Tensile and Impact Properties of Shielded Metal Arc Welded AISI 409M Ferritic Stainless Steel Joints

The present study is concerned with the effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the joints fabricated by austenitic stainless steel, ferritic stainless steel and duplex stainless steel filler metals were evaluated and the results were reported. From this investigation, it is found that the joints fabricated by duplex stainless steel filler metal showed higher tensile strength and hardness compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Joints fabricated by austenitic stainless steel filler metal exhibited higher ductility and impact toughness compared with the joints fabricated by ferritic stainless steel and duplex stainless steel filler metals.

Shielded metal arc welding of cemented carbide to carbon steel

Electrode ENiFe-C1 and E4303 were selected to join the cemented carbide WC-20Co and carbon steel 45 by shielded metal arc welding process. Microstructure and bending property of the corresponding joints were analyzed. The results showed that the carbon steel electrode E4303 had no proper metallurgy condition for the arc welding of cemented carbide and carbon steel. The C and Ni content of the cast iron electrode ENiFe-C1 could meet the condition of preventing the formation ofη carbide,which was suit to the arc welding of cemented carbide and carbon steel,but the operation parameters needed to be optimized to minimize the slag inclusion. The alloy WC-20Co which did not fit for cold arc welding,by adopting the measure of being preheated at 723 K for 1 h before welding,and being kept at 723 K for 3 h after welding then followed furnace cooling could avoid the happening of crack in the WC-20Co base metal.

The Real-Time Arc Protection Circuit for ECRH on HL-2A Tokamak

In 2005 year, SWIP carded through a general engineering and physics experiment of ECRH on HL-2A tokamak. The ECRH protection system is studied and set up to insure the security of ECRH system, and the work is normal. The main protection object of all ECRH system is the gyrotron, and the arc protection for it is more important in the protection system.

Effect of Tempering Temperature on Strength and Toughness of Novel Carbide-Free Bainite/Martensite Duplex Phase Steel

The microstructure in the weld metals for HQ130+QJ63 high strength steels, which are welded by Ar CO 2 gas shielded metal arc welding, was analyzed by means of microscope and scan electron microscope (SEM). The relative content of different microstructure was evaluated with XQF 2000 micro image analyzer. The effect of acicular ferrite content on the impact toughness was also studied. The test results indicated that the main microstructure in the weld metals of HQ130+QJ63 high strength steels is acicular ferrite and a few pro eutectic ferrite on the boundary of original austenite grain. Near the fusion zone there are columnar grains whose direction coefficient (X) is 3 22, but the microstructure in the center of the weld metal is isometric grain, whose direction coefficient X=1 In order to avoid welding crack and improve welding technology the weld heat input should be strictly controlled in 10-16 kJ/cm. Thus, the main microstructure in the weld metals is fine acicular ferrite and the content of pro eutectic ferrite is limited. The impact toughness in the weld metals of HQ130+QJ63 steels can be ensured and can meet the requirements for application in engineering and machinery.

Numerical simulation of DE- GMAW of magnesium alloy cylinder

Double-electrode gas shielded arc welding （ DE - GMAW） was used to weld the magnesium alloy cylinder with the diameter of 200 mm and the thickness of 6 mm. In order to study the residual stress distribution of AZ31B magnesiunl alloy welding point, numerical sinmlation of welding temperature field, stress field and residual stress were carried out by MSC. mare software. The results show that the residual stress in the weld and the heat affected zone is large, and with the increase of the distance away from the weld center, the residual stress decreases. In most areas, the longitudinal residual stress is greater than the transverse residual stress （except for the inside and outside surfaces of the weld） , all of which provides theoretical support for the study of magnesiunl alloy welding residual stress.

Effect of Notch Location on Fatigue Life Prediction of Strength Mismatched HSLA Steel Weldments

Welding of high strength low alloy steels (HSLA) involves usage of low, even and high strength filler materials (electrodes) than the parent material depending on the application of the welded structures and the availability of the filler material. In the present investigation, the fatigue crack growth behaviour of weld metal (WM) and heat affected zone (HAZ) regions of under matched (UM), equal matched (EM) and over matched (OM) joints has been studied. The base material used in this investigation is HSLA-80 steel of weldable grade. Shielded metal arc welding (SMAW) process has been used to fabricate the butt joints. Centre cracked tension (CCT) specimen has been used to evaluate the fatigue crack growth behaviour of the welded joints. Fatigue crack growth experiments have been conducted using servo hydraulic controlled fatigue testing machine at constant amplitude loading (R=0).A method has been proposed to predict the fatigue life of HSLA steel welds using fracture mechanics approach by incorporating influences of mismatch ratio (MMR) and notch location.

