Bevel Groove Research Articles

The Effects of Undercut Depth and Length on Weldment Mechanical Properties

Undercutting is a fusion welding defect that appears as a groove at the weld metal's toe. An undercut discontinuity forms when welding, particularly when the current is applied at an extremely rapid rate. It decreases the static and fatigue strength of the weld and produces stress concentration at the welding zone. The height of the reinforcement, the weld bead's contact angle, the undercut's breadth, depth, length, and root radius, as well as other factors, affect the stress concentration factor's size. In this study, two mild steel plates with a 20 mm thickness were welded together using gas metal arc welding. Each test plate was machined to have a 30° single bevel groove angle prior to welding. The butt welded plate underwent radiographic NDT testing. A weldment free of defect was created. The weldment was machined into typical test specimens for tensile strength. An undercut defect was simulated by drilling a groove through each tensile test sample. Grooves had different depths and lengths. After that, samples were put through a tensile test. The test findings allowed for the identification of the impacts of groove shape on tensile strength, ductility, and static stress concentration factor.

The effect of weld groove variations on the toughness of welding joints of AISI 1050 material

SMAW (Shielded Metal Arc Welding) welding is a metal joining process that uses heat energy to melt the workpiece and electrode (fill material). The flux material used for type E7016, a low hydrogen electrode wire typically used for welding heavy-duty plates and structures. Its use is for welding medium carbon steel, bridges, ships and machinery. The result of welding electrode E7016 is very smooth, deep penetration, crack resistant, ductile, good weld appearance and stable arc, the material used in the SMAW welding process is AISI 1050 steel. While AISI 1050 steel is steel that has a carbon content of 0.50 % so that it is classified as medium carbon steel. This steel is widely used in the market because it has many advantages, one of which is as an automotive component. This steel has the characteristics of good machinability, good wear resistance and medium mechanical properties. This study aims to determine the shock strength (impact) and the difference in the time of making weld grooves on SMAW welding results on AISI 1050 steel with variations of Double Bevel and Double V Groove grooves. In testing in the Weld Metal area with a current used of 110 Ampere. From the tests that have been carried out, it is known that the value of the highest impact strength is in the Double Bevel groove which has a value of 1.91 Joule/mm2, for the manufacture of welded grooves where the Double Bevel time is shorter than Double V Groove, so the time produced by Double Bevel which is 3.44 minutes/second.

Effect of Single Bevel Groove Geometry on the Impact Strength of Dissimilar Welded Joint of P22 and P91 Steel

The dissimilar combination of 2.25Cr-1Mo (P22) and modified 9Cr-1Mo (P91) obtained using Gas Tungsten Arc Welding (GTAW) process employing the Ni-based superalloy filler ERNiCr-3 (IN82) and ERNiCrMo-3 (IN625) have been investigated for microstructure evolution and mechanical properties. The butt weld joint was produced using single bevel groove geometry. The structural integrity of the welded joint was measured in respect of tensile strength, impact toughness and hardness. The alloying elements’ segregation at the inter-dendritic areas of the weld metal was witnessed while using the IN82 and IN625 filler. The impact test trials showed the mixed mode of fracture with an impact toughness of 82 ± 6 J and 70 ± 5 J for IN82 and IN625 filler, respectively, ensuring that the welded joint was safe for the end boiler application. The tensile test coupons were fractured from the P22 base metal in all the trials and for both the fillers which confirmed the negligible effect of the filler composition on the tensile properties. The hardness plots showed the inhomogeneity in hardness value, which was also supported by the microstructure evolution along the weldments. The average hardness of the IN82 filler was measured lower than the IN625 filler.

Effect of welding parameters on the mechanical and metallurgical properties of armor steel weldment

