51results about "Elongation control device" patented technology

This invention discloses a short-process bar rolling method and system. The method includes the following steps: S1, heating the billet in a heating furnace; S2, descaling with high-pressure water; S3, completing eight rolling passes in rolling zone one; S4, performing multiple-length segmentation with a first flying shear; S5, performing four rolling passes in rolling zone two; S6, performing multiple-length segmentation with a second flying shear; S7, performing diameter reduction rolling on the bar using a KOCKS mill; S8, a third flying shear; S9, water cooling; S10, cooling; S11, shearing the bar to length; S12, finishing and annealing; S13, magnetic flux leakage testing. This invention can meet the requirements for bar shape and size as well as the requirements for flaw detection, achieving integrated bar heating, controlled rolling and cooling, and flaw detection while saving space. This invention can reduce the number of traditional bar rolling passes, realizing short-process bar production with small space requirements, low power consumption, customization, greenness, and low carbon emissions.

The invention discloses an elongation switching control method when a strip steel welding seam passes through a tension withdrawal and straightening machine. The method comprises the steps that a tension amplitude limiting model with the sectional area of strip steel as an independent variable is established; an interval automatic switching control mode is adopted for the elongation rate of the tension withdrawal and straightening machine equipment; and constructing an elongation switching interval model taking the thickness of the strip steel as an independent variable. According to the invention, the stability of unit operation can be improved, the labor intensity of operators is reduced, and the accident of strip breakage of strip steel welding seam over-tension withdrawal and straightening machine equipment is avoided.

This invention discloses a method for controlling the overall quality of thin-gauge ultra-high-strength steel plates, belonging to the field of steel plate production. It includes the following steps: 1) Heating: The slab is fed into a heating furnace for heating; 2) Rolling: Rolling is performed using a 2-stand roughing mill and a 7-stand finishing mill hot continuous rolling mill; 3) Cooling: After rolling, the slab undergoes three-stage cooling: ultra-rapid cooling, air cooling, and water cooling, followed by coiling after water cooling; 4) Tension straightening: The coiled steel, cooled to room temperature, is sequentially uncoiled, laser-welded, and tension straightened; 5) Pickling: After tension straightening, the strip is pickled using a three-stage continuous hydrochloric acid pickling process; 6) Leveling: After pickling, the strip is rinsed, dried, and then leveled online. This invention effectively improves the overall quality of steel plates and solves the problems of poor surface quality, large fluctuations in mechanical properties, and difficulty in shape control in phase transformation strengthened thin-gauge ultra-high-strength hot-rolled steel plates.

The application discloses a rolling force slope setting method of a continuous annealing and skin pass mill, wherein a slope setting, a difference between a lower limit of an elongation setting value and an actual elongation value, a rolling force of a welding seam and a preset rolling force of a current coil are taken as setting inputs of a slope generator; the slope setting is determined according to a yield strength σ s of the strip steel; different slope settings are set according to different conditions; when the welding seam is located at a specified position of an inlet of the continuous annealing and skin pass mill, the slope generator starts a rolling force falling calculation process; and when the welding seam is located at a specified position of an outlet of the continuous annealing and skin pass mill, the slope generator starts a rolling force rising calculation process. The application can guarantee the elongation index of the continuous annealing product and the surface quality of the continuous annealing product.

The application provides a tempering method suitable for an acid pickling line, comprising the following steps: step S1: calculating actual elongation rate by using a laser speed meter and a thickness gauge to respectively measure the front and rear speed and the front and rear thickness in real time; step S2: performing elongation rate closed-loop control according to the actual elongation rate measured in real time by taking the rolling force as an adjusting amount; step S3: performing compensation on the rolling force to eliminate the elongation rate fluctuation caused by acceleration and deceleration of the unit; and step S4: performing feedforward control by using the thickness deviation measured by the front thickness gauge to suppress the elongation rate fluctuation. The application also provides a tempering system and device suitable for the acid pickling line and a medium. The application realizes the tempering function of high-precision elongation rate closed-loop control by using the last stand in the acid pickling line, widens the use function of the acid pickling line, and improves the surface quality and material performance of the product.

