Evaluation of Cross-Weld Properties of Austenitic Stainless Steels Before and After PWHT

2008 ◽  
Author(s):  
M. M. Ibrahim ◽  
H. G. Mohamed ◽  
Y. E. Tawfik ◽  
Ibrahim Taha
Keyword(s):  
Tensile Strength ◽  
Stainless Steels ◽  
Plate Thickness ◽  
Postweld Heat Treatment ◽  
Austenitic Stainless Steels ◽  
Tensile Tests ◽  
Steel Plates ◽  
Aisi 304L ◽  
Before And After ◽  
Weld Properties

Different types of austenitic stainless steels, which are commonly used for piping systems, tanks, and vessels, required postweld heat treatment (PWHT), at temperatures between 540 and 590 °C, regardless of the plate thickness. This paper reports on the weld procedures and cross-weld performance evalution of weldments in 6 mm AISI 304L, 316L, and 347 steel plates before and after PWHT. This welds were produced by SMAW and GTAW techniques using a single vee preparation and multiple weld beads, and welded by various types of consumables. After PWHT, tensile tests indicated a reduction in the ultimate tensile strength of all samples and a decrease in the yield strength for some cases only. The hardness results were consistent with the tensile test results because they both revealed significant softening in the HAZ and WM as a result of PWHT. In spite of the fact that PWHT exerts a beneficial effect on reducing residual stresses, it is concluded that the ductility of the weld region was satisfactory without PWHT, and PWHT decreased the cross-weld tensile strength.

Hard PVD Coatings for Austenitic Stainless Steel Machining: New Developments

2004 ◽  
Vol 843 ◽  
Author(s):  
J. L. Endrino ◽  
A. Wachter ◽  
E. Kuhnt ◽  
T. Mettler ◽  
J. Neuhaus ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
High Speed ◽  
Great Part ◽  
Austenitic Stainless Steels ◽  
Steel Plates ◽  
Oxide Surface ◽  
High Plasticity ◽  
Coating Surface ◽  
Before And After

ABSTRACTThe machinability of austenitic stainless steels is, in general, considered to be a difficult process. This is due in great part to the high plasticity and tendency to work-harden of the workpiece, which normally results in extreme conditions imposed on cutting edges. Additionally, austenitic stainless steels have much lower thermal conductivities in comparison to plain carbon and tool steels; this inflicts high thermal loads within the chip-tool contact zone, which can significantly increase the wear rate. The complex machining of austenitic stainless steels can be, in part, relieved by use of a hard coating with low thermal conductivity and an adequate coating surface quality. This can lead to a low friction coefficient between the parts and an improved chip evacuation process. In this study, stainless steel plates were machined using a high speed finishing process and cemented carbide tools coated with four high aluminum containing coatings namely, AlCrN, AlCrNbN, fine grained (fg) AlTiN, and nanocrystalline (nc) AlTiN. Both AlTiN and AlCrN-based coatings are known for their high oxidation resistances and the formation of aluminum oxide surface layers during oxidation [1]. The coating surface textures before and after post-deposition treatment were analyzed by means of the Abbot-Firestone ratio curves in order to study the influence of surface configurations leading to reduced tool wear. A maximum tool life of 150 m was observed for the tool coated with the nc-AlTiN coating.

Selection of Metal Electrodes for and Effect of Welding Treatment on Hardness and Microstructure of Some Type of Austenitic Stainless Steels

2009 ◽  
Author(s):  
M. M. Ibrahim ◽  
H. G. Mohamed ◽  
Y. E. Tawfik
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Pressure Vessel ◽  
Nuclear Power ◽  
Plate Thickness ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Aisi 304L ◽  
Stress Relieving ◽  
Selection Of

