Material Properties Of Stainless Steel Research Articles

Strength enhancements induced during cold forming of stainless steel sections

The material properties of stainless steel are sensitive to plastic deformation which causes an increase in yield strength by a process termed cold working. The different strain paths experienced around cold-formed cross sections during manufacture create unique material strength distributions for sections from different forming routes and also influence residual stress patterns. The research program presented herein has examined experimentally the material and residual stress distributions found in two types of cold-formed sections–cold-rolled box sections and press-braked angles. Predictive tools to harness the observed strength enhancements have been proposed and incorporated into models. Subsequent comparisons have shown that these strength enhancements, in particular those observed for cold-rolled box sections, should be employed in structural design to avoid considerable underestimation of member resistance.

Dynamic Material Properties of Stainless Steel and Multiphase High Strength Steels

This work presents results of tensile testing of H400 stainless steel, DP600 and TRIP600 at different strain rates. Mechanical properties were determined from tensile test using flat sheet specimens and recurring to different test techniques: servo-hydraulic machine and a tensile-loading Hopkinson bar. The test results were used to compare different mechanical properties of the tested steels and to validate constitutive equations intended to provide a mathematical description of strain rate dependence, namely the Cowper-Symonds equation. Following previous research work in dynamic material proprieties of multiphase and stainless steel grades, the energy absorption in quasi-static crushing of thin walled section made of the tested materials was subsequently investigated. Crush tests were performed in top-hat and hexagonal section tubes manufactured using laser welding. The experimental results were compared in order to assess the efficiency of the different steel grades for energy absorption.

Stress–strain curves for stainless steel at elevated temperatures

This paper presents the mechanical properties data of stainless steel at elevated temperatures. Accurate prediction of the material properties of stainless steel at elevated temperatures is necessary for determining the load-carrying capacity of structures under fire conditions. However, full utilization of the special feature of stainless steel has not been possible due to lack of technique data on the fire resistance of stainless steel structural material. Therefore, both steady and transient tensile coupon tests were conducted at different temperatures ranging from approximately 20 to 1000 ∘C to obtained the material properties of stainless steel types EN 1.4462 (Duplex) and EN 1.4301 (AISI 304) with plate thickness of 2.0 mm. The elastic modulus, yield strength obtained at different strain levels, ultimate strength, ultimate strain and thermal elongation versus different temperatures are also plotted and compared with the prediction from the Australian, British and European standards. The test results obtained from this study are also compared with the test results predicted by other researchers. A unified equation for yield strength, elastic modulus, ultimate strength and ultimate strain of stainless steel at elevated temperatures is proposed in this paper. It is shown that the proposed equation accurately predicted the yield strength, elastic modulus, ultimate strength and ultimate strain compared with the test results. Furthermore, stress–strain curves at different temperatures are plotted and a stress–strain model is also proposed.

A technique for the determination of post-yield material properties from the small punch test

The aim of the present work was to determine post-yield material properties from small punch test results, i.e. from the force-displacement curve obtained in such a test. This determination was made by comparing the experimental curve with a large set of previously determined finite element (FE) curves for differing post-yield properties expressed in terms of Ramberg and Osgood parameters. A simple cost function was then used to find the closest FE curve and thus provide an estimate of the post-yield properties. This estimate was then updated using an optimization technique based on the Matlab ‘fminsearch’ function and an interface with the ABAQUS FE code, giving a reliable estimate of the post-yield material properties. The FE analysis and model were validated by comparison with other small punch tests and the FE curves were additionally used to determine von Mises stresses, equivalent plastic strains and displacements. The method used to determine post-yield properties from small specimens has been demonstrated by determining the material properties of stainless steel. The technique is particularly relevant to those steels used in pressure vessels.

Cryogenic material properties of stainless steel tube-to-flange welds

The mechanical properties of stainless steel tube-to-flange welds for a cryogenic piping application were measured. A planar specimen was developed to duplicate the constraint, loading and heat-sink properties of the circular joint, while reducing preparation time and cost. Specimens were evaluated containing welds between the tube material (21 Cr-6Ni-9Mn) and the three stainless steels being considered for the flange materials: type 304L, type 316L and 21 Cr-6Ni-9Mn. The mechanical property tests consisted of three phases: simple tensile testing to failure, tensile testing of notched specimens (where the notch simulated fabrication flaws) and fatigue testing of notched specimens for the 4 × 10 4 cycle design life of the structure. The type 316L stainless steel flange produced welds with the best combination of strength and ductility at 295 and 4 K in all three phases of testing.

