SPCC Steel Research Articles

Numerical simulation and testing of laser-MIG hybrid-welding angle-structure sheets.

Numerical simulation and experimental investigation of laser-MIG hybrid angle-welding low-carbon 1.5-mm-thin SPCC steel sheets are presented in this work. The transient simulation analysis provides an access to the thermal-fluid phenomena prediction by employing a hybrid three-dimensional heat source model. Special attention is paid to the melt dynamic behaviors within the triangular molten pool affected by the Marangoni convection. The simulation results show that the temperature and its gradient distribution are symmetrical with respect to the laser beam, which is validated well by the experimental study. The microstructure of the welded joints was analyzed by scanning electron microscopy and transmission electron microscopy. The results show that the cross-section microstructures of welded joint are mainly composed of the weld zone, narrow heat-affected zone, and substrate. The semielliptic-like molten pool shape is consistent with that of the simulated results. The finer microstructure in the weld bead results from the rapid cooling rate of laser welding confirmed by the FEM calculation. The columnar and equiaxed dendrites are formed in the peripheral and central region of the molten pool, which is beneficial for the improvement of the microhardness.

Interfacial microstructure and strength of magnetic pulse welded A5052 aluminum alloy/SPCC steel lap joint

A5052 aluminum alloy and SPCC steel plates were welded using magnetic pulse welding, and interfacial microstructure and strength of the lap joint were examined. The A5052 aluminum alloy and the SPCC steel plates were used for a flyer plate and a parent plate, respectively. Charging energy stored in capacitor and gap between the A5052 aluminum alloy and the SPCC steel plates were changed. Microstructure was examined by using an optical microscope, a scanning electron microscope and a scanning transmission electron microscope. Tensile-shear test was used for evaluating the strength of the joint. The magnetic pulse welding of A5052 aluminum alloy and SPCC steel was achieved at the charging energy above 6.0 kJ and at the gap between the plates above 1.0 mm. The range of charging energy in which the strong welding is accomplished was different at each gap and the range increased with decreasing the gap. The lap joint was not fractured at the welding interface by the tensile-shear test whereas the fracture occurred at a part of the aluminum base metal. The welding interface exhibited characteristic wavy morphology. An intermediate layer was produced along the wavy interface. Scanning transmission electron microscope observation revealed that the intermediate layer is composed of fine Al-Mg grains and dispersed dendritic Al-Fe intermetallic compound particles.

Interfacial Microstructure and Strength of Magnetic Pulse Welded A5052 Aluminum Alloy/SPCC Steel Lap Joint

A5052 aluminum alloy and SPCC steel plates were welded using magnetic pulse welding, and interfacial microstructure and strength of the lap joint were examined. The A5052 aluminum alloy and the SPCC steel plates were used for a flyer plate and a parent plate, respectively. Charging energy stored in capacitor and gap between the A5052 aluminum alloy and the SPCC steel plates were changed. Microstructure was examined by using an optical microscope, a scanning electron microscope and a scanning transmission electron microscope. Tensile-shear test was used for evaluating the strength of the joint. The magnetic pulse welding of A5052 aluminum alloy and SPCC steel was achieved at the charging energy above 6.0 kJ and at the gap between the plates above 1.0 mm. The range of charging energy in which the strong welding is accomplished was different at each gap and the range increased with decreasing the gap. The lap joint was not fractured at the welding interface by the tensile-shear test whereas the fracture occurred at a part of the aluminum base metal. The welding interface exhibited characteristic wavy morphology. An intermediate layer was produced along the wavy interface. Scanning transmission electron microscope observation revealed that the intermediate layer is composed of fine Al–Mg grains and dispersed dendritic Al–Fe intermetallic compound particles.

Investigation of the Preparation, Corrosion Inhibition, and Wear Resistance of the Chromized Layer on the Surfaces of T9 and SPCC Steels.

