Showing papers in "Welding International in 1995"
TL;DR: In this paper, the authors describe an investigation of the creep rupture strength (CRS) of 9Cr•1Mo•V•Nb•N steel welded joints by welding thermal cycle simulation.
Abstract: Summary This paper describes an investigation of the creep rupture strength (CRS) of 9Cr‐1Mo‐V‐Nb‐N steel welded joints by welding thermal cycle simulation. The reduction in the CRS of the welded joints is successfully reproduced, and the reasons for this reduction are discussed from the perspective of fine precipitates in the matrix. The CRS of the simulated HAZ (heat affected zone) varies with the peak temperature of welding thermal cycle simulation (PT). It falls sharply beyond the Ac1 temperature, gradually reaching the minimum at the Ac3 temperature of 925 °C. At any higher temperature than Ac3, it rises steadily, showing almost the same CRS as the base metal at 1100°C. The weakest CRS of the simulated HAZ lies at the lowest limit of the CRS data band of various welded joints prepared by GTA (TIG), MMA, and submerged‐arc (SA) welding with the same base metal. The simulated HAZ is useful for evaluation and analysis of the CRS reduction of welded joints. Heating to the Ac3 temperature by welding change...
30 citations
TL;DR: In this article, the effects of M•A (martensite-austenite) constituent on the initiation and propagation of cracks have been investigated by observation of the fracture morphology and cracks around the M'A constituent.
Abstract: Summary The effects of M‐A (martensite‐austenite) constituent on the initiation and propagation of cracks have been investigated by observation of the fracture morphology and cracks around the M‐A constituent. Crack initiation and propagation energies were estimated using an instrumented Charpy impact test machine. The concentration and distribution of the tensile plastic deformation introduced into the soft phase around the hard constituent were also qualitatively analysed by the finite element method (FEM) to explain the effect of the M‐A on crack initiation and propagation. The results show a sharp decrease in the crack initiation and propagation energies with increasing area fraction of the massive M‐A constituent. The FEM analysis suggests that the greater amount of hard phase reduces the crack initiation energy in the surrounding soft phase, which explains the observed decrease in the crack initiation energy with increasing area fraction of the massive M‐A constituent. It was also shown that the dec...
19 citations
TL;DR: In this article, an investigation of the effect of tungsten on the HAZ properties of duplex stainless steel in a program to develop highly pitting corrosion resistant duplex steel was described.
Abstract: Summary This paper describes an investigation of the effect of tungsten on the HAZ properties of duplex stainless steel in a programme to develop highly pitting corrosion resistant duplex stainless steel The steels tested were modified SUS329J4L duplex stainless steel containing added tungsten The welded joints produced by gas tungsten arc (GTA or TIG) welding and the simulated HAZ were evaluated in terms of the pitting corrosion resistance, impact toughness, and microstructure, including an analysis of precipitates The results suggest that tungsten added up to 2 mass% is effective for improvement of the pitting corrosion resistance without heavy loss of impact toughness in the HAZ Tungsten addition exceeding 3 mass%, however, decreases both the HAZ impact toughness and pitting corrosion resistance by accelerating the precipitation of intermetallic compounds during the welding thermal cycles It is thus demonstrated that the pitting corrosion resistance in the HAZ of duplex stainless steel is improved
14 citations
TL;DR: In this article, the formation of intermetallic phases and the shear strength in the bond interface subjected to welding thermal cycles were investigated. And the results obtained may be summarised as follows: Even under rapid heating at a temperature just under the melting point of aluminium, no intermetall phases are formed in bond interface of aluminium clad steel unless there is holding at this temperature.
Abstract: Summary This paper describes production of aluminium clad steel by vacuum roll bonding. The clad steel was heated at 560–650 °C × 0–20 sec to study the formation of intermetallic phases and the shear strength in the bond interface subjected to welding thermal cycles. The results obtained may be summarised as follows: Even under rapid heating at a temperature just under the melting point of aluminium, no intermetallic phases are formed in the bond interface of aluminium clad steel unless there is holding at this temperature. The intermetallic phases formed in the bond interface are FeAl3 and Fe2Al5. The activation energy of their formation is 41 kcal/mol. Even under rapid heating at a temperature just under the melting point of aluminium, the bond shear strength is the same as that of the as‐welded material unless there is holding at this temperature. The bond shear strength depends on the heating temperature and holding time, sharply decreasing under short‐term holding with a rising heating temperature an...
12 citations
TL;DR: In this paper, a comparative study on the glycerine, mercury and gas chromatography methods for determining the diffusible hydrogen content in welded joints is presented, and the effects of the variables of time and temperature for hydrogen collection are also considered.
Abstract: Summary This paper presents a comparative study on the glycerine, mercury and gas chromatography methods for determining the diffusible hydrogen content in welded joints. The effects of the variables of time and temperature for hydrogen collection are also considered. AWS type E9018‐M electrodes were wetted, then dried at different temperatures for different times in order to obtain a wide range of diffusible hydrogen contents. The results showed that the collection time may be reduced when the sampling temperature is increased. The gas chromatography and mercury methods give similar results, much higher than those obtained with the glycerine method, without the need to use liquid nitrogen for preparation of test specimens. The gas chromatography method presents less scatter of results and a shorter sample collection time due to the increased sampling temperature. The use of equations found in the literature for comparison of the results obtained by the different methods is also discussed.