The invention belongs to the technical field of special-shaped forge piece manufacturing, and particularly relates to a rolling device and method for a hard-to-deform high-temperature alloy high-pressure compressor casing forge piece. The device comprises a base, a workpiece clamping driving mechanism, a core roller, a driving roller and a connecting rod, the workpiece clamping driving mechanism comprises a plurality of stand columns arranged on the base in the circumferential direction, the stand columns can move in the radial direction, the side wall of each stand column is provided with an upper pressing roller and a lower supporting roller which can ascend and descend and rotate around the axis of the upper pressing roller, and the lower supporting rollers are used for lifting ring blanks; the upper compression roller is used for outputting constant pressure above the ring blank; the core roller and the driving roller are rotationally installed on the base and clamped on the inner side and the outer side of a ring blank respectively, the top of the core roller and the top of the driving roller are hinged through a connecting rod, and rotating generatrixes of the core roller and the driving roller are matched with generatrixes of the ring blank and a forge piece from top to bottom respectively. According to the method, the material utilization rate is increased, the machining period is shortened, and the method is suitable for rolling of high-pressure compressor casing forgings made of nickel-based high-temperature alloy and other difficult-to-deform materials.

The invention provides a brass-aluminum-brass composite material and a preparation method and application of cold compositing of the brass-aluminum-brass composite material, the preparation method comprises the steps that brass, aluminum and brass are subjected to solid-solid cold composite rolling, a first intermediate composite material is obtained, the thickness ratio of the brass, the aluminum and the brass is 1: (1-8): 1, the solid-solid cold composite rolling is single-pass rolling, and the reduction rate of the single-pass rolling is 50%-70%; then diffusion annealing treatment is conducted, the temperature of the diffusion annealing treatment ranges from 350 DEG C to 480 DEG C, and the time ranges from 2 min to 10 min; and finally carrying out cold rolling treatment to obtain the composite material with the target thickness. An interlayer surface oxidation film of the two metals is extruded and broken through 50%-70% of pressing deformation; an intermetallic compound layer is formed at the joint of two layers of metal through control of a diffusion annealing process, so that the bonding strength between the metal layers is improved. The composite material is high in interlayer bonding strength, and compared with brass, the heat-conducting property is improved, the density is lower, and the electrical conductivity is good.

The invention discloses a high-strength steel hot rolling leveling process, which relates to the technical field of metal rolling and comprises the steps of tapping temperature control, hot coil box relaxation, finish rolling temperature control and segmented cooling relaxation. By controlling the tapping temperature, the residence time of an intermediate billet, the finish rolling temperature and rapid cooling, temperature returning and relaxation in the segmented cooling process and combining specific chemical component design, the crack problem caused by the internal and external temperature difference in the rolling process is effectively avoided, and formation of a brittle phase and a soft phase is restrained. The obtained high-strength steel mainly comprises fine lath bainite, has the comprehensive performance of high strength, high toughness and high ductility, and is suitable for the field of high-end structural materials.

According to the method for improving the surface energy of the high-chromium ferritic stainless steel, the surface energy of the high-chromium ferritic stainless steel is remarkably improved through combined control over the procedures of hot-rolled coiled plate pickling annealing, cold-rolled rolling, cold-line pickling annealing, leveling and the like, the surface energy can reach 44 N / m or above, and the purpose of improving the wettability of the surface of the stainless steel is achieved; and the stainless steel surface easy to coat is obtained.

The application discloses a preparation method of a large-diameter seamless gas cylinder pipe and relates to the field of seamless steel pipe manufacturing. The preparation method of the large-diameter seamless gas cylinder pipe comprises the following steps: continuous casting blank heating, plug-type piercing, precision rolling, sizing, straightening, primary cold drawing, grinding, primary flaw detection and thickness measurement, secondary cold drawing, and secondary flaw detection and thickness measurement. Through a double treatment mode of hot rolling and cold drawing, the deformation amount in the hot rolling and cold drawing steps of the gas cylinder pipe is reasonably distributed, the wall thickness precision of the large-diameter gas cylinder pipe and the quality of the inner and outer surfaces of the gas cylinder pipe are improved, and the yield of the seamless gas cylinder pipe reaches more than 85%.

