Effect of Brazing and Heat Treatment Cycle on the Mechanical Properties of Base Materials

2015 ◽  
Vol 830-831 ◽  
pp. 310-313
Author(s):  
N. Dileep Kumar ◽  
K. Thomas Tharian ◽  
Aby Isaac ◽  
P.V. Venkitakrishnan
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Grain Growth ◽  
Braze Alloy ◽  
Base Material ◽  
Growth Patterns ◽  
Outer Shell ◽  
Liquid Oxygen ◽  
Gas Generator ◽  
Base Materials

Brazing is extensively used in liquid rocket engines for realizing various subsystems. In the case of cryogenic engines, brazing operation is done to realize the gas generator. Gas Generator is one of the major systems of cryogenic engine. It generates and supplies hot gases required for running turbine of main turbo pump. This uses liquid oxygen and gaseous hydrogen as propellant combination. Combustion chamber of Gas Generator is of double walled construction with the cylindrical outer shell of transition class ICSS-0716-301 austenitic-martensitic stainless steel and inner shell of ICSS-1218 321, aTi stabilized austenitic stainless steel material brazed together with Fe-Ni-Mn type braze alloy at a temperature of 1180°C. This temperature can cause the grain growth and related issues to the base material. Thus the present work focuses on the effect of the brazing/thermal cycle on mechanical properties and microstructure of the base materials in post braze condition. The results obtained on metallurgical/mechanical behavior of the material showed the different grain growth patterns in inner and outer shell materials. This helped in understanding the effect of brazing condition on the changes in mechanical properties of base materials.

Yb:YAG Disc Laser Welding of Austenitic Stainless Steel Without Filler Material

2009 ◽  
Vol 410-411 ◽  
pp. 87-96 ◽  
Author(s):  
Markku Keskitalo ◽  
Kari Mäntyjärvi
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cross Sections ◽  
Base Material ◽  
Tensile Tests ◽  
Solidification Cracking ◽  
Filler Material ◽  
Test Material ◽  
Butt Weld

The laser weldability of austenitic stainless steel (ASS) is good because of the material’s high absorptivity and favourable microstructure. There can be a slight possibility of solidification cracking at high welding speeds and low Crekv/Niekv ratios. Test welds were welded with a Yb:YAG disc laser. The test material was 3.2 mm EN 1.4404 2H C700 type stainless steel plate which was work hardened by cold rolling. The test materials were welded with different heat inputs ranging from 0.024 kJ/mm to 0.12 kJ/mm and with 300 mm and 200 mm focal lengths. The weld seams were square-groove welded as butt weld without filler material. The edges of the groove were made by mechanical or laser cutting. The hardness profiles from cross-sections of the welds were measured with a Vickers microhardness tester using 200 g weight. The mechanical properties were tested with tensile tests. The welds were classified with radiographic verification by an accredited laboratory. A number of the welds were fatigue tested with a bending fatigue tester. The mechanical properties (Rp 0.2%, Rm) of the laser welds were almost the same as in the base material except at the highest heat input. In the radiographic classification, the welds which were welded to the laser-cut edge were classified as class B (accepted). The other welds were classified as class D or C (rejected). The main reasons for the rejection of welds made on mechanically cut edges were lack of penetration or undercut of the weld. A problem with mechanically cut edges, and hence the welds, is that they can be non-square and bent edge. Fatigue tests and tensile tests gave no evidence of solidification cracking in the microstructure of the solidified parts of the welds.

Properties of Silver Brazing Alloys Containing Lithium / Właściwości Spoiw Srebrnych Do Lutowania Twardego Z Dodatkiem Litu

2012 ◽  
Vol 57 (4) ◽  
pp. 1087-1093 ◽  
Author(s):  
W. Gąsior ◽  
A. Winiowski
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Shear Strength ◽  
Tensile Test ◽  
Beneficial Effect ◽  
Braze Alloy ◽  
Silver Alloys ◽  
Wetting Properties ◽  
Slag Inclusions ◽  
Brazed Joints

The analysis of the influence of lithium on wetting properties of Ag-Cu brazing alloys and the shear strength of stainless steel/braze/stainless steel joint was conducted. The brazing alloys of designations and composition according to ANSI/AWS A5.8: BAg-8a (71÷3 wt.% Ag, 0.25÷0.50 wt.% Li, Cu) and BAg-19 (92÷93 wt.% Ag, 0.15÷0.30 wt.% Li, Cu) and a braze alloy containing 70÷72 wt.% Ag, 0.6÷0.7 wt.% Li and Cu were subjected to the investigations. The wettability properties of the brazing silver alloys were examined in a spread test. The shear strength of joints were measured on the joints of stainless steel in the tensile test. The comparison of results showed a beneficial effect of lithium on the spreading properties and the wettability of braze alloys as well as the quality and shear strength of the brazed joints. The observed slag inclusions in the solid braze did not affect considerably the mechanical properties of the prepared joints because of the intensive deoxidation of the brazing surfaces of stainless steel elements.

