Coarsening, embrittlement and corrosion sensitization in a high temperature heat-affected zone （HTHAZ） are the major problems when 12% chromium low carbon stainless steel is being welded, which induce the deteriorat...Coarsening, embrittlement and corrosion sensitization in a high temperature heat-affected zone （HTHAZ） are the major problems when 12% chromium low carbon stainless steel is being welded, which induce the deterioration of the impact toughness at a low temperature and intergranular corrosion resistance property. This study investigates the corresponding microstructures in HTHAZ with different chemical compositions and heat inputs through thermal simulation tests. The results show that the martensite content increases with the descending of ferrite factor （FF） when FF is below 9.0 and heat input influences the microstructure of high FF steel in HTHAZ. Martensite of 12% Cr stainless steel in HTHAZ with only Nb stabilization reticularly distributes at ferrite grain boundaries.展开更多
With the increase in the content of carbon, nitrogen and titanium in 430 ferritic stainless steel, the refinement of the solidification structure is obvious and the proportion of equiaxed grain increases remarkably as...With the increase in the content of carbon, nitrogen and titanium in 430 ferritic stainless steel, the refinement of the solidification structure is obvious and the proportion of equiaxed grain increases remarkably as well. This is attributed to the increasing role of the inhomogeneous nucleation by TiN particles during solidification. In addition, more fine precipitations of （Ti ,Nb）N are found in steel with increased carbon and nitrogen content.展开更多
The dull-finish ferritic stainless steel （FSS） sheet B445R for architectural roofing has been developed by Baosteel. This steel product exhibits excellent corrosion resistance superior to that of SUS 316L with a low...The dull-finish ferritic stainless steel （FSS） sheet B445R for architectural roofing has been developed by Baosteel. This steel product exhibits excellent corrosion resistance superior to that of SUS 316L with a lower cost. It can be easily formed into roofing panels by ordinary processes. Moreover,the thermal strain of it is less than SUS 316L because of its lower thermal expansion coefficient, and its reflectivity is lower due to the dull-finish treatment. All of these features make it capable of being used as architectural roofing materials in coastal regions.展开更多
In order to understand the effect of the solidification structure on the formability of ultra low carbon ferritic stainless steel （FSS） ,this work studies the ridging phenomenon and the deep-drawing property in deta...In order to understand the effect of the solidification structure on the formability of ultra low carbon ferritic stainless steel （FSS） ,this work studies the ridging phenomenon and the deep-drawing property in detail and the research method was X-ray diffraction （XRD） and scanning electron microscope （SEM） technique. The result shows that the columnar grain specimen had a higher ridging height than the equiaxed grain specimen, which was mainly attributed to the formation of grain colonies in the columnar grain specimen. After final recrystallization annealing, the equiaxed grain specimen obtained a high-intensity T-fiber texture and an excellent deep-drawing property.展开更多
Problems encountered in the production of low nickel austenitic stainless steel have been studied. These problems primarily include the changes to the microstructure of the slab during the heating process, the formati...Problems encountered in the production of low nickel austenitic stainless steel have been studied. These problems primarily include the changes to the microstructure of the slab during the heating process, the formation and removal of deformation - induced martensite during cold rolling, and the effects of the annealing process on the surface oxide structure. A reasonable manufacturing process has been proposed on the basis of the research results and high-quality cold-rolled strips of low nickel austenitic stainless steel have been produced.展开更多
The beneficial effects of niobium addition on properties such as high-temperature strength, toughness, and formability of ferritic stainless steels have been addressed. Based on the Thermo-Calc analysis, precipitation...The beneficial effects of niobium addition on properties such as high-temperature strength, toughness, and formability of ferritic stainless steels have been addressed. Based on the Thermo-Calc analysis, precipitation of niobium carbonitride and solubility of niobium have been predicted and characterized via scanning electron microscope （SEM） and transmission electron microscope （TEM） observations. It is shown that addition of niobium has a beneficial effect on improving the high-temperature strength, toughness, formability, and corrosion resistance of ferritic stainless steel. Soluted niobium is very effective in improving the high-temperature strength, which is beneficial to reducing the sticking propensity during hot rolling. Although niobium increases the recrystallization temperature, niobium-added ferritic stainless steels show a high mean r value, or a high plastic strain ratio, as long as the annealing temperature is high enough. Furthermore, because niobium helps to inhibit the formation of chromium carbides, ferritic stainless steel can keep an effective chromium content in the matrix, leading to improved corrosion resistance. Applications of these ferritic stainless steels for construction and home appliances have also been presented.展开更多