Study for mechanism of corrosion fatigue crack propagation for HT80 steel at low [formula omitted] region by variable loading [formula omitted] decreasing and test method : Masuda, H. and Matsuoka, S.Boshoku Gijutsu (Corros. Eng.) July 1989 38, (7), 378–383 (In Japanese)

The current design rules on bolted connections of cold-formed stainless steel structures are allowed for room (ambient) temperature condition only. Research on structural behavior of single shear bolted connections at elevated temperatures is limited. In this study, 100 single shear bolted connection specimens and 22 coupon specimens involving three different grades of stainless steel were conducted by using steady state test method in the temperature ranged from 200 to 950 °C. The three different grades of stainless steel are austenitic stainless steel EN 1.4301 (AISI 304) and EN 1.4571 (AISI 316Ti having small amount of titanium) as well as lean duplex stainless steel EN 1.4162 (AISI S32101). Furthermore, different bolts arrangement was also considered in the investigation. Two main failure modes were observed in the single shear bolted connection tests, namely the net section tension and bearing failures. The test results were compared with the predicted strengths calculated from the American Specification, Australian/New Zealand Standard and European Codes for cold-formed stainless steel structures. In calculating the nominal strengths of the connections, the reduced material properties of stainless steel obtained at elevated temperatures were used. It is shown that the strengths of the single shear bolted connections predicted by the specifications are generally conservative at elevated temperatures. A similar tendency of reduction was found when compared the reduction factor of material properties with that of the deterioration of the bolted connection test strengths with the corresponding type of cold-formed stainless steel at elevated temperatures. The austenitic stainless steel type EN 1.4571 (AISI 316Ti) generally performed better than the other two stainless steel types at elevated temperatures.

The use of aluminium for stressed components : Woodward, A.R.Mech. Inc. Eng. Apr. 1989 1, (4), 68–70

The current design rules on bolted connections of cold-formed stainless steel structures are allowed for room (ambient) temperature condition only. Research on structural behavior of single shear bolted connections at elevated temperatures is limited. In this study, 100 single shear bolted connection specimens and 22 coupon specimens involving three different grades of stainless steel were conducted by using steady state test method in the temperature ranged from 200 to 950 °C. The three different grades of stainless steel are austenitic stainless steel EN 1.4301 (AISI 304) and EN 1.4571 (AISI 316Ti having small amount of titanium) as well as lean duplex stainless steel EN 1.4162 (AISI S32101). Furthermore, different bolts arrangement was also considered in the investigation. Two main failure modes were observed in the single shear bolted connection tests, namely the net section tension and bearing failures. The test results were compared with the predicted strengths calculated from the American Specification, Australian/New Zealand Standard and European Codes for cold-formed stainless steel structures. In calculating the nominal strengths of the connections, the reduced material properties of stainless steel obtained at elevated temperatures were used. It is shown that the strengths of the single shear bolted connections predicted by the specifications are generally conservative at elevated temperatures. A similar tendency of reduction was found when compared the reduction factor of material properties with that of the deterioration of the bolted connection test strengths with the corresponding type of cold-formed stainless steel at elevated temperatures. The austenitic stainless steel type EN 1.4571 (AISI 316Ti) generally performed better than the other two stainless steel types at elevated temperatures.

Fatigue behaviour of stainless steels under simultaneous corrosion attack: I. Behaviour at elevated temperatures and in hot gas environment : Roeder, E. and Schumacher, G.Steel Res. 1989 60, (8), 375–382 (in German)