To improve the corrosion inhibition and wear resistance of materials, the pack cementation method was used to prepare chromized coatings on the surfaces of high-carbon T9 steel and low-carbon SPCC steel. The results showed the formation of a uniform and dense double-layer structure with a thickness of ~10 μm on the surfaces of two different types of steel. The coating layer for T9 steel was mainly composed of Cr23C6 and Cr7C3, while that for SPCC steel was mainly composed of Cr23C6 and Fe-Cr solid solution. Additionally, both of the steels showed different hardness distributions. The hardness measurements of the outer layers of the T9 steel and SPCC steel were ~1737.72 HV and 1771.91 HV, while the hardness values of the secondary layers were 1378.31 HV and 448.52 HV, respectively. The polarization curves in 3.5 wt.% NaCl solution demonstrated the better corrosion resistance of the chromized coating. Chromizing increased the corrosion potential by ~0.2 V and reduced the corrosion current density by one order of magnitude. Under the presence of an 8 N load, the friction factor before and after the chromizing of T9 steel was about 0.69, and the mass wears were 2 mg and 0.6 mg, respectively. Meanwhile, the friction factor of the SPCC steel before and after chromizing was about 0.73, with respective mass wears of 2 mg and 2.9 mg. The wear resistance of T9 steel after chromizing was superior, but it became worse after chromizing for the SPCC steel.

Application of integrated CRITIC and GRA-based Taguchi method for multiple quality characteristics optimization in laser-welded blanks

There is a need to study the multi-objective optimization technique as the appropriate method to enhance welding qualities under optimal process conditions. Therefore, this study investigated the application of the integrated Criteria Importance Through Intercriteria Correlation (CRITIC), which is an objective weighting technique, and the Grey Relational Analysis (GRA)-based Taguchi method to solve multiple criteria optimization problem in the Nd:YAG laser welding process. The Taguchi-based L36 orthogonal array table was employed in this study to optimize six process parameters, including the beam diameter, laser power, flow rate, welding speed, laser offset, and pulse shape, with the aim to simultaneously achieve maximum weld strength and minimum weld width. The base metal JIS G3141 SPCC steel with 0.5 and 1.0 mm thicknesses was used in the present experiment. Following the welding process and optimization, the weld strength was measured using a Cometech QC-506M1 universal testing machine, while the weld width was determined under a Nikon SMZ25 stereomicroscope. Based on the results, the weight fractions of the weld strength and weld width from the applied CRITIC method were equal to 0.4157 and 0.5843, respectively. Meanwhile, the GRA revealed that the process parameters recorded an optimal setting for beam diameter of 0.8 mm, flow rate of 8 L/min, laser power of 0.6 kW, welding speed of 2.5 mm/s, laser offset of 0.2 mm, and pulse shape I. Furthermore, the weld strength and the weld width were enhanced from 236 to 328 MPa and from 1.13 to 1.04 mm, respectively. Additionally, the Analysis of Variance (ANOVA) indicated that the laser power and welding speed were the most influential parameters on the welding qualities. Most importantly, the findings of the confirmation experiment showed that the proposed approach was able to effectively identify the optimal laser welding parameters, which ultimately improved the multiple quality characteristics.

OPTIMALISASI PARAMATER RESISTANCE SPOT WELDING UNTUK PENGELASAN TIGA TUMPUK LEMBAR BAJA SPCC

In the automotive industry, the latest breakthroughs and innovations are strongly influenced bymaintaining and increasing production results so that the use and application of technology is anabsolute must, as is welding technology. Thin sheet-shaped components are found in many car bodies.One of the methods used in joining plate sheets is to use the resistance spot welding method, which is awelding process that is only carried out at a certain point using copper electrodes. In the welding method,maintaining quality in order to produce products and services that can meet the needs and expectationsof consumers related to the product's life time or service. SPCC steel (Cold Roller Stell Sheet) is one ofthe most widely used materials in car body welding applications. The characteristics and mechanicalproperties of SPCC steel from the results of the three-sheet welding were examined using the parametersof welding current, welding time, welding distance. The results showed that the increase in current wouldaffect the diameter of the electrode traces and the nuggets that were formed. The greater the current used,the larger the diameter of the trail, so that the optimum pull-shear load is at a current of 6.5 kA at adistance of 20mm with a value of 365.53 MPa, also the highest hardness value is in the nugget area witha hardness value of 595, 14 HVN at a current of 6.5 kA and from the results of measuring grain diameterin microstructural testing for the HAZ area the best at a welding current of 6.5 kA. Because the smallerthe weld grain diameter, the greater the strength of the weld joint. Then the data from the results of theshear-shear test are analyzed using the Taguchi method, and the most effective parameters in the tensilesheartest with a combination of A (6.5) B (1.5) C (15) and from the experimental results for tensile loads.slide obtained 397 MPa.