Austenitic stainless steels have been the focus of considerable research recently because of their high strength, good ductility, excellent corrosion resistance and a reasonable weldability. These properties make austenitic stainless steels attractive candidate materials for use in the fabrication of piping systems, automotive exhaust gas systems and in a variety of equipment associated with the chemical and nuclear power industries. PWHT is a stress relieving process whereby residual stresses are reduced by typically heating to 550–650 °C for a set time depending upon plate thickness. The effect of PWHT on mechanical properties such as hardness, ultimate tensile strength, yield strength, impact energy and ductile to brittle transition temperature are of great concern to the pressure vessel industry and pressure vessel codes. This paper reports on the effect of multiple PWHT on hardness and microstructure of austenitic stainless steels. The 6 mm AISI 304L, 316L, and 347 austenitic stainless steels were used for this work. This welds were produced by SMAW and GTAW techniques using a single vee preparation and multiple weld beads, and welded by various types of consumables. Selection of a suitable consumables metals for joining those weldment sample joints are an important criterion in view of the differences in physical, chemical, and mechanical properties of the base materials involved.

Effect of PWHT Cycles on Impact Toughness of Austenitic Stainless Steel Weldments

2009 ◽  
Author(s):  
M. M. Ibrahim ◽  
H. G. Mohamed ◽  
Y. E. Tawfik
Keyword(s):  
Impact Toughness ◽  
Impact Energy ◽  
Stainless Steels ◽  
Nuclear Power ◽  
Power Plants ◽  
Plate Thickness ◽  
Austenitic Stainless Steels ◽  
Aisi 304L ◽  
Stress Relieving ◽  
The Impact

Austenitic stainless steels are widely used welding materials in nuclear reactors and power plants because of their high strength, good ductility, excellent corrosion resistance and a reasonable weldability. These properties make austenitic stainless steels attractive candidate materials for use in the fabrication of piping systems, automotive exhaust gas systems and in a variety of equipment associated with the chemical and nuclear power industries. PWHT is a stress relieving process whereby residual stresses are reduced by typically heating to 550–650 °C for a set time depending upon plate thickness. It concerns have emerged about possible effects on the mechanical properties of the base (parent) and weld plates (PM and WM). The 6 mm AISI 304L, 316L, and 347 austenitic stainless steels were used for this work. These welds were produced by SMAW and GTAW techniques using a single vee preparation and multiple weld beads, and welded by various types of consumables. The fracture surfaces of the Charpy V-notch PM and WM (before and after PWHT) samples were examined by SEM. Scanning electron fractographs was critical in this study, in that valuable information regarding the mechanism and nature of failure could be determined. This paper reports work on the impact toughness of the three types of austenitic stainless steels. The parent and weld regions were examined for all types of steels used, and then exposed to temperature in the PWHT range. The effect of exposure to multiple PWHT cycles on these properties is discussed. A decrease in impact energy and fracture toughness with an increase in the number of heat treatments was evident in the parent metal. Similary, the weld metal showed a decrease in impact energy after two PWHT cycles.

scholarly journals Microstructural Characterization of Laser Weld of Hot-Stamped Al-Si Coated 22MnB5 and Modification of Weld Properties by Hybrid Welding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3943
Author(s):  
Hana Šebestová ◽  
Petr Horník ◽  
Šárka Mikmeková ◽  
Libor Mrňa ◽  
Pavel Doležal ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fusion Zone ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Laser Weld ◽  
Martensitic Microstructure ◽  
Laser Welds ◽  
Weld Properties ◽  
Weld Fusion Zone

The presence of Al-Si coating on 22MnB5 leads to the formation of large ferritic bands in the dominantly martensitic microstructure of butt laser welds. Rapid cooling of laser weld metal is responsible for insufficient diffusion of coating elements into the steel and incomplete homogenization of weld fusion zone. The Al-rich regions promote the formation of ferritic solid solution. Soft ferritic bands cause weld joint weakening. Laser welds reached only 64% of base metal's ultimate tensile strength, and they always fractured in the fusion zone during the tensile tests. We implemented hybrid laser-TIG welding technology to reduce weld cooling rate by the addition of heat of the arc. The effect of arc current on weld microstructure and mechanical properties was investigated. Thanks to the slower cooling, the large ferritic bands were eliminated. The hybrid welds reached greater ultimate tensile strength compared to laser welds. The location of the fracture moved from the fusion zone to a tempered heat-affected zone characterized by a drop in microhardness. The minimum of microhardness was independent of heat input in this region.