The effect of welding parameters on the mechanical and metallurgical properties of armor steel weldment was studied using gas tungsten arc welding process with two filler wires: carbon steel and austenitic stainless-steel filler wires (AWS A5.18 ER 70S-6 and AWS A5.9 ER 307, respectively). The joint configurations were mainly single V and single bevel grooves. Using both AWS A5.18 ER70S-6 carbon steel filler wire and AWS A5.9 ER307, austenitic filler wire for the two joints passed the required tensile strength by the military standard. The joints successfully regained the base metal hardness at a distance of less than 15 mm. The ultimate tensile strength of the joints welded in a single bevel groove is 906 MPa which is higher than the joints welded using a single V groove is 865 MPa. This could be attributed to the increase in dilution percentage with the single bevel joints. Both single V joint and single bevel joints passed the required Charpy V-notch impact test whether using both carbon and stainless-steel wires. The effect of heat input and cooling rate on the mechanical and microstructure of welded joints was studied. The reduction of heat input caused a narrow HAZ with a small reduction in its hardness values with much reduction in the width of softening microstructure zone. SEM observations show that the base metal has a martensitic structure, but the weld metal microstructures depend on the filler: carbon steel or austenitic steel types. Using a single bevel groove with an austenitic steel filler metal, the weld metal shows a martensitic/austenitic microstructure by SEM observation, and this was verified by the Schaeffler diagram which showed a high dilution percentage (about 35% dilution). This resulted in a significant increase in joint strength and a higher weld metal impact resistance.

Multiple weld seam laser vision recognition method based on the IPCE algorithm

Robotic weldingis a critical technology in manufacturing. Vision sensor is critical for increasing the flexibility and adaptability of robot welding, and the line-structured laser(LSL) visionsensor, in particular, is a long-standing research hotspot in robot intelligent welding.The key technology of the LSL vision sensor used in robot welding is the weld seam recognition algorithm.However, the common weld seam recognition algorithm is hampered by heavyarc and spatter noise during welding. Furthermore, many common weld seam recognition methods can only recognize specifictypes of weld seams and have limitations in terms of flexibility and robustness. To overcome thesechallenges,in this paper, we present a fast, accurate, and robustmultiple-type weld seam recognition algorithm.The algorithm consists primarily of our proposed dynamic ROI method, local adaptive threshold method, internal propulsioncenter extracting(IPCE)algorithm, a weld seam edge point detection operator, and a center analyzing method. Experiment results show that the proposed algorithm can recognize multiple types of weld seams, including I-groove butt weld seams, V-groove butt weld seams, single bevel groove butt weld seams, lap weld joints, etc., even in the presence of heavy arc and spatter noise.

In-process monitoring of welding quality by robotic laser ultrasonic measurement system using microchip laser

ABSTRACT Laser ultrasonic technique (LUT) is applicable even in a high temperature state such as during welding because the laser is irradiated remotely without contact. Recent studies have reported that LUT is applicable during welding, and it is effective for in-process monitoring. However, in the previous studies, there was a problem with the portability of the measurement device especially in a generation laser, so the scope of its application was limited. In this study, we constructed a robotic measurement system of laser ultrasonic with a small microchip laser mounted on a robotic arm. Microchip laser, which is a prototype product (1064 nm, 20 mJ/pulse, 1.5 ns, 20 Hz), was used to generate ultrasonic, and a laser interferometer (532 nm, 1 W) was used to detect the surface micro-vibration caused by the arrival of ultrasonic wave and was scanned using an uniaxial stage. After acquiring the B scope, which is composed of a generation point and multi-detection points, the synthetic aperture focussing technique (SAFT) is applied. SAFT image obtained by in-process measurement was evaluated to confirm the presence or absence of welding defect indication. Then, during gas metal arc (GMA) welding process in the mid-pass of a multi-layer welding for a single bevel groove, we attempted to detect welding defects generated by introducing slits before welding. As a result, in the second pass, defects were indicated in all areas where defects existed, and no indications were found in areas without defects. Therefore, it was shown that the robotic laser ultrasonic measurement system constructed in this study can detect defects in the process of welding. In conclusion, we were able to show the possibility of evaluating the welding quality in the process of welding even at the construction site by selecting the appropriate generation position and detection range according to the required accuracy and laser specifications.

