The rate of steel sheet in India and around the world is different and fluctuates every second. Today every popular company and factory introduces us to a website that gives us information like price etc.
High-speed deformation can be very effective in increasing the forming limit of sheet metal and effectively deal with some other common metal forming problems such as wrinkling and deformation. This study investigated the high-speed formability of cold-rolled steel sheets when impacted with a bend.
To study large-area forming, a flat helical electromagnetic coil and an aluminum drive plate were used to electromagnetically fire a steel plate sample under a forming punch at a speed of 50-220 m/s. An estimate of the impact speed was obtained using a high-speed camera.
It was observed that the impact velocity of the samples increased almost linearly with the emission energy. As expected from the yield strength diagrams, the fracture strains for all steels increased significantly and exceeded the strains obtained in the tensile tests. The forming limits for very low and high pseudo static ductility steels are similar for high-speed forming.
Formability appears to be highly dependent on the local boundary conditions dictated by the punch/tool geometry used. The load distribution achieved depends on the shape of the punch used for impact.
Therefore, the quasi-static ductility of the material at high speed impact does not seem to be the most important for the formability of the material.
At high speeds, high breaking strains can be achieved for steels with very low quasi-static ductility. Based on these observations, one may be able to develop significantly improved forming operations that take advantage of this malleability. This enables the use of high-strength, inexpensive materials in many complex parts.
The body’s multi-material structure, which is partly made of aluminum alloy sheets, can be adapted to meet the requirements while improving crash safety and light weight. This article describes the various metal joining techniques required to realize multi-material structures.
In resistance spot welding, high current and short time welding were used to avoid the formation of a brittle Fe-Al intermetallic layer at the joint interface and to study the strength of the joint. In terms of mechanical connection, the application status of SPR, Tog-L-Loc®, TOX® and FDS® methods is outlined, and application examples of blind rivets in automotive bodies are introduced.
In addition to this, the joint strength in the shear direction of the SPR joint for cold-rolled steel and 6000 series aluminum alloy plates is also described. In gluing, it was shown that TSS joint strengths in excess of 20 MPa can be achieved using newer automotive adhesives in a combination of cold rolled mild steel sheets and 6000 series aluminum alloy sheets.
In FSSW, the effect of dwell time, rotation speed and coating on joint strength was elucidated in a combination of Super Dyma® steel plate and 6000 series aluminum alloy plate. In addition, laser brazing has shown that cold rolled or GA mild steel and 6000 series aluminum alloy sheets can be joined using 4000 series aluminum alloy filler (A4043) and fluoride type NOCOLOK® flux.
Finally, combined with the past development process, the future development direction of steel and aluminum alloy dissimilar metal joining technology is explained.
Today, measures are being taken to curb global warming in various fields such as energy, ships, aircraft, railway vehicles, automobiles and household appliances. The same applies to the automotive industry.
An active effort has been made to reduce CO2 emissions by reducing body weight. The most notable of these efforts is the use of high-strength steel sheets (590 to 1,470 MPa) for automotive components. ) A large number of high-strength steel plates have been applied to not only reduce the weight of the vehicle’s body, but also improve its crashworthiness. Efforts to further reduce vehicle body weight by making the most efficient use of high-strength steel plates are expected to continue in the future.
However, given the required stiffness of each element, there is a limit to reducing weight by using thinner steel sheets. If further weight reductions of 30% or more are required in the future, it will be necessary to develop and implement multi-material structures partially composed of lightweight materials. )
Various methods of joining materials have been proposed, including fusion welding (eg resistance spot welding, resistance seam welding, arc welding), solid state joining (eg explosion welding, friction welding, electromagnetic welding, seam welding, diffusion welding).
soldering (eg torch soldering, arc soldering, laser soldering), mechanical joining (eg self-piercing riveting (SPR), TOX®, flow drill screws (FDS®), blind riveting) and bonding agent.) In addition, bonding methods using coatings or inserts have been investigated.
For any bonding method that requires high temperatures, a brittle layer of intermetallic compounds (IMC) forms at the bonding interface, making it difficult to achieve the desired bond strength. Therefore, the first concern in practice is mechanical methods that do not form this unwanted IMC layer.
steel sheet rate today in India
the procedure of steel sheet making and the rate of production today in India is very different and as you know when two dissimilar metals come into contact, differences in their ionization tendencies can lead to corrosion at the interface. To prevent this, attempts have been made to combine mechanical bonding with adhesives.)
This method was put into practical use before other joining methods and is still widely used.) can also suppress the formation of brittle IMC layers by using solid bonding.
Therefore, friction welding and friction stir spot welding (FSSW) have been used for propeller shafts) and hatchbacks respectively. Therefore, various methods have been developed for joining steel sheets and aluminum alloy sheets, which were previously considered difficult.
With the recent strong demand for lighter bodywork, the need for this joining method has again increased. Spot welding, mechanical joining, bonding, FSSW, and laser brazing are considered particularly promising techniques for joining steel and aluminum alloy sheets; therefore, we describe here recent research on these materials and their use in actual cars.
spot welding
Highly brittle IMC at the interface during welding becomes a problem in spot welding of steel and aluminum alloy plates.) The presence of this material reduces joint strength, especially cross-tensile strength (CTS). For today’s automotive bodies, the most common joining method is a combination of mechanical joining and adhesive joining. ) In this section, spot weldability and joint strength are checked by combining a 0.8 mm thick galvanized (GA) mild steel plate and a 1.0 mm thick 6000 series aluminum alloy plate.