scholarly journals MICROSTRUCTURE RESEARCH OF THE UNIDIRECTIONAL ORGANOPLASTIC BASED ON RUSAR-NT ARAMID FIBERS AND EPOXY-POLYSULFONE BINDER

2020 ◽  
pp. 19-26
Author(s):  
E.N. Kablov ◽  
◽  
G.S. Kulagina ◽  
G.F. Zhelezina ◽  
S.L. Lonskii ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Material ◽  
Polymer Matrix ◽  
Packing Density ◽  
Tensile Tests ◽  
Polymer Composite Material ◽  
Aramid Fibers ◽  
Before And After ◽  
Binder Structure

This paper studies a polymer composite material - a unidirectional organoplastic based on Rusar-NT aramid fiber and a melt epoxy-polysulfone binder. Organoplastic has the following mechanical properties: tensile strength 2060 MPa, Young's modulus 101 GPa. The microstructure of the fiber and the polymer matrix in the organoplastic samples was studied before and after tensile tests. The features of the formation of the binder structure depending on the packing density of the fibers in organoplastics have been determined. The nature of the destruction of fibers and polymer matrix caused by the uniaxial tension has been studied.

Proposal of Fatigue Life Equations for Carbon and Low-Alloy Steels and Austenitic Stainless Steels as a Function of Tensile Strength

2013 ◽  
Author(s):  
Hiroshi Kanasaki ◽  
Makoto Higuchi ◽  
Seiji Asada ◽  
Munehiro Yasuda ◽  
Takehiko Sera
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Room Temperature ◽  
Austenitic Stainless Steels ◽  
Low Alloy Steels ◽  
Strength Based ◽  
Fatigue Data ◽  
Current Design ◽  
Alloy Steels

Fatigue life equations for carbon & low-alloy steels and also austenitic stainless steels are proposed as a function of their tensile strength based on large number of fatigue data tested in air at RT to high temperature. The proposed equations give a very good estimation of fatigue life for the steels of varying tensile strength. These results indicate that the current design fatigue curves may be overly conservative at the tensile strength level of 550 MPa for carbon & low-alloy steels. As for austenitic stainless steels, the proposed fatigue life equation is applicable at room temperature to 430 °C and gives more accurate prediction compared to the previously proposed equation which is not function of temperature and tensile strength.

Effects of Primary Water Environment on the Thermal Aged Cast Austenitic Stainless Steels

2015 ◽  
Author(s):  
Yuichi Fukuta ◽  
Hiroshi Kanasaki ◽  
Takahisa Yamane
Keyword(s):  
Fracture Toughness ◽  
Stainless Steels ◽  
Water Environment ◽  
Prediction Method ◽  
Austenitic Stainless Steels ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Ferrite Content ◽  
Pressurized Water ◽  
Primary Water

This report summarizes the results of a scoping fracture toughness tests at high and low temperature for thermally aged cast austenitic stainless steels (CASSs) in a pressurized water reactor (PWR) environment. CF8M (ferrite content = 10.1%, 18.9%) and CF8 (ferrite content = 10.5%) were thermally aged up to 5,000 hours at 465°C. Tensile tests, Charpy impact tests and fracture toughness tests were conducted in air at 325°C and 50°C. Fracture toughness tests were also performed in simulated PWR primary water. Although the effect of 325°C and 50°C in simulated PWR primary water and dissolved hydrogen on the fracture toughness (JIc and J-Δa relationship) were slightly observed, fracture toughness was greater than that predicted by the thermally aged fracture toughness prediction method (Hyperbolic-Time-Temperature-Toughness (H3T) model).

Sign in / Sign up

Export Citation Format

Share Document