Two ferrite-martensite stainless steels （FMSSs） were developed by Baosteel based on the T4003 composition, through optimizing the manganese and nickel contents ,reducing silicon, carbon and nitrogen contents, contro...Two ferrite-martensite stainless steels （FMSSs） were developed by Baosteel based on the T4003 composition, through optimizing the manganese and nickel contents ,reducing silicon, carbon and nitrogen contents, controlling remnant niobium and molybdenum ,adding sufficient titanium and controlling the processing. In this study ,the physical metallurgy of such FMSSs was investigated with the emphasis on the alloying effect on the phase balance during processing and the transformation behavior during welding for different microstructures. In addition, the mechanical behavior and the weldability were investigated. The results indicate that such steels have a good combination of strength and toughness and better weldability compared with the traditional 1. 4003 steel. Such high strength steels are highly suitable for railway cargo transportation where the wall thickness of the wagons can be reduced,resulting in weight savings.展开更多
Effects of Mo, Nb, Ti on mechanical properties and corrosion resistance of 22.5% Cr ferritic stainless steel were investigated. The results show that Mo exists in ferritic stainless steel mainly in the solution treatm...Effects of Mo, Nb, Ti on mechanical properties and corrosion resistance of 22.5% Cr ferritic stainless steel were investigated. The results show that Mo exists in ferritic stainless steel mainly in the solution treatment condition, and it can enhance steel＇ s strength through solid solution strengthening. In Ti ＋ Nb dual-stabilized ferritic stainless steel, the steel＇s toughness decreases obviously because coarse TiN particles form and some metallic compounds precipitate along the grain boundaries. In Nb single-stablized ferritic stainless steel, Nb exists either in the solution treatment condition or in the form of dispersed precipitates Nb（C, N）, which will act as the nuclei of precipitation of the fine （r phase. As a result, the precipitation of the coarse σ phase along the grain boundary can be inhibited, leading to significant improvement in steel＇ s toughness at a low temperature. Based on these, high corrosion-resistant ferritic stainless steel B445R was developed for the building cladding system. Test results show that B445R has a superior corrosion resistance to austenitic 316 L in chloride solution. Besides, it has a good forming property and weldability. All these make it an ideal decorating material for the building cladding system in severe coastal regions.展开更多
The study investigates the effects of cold-rolling reduction on the recrystallization-annealed Nb ＋ Ti stabilized ultra-pure ferritic stainless steel with 21% Cr in regards to its microstructure evolution, grain size...The study investigates the effects of cold-rolling reduction on the recrystallization-annealed Nb ＋ Ti stabilized ultra-pure ferritic stainless steel with 21% Cr in regards to its microstructure evolution, grain size,recrystallization texture, and grain boundary characteristic distribution and disorientation angle. The research employed the electron back scattered diffraction technique and its results have shown that the average grain size was reduced and the {111 / 〈 112 〉 component was strengthened,which rotated towards {5541 〈225 〉 and {4451 〈384 〉 ,with an increasing cold-rolling reduction. The number fraction of the low-angle grain boundary and the coincidence site lattice （CSL） boundary ,which was mainly made up of ∑3,∑7∑11 and ∑13b, also increased.展开更多
Ferritic stainless steel （FSS） for various applications was developed on the basis of Thermo-calc simulation. Alloy design, precipitate analysis and processing parameters optimization were carried out on the basis o...Ferritic stainless steel （FSS） for various applications was developed on the basis of Thermo-calc simulation. Alloy design, precipitate analysis and processing parameters optimization were carried out on the basis of the simulation results according to the technical requirements of the applications. These developed products have outstanding properties, such as mechanical strength, ductility, formability, weldability and corrosion resistance. Baosteel has formed a series of FSS products which will increase the profit of the company and enhance the product variety of stainless steel.展开更多
In order to meet the demands of service life and the synthetical performance/price ratio of stainless steel in the solar water heater industry, the low molybdenum ultra-pure ferritic stainless steel （FSS） B445J1M wa...In order to meet the demands of service life and the synthetical performance/price ratio of stainless steel in the solar water heater industry, the low molybdenum ultra-pure ferritic stainless steel （FSS） B445J1M was developed at Baosteel. In this study, comparative studies were carried out on the mechanical properties, the formability and the corrosion resistance of B445J1M ,304 and 444 ,and the advantages and application fields of B445J1M were summarized.展开更多
Over the past five years, stainless steel products in Baosteel have got a very rapid development in R＆D and application. In Baosteel Stainless, ultra-pure ferritic stainless steel with medium chromium, nitrogen alloy...Over the past five years, stainless steel products in Baosteel have got a very rapid development in R＆D and application. In Baosteel Stainless, ultra-pure ferritic stainless steel with medium chromium, nitrogen alloyed austenitic stainless steel and duplex stainless steel with high properties have been developed with the technical properties reaching, or even better than those of the similar products in China and abroad. Some products have been widely used in automobile, household appliances, building, railway, nuclear power and chemical industries as the Chinese economy develops. The significant progress has been made for processing technologies, such as C ＋ N control, non metallic inclusion control during steelmaking, equiaxed crystal control during continuous casting, sticking and edge crack control during hot rolling as well as cold tandem rolling for ultra-pure ferritic stainless steels through continuous effort of innovative research and development. Baosteel Stainless is now the leading stainless steel producer in China and one of the best in the world regarding products and processing technologies for ferritic stainless steels.展开更多