Ultrasonic welding of SS400 low carbon steel plate and magnesium aluminum alloy plate (A5052). In this study, the authors investigated the effects of ultrasonic welding conditions on the mechanical properties and interface microstructure of the joints, as well as the effect of embedded metal on the improvement of joint strength. The main results obtained in this study are as follows.
SS400 mild steel plate can be ultrasonically welded to an A5052 aluminum alloy plate containing magnesium. The strength of the welded joints with different clamping forces and a constant welding time of 1.0 s showed a maximum value at a clamping force of 588 N and decreased when the clamping force exceeded 588 N, because excessive clamping force reduced the strength at the interface.
Friction effect The joint strength welded with a constant clamping force of 588 N and different welding times showed a maximum value at a welding time of 2.5 s. However, the strength of the joint welded with the 3.0 s welding time decreased due to the formation of Fe2Al5 intermetallic compounds at the interface.
By using the insert metal of commercially pure aluminum, the joint strength was successfully increased, and the weld strength using a 3.0 s welding time was approx. 3 times the size of the metal assembly without the insert.
These products have many more features. Body weight reduction and crash safety are two important goals for body design and improvement. In order to reduce vehicle weight without compromising crashworthiness, a method has been proposed to replace body component material from low-carbon steel plate to high-strength steel plate with reduced depth.
The depth reduction equations were derived from mechanical analysis and verified by finite element simulations of body parts colliding with rigid walls.
According to the equation proposed in this paper, the depth of several parts that mainly absorb impact energy is reduced, and the simulation results of the car crashing into a rigid wall show that the method proposed in this paper, is efficient.
steel sheet rate today
One of the most sensitive features of the plate forming process and steel sheet rate today is the elastic recovery during unloading, called rebound, which causes some geometric changes in the product.
Rebound refers to the elastic recovery that occurs during unloading and is one of the most sensitive aspects of today’s plate-forming process and steel sheet rate. Rebound is responsible for some of the geometric changes that occur in the final product.
This phenomenon influences the bending angle as well as the bending curvature, and it is influenced by a number of different elements. Experiments and numerical simulations were used in this research to evaluate the impacts of significant parameters on the recoil bending of CK67 anisotropic steel U-die and V-die.
The results of these investigations are presented below. In addition to this, a comparison of the data obtained from experiments and those obtained from finite element simulations was carried out. The rotational power loss for non-oriented oriented silicon steel sheets has been measured under various rotational flux conditions.
Several methods have been proposed for this purpose. Among them, the method based on the measurement of the field quantities B/sub x/, B/sub y/, H/sub x/ and H/sub y/ seems to be the most convenient method. sample related.
In this method, the rotational power loss P/sub r/ is measured as the torque loss due to the offset angle between the H and B vectors caused by the rotating field. Using this method, the effects of the axial ratio of the rotating magnetic flux component and the slope of the field strength relative to the sample’s rolling direction on the rotating power loss are investigated.
Compare this loss with the regular loss shown as the sum of the loss P/sub t/ in the x and y directions. P/sub t/ (conventional rotational loss) for a non-oriented steel plate is greater than P/sub r/, but P/sub t/ for a grain-oriented steel plate is less than P/sub r/.
The rotational power loss is minimized when the field strength is applied to the non-oriented plate at an angle of 45 degrees to the plate’s rolling direction.
Non-oriented 6.5 wt% Si electrical cast steel strips with equiaxed microstructure were fabricated using double-rolled strip casting methods and then subjected to hot, hot rolling and annealing treatments at different reduction ratios.
The results show that when the hot rolling reduction exceeds 52%, the as-cast microstructure gradually pancakes and then undergoes dynamic and static recrystallization.
Subsequent hot rolling produces shear bands in partially deformed grains. The texture evolution of multiple roll paths is basically consistent with the classic reinforcement-oriented rotation path. The decrease in hot rolling reduction accompanied by an increase in hot rolling reduction increases the number of shear bands in the hot rolled sheet and reduces the annealed grain size.
Improper combinations of hot-rolling and hot-rolling reductions tend to give γ-nuclei numerical dominance through grain boundary or shear band nucleation, resulting in the appearance of γ-annealed texture.
In contrast, alternative rolling regimes of moderate heat (~50%) and hot (~70%) reductions promote λ, {1 1 4} <4 1> and many others in the shear band Oriented nucleation of non-γ nuclei {2 2 3} <1 1 0> deformed grains have achieved high volume fractions in hot-rolled sheets.
A mixed λ, α* and γ annealed texture is thus formed, which improves the magnetic properties. The combined directional nucleation and directional growth mechanisms are responsible for the overall evolution of the annealed texture.
Non-oriented (NO) 6.5 wt% Si electrical steel has high magnetic permeability, low mid-high frequency iron loss, and near zero magnetostriction. Therefore, the core material made of NO 6.5 wt% Si electrical steel is beneficial for energy savings and noise reduction.
However, the limited formability due to the solid solution and order-enhancing effects caused by excessive Si content and the formation of Fe-Si covalent bonds limit its large-scale commercial application.
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