K Srinivasan
,
V Balasubramanian
钢铁研究学报(英文版)
The effect of heat input on fume and their compositions during gas metal arc welding (GMAW) of AISI 316 stainless steel plates are investigated. Fume generation rate (FGR) and fume percentage were determined by ANSI/AWS F12 methods. Particle characterization was performed with SEM-XEDS and XRF analysis to reveal the particle morphology and chemical composition of the fume particles. The SEM analysis reveals the morphology of particles having three distinct shapes namely spherical, irregular, and agglomerated. Spherical particles were the most abundant type of individual particle. All the fume particle size falls in the range of less than 100 nm. Mechanical properties (strength, hardness and toughness) and microstructural analysis of the weld deposits were evaluated. It is found that heat input of 115 kJ/mm is beneficial to weld stainless steel by GMAW process due to lower level of welding fume emissions and superior mechanical properties of the joints.
关键词:
gas metal arc welding
,
fume generation rate
,
austenitic stainless steel
,
tensile property
,
scanning electron microscope
,
X-ray florescence spectrometer
A K Lakshminarayanan
,
V Balasubramanian
钢铁研究学报(英文版)
The microstructure analysis and mechanical properties evaluation of laser beam welded AISI 409M ferritic stainless steel joints are investigated. Single pass autogeneous welds free of volumetric defects were produced at a welding speed of 3000 mm/min. The joints were subjected to optical microscope, scanning electron fractographe, microhardness, transverse and longitudinal tensile, bend and charpy impact toughness testing. The coarse ferrite grains in the base metal were changed into dendritic grains as a result of rapid solidification of laser beam welds. Tensile testing indicates overmatching of the weld metal is relative to the base metal. The joints also exhibited acceptable impact toughness and bend strength properties.
关键词:
laser beam welding
,
ferritic stainless steel
,
tensile property
,
impact property
V Balasubramanian
,
A K Lakshminarayanan
,
R Varahamoorthy
,
S Babu
钢铁研究学报(英文版)
The application of response surface methodology was highlighted to predict and optimize the percentage of dilution of ironbased hardfaced surface produced by the PTA (plasma transferred arc welding) process. The experiments were conducted based on fivefactor fivelevel central composite rotatable design with full replication technique and a mathematical model was developed using response surface methodology. Furthermore, the response surface methodology was also used to optimize the process parameters that yielded the lowest percentage of dilution.
关键词:
plasma transferred arc hardfacing;dilution;response surface methodology
G Magudeeswaran
,
V Balasubramanian
,
G Madhusudhan Reddy
,
T S Balasubramanian
钢铁研究学报(英文版)
Quenched and tempered steels are prone to hydrogen induced cracking in the heat affected zone after welding. The use of austenitic stainless steel consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase. In this investigation, an attempt was made to determine a suitable consumable to replace expensive austenitic consumables. Two different consumables, namely, austenitic stainless steel and low hydrogen ferritic steel, were used to fabricate the joints by shielded metal arc welding (SMAW) and flux cored arc welding (FCAW) processes. The joints fabricated by using low hydrogen ferritic steel consumables showed superior transverse tensile properties, whereas joints fabricated by using austenitic stainless steel consumables exhibited better impact toughness, irrespective of the welding process used. The SMAW joints exhibited superior mechanical and impact properties, irrespective of the consumables used, than their FCAW counterparts.
关键词:
shielded metal arc welding process;flux cored arc welding process;austenitic
R Paventhan
,
P R Lakshminarayanan
,
V Balasubramanian
钢铁研究学报(英文版)
Friction welding is a solid state joining process used extensively currently owing to its advantages such as low heat input, high production efficiency, ease of manufacture, and environment friendliness. Materials difficult to be welded by fusion welding processes can be successfully welded by friction welding. An attempt was made to develop an empirical relationship to predict the tensile strength of friction welded AISI 1040 grade medium carbon steel and AISI 304 austenitic stainless steel, incorporating the process parameters such as friction pressure, forging pressure, friction time and forging time, which have great influence on strength of the joints. Response surface methodology was applied to optimize the friction welding process parameters to attain maximum tensile strength of the joint. The maximum tensile strength of 543 MPa could be obtained for the joints fabricated under the welding conditions of friction pressure of 90 MPa, forging pressure of 90 MPa, friction time of 6 s and forging time of 6 s.
关键词:
friction welding
,
stainless steel
,
response surface methodology
,
optimization
A K Lakshminarayanan
,
K Shanmugam
,
V Balasubramanian
钢铁研究学报(英文版)
The effect of autogeneous arc welding processes on tensile and impact properties of ferritic stainless steel conformed to AISI 409M grade is studied. Rolled plates of 4 mm thickness have been used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure, and fracture surface morphology of continuous current gas tungsten arc welding (CCGTAW), pulsed current gas tungsten arc welding (PCGTAW), and plasma arc welding (PAW) joints are evaluated and the results are compared. It is found that the PAW joints of ferritic stainless steel show superior tensile and impact properties when compared with CCGTAW and PCGTAW joints, and this is mainly due to lower heat input, finer fusion zone grain diameter, and higher fusion zone hardness.
关键词:
ferritic stainless steel;plasma arc welding;continuous current gas tungsten arc
ZHONG Jiaxiang ZHENG Xiuhua XU Zongrui Beijing Institute of Technology
,
Beijing
,
ChinaBAI Dezhong Nei Monggol Machine Works No.2
,
Nei Monggol
,
China Beijing Institute of Technology
,
Beijing 100081
,
China
金属学报(英文版)
Three types of alloy carbides have been observed in tempered steel 4335V:M_3C,M_7C_3 and M_4C_3.The precipitation temperatures are 200—700,400 and 500 ℃ respectively.The com- position,morphologies and distribution patterns of the carbides as well as the relationship be- tween them and as-quenched substructures have been investigated.The influence of the car- bides on the low temperature impact toughness of the steel has also been discussed.
关键词:
steel 4335V
,
null
,
null
Journal of Physics and Chemistry of Solids
The tetragonal distortion for the tetragonal V2+-V-M center in KBr:V2+ crystal is estimated by analyzing its EPR data from two theoretical models, one is the two spin-orbit (S.O.) parameter model where the contributions to EPR parameters from both the S.O. coupling of the central metal ion and that of the ligands are considered and another is the conventional one-S.O.-parameter model where only the contribution from the S.O. coupling of the central metal ion is included. The result from the two-S.O.-parameter model is more than ten times that of the one-S.O.-parameter model. The reasonableness of the former is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.
关键词:
inorganic compounds;crystal fields;defects;electron paramagnetic;resonance (EPR);epr parameters;transition;ions