Microstructural Evolution and Fracture Mechanism for Scar Defect Formation on Advanced High Strength Steel During a Shearing Process

Abstract To form the required shapes from advanced high strength steels sheets, such as dual-phase (DP) steel, shearing processes are commonly used. In general, although good cut-edge characteristics can be often achieved by setting a small shearing clearance, a scar still remains a major defect on the cut-edge. Therefore, in the present study, the mechanism of scar formation of a DP steel sheet, grade SPFC980Y (JIS) subject to a shearing process was investigated and clarified based on the microstructural evolution, fracture mechanism, and a stress distribution analysis. The microstructural evolution in both tensile test specimens and sheared workpieces were observed to identify the fracture mechanism. The angle between the shear band and the elongated grain flow direction during tensile testing was examined and used to predict the angle of initial fracture and its propagation during the shearing process. With the stress distribution analysis of the shearing zone during the shearing process, the fracture could not propagate into the shearing zone and be directed to the die tip, resulting in the formation of a smooth region again. This feature occurred as a cyclic loop as the punch stroke proceeds and resulted in scar defects in the case of SPFC980Y. However, when the fracture propagation remained in the shearing zone, the fracture was not delayed and fracture was completely generated on the cut-edge in the case of a baseline SPCC steel.

Quantitative evaluation of residual stress and surface hardness in deep drawn parts based on magnetic Barkhausen noise technology

In this study, the method of magnetic Barkhausenn noise (MBN) and tangential magnetic field (TMF) was employed for achieving simultaneous, quantitative prediction of residual stress and surface hardness in box-shape deep drawn parts of SPCC steel. Bi-directional MBN and TMF signals, profiles of surface hardness and residual stress were experimentally measured. Pearson correlation analysis results show that the averaged amplitude of MBN in one magnetization cycle and Root mean square of MBN signal demonstrates approximate linear dependency on residual stress (or surface hardness) in both the measured directions. Three-layer BP models are established after input nodes screening and optimization of neurons’ number in the middle hidden layer. BP models are marked corresponding to scanning or magnetization directions. For each direction, two independent models are established and they are combined to use for realizing high accuracy and simultaneous evaluation of the residual stress and surface hardness.

High-productivity and high-strength Fe/Al dissimilar metal joining by spot forge welding

To develop a high-productivity dissimilar joining technique, which is highly sought after in the automobile assembly process, I developed a new method based on spot forge-welding. In the lap joint of 1-mm-thick SPCC steel and A5083 aluminum plates, within the 10-mm forge diameter, a base metal fracture occurred at a reduction ratio R of 1.8. The maximum tensile-shear load reached 3.8 kN during the approximately 80-ms forge welding process. The newly formed surface at the bonded interface exhibited a mesoscopic reaction layer, in which the brittleness was minimal given the short diffusion time. Thus, this approach shows great potential to replace conventional resistance spot welding for next-generation solid-state spot welding of dissimilar joints, for high-throughput welding applications and high-strength joints.

Optimization of Spot Welding for Peel load on SPCC Steel Sheets

Spot welding is a process of connecting two metal components through one or more connection points by using heat from electrical resistance which is carried by two electrodes to the metal to be connected with a certain welding time. The purpose of this study is to determine the effect of voltage and time of pressure used for spot welding on the shear strength and peel strength on the SPCC plate. The variables used in this study are independent variables of electric current variation of 2.30 V, 2.70 V, 3.20 V and time variation of 3 seconds, 4 seconds, and 5 seconds with 1mm plate thickness. The dependent variable in this study is the calculation of shear strength and peel strength in universal testing machine, and the controlled variable in this study is 1mm plate thickness characteristic of SPCC palate work piece. The research method was carried out using the ANOVA Factorial with the null hypothesis that there was no influence of the spot welding time and voltage on spot welding on the shear strength and strength of the SPCC material's peel. The results of the study are for the shear test seen from the calculation using MINITAB, the time variation of the pressure is no effect, while for the voltage and the combination of time suppression and voltage there is influence. For strength testing, the null hypothesis is rejected for all variations, which means that there is an influence on the strength of the peel test.