After the integration for Baosteel Group Corporation, stainless steel is being rapidly developed and is becoming one of Baosteel＇ s strategic products. Since stainless steel is a high-tech and a high value-added prod...After the integration for Baosteel Group Corporation, stainless steel is being rapidly developed and is becoming one of Baosteel＇ s strategic products. Since stainless steel is a high-tech and a high value-added product,展开更多
文摘Coarsening, embrittlement and corrosion sensitization in a high temperature heat-affected zone （HTHAZ） are the major problems when 12% chromium low carbon stainless steel is being welded, which induce the deterioration of the impact toughness at a low temperature and intergranular corrosion resistance property. This study investigates the corresponding microstructures in HTHAZ with different chemical compositions and heat inputs through thermal simulation tests. The results show that the martensite content increases with the descending of ferrite factor （FF） when FF is below 9.0 and heat input influences the microstructure of high FF steel in HTHAZ. Martensite of 12% Cr stainless steel in HTHAZ with only Nb stabilization reticularly distributes at ferrite grain boundaries.
基金this project by both the National Natural Science Foundation of China(NSF 50734002)and Baosteel is fully acknowledged.
文摘With the increase in the content of carbon, nitrogen and titanium in 430 ferritic stainless steel, the refinement of the solidification structure is obvious and the proportion of equiaxed grain increases remarkably as well. This is attributed to the increasing role of the inhomogeneous nucleation by TiN particles during solidification. In addition, more fine precipitations of （Ti ,Nb）N are found in steel with increased carbon and nitrogen content.
文摘The dull-finish ferritic stainless steel （FSS） sheet B445R for architectural roofing has been developed by Baosteel. This steel product exhibits excellent corrosion resistance superior to that of SUS 316L with a lower cost. It can be easily formed into roofing panels by ordinary processes. Moreover,the thermal strain of it is less than SUS 316L because of its lower thermal expansion coefficient, and its reflectivity is lower due to the dull-finish treatment. All of these features make it capable of being used as architectural roofing materials in coastal regions.
基金funded by both the National Natural Science Foundation of China(50734002)CITIC-CBMM R&D Subject Foundation (2010-D046).
文摘In order to understand the effect of the solidification structure on the formability of ultra low carbon ferritic stainless steel （FSS） ,this work studies the ridging phenomenon and the deep-drawing property in detail and the research method was X-ray diffraction （XRD） and scanning electron microscope （SEM） technique. The result shows that the columnar grain specimen had a higher ridging height than the equiaxed grain specimen, which was mainly attributed to the formation of grain colonies in the columnar grain specimen. After final recrystallization annealing, the equiaxed grain specimen obtained a high-intensity T-fiber texture and an excellent deep-drawing property.
文摘Problems encountered in the production of low nickel austenitic stainless steel have been studied. These problems primarily include the changes to the microstructure of the slab during the heating process, the formation and removal of deformation - induced martensite during cold rolling, and the effects of the annealing process on the surface oxide structure. A reasonable manufacturing process has been proposed on the basis of the research results and high-quality cold-rolled strips of low nickel austenitic stainless steel have been produced.
基金support of the CITIC-CBMM R&D Subject Foundation(No.2010-D046)CITIC-CBMM-Baosteel Technical Cooperation Projects"Development of High-quality Niobium-bearing Ferritic Stainless Steel for Home Appliances in Baosteel"
文摘The beneficial effects of niobium addition on properties such as high-temperature strength, toughness, and formability of ferritic stainless steels have been addressed. Based on the Thermo-Calc analysis, precipitation of niobium carbonitride and solubility of niobium have been predicted and characterized via scanning electron microscope （SEM） and transmission electron microscope （TEM） observations. It is shown that addition of niobium has a beneficial effect on improving the high-temperature strength, toughness, formability, and corrosion resistance of ferritic stainless steel. Soluted niobium is very effective in improving the high-temperature strength, which is beneficial to reducing the sticking propensity during hot rolling. Although niobium increases the recrystallization temperature, niobium-added ferritic stainless steels show a high mean r value, or a high plastic strain ratio, as long as the annealing temperature is high enough. Furthermore, because niobium helps to inhibit the formation of chromium carbides, ferritic stainless steel can keep an effective chromium content in the matrix, leading to improved corrosion resistance. Applications of these ferritic stainless steels for construction and home appliances have also been presented.
