

High-strain fatigue of stainless-steel cylinders: Experimental results and their application to pressure-vessel design

1967 ◽  
Vol 2 (4) ◽  
pp. 290-297 ◽  
Author(s):  
C Ruiz
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Static Pressure ◽  
Elastic Stress ◽  
High Strain ◽  
Pressure Vessels ◽  
Supplementary Information ◽  
Test Results ◽  
Stress Range ◽  
Fatigue Design

Thin cylindrical specimens, plain and with deep axial grooves, have been tested under pulsating pressure and under static pressure with cyclic axial straining. The test results, together with some supplementary information from other authors, show that Langer's method, based on an elastic-stress analysis, is applicable to the fatigue design of pressure vessels. Design curves for the establishment of the acceptable elastic-stress range corresponding to a given fatigue life are proposed. Attention is drawn to the limitations of Langer's method.

Accounting for Negative R-Ratio (Crack Closure) in Fatigue Crack Growth Calculations on Stainless Steel Components

2015 ◽  
Author(s):  
Chris Watson ◽  
Chris Currie ◽  
Julian Emslie
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Crack Opening ◽  
Stress Range ◽  
Stress Cycle ◽  
R Ratio ◽  
Cylindrical Test

Negative R-ratio crack closure effects on Fatigue Crack Growth (FCG) are defined as the contribution of the compressive portion of the stress cycle to the crack extension, in addition to that contributed from the tensile portion of the cycle. Any potential decrease in FCG may be attributed to the mechanical effects of crack closure during the compressive part of the cycle. The overall effect is to decrease the crack opening portion of the stress range and to therefore reduce the crack growth rate compared to that obtained using the full stress range. This paper provides a brief overview of the treatment of negative R-ratio crack closure in FCG calculations on stainless steel components by reference to existing codes and standards. Then, using the results from crack closure tests on small cylindrical test specimens, a set of guidelines for the treatment of crack closure in the FCG assessment of stainless steel components are provided.

Neutron Diffraction Measurement and Numerical Simulation to Study the Effect of Repair Depth on Residual Stress in 316L Stainless Steel Repair Weld

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Wenchun Jiang ◽  
Yun Luo ◽  
BingYing Wang ◽  
Wanchuck Woo ◽  
S. T. Tu
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
316L Stainless Steel ◽  
Diffraction Measurement ◽  
Transverse Stress ◽  
Longitudinal Stress ◽  
Hardening Model ◽  
Mixed Hardening

Welding is often used to repair the defects in pressure vessels and piping, but residual stresses are generated inevitably and have a great effect on structure integrity. According to the defect size, different repair depth will be carried out, which leads to different stress state. In this paper, the effect of repair depth on residual stress in 316L stainless steel repair weld has been studied by neutron diffraction measurement and finite element modeling (FEM). The results show that the residual stresses in the deep repair are larger than those in shallow repair weld, because the deep repair involves multipass welding and brings a serious work hardening. In the weld metal, the longitudinal stress has exceeded the yield stress, and increases slightly with the increase of repair depth. In contrast to the longitudinal stress, the transverse stress is more sensitive to the repair depth. With the increase of repair depth, the transverse stress increases and even exceeds the yield strength as the repair depth is 45% of the plate thickness. At the bottom surface of the plate and heat affected zone (HAZ), both the longitudinal and transverse stresses increase as the repair depth increases. It also shows that the mixed hardening model gives the best agreement with the measurement, while isotropic and kinematic hardening models cause an overestimation and underestimation, respectively. Therefore, the mixed hardening model is recommended for the prediction of residual stresses.

SPALL EXPERIMENTS ON STAINLESS STEEL 21-6-9 VARYING PULSE LENGTHS AND LONGITUDINAL STRESS

2009 ◽  
Author(s):  
G. Whiteman ◽  
N. K. Bourne ◽  
J. C. F. Millett ◽  
Mark Elert ◽  
Michael D. Furnish ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Longitudinal Stress

Inelastic Behavior of Type 316 Stainless Steel Under Multiaxial Nonproportional Cyclic Stressings at Elevated Temperature

1985 ◽  
Vol 107 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Y. Ohashi ◽  
M. Kawai ◽  
T. Kaito
Keyword(s):  
Stainless Steel ◽  
Cyclic Hardening ◽  
Uniaxial Stress ◽  
Cyclic Stress ◽  
Torsional Stress ◽  
Inelastic Behavior ◽  
Stress Range ◽  
Cyclic Tests ◽  
316 Stainless Steel ◽  
Stress Plane

The stress-range and path-shape dependencies of multiaxial nonproportional cyclic hardening were studied for annealed type 316 stainless steel at 600°C by means of stress controlled tests. Cyclic experiments along circular stress paths with constant effective stresses in the axial-torsional stress plane were first performed. The significant cyclic hardening and its stress-range dependency observed for the circular stress cyclings were quantitatively shown in reference to the cyclic stress-strain curves resulted from uniaxial stress cyclings. Then, to discuss the effect of path-shape, the cyclic tests along square stress paths inscribed by the above circular paths, as well as the tests where uniaxial cyclings and torsional ones were alternated, were also carried out. As a result of these tests, the cyclic hardenings for square paths were found to be almost equivalent to those for their circumscribed circular paths. The other type of stress cyclings caused almost the same amount of cyclic hardenings as those for the circular cyclings of the identical stress-ranges.

Considerations for Selecting the Optimum Bolt Assembly Stresses for Piping Flanges

2006 ◽  
Author(s):  
Warren Brown ◽  
David Reeves
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Stress Level ◽  
Good Practice ◽  
Stress Range ◽  
Practical Application ◽  
Alternative Approach ◽  
Bolt Stress ◽  
Standard Value ◽  
The Difference

In order to minimize the likelihood of leakage from flanged piping joints, it is a good practice to maximize the initial bolt assembly stress. Present bolting guidelines (ASME PCC-1 [1]) use a standard percent of bolt yield to set the assembly stress level. This approach does not allow for the difference in strength between standard pipe flange sizes, differences in material yield strengths (carbon steel versus stainless steel), raised face (RF) versus ring type joint (RTJ) flange configurations and the actual gasket stress achieved across all flange sizes and classes. Since there is no assessment of stresses, such an approach may cause failure of joint components. In addition, because the standard percentage of bolt yield technique does not look at gasket stress, it is prone to gasket leakage due to low stress or gasket destruction due to over-compression for some joints. In addition, some joints may require bolt loads well in excess of the standard value to develop an acceptable gasket stress level in order to prevent leakage. This paper examines an alternative approach, based on the actual gasket and flange stresses. The approach examines the minimum and maximum gasket stress levels to determine what bolt stress range is acceptable and then looks at the flange stresses and flange deformation issues to ensure that the flange will not be permanently damaged, while maximizing the specified bolt load. The practical application of this method is in the development of standard bolt assembly stress (or torque) tables for standard pipe flanges using a given gasket type.

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