Fabrication of clean cut surface on high strength steel using a new shaving die design

A shaving process is commonly applied to achieve a smooth cut surface thorough the workpiece thickness and a square cut-edge, also known as a finishing operation. However, this process is rarely successful for high-strength steel sheets, which is a major problem. In the present study, finite element method (FEM) simulation was used to clarify the main causes of this problem by comparing the shaving mechanisms between medium carbon steel grade SPCC (JIS) and high-strength steel grade SPFH 590 (JIS). Results show that in the case of SPFH 590 based on material flow, stress distribution, and strain distribution analyses, the shaved chip was difficult to form by sliding along the punch face. Moreover, the tensile stress generated in the shearing zone was increased and readily generated cracks. The shaving process was developed in the present study by generating the cutting-edge angle and rake radius on the punch. The cutting edge angle was designed to generate high compressive stress in the cutting-edge vicinity and shearing zone, and the rake radius was designed to tear a shaving allowance off and move it along the rake radius instead of moving downward along the punch movement direction, thereby decreasing the tensile stress in the shearing zone. Under these mechanisms, the increases in the generated tensile stress in the shearing zone could be delayed, and cracks could thus be prevented. The effect of the punch geometry on the cut surface characteristics and cutting forces were also investigated. Laboratory experiments were performed to validate the FEM simulation results. Experimental results agreed well with the FEM simulation results. Therefore, a smooth cut surface thorough the workpiece thickness of high-strength steel sheets could be successfully achieved by using the developed shaving process.

Pseudo linear joining for dissimilar materials utilizing punching and Friction Stir Forming

This study presents a new technique for pseudo-linear joining of dissimilar materials. First, multiple holes on a joined material, such as a steel plate, are pierced with a press or a punching machine. The holes have an inclined surface owing to the breakout angle. The breakout side of the joined material is then brought into contact with a backing plate to enclose the holes. Next, a base material such as an aluminum alloy plate is placed on it, and friction stirring with horizontal tool traveling is conducted on it to fill the holes with the deformed material. Eventually, a pseudo linear mechanical joint is created by the undercut in the holes, which is derived from the shear droop. Herein, the pseudo-bead-width and strength of the joints were investigated with a 3 mm-thick A5083 aluminum alloy plate and a 1 mm-thick perforated SPCC steel plate.

A study on a deep-drawing process with two shaping states for a fuel-filter cup using combined simulation and experiment

In this article, a deep-drawing process using a double-action hydraulic press is examined for its ability to machine the shaping deformation of a fuel-filter cup made from SPCC steel. Many researchers have studied the geometric, physical, and technological parameters of the deep-drawing process. However, most of those studies ignored the optimization parameters of the two shaping deformation states to ensure uniformity of thickness and the disappearance of wrinkling and tearing during machining. In this study, geometric and technological parameters (e.g. blank-holder force, die-shoulder radius, and radial clearance between punch and die) are optimized in both states. The deep-drawing process for a fuel-filter cup is simulated using ABAQUS software, and optimal parameters are determined by applying the Taguchi orthogonal array computation and combining it with an analysis of variance method. The numerical results are then verified with corresponding experiments. The obtained numerical and experimental results show that the die-shoulder radius is one of the most influential parameters affecting the shaping of the cup during the deep-drawing process. Moreover, the influences of technological parameters on the formability of sheet metal are finally analyzed and selected for designing and improving deep-drawing molds.

Characterization of SPCC Steel Stress Behaviour in Brine Water Environment

Characterization of SPCC Steel Stress Behaviour in Brine Water Environment

Friction anchor welding between Al alloy and Zn-coated steel using insert steel difference in the mechanism of friction anchor welding between the types of Zn coatings on Zn-coated steel

ABSTRACTThe lap joints of upper Al alloy sheets (1.0-mm-thick A5052) and lower Zn-coated steel sheets (1.2-mm-thick GI steel or GA steel) were welded using insert steel sheets (0.6-mm-thick SPCC) by a spot welding process with a tool having a spherical ceramic tip, i.e. ‘Friction Anchor Welding.’ As a result, straight (not-rugged) steel projections were formed in the Al alloy sheets for both the GI and GA, while steel projections were not formed for the GI, rugged steel projections were formed for the GA without the insert steel sheets. In addition, the tensile shear strength for the GI was greater than that for the GA. In other words, the tensile shear strengths reached about 3.9 kN/point for the GI and about 3.2 kN/point for the GA, which were greater than those of the welds without the insert steel sheets. On the other hand, the cross tensile strengths for the GI and GA were almost the same, which reached about 2.6 kN/point. Additionally, for the GI, the Zn layer on the GI steel sheet melted and was totally removed due to the pressure and heat caused by the rotating tool, which facilitated the welding between the SPCC and GI steel sheets. For the GA, however, the Zn-Fe layer on the GA steel sheet changed to a solid-liquid mixture and was not completely removed, which prevented the welding between the SPCC and GA steel sheets. Therefore, the thickness of the steel-steel welded region (i.e. the SPCC-GI or the SPCC-GA welded region) for the GI was greater than that for the GA. We estimated that the difference in this thickness is significantly related to the fracture mechanism during the tensile shear test and the cross tensile test.