In-process monitoring of welding quality by robotic laser ultrasonic measurement system using microchip laser

Laser Ultrasonic Technique (LUT) is applicable even in a high temperature state such as during welding because the laser is irradiated remotely without contact. Recent studies have reported that LUT is applicable during welding and it’s effective for in-process monitoring. However, in the previous studies, there was a problem with the portability of the measurement device especially in a generation laser, so the scope of its application was limited. In this study, we constructed a robotic measurement system of laser ultrasonic with a small microchip laser mounted on a robotic arm. Microchip laser, which is prototype product (1064nm, 20mJ/pulse, 1.5ns, 20Hz), was used to generate ultrasonic, and a laser interferometer (532nm, 1W) was used to detect the surface micro vibration caused by arrival of ultrasonic wave and was scanned using a mechanical stage. After acquiring the B-scope, which is composed of a generation-point and multi detection-points, the synthetic aperture focusing technique (SAFT) is applied. SAFT image obtained by in process measurement was evaluated to confirm the presence or absence of welding defect indication. Then, during Gas Metal Arc (GMA) welding process in the mid-pass of multi-layer welding for a single bevel groove, we attempted to detect welding defects generated by introducing slits before welding. As a result, in the second pass, defects were indicated in all areas where defects existed, and no indications were found in areas without defects. Therefore, it was shown that the robotic laser ultrasonic measurement system constructed in this study can detect defects in process of welding. In conclusion, we were able to show the possibility of evaluating the welding quality in process of welding even at the construction site by selecting the appropriate generation position and detection range according to the required accuracy and laser specifications.

In-situ measurement of weld quality during MAG welding using laser ultrasonic

ABSTRACT Laser ultrasonic technique (LUT) is applicable for measurement under high temperature condition because of the non-contact and remoteness. In this study, LUT was applied to detection the welding defect such as solidification crack and/or lack of penetration at single bevel groove during Gas Metal Arc (GMA) welding process. Nanosecond pulse laser (1064 nm, 60 mJ/pulse 100 Hz) was used to generate ultrasonic, and was scanned using a galvanometer mirror. Nd:YAG laser interferometer (532 nm, 1 W) was used for detection the surface micro vibration caused by arrival of ultrasonic wave. After acquiring the B-scope, which is composed of multi transmit- and receive-points, the synthetic aperture focusing technique (SAFT) is applied. SAFT image obtained by in-process measurement was evaluated to confirm the presence or absence of welding defect indication. As a result, it was possible to indicate the solidification crack and the lack of penetration in the joint even during the welding process. Furthermore, it was able to indicate the penetration depth change (2 mm difference) due to the welding condition change during process. These results suggest that in-process measurement using LUT is very effective technique for detecting weld defects.

Fracture resistance of incisal tooth fragment reattached with different adhesive materials and retentive techniques

OBJECTIVE: This study evaluated in vitro the shear bond strength of experimentally fractured human tooth fragments reattached with different adhesive materials and retentive techniques.METHODS: Forty-eight sound mandibular incisors were randomly divided into 6 groups (n=8). Their incisal edges were cut off in 5 groups, representing an enamel-dentin fracture. Intact teeth were used as control (Group 1). The fragment edges were reattached with adhesive system (Scotch Bond Multipurpose – 3M ESPE) (Group 2), adhesive system and composite resin (ICE – SDI) (Group 3), adhesive system and composite resin with circumferential bevel (Group 4), adhesive system and composite resin with internal dentin groove (Group 5), and adhesive system and composite resin with the circumferential bevel and internal dentin groove (Group 6). Shear bond strength was determined in a universal testing machine. Fracture modes were identified by light microscope. Kruskal-Wallis was used to analysis resistance to fracture and fracture patterns.RESULTS: The results showed statistically significant differences (p<0.05) among groups. The intact teeth (Group 1) showed higher fracture resistance than the other groups. Groups 2 and 6 did not differ and were statistically superior to other techniques. Group 4 presented statistically higher than in Group 5, which in turn was more resistant than Group 3.CONCLUSIONS: None of the fragment reattachment techniques was able to achieve the strength of sound teeth. Fragments reattached only with adhesive system or with adhesive system and composite resin with the circumferential bevel and internal dentin groove showed the best performance for resistance to fracture.

Microstructure and Stress Distribution Analysis of T-Joint of Clam Steel

The microstructure and stress distribution on T-joint of China Low Activation Martensitic steel was investigated in this research. Two kinds of grooves, single bevel groove and K groove, were prepared to study the residual deformation of T-joint. Microstructure and microhardness distributions along web plate on K groove sample were detected. The distributions of the longitudinal and transverse residual stress on T-joint were simulated by a finite element model, residual deformation process of T-joint was discussed. All the results indicate that tempered martensite are found in the weld metal and heat affected zone on web plate and flange plate. The obvious residual deformation can be observed in two kinds of T-joint sample. According to the results of numerical studies, transverse residual stress is tensile stress at middle section of weld joint and pressure stress at start and end section of weld joint, the longitudinal residual stress is tensile stress along the welding direction.