A metal-strip warped-shape control method for controlling an exit-side warped shape, which is a warped shape of a metal strip downstream of a temper rolling mill in a metal-strip manufacturing facility, the metal-strip manufacturing facility including the temper rolling mill that corrects a shape of the metal strip continuously conveyed, and a warped-shape measurement device that measures a warped shape of the metal strip, the metal-strip warped-shape control method including: calculating an approximation curve for the warped shape of the metal strip using an approximation method selected from parabolic approximation, circular arc approximation, and envelope approximation; and setting operating parameters of the temper rolling mill that can reduce a warp height of the exit-side warped shape based on the approximation curve that is calculated.

The application discloses a method and system for improving the quality of a steel coil plate surface and reducing strip breakage, and relates to the technical field of steel cold rolling processing. The method comprises a welding process and a phosphorus breaking and tension leveling process. In the welding process, the strip head and tail of the front and rear steel coils are welded and connected. In the phosphorus breaking and tension leveling process, the welded steel plate is subjected to combined deformation of stretching and bending. The elongation is controlled according to the steel plate grade, and the insertion amount of the phosphorus breaking and tension leveling roller is adjusted according to the steel plate grade and the silicon content, so that the plate shape is improved and the stress is eliminated. The method establishes a collaborative control system of welding parameters and phosphorus breaking and tension leveling parameters, and adopts differentiated setting according to different grades and material characteristics, so that the problem of strip breakage caused by the insufficient weld strength and the upward bending of the strip head and tail of the high yield strength steel plate after straightening is solved.

The present invention discloses a method for preparing a reverse gradient nano-twinned high-strength and tough metal material by wire rolling, which includes the following steps: annealing and polishing the metal material, performing rolling by means of a multi-pass rolling process, controlling the total deformation amount to be 10-48%, and preparing a reverse gradient nano-structure from central nano-twins to surface coarse grains. The present invention constructs a reverse gradient nano-structure from surface coarse grains to core nano-twins by regulating the pass reduction and rolling temperature. The reverse gradient nano-twinned material prepared by the present invention has excellent mechanical properties compared with the annealed state. Among them, for 316L with a gradient deformation of 20%, the tensile strength is 600-800 MPa, the elongation is 40-50%, and the uniform elongation is increased by 50-100%. The process of the present invention is compatible with the existing rolling production line, and has advantages such as low cost, high efficiency, and scalable production, and is applicable to fields with strict requirements for strength and toughness such as aviation fasteners and automobile anti-collision components.

This application provides a brass-aluminum-brass composite material and its preparation method and application. The preparation method includes: heating a first brass, an aluminum material, and a second brass material to a temperature of 400-500℃ for 2-6 minutes, with a thickness ratio of 1:(1-8):1 for the first brass, aluminum material, and second brass; rolling the heated material according to a brass-aluminum-brass structure, with a single-pass rolling reduction rate of 50%-70%; and then cold rolling to obtain a composite material of the target thickness. The solid-solid-temperature composite process softens the brass and aluminum alloy, making the metal flow and synergistic deformation more favorable during rolling. Simultaneously, the material is in a hot state during rolling, increasing the self-diffusion ability of copper and aluminum at the interface, enabling mutual diffusion of copper and aluminum atoms. The bonding interface transitions from mechanical bonding to metallurgical bonding, forming an IMC layer, which improves the bonding strength of the composite material.

The invention relates to the technical field of thermal management materials, in particular to a graphene copper-based composite material and a preparation method thereof. The preparation method of the graphene copper-based composite material comprises the following steps: depositing graphene on a copper foil to obtain a graphene copper foil base material; superposing a plurality of layers of graphene copper foil base materials to form a plurality of layers of base materials; and the multi-layer base material is heated to 800-1100 DEG C, and meanwhile multi-pass hot rolling is conducted on the multi-layer base material, so that the ductility of the multi-layer strip reaches 20-200%. According to the preparation method of the graphene copper-based composite material, graphene sheet layers can be actively and controllably guided to achieve uniform dispersion and height orientation arrangement in a copper matrix, so that an efficient and continuous internal heat conduction network is constructed, and the heat conductivity of the composite material is improved in a breakthrough mode.