文摘Two ferrite-martensite stainless steels （FMSSs） were developed by Baosteel based on the T4003 composition, through optimizing the manganese and nickel contents ,reducing silicon, carbon and nitrogen contents, controlling remnant niobium and molybdenum ,adding sufficient titanium and controlling the processing. In this study ,the physical metallurgy of such FMSSs was investigated with the emphasis on the alloying effect on the phase balance during processing and the transformation behavior during welding for different microstructures. In addition, the mechanical behavior and the weldability were investigated. The results indicate that such steels have a good combination of strength and toughness and better weldability compared with the traditional 1. 4003 steel. Such high strength steels are highly suitable for railway cargo transportation where the wall thickness of the wagons can be reduced,resulting in weight savings.
文摘Effects of Mo, Nb, Ti on mechanical properties and corrosion resistance of 22.5% Cr ferritic stainless steel were investigated. The results show that Mo exists in ferritic stainless steel mainly in the solution treatment condition, and it can enhance steel＇ s strength through solid solution strengthening. In Ti ＋ Nb dual-stabilized ferritic stainless steel, the steel＇s toughness decreases obviously because coarse TiN particles form and some metallic compounds precipitate along the grain boundaries. In Nb single-stablized ferritic stainless steel, Nb exists either in the solution treatment condition or in the form of dispersed precipitates Nb（C, N）, which will act as the nuclei of precipitation of the fine （r phase. As a result, the precipitation of the coarse σ phase along the grain boundary can be inhibited, leading to significant improvement in steel＇ s toughness at a low temperature. Based on these, high corrosion-resistant ferritic stainless steel B445R was developed for the building cladding system. Test results show that B445R has a superior corrosion resistance to austenitic 316 L in chloride solution. Besides, it has a good forming property and weldability. All these make it an ideal decorating material for the building cladding system in severe coastal regions.
文摘The study investigates the effects of cold-rolling reduction on the recrystallization-annealed Nb ＋ Ti stabilized ultra-pure ferritic stainless steel with 21% Cr in regards to its microstructure evolution, grain size,recrystallization texture, and grain boundary characteristic distribution and disorientation angle. The research employed the electron back scattered diffraction technique and its results have shown that the average grain size was reduced and the {111 / 〈 112 〉 component was strengthened,which rotated towards {5541 〈225 〉 and {4451 〈384 〉 ,with an increasing cold-rolling reduction. The number fraction of the low-angle grain boundary and the coincidence site lattice （CSL） boundary ,which was mainly made up of ∑3,∑7∑11 and ∑13b, also increased.
文摘Ferritic stainless steel （FSS） for various applications was developed on the basis of Thermo-calc simulation. Alloy design, precipitate analysis and processing parameters optimization were carried out on the basis of the simulation results according to the technical requirements of the applications. These developed products have outstanding properties, such as mechanical strength, ductility, formability, weldability and corrosion resistance. Baosteel has formed a series of FSS products which will increase the profit of the company and enhance the product variety of stainless steel.
文摘In order to meet the demands of service life and the synthetical performance/price ratio of stainless steel in the solar water heater industry, the low molybdenum ultra-pure ferritic stainless steel （FSS） B445J1M was developed at Baosteel. In this study, comparative studies were carried out on the mechanical properties, the formability and the corrosion resistance of B445J1M ,304 and 444 ,and the advantages and application fields of B445J1M were summarized.
文摘Over the past five years, stainless steel products in Baosteel have got a very rapid development in R＆D and application. In Baosteel Stainless, ultra-pure ferritic stainless steel with medium chromium, nitrogen alloyed austenitic stainless steel and duplex stainless steel with high properties have been developed with the technical properties reaching, or even better than those of the similar products in China and abroad. Some products have been widely used in automobile, household appliances, building, railway, nuclear power and chemical industries as the Chinese economy develops. The significant progress has been made for processing technologies, such as C ＋ N control, non metallic inclusion control during steelmaking, equiaxed crystal control during continuous casting, sticking and edge crack control during hot rolling as well as cold tandem rolling for ultra-pure ferritic stainless steels through continuous effort of innovative research and development. Baosteel Stainless is now the leading stainless steel producer in China and one of the best in the world regarding products and processing technologies for ferritic stainless steels.
文摘After the integration for Baosteel Group Corporation, stainless steel is being rapidly developed and is becoming one of Baosteel＇ s strategic products. Since stainless steel is a high-tech and a high value-added product,