Low cycle fatigue assessments of corner welded joints based on local strain approach

Low cycle fatigue strengths of corner welded joints with single bevel groove welding were studied. Low cycle fatigue tests were performed with three types of specimens which have different sizes of weld root face. The test results indicated that the low cycle fatigue strength of the corner welded joints strongly depends on the weld root size. Then, the fatigue strength of the corner joints was evaluated based on the effective notch strain at the weld root tip which was calculated by elasto-plastic finite element analyses. A unique relationship between the effective notch strain and the fatigue life of the joint was observed regardless of the weld root size. Therefore, it was revealed that the effective notch strain approach is applicable to evaluate the low cycle fatigue strength of the corner welded joints.

A judicious restorative approach for management of fractured anterior tooth: Report of three cases

Anterior crown fractures are common form of traumatic dental injuries that mainly affect the maxillary central incisors, in children and teenagers. During their first dental visit, these patients with trauma are quite apprehensive because of impaired functions, esthetics and phonetics. The advances in adhesive dentistry have allowed dentists to use the patient's own fragment to restore the fractured tooth if the fragment is available. Reattachment is such an ultraconservative technique which provides safe, fast, and esthetically pleasing results with immediate restoration of function and phonetics. This paper discusses three cases in which fragment reattachment was done using a different combination of techniques viz. simple reattachment, circumferential bevel and internal dentinal groove.

25度レ形狭開先における組立溶接と本溶接初層の施工条件範囲

25度レ形狭開先における組立溶接と本溶接初層の施工条件範囲

Treatment regime for crown fractures: Autogenous tooth fragment reattachment – A case series

Abstract Maxillary crown fractures are most common form of traumatic dental injuries that mainly affect the maxillary central incisors, in children and teenagers. The improvement in adhesive dentistry has allowed dentists to use the patient's own fragment to restore the fractured tooth, if the fragment is available. Reattachment is such an ultraconservative and advanced technique which provides safe, fast, and aesthetically pleasing results with immediate restoration of function and phonetics. This article describes few cases in which fragment reattachment was done using different combination of techniques viz. simple reattachment, circumferential bevel and internal dentinal groove. How to cite this article Nagaveni N. B, Bajaj M, Lobo N, Poornima P. Treatment regime for crown fractures: Autogenous tooth fragment reattachment - A Case Series. CODS J Dent 2015;7: 96-99.

Biological approach for management of anterior tooth trauma: Triple case report

Anterior crown fractures are a common form of injury that mainly affect children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure, and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient's own fragment to restore the fractured tooth. Three cases are presented here with complicated crown fracture of maxillary central incisors; the reattachment of the fractured tooth segment in these cases has been performed using different combinations of techniques, viz. simple reattachment, circumferential bevel and internal dentinal groove.

Biological approach for management of anterior tooth trauma: Triple case report

Anterior crown fractures are a common form of injury that mainly affect children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient's own fragment to restore the fractured tooth. Three cases are presented here with complicated crown fracture of maxillary central incisors; the reattachment of the fractured tooth segment in this case has been performed using different combinations of techniques, viz. simple reattachment, circumferential bevel and internal dentinal groove.

Reply to discussion by S. Guravich and S. Skarborn on “Double-angle shear connections with short outstanding legs”Appears in the Canadian Journal of Civil Engineering, 35(8): 786–795.