This application provides a brass-aluminum-brass composite material, its preparation method, and its application. The preparation method includes: performing solid-solid cold composite rolling on brass, aluminum, and copper to obtain a first intermediate composite material, wherein the thickness ratio of brass, aluminum, and copper is 1:(1~8):1, the solid-solid cold composite rolling is a single-pass rolling process with a single-pass reduction rate of 50%~70%; followed by diffusion annealing treatment at a temperature of 350~480℃ for 2~10 minutes; and finally, cold rolling to obtain a composite material of the target thickness. The 50%-70% reduction deformation breaks down the surface oxide film between the two metal layers; the diffusion annealing process controls the formation of an intermetallic compound layer at the junction of the two metal layers, improving the bonding strength between the metal layers. This composite material has high interlayer bonding strength, improved thermal conductivity, lower density, and good electrical conductivity compared to brass.

The invention discloses a method for preparing a reverse gradient nano twin crystal high-toughness metal material through wire rolling. The method comprises the following steps that the metal material is annealed and then polished, a multi-pass rolling technology is adopted for rolling, the total deformation is controlled to be 10-48%, and a reverse gradient nano structure from center nano twin crystals to surface coarse crystals is prepared. According to the preparation method, the reverse gradient nano structure from surface coarse crystals to core nano twin crystals is constructed by regulating and controlling the pass reduction and the rolling temperature. Compared with an annealed state, the reverse gradient nano twin crystal material prepared by the method has excellent mechanical properties. Wherein the tensile strength of 316L under gradient deformation of 20% is 600-800MPa, the ductility is 40-50%, and the uniform ductility is improved by 50-100%. The technology is compatible with an existing rolling production line, has the advantages of being low in cost, high in efficiency, capable of achieving large-scale production and the like, and is suitable for the fields such as aviation fasteners and automobile anti-collision components which have strict requirements for obdurability.

The invention belongs to the technical field of 430 stainless steel hot rolling, and particularly relates to a hot rolling method for improving the surface stripping defect of a 430 stainless steel unannealed material, which comprises the following specific steps: S1, plate blank heating control: in a heating stage, according to the actual carbon content of a plate blank, calculating and setting a furnace temperature control target value T by a dynamic regulation and control model; s2, descaling with high-pressure water; s3, rough rolling of the blank, wherein rough rolling of the descaled plate blank is started at the temperature larger than or equal to 1080 DEG C; rolling the plate blank into an intermediate blank through five to seven rolling passes; s4, finish rolling deformation control, wherein after the head and the tail of the intermediate billet are subjected to flying shearing, the intermediate billet enters a finish rolling unit composed of seven racks; the total deformation rate of finish rolling is controlled to be 86%-92%; and S5, laminar cooling and coiling cooperative control is conducted, specifically, the strip steel obtained after finish rolling enters a laminar cooling area to be subjected to controlled cooling. According to the method, heating control, finish rolling deformation and a layer cooling mode are optimized and integrated in multiple aspects, so that the intrinsic characteristics of the oxide scale are fundamentally improved, and the surface stripping defect rate is remarkably reduced.

The invention discloses a novel snakelike short-process rolling composite process method for a metal plate and a composite plate, and belongs to the technical field of material processing, and the novel snakelike short-process rolling composite process method comprises the following steps: determining a hot working plastic temperature interval shared by base layer metal and coating metal as a process window, selecting a casting blank and processing, and polishing and cleaning a surface to be composited. The blanks are tightly attached and welded in a sealed mode to form a composite blank, the blank is transferred to a two-roller reversible rolling mill with the upper and lower roller diameter difference to be rolled in a snakelike mode after being heated and subjected to heat preservation, water quenching and cooling are conducted immediately after rolling, a composite plate is obtained, a theoretical model is established to predict the layer thickness and strain, and mechanical property testing and microstructure characterization are conducted on the composite plate; by the adoption of the novel snakelike short-process rolling compounding process method for the metal plate, the strain and layer thickness ratio in the compounding process is effectively controlled, and the interface bonding quality and the product plate shape are remarkably improved.

The invention relates to the technical field of austenitic stainless steel production, in particular to a grain size control method in a hot rolling process of ultra-pure austenitic medical stainless steel, which comprises the following steps: smelting, refining and preheating a steel billet; a multi-pass rolling mode is adopted, and the temperature in the hot rolling process of each pass is regulated and controlled, specifically, for each pass, the temperature distribution deviation, the adjacent temperature deviation and the temperature comprehensive deviation degree at each collection moment are obtained; by comparing distribution of hot rolling temperature data in a scanning area at each acquisition moment with distribution of plate rolling thickness, pressure rate deviation distribution at each acquisition moment is obtained, and the temperature of a steel billet area corresponding to the scanning area at each acquisition moment in the next-pass hot rolling process is regulated and controlled. The grain size in the hot rolling process for preparing the stainless steel is controlled. According to the method, the stability and consistency of grain size control are improved by regulating and controlling the hot rolling temperature.

