A new cold rolling lubrication method combining emulsion and neat oil lubrication

The cooling and lubrication process is one of the key processes in cold rolling,as it not only determines surface quality and strip shape,but also reduces the rolling power consumption and extends the life of the roll even during high-speed operation.In this study,an innovative method combining emulsion lubrication and neat oil lubrication was used to solve some problems associated with individual passes.Laboratory tests on stainless steel strips showed that this new lubrication method could improve the surface quality of the strip,control the rolling friction in the deformation zone,and has the potential of making lubrication systems simpler and easier to operate,all while reducing the negative environmental impact from emulsion processing.

Improving emulsion odor in cold rolling production

This paper describes the formation mechanism and mode of the emulsion odor of the cold rolling process,and introduces the relevant environmental regulations and methods used to measure the emulsion odor.Studies were conducted with respect to these issues.The technical measures used to minimize the emulsion odor,particularly the adjustment of the chemical formula of the cold rolling emulsion,are illustrated in detail.The study results have been successfully applied in cold rolling production,and a significant reduction in the emulsion odor is achieved.

Internal oxidation of hot-rolled ultra-high strength steel and its effect on the surface quality of cold-rolled sheets

In this study,the scale and internal oxidation of hot-rolled ultra-high strength steel sheets were characterized.It was found that both the formation of the scale and the internal oxidation of Si and Mn depended on the coiling temperature and position of the steel sample on the strip coil.At a relatively high coiling temperature,a large amount of internal oxidation was observed on the samples cut from the middle of the coil.The depth of the internal oxidation zone exceeded 10 μm and a thin iron layer covering the scale was observed in some cases.Pickling and cold-rolling experiments were conducted on selected samples.Scale pickling was found to be greatly delayed by the formation of an iron layer,which frequently resulted in under-pickled defects.In addition,pickling of the entire internal oxidation zone was difficult,except at the grain boundaries,where the degree of internal Si and Mn oxidation was enriched.The surface of the cold-rolled steel sheet was ruined by the remaining oxidation zone in the subsurface of the pickled steel.The internal oxidation of hot-rolled ultra-high strength steel must be precisely controlled to improve the subsequent surface quality of cold-rolled steel.

Baosteel's development of cold strip technology

Throughout 30 years of importation, adoption and innovation, the Cold Rolling Plant of Baosteel has adhered to a market-oriented strategy, and gradually expanded its output and raised its technical level through the expansion of production scale ,the optimization of production lines, the development of high added value products, the improvement of product quality, environmentally friendly manufacturing and technological innovation. In this way, the plant has developed into a world class cold rolling plant that produces cutting-edge economic and technical indices.

Surface rust of cold-rolled bell-type annealing strip steel

This paper offers systematic analysis and in-depth research on the surface rust problem of cold-rolled bell-type annealing strip products.The defect characteristics,occurrence rules,generation mechanism,and influencing factors of surface rust are presented.This research employed a cold-rolled bell-type furnace annealing unit in a coastal steel factory as an example and conducted production process tests,on-site production tests,scanning electron microscopy,energy spectrum analysis,MINITAB statistical analysis,etc.Moreover,six significant influencing factors and their rules were studied:the cooling time of the final cooling table,the storage time of the intermediate storage,the temperature setting of the intermediate storage,the temperature of leveling liquid,the purging pressure of leveling machine,and the dust in the environment.

Development and application of an online pinhole detector for cold-rolled strips

An online pinhole detector based on the photoelectric inspection of cold-rolled steel strips was introduced. Pinhole detection is important to guarantee the quality of cold-rolled steel strips. The detector here was developed independently by Baosteel,and is designed based on the principle of photoelectric transfer. Typically, an inspection light source is installed above the steel strip to be inspected, and a photoelectric receiver is installed beneath the steel strip. The pinhole detector consists of a super-bright LED light source and a photoelectric receiver, which is composed primarily of photomultipliers. The super-bright LED light source illuminates the strip surface, and the light that permeates from pinholes is detected and amplified by a photoelectric receiver. The photomultiplier transforms the detected light into an electrical signal ,which is later recognized and classified by a signal-processing circuit and collected by a data-acquisition card. The detector can accurately track the strip edge and shield the strip edge from outside light. As a result,this system can detect a pinhole in the strip edge with a small blind zone on the edge. Most importantly, the detector exhibits good inspection accuracy and can accurately detect a pinhole with a diameter of 15 μm.