Analysis Microstructure of Weld Metal for HQ130+QJ63 High Strength Steel

The microstructure in the weld metals for HQ130 + QJ63 high strength steels,which are welded by Ar-CO_2 gas shielded metal arc welding,was analyzed by means of microscope and scan electron microscope(SEM).The relative content of different microstructure was evaluated with XQF-2000 micro-image analyzer.The effect of acicular ferrite content on the impact toughness was also studied.The test results indicated that the main microstructure in the weld metals of HQ130 + QJ63 high strength steels is acicular ferrite and a few pro-eutectic ferrite on the boundary of original austenite grain.Near the fusion zone there are columnar grains whose direction coefficient(X) is 3.22,but the microstructure in the center of the weld metal is isometric grain,whose direction coefficient X = 1.In order to avoid welding crack and improve welding technology the weld heat input should be strictly controlled in 10-16 kJ/cm.Thus,the main microstructure in the weld metals is fine acicular ferrite and the content of pro-eutectic ferrite is limited.The impact toughness in the weld metals of HQ130+ QJ63 steels can be ensured and can meet the requirements for application in engineering and machinery.

Effect of Welding Processes and Consumables on Tensile and Impact Properties of High Strength Quenched and Tempered Steel Joints

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, austenitie stain less steel and low hydrogen ferritic steel, were used to fabricate the joints by shielded metal are 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.

Weldability of Ferritic Ductile Cast Iron Using Full Factorial Design of Experiment

The weldability of a ferritic ductile cast iron was investigated as a function of different consumables and welding conditions. A 23 full factorial experimental design was used to analyze the effect of factors and their interac- tions on ultimate tensile strength of weldments. The shielded metal arc welding （SMAW） process was used with two types of consumables （E7018 and ENi-CI） under eight different conditions using as-cast samples. The microstructur- al evolution and fracture mechanisms were investigated by optical microscopy and scanning electron microscopy （SEM）, respectively. The hardness, tensile and impact tests were also performed to determine the weld quality. Based on experiment design, preheat, consumable, cooling condition, preheat cooling and preheat-consumable inter- actions were significant factors. Preheat is the most effective factor and in the case of E7018, preheat and cooling conditions were the most sensible factors. It was found that buttering was the most appropriate welding method for ferritic ductile cast iron.

Effect of Welding Processes on Tensile and Impact Properties,Hardness and Microstructure of AISI 409M Ferritic Stainless Joints Fabricated by Duplex Stainless Steel Filler Metal

The effect of welding processes such as shielded metal arc welding, gas metal arc welding and gas tungsten arc welding on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade is studied. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the welded joints have been evaluated and the results are compared. From this investigatio.n, it is found that gas tungsten arc welded joints of ferritic stainless steel have superior tensile and impact properties compared with shielded metal arc and gas metal arc welded joints and this is mainly due to the presence of finer grains in fusion zone and heat affected zone.

Comparative Study on Processing Property Between CWW CO_2 Gas Shielded Welding and SAW

Cable welding wire（CWW）CO2gas shielded welding is an innovative process arc welding with high efficiency,high quality and low consumption,in which cable wire is used as consumable electrode.CWW CO2gas shielded welding and submerged arc welding（SAW）are used for contrast studies on processing property of high strength steel A36used in ship structure.The results show that the shapes of weld seam,using CWW CO2gas shielded welding and SAW,are good and no weld defect such as air hole,flaw,slag inclusion,incomplete fusion,lack of penetration and so on are found in the weld seam.Because the rotating of arc during CWW CO2gas shielded welding process has a strong stirring effect on molten pool,the grain in the heat affected zone（HAZ）of the joints,using CWW CO2 gas shielded welding,is small.Tensile failure positions of joints by CWW CO2gas shielded welding and SAW are all in the base metal,but tensile strength of CWW CO2gas shielded welding joint is higher than that of SAW joint by an average of 2.3%.The average impact energy of HAZ,using CWW CO2gas shielded welding and SAW,is almost equal,but the average impact energy of the weld seam using CWW CO2gas shielded welding is increased by 6%,and the average impact energy of the fusion line is increased by 7%.The 180°bending tests for the joints of CWW CO2 gas shielded welding and SAW are all qualified,and the joints hardness is all less than HV 355,but hardness of CWW CO2gas shielded welding wire welding joint near the fusion line is obviously lower.It can be concluded that the properties of CWW CO2gas shielded welding are better than those of the SAW joint,and CWW CO2gas shielded welding is suitable for welding high strength steel A36used in ship structure.

Evaluation of Zero and Sub-zero Temperature Tensile and Impact Properties of Quenched and Tempered Steel Weldments

Combat vehicles using armour grade quenched and tempered （Q＆T） steel are needed to be operated under different climatic conditions. However, the properties meeting the room temperature test conditions may not neces-sarily be required to meet the low temperature operating conditions. The influences of shielded metal arc welding （SMAW） process, flux cored arc welding （FCAW） processes and test temperatures below room temperature up to 60℃ on tensile and impact toughness properties of armour grade Q＆T steel welds were reported. The tensile and impact properties of the joints showed incremental trend with respect to the decrement in test temperature up to -40℃ irrespective of the welding processes used. The increment in tensile and impact properties of SMAW and FCAW joints subjected to the low temperature environment is due to plastic strain-induced phase transformation of retained austenite into martensite phase. Among the two processes, SMAW process welded joint showed better tensile and impact properties than its FCAW counterpart joints.