The invention discloses a copper base material calendering device for photovoltaic welding strip machining, and relates to the technical field of new material industries. An arch-shaped circular ring is fixed to an upper roller, and an arch-shaped circular groove is formed in a lower roller, so that the section of a copper base material formed through calendering is of an arc-shaped structure; when a photovoltaic welding strip produced by taking the copper base material as a main body is connected with a battery piece, the two sides of the photovoltaic welding strip can be tilted upwards, so that external light can irradiate the battery piece covered below the photovoltaic welding strip through the side surface, the light receiving area of a photovoltaic module in the actual use process can be effectively increased, and the service life of the photovoltaic module is prolonged. And meanwhile, through the arrangement of two times of calendering rolling, the deformation amount of single-time calendering rolling of the copper blank can be effectively controlled, the probability that the surface of the copper base material is cracked due to overlarge sudden stress is avoided, and the calendering production quality of the copper base material is effectively guaranteed.

To provide a metal-strip warped-shape control method capable of controlling the warped shapes with a W-shaped cross-section in the width direction and the warped shapes approximated with higher-order functions, enabling the reduction of the warp height of a metal strip downstream of a temper rolling mill. In a metal-strip manufacturing facility including a temper rolling mill 31 that corrects a shape of a metal strip 1 continuously conveyed, and a warped-shape measurement device that measures a warped shape of the metal strip, a metal-strip warped-shape control method for controlling an exit-side warped shape, which is a warped shape of the metal strip 1 downstream of the temper rolling mill 31, includes: calculating an approximation curve for the warped shape of the metal strip 1 using an approximation method selected from parabolic approximation, circular arc approximation, and envelope approximation; and, based on the calculated approximation curve, setting operating parameters of the temper rolling mill 31 that can reduce the warp height of the exit-side warped shape.

The application discloses a preparation method of a shape memory alloy plate with high-temperature super-elasticity, and belongs to the technical field of shape memory alloys. The shape memory alloy is a nickel-titanium-tantalum alloy, and the preparation method mainly comprises hot rolling, batch cold rolling large plastic deformation and recrystallization annealing, so as to refine the microstructure and control the grain size. The nickel-titanium-tantalum shape memory alloy plate prepared by the method has good super-elasticity when the temperature is higher than 100 DEG C, can recover a strain of more than 5%, and has high cycle stability. Compared with the nickel-titanium-hafnium high-temperature shape memory alloy, the shape memory alloy plate only adds 5.7% of Ta, and the raw material cost is obviously reduced, and is a super-elastic material which can be applied to a high-temperature environment of 100-180 DEG C.

This invention relates to a novel one-step titanium alloy wire drawing process using rollers. This process replaces the traditional stretching method with multi-angle composite roller rolling, processing the wire in a circular-elliptical-circular pattern. By rationally allocating the elongation coefficient and the horizontal angle between the rollers for each pass, continuous one-step forming of the titanium alloy wire is achieved. This process is carried out at room temperature, requiring no auxiliary lubricants or intermediate heat treatment. Only one annealing after wire forming is needed to obtain a bright wire. The final finished wire exhibits excellent mechanical properties and high dimensional accuracy, significantly simplifying the titanium alloy wire manufacturing process, reducing production costs, and making it suitable for large-scale industrial production.

The application discloses a preparation method of high-strength high-nitrogen austenitic stainless steel plate material, and the high-nitrogen austenitic stainless steel plate material is subjected to solid solution treatment in a heating furnace at 1150±50 DEG C for 6-8 hours, and then is water-cooled to rapidly reduce the temperature to room temperature; after the solid solution treatment is completed, the high-nitrogen austenitic stainless steel plate material is first placed into a heating furnace at 300 DEG C for heat preservation for 10 minutes, and then is placed into the heating furnace at 300 DEG C for heat preservation for 5 minutes before each pass rolling, and the cumulative reduction is 40-75%. The warm rolling process is used, the rolling force required by the warm rolling process is smaller than that required by room temperature rolling, the strength of the obtained material is equivalent to that of the material rolled at room temperature, and the processing is easier to carry out.