Experimental Research on Mechanical Properties of Polypropylene Flexible Intermediate Bulk Container Base Materials

2013 ◽  
Vol 811 ◽  
pp. 146-151
Author(s):  
Chen Wei Chen ◽  
Fu Xin Yang ◽  
Li Xin Lu ◽  
Jin Xie ◽  
Li Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Low Temperature ◽  
Base Material ◽  
Powder Materials ◽  
Base Materials ◽  
Natural Exposure ◽  
Exposure Experiment ◽  
Tensile Experiment

The Flexible Intermediate Bulk Container (FIBC) is a flexible transportation packaging container that is weaved by polyolefin plastic ribbon-like filament, which is widely used in the storage and transportation of granular and powder materials. When the FIBC was affected by environment factors synthetically under using, such as light, heat and air etc, it would come into degradation and its mechanical properties reduced. In this study, the basic mechanical properties of polypropylene FIBC base material were tested by tensile experiment and the reason of main base material mechanical properties difference between theoretical value and experimental value was analyzed. Based on the FIBC different using environments, the natural exposure experiment and high/low temperature experiments were carried out, we took tensile strength holding ratio and elongation holding ratio as evaluating indicator and analyzed law of influence of the different experiment condition on base material mechanical properties, which provided valuable reference for FIBC designing and manufacturing. Along with the experiment time increased, the color of base material changed from milk white to yellow slowly, the tensile strength and elongation reduced, the influencing grade was as follow: natural exposure>high temperature>low temperature. The results of natural exposure experiment showed that there was difference of anti-aging performance among the FIBC base material, the mechanical properties of woof fabric and belt reduced evidently, while others reduced slowly. For high (45°C)/low (-25°C) temperature experiments, the reduction of FIBC base materials mechanical properties were not obvious and woof fabric reduced a little faster comparatively.

Mechanical Properties Comparison of Stainless Steel 304L and Carbon Steel BS1387 Prior to Orbital Welding

2015 ◽  
Vol 761 ◽  
pp. 79-82
Author(s):  
Mohamad Nizam Ayof ◽  
Z.M. Noh ◽  
N.I.S. Hussein
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Steel Pipe ◽  
Base Materials ◽  
Orbital Welding ◽  
Plant Chemical ◽  
Higher Temperature ◽  
Welding Processes ◽  
Temperature Water

Dissimilar metal joint (DMJ) is one of many joining methods for welding processes which is common in the power plant, chemical and petrochemical industries. Stainless steel pipe and carbon steel pipe are the most widely used in this technique. In order to perform DMJ to these metals, it is important to understand the mechanical properties of both base materials. In this study, the characterizations of stainless steel (SS) 304L and carbon steel (CS) BS1387 were made. The SS 304L and CS BS1387 were cut out from pipes according to ASTM E 8M-04, before their tensile and microhardness properties were measured and evaluated. The results show that the SS 304L has better mechanical properties compared to the CS BS1387 pipe in terms of tensile strength and hardness. Due to the higher mechanical properties, SS 304L was selected to conduct higher temperature water, while CS BS1387 was selected to conduct room temperature water.

scholarly journals Microstructure and mechanical properties of AISI 439 ferritic stainless steel welds without filler metal

2019 ◽  
Vol 29 ◽  
pp. 1-12
Author(s):  
Juan Manuel Salgado López ◽  
Marc Preud homme ◽  
Francisco Lopez Monroy ◽  
Jose Luis Ojeda Elizarráraz ◽  
Arturo Toscano Giles
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Tensile Test ◽  
Grain Growth ◽  
Ferritic Stainless Steel ◽  
Filler Metal ◽  
Testing Machine ◽  
Thin Plates ◽  
Technical Literature ◽  
Steel Welds

In literature, it has been reported that a current intensity lower than 120 A leads to a microstructure without grain growth in the heat affected zone (HAZ) of ferritic stainless steel welds. Nevertheless, in technical literature there is little information about the reduction in mechanical properties of ferritic stainless steel welds without filler metal due to grain growth in the HAZ. In this work, thin plates of ferritic stainless 439 steel were welded using pulse current gas tungsten arc welding (P-GTAW) without filler metal. The microstructures in the HAZ were analyzed and the mechanical properties on the welded joint were found by tensile test. This was carried out by cutting samples for the tensile test from the weldments and then tested in a universal testing machine. The fracture surface were observed using scanning electron microscope.