Similarity evaluation model for the internal defect detection of strip steel

An internal defect meter is an instrument to detect the internal inclusion defects of cold-rolled strip steel.The detection accuracy of the equipment can be evaluated based on the similarity of the multiple detection data obtained for the same steel coil.Based on the cosine similarity model and eigenvalue matrix model,a comprehensive evaluation method to calculate the weighted average of similarity is proposed.Results show that the new method is consistent with and can even replace artificial evaluation to realize the automatic evaluation of strip defect detection results.

Experimental Study on Corrosion of Stainless Steel in Low Temperature Multi effect Seawater Desalination

Starting from the corrosion mechanism,this paper analyzes the characteristics of various types of stainless steel and selects the best performance composite plate composite plate stainless steel.Analyze and select the most suitable corrosion detection method based on specific practical multi working conditions,discuss the interference factors that affect metal corrosion during experimental simulation,and the advantages of newly developed sheet metal.The new development of composite board panels,with the substrate and composite materials applying their respective capabilities for MED,will bring breakthrough progress to the scientific research and engineering applica-tion of composite boards.

Corrosion action and passivation mechanism of magnesium alloy in fluoride solution

Corrosion action and passive mechanism of magnesium alloy in the fluoride solution were studied by means of scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and electrochemistry methods. The results show that an insoluble MgF2 film is generated on the surface of magnesium alloy activated in the hydrofluoric acid. And the mass of the deposited MgF2 film may reach a constant value, when the mass ratio of Mg/F on the magnesium alloy surface is fixed at 11.3-1. The activated magnesium alloy gains a ‘passivation state’ in a mixture of sulfuric acid and hydrofluoric acid at a volume ratio of less than 1.2. At the same time the mass of magnesium alloy is maintained as a function of the time. When the ratio is above 1.4, the mass of magnesium alloy rapidly decreases. The passive film formed through adsorption of HF2- (or H2F3-, H3F4-) ions by the deposited MgF2 film can protect the magnesium alloy from corrosion in fluoride solution, but not in non-fluoride solutions. The passive state is maintained for activated magnesium alloy in an acidic sulfuric nickel solution with added fluoride. If fluoride and carbonate are added to the acidic sulfuric nickel solution, a replacement reaction between magnesium alloy and solution takes place.

Control of thermal crown in the roller inside the continuous annealing furnace

In a continuous annealing furnace, the hearth rollers are affected by heat, which in turn affects the stable operation of the steel strips. In order to ensure the stable operation of the steel strips the ability of the rollers to correct themselves and to prevent the steel strips from buckling, effective measures are required to control the surface crown of the rollers inside the furnace. Starting from production, this study analyzes the way in which the crown of the hearth rollers inside the continuous annealing furnace changes. The study suggests control measures to prevent buckling and and misalignment. The study definitely provides guidance to the stable operation of steel strips in continuous annealed furnaces.

Study of the spangle size of 55% Al- Zn- Si steel

The spangle size of the 55% Al-Zn-Si steel is affected by the composition of the zinc pot, the cooling capacity after plating, and the substrate. According to previous studies, the size of spangles can be reduced by increasing the cooling ability after plating, and by adding Ti in the zinc pot. However, these two methods cannot reduce the spangle size smaller than 1. 5 mm. Therefore, in this study, we have focused on the influence of substrates on the formation of spangles of 55% Al-Zn-Si steel by comparing and analyzing substrates with different surface roughness, composition, morphology, crystal orientation, and alloy layers.

Investigation of the transformation of sink-roll groove-mark defect in the galvannealing process

The influence of galvannealing on the transformation of the sink-roll groove-mark defect was studied by comparing the defects on galvannealed( GA) coating with those on galvanized( GI) coating. It was found that defects on GI coating contained high amounts of aluminum,zinc dross,and a zinc-iron intermetallic outburst structure,as well as slight scratches on the substrate. After being galvannealed,the aluminum content was higher and there was a much greater outburst structure,which made the coating of the defect thicker than the normal coating,while the zinc dross and scratches on the substrate had disappeared due to zinc and iron diffusion during the galvannealing process.

Failure Mechanism of Reflow Conductor Roll of Electroplating Tinning Line

The surface roughness of reflow conductor roll was checked on membrane sample. The surface morphology of conductor roll was observed by microscope, and the composition of adhered layer on conductor roll surface was analyzed by X-ray spectroscope. The results show that tin adhesion is the main reason for failure of conductor roll, and the failure of conductor roll is accelerated by wear. The measures to decrease tin adhesion and improve wear resistance were put forward.

