Sumitomo Metals Group Companies Win
Three Technical Development Awards from Japan Institute of Metals
Three Technical Development Awards from Japan Institute of Metals
Sumitomo Metal Industries, Ltd. (Sumitomo Metals), Sumitomo Metals (Naoetsu), Ltd. (Naoetsu), and Sumitomo Metals (Kokura), Ltd. (Kokura) today received three awards at the 32nd Technical Development Awards*1 from the Japan Institute of Metals as the Sumitomo Metals Group.
The awards were presented for the following technologies: the "Development of new continuous casting technologies for very thick plate (PCCS method)" by Sumitomo Metals; "Development of stainless steel foils for bipolar plates of polymer electrolyte fuel cells" by Sumitomo Metals and Naoetsu; and "Development of a new class of steel requiring no normalizing heat treatment before nitrocarburization for the application of high strength nitrocarburized crankshafts" by Sumitomo Metals and Kokura. In the case of the last technology, we received the award jointly with Honda R&D Co., Ltd.
Background and features of the technologies
1."Development of new continuous casting technologies for very thick plate (PCCS*2)" by Sumitomo Metals
(1) Background
Continuous casting is the widely used method for manufacturing slabs and is thus an indispensable process for the mass production and stable supply of steel plates.
However, in the manufacture of high-quality steel plates such as high-carbon steel plates for dies and for large-scale industrial machinery, porosities*3 arising during solidification in the slab center detrimentally affect quality. As a consequence, these steel plates have typically been produced by slabbing of a large-sized ingot before rolling.
(2) Features and benefits
Sumitomo Metals' PCCS method facilitates the manufacturing process of very thick plates of more than 100mm in thickness using the continuous casting method by reducing central porosities, an issue associated with inner quality, during casting. This is achieved through hard reduction of the slab with a roll pair in the final solidification stage. These innovative continuous casting technologies are already in use in the No.2 continuous caster at Sumitomo Metals' Kashima Steel Works.
Very thick plates can therefore be manufactured efficiently and with a short lead-time by using a conventional continuous casting machines and a rolling mill. In addition, using continuous casting instead of slabbing of an ingot has reduced CO2 emission by approximately 110 Kg per unit ton of crude steel.
2."Development of stainless steel foils for bipolar plates of polymer electrolyte fuel cells*4" by Sumitomo Metals and Naoetsu
(1) Background
Fuel cells are expected to be the next-generation, eco-friendly, highly-efficient electrical power supply source, for practical application in automobiles and other diverse fields. A bipolar plate, also called a separator, in a fuel cell combines the functions of a flow-field for fuel gas and cooling water and a conductor of generated electricity. A fuel cell uses separators in tens and hundreds. Thus, separators need to display stable performance and quality, excellent mass production capability, and a low unit cost.
(2) Features and benefits
Sumitomo Metals and Naoetsu have developed stainless steel foils for bipolar plates that are suitable for mass production and can be formed with ease. The stainless steel develops a passive-state surface*5 that excels in corrosion resistance, but its extremely-low electrical conductivity makes it unapplicable for bipolar plates. Accordingly, Sumitomo Metals and Naoetsu subsequently developed a method to significantly lower the electrical surface contact resistivity of the plate surface by making electrically conductive metallic inclusions, widely dispersed in the steel, protrude on the passive-state surface.
Contrary to the previous expensive method of lowering resistance by gold plating, this development has realized low-cost manufacturing of bipolar plates.
Part of the technological development for mass production of this technology was jointly achieved with the New Energy and Industrial Technology Development Organization (NEDO).
3."Development of a new class of steel requiring no normalizing heat treatment before nitrocarburization*6 for the application of high strength nitrocarburized crankshafts" by Sumitomo Metals and Kokura
(1) Background
Crankshafts with higher strength are needed for high-powered and light-weight engines. At the same time, a cost-effective manufacturing process and reduction of CO2 emissions through the crankshaft manufacturing process are demanded.
Nitrocarburized crankshafts used for high-powered engines have required heat treatment processes, such as normalizing*7, prior to the nitrocarburization process, as heat forging causes crystal grains to become coarse and friable.
(2) Features and benefits
Sumitomo Metals and Kokura have developed a material which has, without heat treatment, a performance equal or superior to normalized heat-treated steel. This is realized by adding titanium, nitrogen, and molybdenum in the steel for the crankshaft and making crystal grains finer enabling structural refinement after forging the material.
The production process for crankshafts made of this steel reduces CO2 emissions by about 22% and costs by about 8%. It has been commercially applied to some passenger cars since 2006.
The Sumitomo Metals Group will continue to conduct technology development and research for practical applications, while aiming to "accelerate distinctiveness" by supplying environmentally-friendly products.
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*1 Technical Development Award
The Japan Institute of Metals presents this award to engineers who have written in "New Technologies and New Products", the column in the Institute's Bulletin magazine called "Materia Japan", and who are engaged in the development of original technologies such as a new technology or a new product relating to metal engineering.
*2 PCCS
Abbreviation of Porosity Control of Casting Slab.
*3 Porosity
Porosities occur as a result of volume shrinkage of molten steel remaining in the slab center during solidification. The common size of the porosities is approximately 2mm.