GTAW Welded Inconel 625 Alloy Fuel Cladding for the Canadian SCWR: Microstructure and Mechanical Property Characterization

2020 ◽  
Author(s):  
German Cota-Sanchez ◽  
Lin Xiao
Keyword(s):  
Mechanical Properties ◽  
Grain Growth ◽  
Dendritic Structure ◽  
Base Material ◽  
Mechanical Tests ◽  
Nuclear Industry ◽  
Reactor Fuel ◽  
Inconel 625 ◽  
Fuel Cladding ◽  
Inconel 625 Alloy

Abstract Inconel 625 is considered one of the candidate materials for reactor fuel cladding in the Canadian supercritical water reactor (SCWR) design. Gas tungsten arc welding (GTAW) is being evaluated as a joining technique for SCWR fuel cladding since this method is widely used to join components in the power and nuclear industry. During the GTAW process, the welding thermal cycle produces different types of microstructures in both the heat-affected zone (HAZ) and fusion zone (FZ) that affect the material's mechanical properties. A series of welding experiments at various weld conditions were performed using an automatic GTAW orbital process on Inconel 625 alloy tubing. Simple analytical heat conduction and grain growth models were developed to predict weld temperature profiles and metallurgical transformations. Weld characterization included mechanical tests, optical microscopy, scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS) elemental analysis, and microhardness measurements. Weld microstructural characterization revealed that a characteristic dendritic structure was formed in the FZ, while the HAZ exhibited larger equiaxed grains than those found in the base material. SEM-EDS analysis showed no distinct alloying element segregation in both the HAZ and FZ. Welds produced with heat inputs of about 3.00 kJ/cm3 presented similar mechanical properties as those observed in the base material. In these welds, grain growth was homogenously minimized in the FZ. It is concluded that the effective welding heat input control can optimize the weld microstructure and the weld mechanical properties in Inconel 625 tubing used as Canadian SCWR reactor fuel cladding.

scholarly journals The Mechanical Properties of a Poly(methyl methacrylate) Denture Base Material Modified with Dimethyl Itaconate and Di-n-butyl Itaconate

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Pavle Spasojevic ◽  
Milorad Zrilic ◽  
Vesna Panic ◽  
Dragoslav Stamenkovic ◽  
Sanja Seslija ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Methyl Methacrylate ◽  
Surface Hardness ◽  
Base Material ◽  
Dynamic Mechanical Properties ◽  
Denture Base ◽  
Mean Values ◽  
Poly Methyl Methacrylate ◽  
Base Materials ◽  
Wide Range

This study investigates a wide range of clinically relevant mechanical properties of poly(methyl methacrylate) (PMMA) denture base materials modified with di-methyl itaconate (DMI) and di-n-butyl itaconate (DBI) in order to compare them to a commercial PMMA denture base material. The commercial denture base formulation was modified with DMI and DBI by replacing up to 10 wt% of methyl methacrylate (MMA) monomer. The specimens were prepared by standard bath curing process. The influence of the itaconate content on hardness, impact strength, tensile, and thermal and dynamic mechanical properties was investigated. It is found that the addition of di-n-alkyl itaconates gives homogenous blends that show decreased glass transition temperature, as well as decrease in storage modulus, ultimate tensile strength, and impact fracture resistance with increase in the itaconate content. The mean values of surface hardness show no significant change with the addition of itaconates. The magnitude of the measured values indicates that the poly(methyl methacrylate) (PMMA) denture base material modified with itaconates could be developed into a less toxic, more environmentally and patient friendly product than commercial pure PMMA denture base material.

scholarly journals Effect of Pore Structure on Thermal Conductivity and Mechanical Properties of Autoclaved Aerated Concrete