The current design rules on bolted connections of cold-formed stainless steel structures are allowed for room (ambient) temperature condition only. Research on structural behavior of single shear bolted connections at elevated temperatures is limited. In this study, 100 single shear bolted connection specimens and 22 coupon specimens involving three different grades of stainless steel were conducted by using steady state test method in the temperature ranged from 200 to 950 °C. The three different grades of stainless steel are austenitic stainless steel EN 1.4301 (AISI 304) and EN 1.4571 (AISI 316Ti having small amount of titanium) as well as lean duplex stainless steel EN 1.4162 (AISI S32101). Furthermore, different bolts arrangement was also considered in the investigation. Two main failure modes were observed in the single shear bolted connection tests, namely the net section tension and bearing failures. The test results were compared with the predicted strengths calculated from the American Specification, Australian/New Zealand Standard and European Codes for cold-formed stainless steel structures. In calculating the nominal strengths of the connections, the reduced material properties of stainless steel obtained at elevated temperatures were used. It is shown that the strengths of the single shear bolted connections predicted by the specifications are generally conservative at elevated temperatures. A similar tendency of reduction was found when compared the reduction factor of material properties with that of the deterioration of the bolted connection test strengths with the corresponding type of cold-formed stainless steel at elevated temperatures. The austenitic stainless steel type EN 1.4571 (AISI 316Ti) generally performed better than the other two stainless steel types at elevated temperatures.

1235. A set of calibration of resistive low-temperature sensors in the range of 77 to 273 K: J Veprek,Slabopr Obzor, 35 (12), 1974, 562–569 ( in Czech)

The solar receiver tube is a key component to convert the solar energy into thermal energy in parabolic trough solar power system. The residual stresses which are generated during the cooling process of glass-to-metal sealing significantly influence the reliability of receiver tube. In order to lower the seal failure probability, the effects of geometry and material properties of glass- to-metal seals on the residual stress are analyzed using finite element method in this paper. The effects of the material properties of stainless steel 304, stainless steel 430, Kovar on the sealing residual stress can be presented. Although each of these different sealing material combinations can have enough sealing strength, the glass-to-metal seals with larger tensile stresses can cause the failure of the receiver tube. Moreover, effects of geometry of the metal tube and the glass tube on the residual stress are also analyzed. The stress distributions in the glass side analyzed by the finite element method (FEM) were in agreement with the ones calculated by analytic solution (AS) approach. The X-ray measurement results also proved the validation of the FEM. The dangerous tensile stresses mainly occur at the glass-metal interface. The results of this study have important implications on the optimization of seal configuration in the solar receiver tubes.

Influence of dielectric films on the resistance of vacuum-deposited chromium films: A A Milgram and C-S Lu, J Appl Phys, 39 (3), 1968, 1624–1628.

The solar receiver tube is a key component to convert the solar energy into thermal energy in parabolic trough solar power system. The residual stresses which are generated during the cooling process of glass-to-metal sealing significantly influence the reliability of receiver tube. In order to lower the seal failure probability, the effects of geometry and material properties of glass- to-metal seals on the residual stress are analyzed using finite element method in this paper. The effects of the material properties of stainless steel 304, stainless steel 430, Kovar on the sealing residual stress can be presented. Although each of these different sealing material combinations can have enough sealing strength, the glass-to-metal seals with larger tensile stresses can cause the failure of the receiver tube. Moreover, effects of geometry of the metal tube and the glass tube on the residual stress are also analyzed. The stress distributions in the glass side analyzed by the finite element method (FEM) were in agreement with the ones calculated by analytic solution (AS) approach. The X-ray measurement results also proved the validation of the FEM. The dangerous tensile stresses mainly occur at the glass-metal interface. The results of this study have important implications on the optimization of seal configuration in the solar receiver tubes.

Measurement of viscoelastic properties of evaporated Se films: C R Wronski, J Appl Phys, 39 (3), 1968, 1477–1478.

The solar receiver tube is a key component to convert the solar energy into thermal energy in parabolic trough solar power system. The residual stresses which are generated during the cooling process of glass-to-metal sealing significantly influence the reliability of receiver tube. In order to lower the seal failure probability, the effects of geometry and material properties of glass- to-metal seals on the residual stress are analyzed using finite element method in this paper. The effects of the material properties of stainless steel 304, stainless steel 430, Kovar on the sealing residual stress can be presented. Although each of these different sealing material combinations can have enough sealing strength, the glass-to-metal seals with larger tensile stresses can cause the failure of the receiver tube. Moreover, effects of geometry of the metal tube and the glass tube on the residual stress are also analyzed. The stress distributions in the glass side analyzed by the finite element method (FEM) were in agreement with the ones calculated by analytic solution (AS) approach. The X-ray measurement results also proved the validation of the FEM. The dangerous tensile stresses mainly occur at the glass-metal interface. The results of this study have important implications on the optimization of seal configuration in the solar receiver tubes.