Effect of substrate grain size on GA streaky marks of IF steel

The micro-characteristics of the streaky marks and the corresponding substrate surface of galvannealed （GA） steel sheets have been investigated using SEM and FIB.The streaky mark area seems to have many cavities,similar to craters,which scatter light and make the surface appear darker when compared with the surrounding normal area.Moreover,it is found that the irregularity or difference in steel grain size tends to affect the surface quality of the GA steel sheets.During alloying,the diffusion speed of Zn-Fe on the grain boundary is faster than that at the center of the grain,which results in the selective formation of crater-like morphology in the coating area with larger steel grains.Due to the clear grain boundary of IF steel,apparent streaky marks will be formed on the coating,if the IF steel surface consists of grains of irregular size.

Comparison of fatigue property between friction stir and TIG welds

The alloy 5052 was welded by friction stir welding （FSW） and tungsten inert gas （TIG） welding. The effect of welding processes （FSW and TIG） on the fatigue properties of 5052 aluminum-welded joints was analyzed based on fatigue testing, and the S-N curve of the joints were established. The results show that the fatigue properties of FSW welded joints are better than those of TIG welded joints. The fatigue strength is determined as 65 MPa under 106 cycling of fatigue life. The microstructure of joints is fine grains and narrow HAZ zone in FSW welds, which inhibit the growth of cracks and produce high fatigue life compared with that of TIG welds. Fracture morphologies also show that the fatigue fracture results from weld defects.

Detection and analysis of gas tightness of continuous annealing furnaces

When a cold rolled strip is being treated in a continuous annealing furnace which is full of protective gas, the gas tightness of the furnace body, the connected facilities and the gas channels become an important indicator that directly affects the product＇s surface quality and shows the technical level of the design, the manufacture and the installation. By considering the problems of the gas tightness of a vertical annealing furnace in the installation and maintenance, this thesis evaluates the gas tightness indicator and gas tightness related level of the furnace body and the circulation duct, while studying and analyzing the technologies of negative-pressure leak detection and sealing.

Study on the heat resistance of 55% Al- Zn steel plates

Post-treated 55% Al-Zn steel plates, which have adequate mechanical properties and corrosion resistance ,are widely used for automobiles, household appliances, and other products. The heat resistance of 55% Al-Zn steel plates is slightly lower than that of aluminum plates or hot-dip aluminized steel plates, but their corrosion resistance is better. Herein,by testing at different baking temperatures and for different periods,the trends of color,gloss,and loss weight have been analyzed. The heat-resistant properties of differently post-treated 55% Al- Zn steel plates,aluminum plates,and hot-dip aluminized steel plates have been studied.

Production and application of Baosteel inorganic-lubricant-coated galvannealed automobile steel sheet

The inorganic-lubricant-coated galvannealed automobile steel sheet is a new product that improves the press formability of automobile body panels.In this paper,the production process,physical and chemical properties,press formability,and corrosion resistance of this new automobile steel sheet were discussed.Test results show that this inorganic solid-lubricant galvannealed automobile steel sheet has good surface friction characteristics and press formability.This product also meets the automobile industry’s requirements for press formability,phosphate pro-perties,and corrosion resistance after coating.

Morphologies and Influential Factors of Forsterite Film in Grain-Oriented Silicon Steel

The product quality of graiworiented silicon steel may be affected by each process because of its complicat- ed production technology. Morphologies, compositions and structures of forsterite film formed in different conditions on the samples subjected to high temperature annealing were measured by using a scanning electron microscope, an energy disperse spectroscope, an X ray diffractometer and Fourier transform infrared technique respectively. The morphologies and influential factors of forsterite film were investigated. The results showed that the major compo- nent of forsterite film composed of light-gray spherical particles was Mg2 SiO4, and the minor was MgAl2O4. If the amount of MgO coated on the surface of the steel was less, bare holes or even large-scale bare grains for forsterite film appeared. The higher temperature of water bath during decarburization annealing led to gaps of strips in forster ite film. Moreover, MgO coating method had great influence on forsterite film. Roller coating method was beneficial to increase compactness and smoothness of forsterite film, but was disadvantageous to its thickness.

Computer Simulation of Fe-Al-Si System Diffusion Couples

DifFusion couples, Fe-6.8 wt% Al-1.0 wt% Si/Fe and Fe-6.3 wt% Al-0.9 wt% Si/Fe were constructed and separately annealed at 1050℃ for 3 h and at 1000℃ for 64 h. The concentration profiles of Fe, Al and Si atoms in these couples were measured by electron probe micro-analysis （EPMA）, while the diffusion behavior was also simulated by coupling thermodynamic and kinetic properties of Fe-Al-Si system. The simulation results were in good agreement with the measured concentration profiles showing the validity of dynamic parameters of Fe-Al-Si system, Calculation was made for Fe-7 wt% Al-1 wt% Si/Fe diffusion couples at 1000℃ with different diffusion time. Silicon uphill was found under the influence of aluminum.