12 citations
TL;DR: In this article, a 1C-17Cr martensitic stainless steel coating material and a low carbon structural steel substrate were used to obtain a stable hard layer of 20 mm width and 1 mm thickness with no dilution being found.
Abstract: Summary Although several surfacing processes have been proposed and applied, none has been able to apply a 1 mm thick hard layer. This paper describes fundamental research to establish friction surfacing as a technique for applying a 1 mm thick hard layer. Experiments were run to clarify the effects of operating parameters on surface quality using a conventional friction welder fitted with a sliding stage. The materials selected were a 1C‐17Cr martensitic stainless steel coating material and a low‐carbon structural steel substrate. A stable hard layer of 20 mm width and 1 mm thickness was obtained, with no dilution being found. The dimensions of the coating depend on the friction speed (rotational speed) of the coating material. Thicker and wider coatings are produced at a lower friction speed. The deposition rate is slightly lower than that of conventional arc welding processes under the experimental conditions presently adopted.
11 citations
10 citations
10 citations
9 citations
TL;DR: In this article, the effects of shielding gas on metal transfer were investigated and the results showed that shielding gas has a negative effect on metal metal transfer performance in the presence of shielding.
Abstract: (1995). Effects of shielding gas on metal transfer. Welding International: Vol. 9, No. 6, pp. 462-466.
9 citations
TL;DR: In this paper, a study on the tensile shear strength of Al-Mg alloy sheet was conducted, and the performance of continuous spot weldability was compared with mild steel and mild steel.
Abstract: The investigation results on the resistance spot weld quality of Al-Mg alloy sheet are summarized as follows;(1) Comparison of continuous spot weldability with mild steel sheet Compared with mild steel, the Al-Mg alloy exhibits degradation and variation of tensile shear strength associated with continuous resistance spot welding, and causes excessively serious wear in electrodes.(2) A study for variation of tensile shear strength in continuous resistance spot welding Variation of tensile shear strength in continuous resistace spot welding is due to nonuniform corona bond formation and nonuniform nugget size and profile.(3) Effects of oxide film and heat condition, (1) The oxide film causes localized wear in electrodes, and in addition, even prevents the formation of corona bond. (2) If the heat input after saturation of nugget growth is regaded as extra heat, it promotes wear in electrodes and causes corona bond formation. (3) Variation of tensile shear strength is improved mainly by removing oxide film. In addition by reducing the heat input, it causes degradation of tensile shear strength and makes the failure mode sparse, the formation of corona bond is suppressed and then tensile shear strength become stable and electrode life is extended.
TL;DR: In this article, the decomposition of an M-A constituent by post weld heat treatment was investigated and the effect on the toughness of the weld CGHAZ of 780 and 980 MPa class HSLA steels.
Abstract: Summary This paper describes an investigation of the decomposition of M‐A constituent by PWHT (post weld heat treatment) together with its effect on the toughness of the weld CGHAZ (coarse‐grained heat affected zone) of 780 and 980 MPa class HSLA steels. For all steels tested, the area fraction of the M‐A constituent decreases with an increasing PWHT temperature and time, but the toughness dependence of the PWHT parameters of the 980 MPa class steels is quite different from that of the 780 MPa class steels. The toughness of the weld CGHAZ of the 780 MPa class steels is increased as the M‐A constituent is decomposed into ferrite and cementite by the PWHT. The weld CGHAZ of the 980 MPa class steels, however, shows embrittlement at PWHT temperatures above 823 K, though the toughness increases with the PWHT time at temperature below 623 K. The foregoing results suggest that the toughness of HSLA steels impaired by high heat input welding can be significantly improved by PWHT at a temperature around 623 K.
TL;DR: In this article, Diffusion bonding dissimilar materials in aerospace technology is discussed. But it is not discussed in the context of the aerospace industry, as discussed in this paper, and
Abstract: (1995). Diffusion bonding dissimilar materials in aerospace technology. Welding International: Vol. 9, No. 6, pp. 477-478.
TL;DR: In this paper, the effect of intermetallic phases formed in the temperature range 675-1000 °C on corrosion resistance and toughness was studied in duplex weld metals with a composition comprising 22% Cr•9% Ni•3% Mo•0.15% N.
Abstract: Summary The effect of intermetallic phases formed in the temperature range 675–1000 °C on corrosion resistance and toughness was studied in duplex weld metals with a composition comprising 22% Cr‐9% Ni‐3% Mo‐0.15% N. The R phase, rich in molybdenum, formed rapidly at 700 °C and was the most important phase which precipitated at 800 °C, while only σ phase formed at 900 °C. At 800 °C, a small quantity of phase x formed. A significant reduction in the ferrite content or an increase in hardness implies a reduction in corrosion resistance. Above 800 °C, corrosion resistance and toughness were both affected while, at temperatures below 800 °C, the deterioration in corrosion resistance occurs before embrittlement. Nevertheless, if the recommended welding procedures are followed, there is no loss of corrosion resistance.