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 339
Author(s):  
Gonglian Chen ◽  
Fenglan Li ◽  
Pengfei Jing ◽  
Jingya Geng ◽  
Zhengkai Si
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Pore Structure ◽  
Pore Size ◽  
Base Material ◽  
Test Results ◽  
Foam Stabilizer ◽  
Base Materials ◽  
Aerated Concrete

With the premise of investigating mechanical properties, the thermal conductivity of autoclaved aerated concrete (AAC) is a key index of self-insulation block walls for building energy conservation. This study focused on the effect of pore structures on the mechanical performance and thermal conductivity of AAC with the comparison of AAC base materials. Different kinds of AAC and their base materials were prepared and experimentally investigated. While maintaining a consistent mix proportion of the AAC base material, the pore structure of AAC was changed by the dosage of aluminum power/paste, foam stabilizer, and varying the stirring time of aluminum paste. The steam curing systems of AAC and the base material were determined based on SEM (Scanning Electronic Microscopy) and XRD (X-Ray Diffraction) tests. With almost the same apparent density, the pore size decreased with the increasing content of foam stabilizer, and the mixing time of aluminum paste and foam stabilizer has a great influence on pore size. The thermal conductivity test and compressive test results indicated that that pore size had an effect on the thermal conductivity, but it had little effect on the compressive strength, and the thermal conductivity of sand aeration AAC was 8.3% higher than that of fly ash aeration AAC; the compressive strength was 10.4% higher, too. With almost the same apparent density, the regression mathematical model indicates that the thermal conductivity of AAC increased gradually with the increase of pore size, but it had little effect on the compressive strength. From the test results of basic mechanical properties, the mechanical model of cubic compressive strength, elastic modulus, axial compressive strength, and splitting tensile strength was obtained. The proposed stress–strain relationship model could well describe the relationship of AAC and the base material at the rising section of the curve.

Resistance Welding by Inserting Wires between Joint Interfaces

2007 ◽  
Vol 127 ◽  
pp. 343-347
Author(s):  
Takeshi Terajima ◽  
Toshio Kuroda
Keyword(s):  
Stainless Steel ◽  
Melting Point ◽  
Base Material ◽  
Resistance Welding ◽  
Joint Interface ◽  
Base Materials ◽  
Steel Wires ◽  
Material Temperature ◽  
Type 316L Stainless Steel

Butt resistance welding of super duplex stainless steel by inserting type 316L stainless steel wires was investigated. When the base material temperature was increased from room temperature to 1100 oC at the heating rate of 550 oC /sec, base materials were jointed through the insert wires and HAZ (heat affected zone) of the joint interface were less than 80 μm. In this joining technique, the insert wires played a role of concentrating current on the wires and increasing their temperature up to melting point or near melting point. When the welding was performed at a load of 10 N, the insert wires consisted of ferrite and austenite growing along the ferrite grain boundary. When the welding was performed at a load of 70N, insert wire remained austenite. That is because the contact resistance between insert wire and base materials at 70 N was lower than that of 10 N, and consequently the insert wire were not adequately heated.

The effect of metal transfer modes on mechanical properties of 3CR12 stainless steel

2020 ◽  
Vol 44 (2) ◽  
pp. 256-262
Author(s):  
Daniel M. Madyira ◽  
Abdullah Kaymakci ◽  
Ntokozo Nkwanyana
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Grain Growth ◽  
Charpy Impact ◽  
Metal Transfer ◽  
Test Material ◽  
Limiting Factor ◽  
Air Cooling ◽  
Butt Welding ◽  
Martensitic Microstructure

The effect of metal transfer modes on mechanical properties of welded 3CR12 stainless steel was investigated. This was achieved by butt welding 10 mm thick plates of 3CR12. The effect of the metal transfer modes on the microstructure and the mechanical properties of the 3CR12 steel was then investigated as it was hypothesized that the change in welding positions will affect the transfer modes partly because of gravity. The microscopic examination revealed that the substrate was characterized by dual phase microstructure. Using the spectroscopic examination results, the ferritic factor calculation had shown that the microstructure was expected to be ferritic–martensitic during air cooling process. The tensile strength and Charpy impact energy were measured to be 498 MPa and 102 J, respectively. The heat input in the material was observed to be greater than 1 kJ/mm, which is the limiting factor for grain growth. Grain growths were observed in the heat affected zone of the welded materials. Ferritic–martensitic microstructure was observed in the microstructure. The grain growth altered the mechanical properties of the test material. Globular down hand had higher mechanical properties than spray down hand. Globular vertical up had better mechanical properties than globular vertical down.

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