The authors thank S. Guravich and S. Skarborn for their thoughtful discussion. First, the authors would like to emphasize that while the bending of the outstanding legs is a significant contributor, it is not the only source for the rotational ductility of double-angle shear connections. Shortening of the outstanding legs does reduce the rotational capacity of the connections. However, for the tested connections in the study, they still possessed a rotational capacity at the level of 0.03 radians. As pointed out by S. Guravich and S. Skarborn, column face widths less than 203 mm may be affected. The paper gave 152 mm as a column face width that would definitely create the problem rather than may create the problem. For face width 203 mm, the fillet welds can often run onto the corner radius of the hollow structural section column to eliminate the need for shortening the outstanding legs. The initial thought for group C specimens to adopt filled flush flare bevel groove welds (FBGW) was to reflect such a fact that ‘‘in general, there is a tendency for flare groove welds to be oversized and filled flush’’ (quote from Packer and Frater 2005). This tendency was likely due to the following two reasons: (1) the CISC Handbook (CISC 2006) only listed filled flush for flare bevel and flare V-welds in its Welding Practice in Part 6; and (2) the concept of a flare bevel fillet weld was introduced for the first time only recently in CSA W59 (Packer, and Frater 2005) and in Supplement No.1 (January 2005) to CSA-S16-01 (CISC 2006). Some extra work on the FBGWs was reported by the first author in a subsequent paper (Gong 2008). For the tested connections, the average corner radius was 22 mm, which was considerably less than the maximum value 36 mm given by the CISC Handbook. The subsequent study found that the weld face width was a better characteristic dimension than corner radius to predict the effective throat of the FBGWs. The authors believe the groups A and B specimens, which used fillet welds, also provided useful information for the design of FBGW using unaltered outstanding legs. For example, corresponding to 6 mm fillet weld, the required effective throat for FBGW is 4.3 mm. To avoid further stress concentration, a weld return can be made at the top of the angles and then ground. In addition, the designer has the option to increase the effective throat of the FBGW. The unique merit of the unaltered outstanding leg is that it is able to provide extra space for stronger FBGW, if necessary. The authors agree that the paper would have been enhanced if additional connections using smaller size flare bevel fillet welds had been tested. The authors will consider doing additional testing subject to financial support being available. As for other preferred solutions, such alternative connection types were beyond the scope of the paper.

Double-angle shear connections with short outstanding legs

This paper describes an experimental study on double-angle shear connections with a narrow outstanding leg width from 31 to 37 mm. When connection angles are welded to a supporting column with a face width less than 152 mm, a common practice is either to weld the angles to the column by flare bevel groove welds or shorten the outstanding legs to accommodate fillet welds. This practice reduces the rotational capacity of the connections; and therefore confirmation of this practice is required. Three groups, comprising 12 full-scale connection specimens, were tested. Each group consisted of four specimens having three, four, five, and six bolts, respectively. Group A used 9.5 mm thick angles and fillet welds, group B used 6.4 mm thick angles and fillet welds, and group C used 9.5 mm thick angles and flare bevel groove welds. The test results demonstrated that both rotational and shear capacities of the connections are satisfactory when either of the two details are used.

Double-angle shear connections with small hollow structural section columns

This paper describes an experimental study on double-angle shear connections when used with small-size hollow structural section columns. Twelve connection specimens were tested to confirm the practice of either fitting the connection angles to the narrow column face by shortening the outstanding legs or by employing flare bevel groove welds. Test results demonstrated that both rotational and shear resistances of the connections were satisfactory when either of the two details was used. In the meantime, the flare bevel groove welds, made by a gas metal arc welding process, were also tested for the purpose of determining their effective throat.

ワンビード溶接法によるHAZ靱性評価法の考察

The engineering method for fracture toughness evaluation of beam-to-column weld HAZ using one-bead welds, called one-bead weld method, has been examined in this study. Materials used are 26 structural steels of 400 to 490 MPa strength class produced by different milling conditions. One-bead welds are made by CO2 arc welding with single bevel groove under heat inputs of 4.0 to 5.0 kJ/mm. From these welded joints, the Charpy specimens and 3-point bend CTOD specimens with the same thickness of 10mm are extracted. The notch is located at the weld HAZ on a straight bond side perpendicular to the plate surface. Charpy tests and CTOD tests are carried out at 0°C and -40°C, respectively, where the CTOD test temperature is determined on the basis of WES2808 correlation formula. It has been found that the Charpy absorbed energy is affected by the chemical composition of the base steel, such as C, Mn, P, S, N, and Ti. Based on similar test results, an engineering parameter, fHAZ, is proposed by the Building Center of Japan for estimating the HAZ toughness. However, the present study indicates that the total amount of N is not a proper measure, but the free N controls the HAZ toughness. From the fracture mechanical point of view, the correlation between the Charpy energy and the critical CTOD is useful. It is noted that the CTOD test results are sensitive to the length of CGHAZ along the crack front. The Charpy-CTOD correlation with respect to the HAZ toughness should be made with attention to the base-metal chemical compositions as well as the CGHAZ size along the crack front.