TL;DR: In this article, the fundamental characteristics of high-power CO2 laser welding of 87% A12O3 ceramics have been investigated, and the results suggest that a penetration depth of 20 mm is possible at a welding speed of 6.5 mm/sec and laser power of 10 kW.
Abstract: Summary To develop a joining technology for thick ceramics, the fundamental characteristics of high‐power CO2 laser welding of 87% A12O3 ceramics have been investigated. The results suggest that a penetration depth of 20 mm is possible at a welding speed of 6.5 mm/sec and laser power of 10 kW. The porosity ratio is lower at lower input powers, also tending to decrease with a decreasing welding speed at the same input power. The bending strength decreases with an increasing porosity ratio. Porosities, especially large sink mark porosities at the bead centre, strongly affect the bending strength of welded joints in alumina ceramics. The root bending strength of 4 mm thick butt‐welded plate has the same value as the base material.
TL;DR: In this article, the ductility characteristics of solidifying weld metal were investigated by external restraint solidification cracking tests, i.e., the Trans-Varestraint test and slow bending TransVares-traint test.
Abstract: Summary This paper describes an investigation of the ductility characteristics of solidifying weld metal by external restraint solidification cracking tests, i.e. the Trans‐Varestraint test and slow‐bending Trans‐Vares‐traint test. The minimum augmented strain necessary for crack initiation (?min), brittleness temperature range (BTR), and critical strain rate for temperature drop (CST) are selected from the ductility characteristics as criteria for evaluation of the weld solidification cracking susceptibility. The solidification cracking susceptibility of 16 types of 1000–7000 series commercial aluminium alloys is also qualitatively evaluated by self‐restraint solidification cracking tests, i.e. the ring casting test, GTAW crater test, Houldcroft test, and fan‐shaped test. The grain size of the weld metal, the dihedral angle of eutectic products at the grain boundaries and the amount of eutectic products are also measured as metallurgical factors. The correlation between the results obtained in the self‐r...
TL;DR: In this paper, the fatigue strength of laser-welded butt joints made of Fe P04•UNI 8092 deep drawing steel with standard and galvanized surfaces is compared with those of a series of seam-weeled joints, which have been subjected to special forging of the beads after welding.
Abstract: Summary This paper summarises fatigue strength in laser‐welded butt joints made of Fe P04‐UNI 8092 deep drawing steel with standard and galvanized surfaces. The Wohler curves obtained are compared with those of a series of seam‐welded joints, which have been subjected to special forging of the beads after welding. Fatigue behaviour is similar to that of the parent material since fracture does not occur in the beads or heat affected zone. Such results are of importance in the current review of design methodologies, when new possibilities are being offered by laser and tailored blank technologies.
TL;DR: In this article, the authors proposed a method for constructing laminated structures of light alloys based on aluminium and titanium, which they called "brazing laminated structure of light alloy alloys".
Abstract: (1995). Brazing laminated structures of light alloys based on aluminium and titanium. Welding International: Vol. 9, No. 7, pp. 570-572.
TL;DR: In this article, the YAG laser welding of aluminium alloys is described and compared to the work presented in this paper, and the results are presented in Table 1.1.
Abstract: (1995). YAG laser welding of aluminium alloys. Welding International: Vol. 9, No. 1, pp. 5-12.
TL;DR: In this article, the experimental conditions for fabrication of multilayered metal base composites by single shot explosive welding are described, and the results show that the resulting composites can be used to construct a multilayer metal base composite.
Abstract: (1995). Experimental conditions for fabrication of multilayered metal base composites by single‐shot explosive welding. Welding International: Vol. 9, No. 2, pp. 116-120.
TL;DR: In this paper, the properties of welded joints in aluminium alloys of the Al-Cu system were investigated and a detailed discussion of the properties and properties of these joints were presented.
Abstract: (1995). Mechanical properties of welded joints in aluminium alloys of the Al‐Cu system. Welding International: Vol. 9, No. 7, pp. 566-569.
TL;DR: In this paper, an investigation of the intergranular corrosion resistance of austenitic stainless steel joints diffusion-bonded with an amorphous insert metal containing 1.5 mass% boron is presented.
Abstract: Summary This paper describes an investigation of the intergranular corrosion resistance of austenitic stainless steel joints diffusion‐bonded with an amorphous insert metal containing 1.5 mass% boron, in order to clarify optimum bonding conditions for austenitic stainless steel pipes joined by a high‐speed diffusion bonding system. The sulphuric acid/copper sulphate test is conducted to evaluate the intergranular corrosion of bonded joints caused by a Cr depletion zone. Joints diffusion‐bonded with lower bonding pressure and shorter bonding time are more sensitive to intergranular corrosion. Under such bonding conditions, Cr boride and Cr carboboride precipitates causing selective corrosion are found in the bonding layer. Joints diffusion‐bonded under higher bonding pressure and with longer bonding time, however, show no intergranular corrosion and few precipitates in the bonding layer. With regard to the B‐containing amorphous insert metal used in the present investigation, the optimum bonding conditions...