The application provides a low-strength high-surface-hardness cold-rolled fine-blanking steel strip and a manufacturing method and application thereof, and the composition is as follows: C: 0.18-0.23%; Si: 0.15-0.35%; Mn: 0.40%-0.60%; P: <=0.020%; S: <=0.020%; Al: 0.015%-0.045%, and the rest is Fe and inevitable impurities. Compared with the prior art, the application precisely controls the hot-rolling, cold-rolling, annealing and flattening processes, and obtains a cold-rolled fine-blanking steel product with matched tensile strength and surface hardness, the tensile strength of which is 400-500 MPa, and the surface hardness is HRB70-80, and the product is suitable for fine-blanking of automobile gearbox friction plate with a thickness of 1.5-3.0 mm.

The invention discloses a high-speed rolling process for a battery aluminum foil, which adopts a multi-pass rolling method and comprises the following steps of: adopting incremental deformation, traction tension and rolling speed at the initial stage of rolling, and adopting progressive deformation, traction tension and rolling speed at the final stage of rolling. And meanwhile, it is ensured that the ratio of the thinning rate of the blank to the rolling speed and the traction tension in the multi-pass rolling process meets the exponential function relation. The method comprises the following steps: accurately setting the reduction rate range, inlet / outlet tension and rolling speed of each pass, configuring a cogging roller, a middle roller and a finished roller with specific convexity, matching with gradient control of the temperature of the rollers of each pass and the injection flow of rolling oil, and arranging an oil removal roller with an adjustable frequency infrasonic wave vibration function on a rolling line. According to the technical scheme, under the high-speed condition that the average rolling speed is 800 m / min, high-efficiency production is guaranteed, meanwhile, the belt breakage risk is reduced, and the foil face rolling oil residues are reduced.

The application discloses a method for improving the thickness uniformity of a magnesium / aluminum composite plate and a product thereof, and belongs to the technical field of metal material composite processing. The method comprises the following steps: magnesium alloy plates and aluminum alloy plates are subjected to composite rolling by adopting differential friction regulation and temperature gradient, so that a magnesium / aluminum composite plate is obtained; the differential friction regulation is specifically that the friction coefficient of the friction functional layer coated on the surface of the magnesium alloy plate is 0.2-0.4 higher than that of the friction functional layer coated on the surface of the aluminum alloy plate; and the temperature gradient is specifically that the pretreatment temperature of the magnesium alloy plate is 50-100 DEG C higher than that of the aluminum alloy plate. That is to say, the magnesium / aluminum interlayer deformation rate can be effectively coordinated by the synergistic effect of the differential friction regulation-temperature gradient, the thickness uniformity is significantly improved, and the bonding stability is effectively improved.

An ultrathin lithium metal / alloy anode, its preparation method, and its application in solid-state batteries belong to the field of lithium-ion battery technology. The ultrathin lithium metal / alloy anode is prepared through a cryogenic pretreatment combined with cyclic rolling. This process can refine the grain size of the anode material to the micrometer or even submicrometer level. Grain boundaries, acting as physical barriers, hinder dislocation movement, significantly increasing the strain rate of the material under high stress, thereby improving the material's resistance to plastic deformation and effectively reducing the stacking pressure requirements of solid-state batteries. Simultaneously, the prepared lithium metal solid-state battery possesses the advantage of high energy density and maximizes battery cycle life by suppressing porosity accumulation during electrode-electrolyte cycling. This invention provides an effective solution for the development of low-cost, high-energy-density, high-safety, and long-cycle-performance lithium metal solid-state battery technology.

This application discloses a high-purity low-carbon steel and its preparation method. The high-purity low-carbon steel comprises the following components by mass percentage: C: 0.02wt%~0.07wt%, Si≤0.03wt%, Mn: 0.15wt%~0.25wt%, P≤0.015wt%, S≤0.01wt%, Alt: 0.04wt%~0.06wt%, N≤0.004wt%, Ni≤0.06wt%, Cr≤0.06wt%, Cu≤0.06wt%, As≤0.01wt%, Sn≤0.02wt%, Cr+Ni+Cu≤0.09wt%, with the remainder being Fe and unavoidable trace elements. The high-purity low-carbon steel of this application has fewer inclusions and higher mechanical properties, exhibiting good machinability.