Study of corrosion behavior on the addition of sodium citrate in nickel electroplating on SPCC steel using EIS

The addition of sodium citrate to nickel electroplating process as additive is useful for refining the grain size of nickel deposit. The refining of grain size in nickel deposit as coating layer can improve surface performance, one of which corrosion resistance. This paper aims to investigate the effect of sodium citrate addition as grain refiner to promote corrosion resistance on SPCC steel. This experiment used Watt’s Bath solution of NiSO4 300 g/L, NiCl4 45 g/L, H3BO3 60 g/L, wetting agent 0.2 cc/L. Sodium citrate was added in composition of 45g/L and 60g/L. Nickel were deposited by direct current using current density on 6 A/dm2 at the acidity level of 5 for 30 minutes by keeping the operating temperature stable at 50°C. The grain size of nickel deposit was observed through Optical Microscope and Atomic Force Microscope (AFM). The corrosion behavior of SPCC was observed by linear polarization and Electrochemical Impedance Spectroscopy (EIS) methods using 3% NaCl solution. Based on the research, the addition of sodium citrate as grain refiner will increasing corrosion resistance on SPCC steel from 0.35 to 0.05 mm/year.

Corrosion Resistance and Mechanical Property Enhancement of SPCC Steel Using an Induction Heat Treatment

Corrosion Resistance and Mechanical Property Enhancement of SPCC Steel Using an Induction Heat Treatment

Effect of abnormal grain growth on microstructure and mechanical properties of friction stir welded SPCC steel plates

Friction stir welded SPCC low carbon steel plates were subjected to isothermal annealing heat treatments at 600, 650, 675 and 700°C for various holding times. All the welds showed abnormal grain growth (AGG) in both the stir zone and the thermal-mechanically affected zone after annealing for a critical time, regardless of the welding condition and annealing temperature. As a comparison, normal grain growth occurred in the base metal. The AGG developed very quickly and finally very coarse grain structure was formed in the joints especially that the extremely large grains propagated from the thermal-mechanically affected zone into the base metal. The steel joints showed a stable D2 {112¯}<111> simple shear texture in the stir zone and the texture did not change during the entire grain growth period, no matter before or after the occurrence of AGG. Due to the AGG, the hardness suddenly decreased in the stir zone and became lower than that of the base metal. The tensile tests also revealed a lower strength in the stir zone of the annealed sample. However, the specimen showed different fracture locations depending on the annealing time.

Production of Tensioner Pulley from Nylon-Glass Fiber Composites

This paper shows the feasibility of replacing the SPCC steel with glass fiber reinforced Nylon composites for the manufacturing of tensioner pulley. Three series of Nylon (Nylon 66, Nylon 46 and Nylon 46 with PTFE) reinforced with 30wt% of glass fiber were investigated. Finite Element Analysis (FEA) was carried out to simulate the stress distribution and to predict the maximum stress located on the pulley component. It was found that all Nylon composites had higher tensile modulus than SPCC steel, while the SPCC steel exhibited higher tensile strength. FEA demonstrated that the maximum stress on Nylon composite pulley was lower than the SPCC steel pulley, however these stresses were higher than yield stress of materials. The addition of supporting rib can reduce the stress concentration to lower the yield stress of materials. Finally the performance of Nylon composite pulley was considered. Pulley with plain-surface bearing was meet the criteria for endurance test, however, the interfacial adhesion between bearing and Nylon composite pulley can be improved by glued and gouged surface. According to the experimental results, glass fiber reinforced Nylon composites can be the representative materials of replacing SPCC steel for tensioner pulley.

Effect of post weld heat treatments on microstructure and mechanical properties of friction stir welded joints of SPCC steel

Effect of post weld heat treatments on microstructure and mechanical properties of friction stir welded joints of SPCC steel