*4 Polymer electrolyte fuel cell
A fuel cell is a power-generating system that produces electricity by causing hydrogen (retrieved from a fuel) to react with oxygen (from air). Its high-power generating efficiency and low emission of CO2 make it an environmentally-friendly system. Fuel cells have an electrolyte membrane that enables protons to permeate inside. When the membrane is made of solid polymer, such a fuel cell is called a polymer electrolyte fuel cell. Depending on the materials used for the electrolyte membrane, various types of fuel cells are available. Among these, the polymer electrolyte fuel cell is considered to be the closest to commercial mass production.
*5 Passive-state surface
Chrome and steel that are contained in stainless steel react with oxygen in the air to form a thin oxide film on its surface. This oxide film is called a passive-state surface and provides excellent corrosion protection for stainless steel.
*6 Nitrocarburization
Nitrocarburization is one of the widely-used means for the surface hardening of crankshafts. Nitrogen (and carbon) are diffused into the steel at a temperature of around 600°C in a nitrocarburization furnace. This process improves the fatigue strength of the material.
*7 Normalizing
A heat treatment method to refine grain size after heat forging.
The awards were presented for the following technologies: the "Development of new continuous casting technologies for very thick plate (PCCS method)" by Sumitomo Metals; "Development of stainless steel foils for bipolar plates of polymer electrolyte fuel cells" by Sumitomo Metals and Naoetsu; and "Development of a new class of steel requiring no normalizing heat treatment before nitrocarburization for the application of high strength nitrocarburized crankshafts" by Sumitomo Metals and Kokura. In the case of the last technology, we received the award jointly with Honda R&D Co., Ltd.
Background and features of the technologies
1."Development of new continuous casting technologies for very thick plate (PCCS*2)" by Sumitomo Metals
(1) Background
Continuous casting is the widely used method for manufacturing slabs and is thus an indispensable process for the mass production and stable supply of steel plates.
However, in the manufacture of high-quality steel plates such as high-carbon steel plates for dies and for large-scale industrial machinery, porosities*3 arising during solidification in the slab center detrimentally affect quality. As a consequence, these steel plates have typically been produced by slabbing of a large-sized ingot before rolling.
(2) Features and benefits
Sumitomo Metals' PCCS method facilitates the manufacturing process of very thick plates of more than 100mm in thickness using the continuous casting method by reducing central porosities, an issue associated with inner quality, during casting. This is achieved through hard reduction of the slab with a roll pair in the final solidification stage. These innovative continuous casting technologies are already in use in the No.2 continuous caster at Sumitomo Metals' Kashima Steel Works.
Very thick plates can therefore be manufactured efficiently and with a short lead-time by using a conventional continuous casting machines and a rolling mill. In addition, using continuous casting instead of slabbing of an ingot has reduced CO2 emission by approximately 110 Kg per unit ton of crude steel.
2."Development of stainless steel foils for bipolar plates of polymer electrolyte fuel cells*4" by Sumitomo Metals and Naoetsu
(1) Background
Fuel cells are expected to be the next-generation, eco-friendly, highly-efficient electrical power supply source, for practical application in automobiles and other diverse fields. A bipolar plate, also called a separator, in a fuel cell combines the functions of a flow-field for fuel gas and cooling water and a conductor of generated electricity. A fuel cell uses separators in tens and hundreds. Thus, separators need to display stable performance and quality, excellent mass production capability, and a low unit cost.
(2) Features and benefits
Sumitomo Metals and Naoetsu have developed stainless steel foils for bipolar plates that are suitable for mass production and can be formed with ease. The stainless steel develops a passive-state surface*5 that excels in corrosion resistance, but its extremely-low electrical conductivity makes it unapplicable for bipolar plates. Accordingly, Sumitomo Metals and Naoetsu subsequently developed a method to significantly lower the electrical surface contact resistivity of the plate surface by making electrically conductive metallic inclusions, widely dispersed in the steel, protrude on the passive-state surface.
Contrary to the previous expensive method of lowering resistance by gold plating, this development has realized low-cost manufacturing of bipolar plates.
Part of the technological development for mass production of this technology was jointly achieved with the New Energy and Industrial Technology Development Organization (NEDO).
3."Development of a new class of steel requiring no normalizing heat treatment before nitrocarburization*6 for the application of high strength nitrocarburized crankshafts" by Sumitomo Metals and Kokura
(1) Background
Crankshafts with higher strength are needed for high-powered and light-weight engines. At the same time, a cost-effective manufacturing process and reduction of CO2 emissions through the crankshaft manufacturing process are demanded.
Nitrocarburized crankshafts used for high-powered engines have required heat treatment processes, such as normalizing*7, prior to the nitrocarburization process, as heat forging causes crystal grains to become coarse and friable.
(2) Features and benefits
Sumitomo Metals and Kokura have developed a material which has, without heat treatment, a performance equal or superior to normalized heat-treated steel. This is realized by adding titanium, nitrogen, and molybdenum in the steel for the crankshaft and making crystal grains finer enabling structural refinement after forging the material.
The production process for crankshafts made of this steel reduces CO2 emissions by about 22% and costs by about 8%. It has been commercially applied to some passenger cars since 2006.
The Sumitomo Metals Group will continue to conduct technology development and research for practical applications, while aiming to "accelerate distinctiveness" by supplying environmentally-friendly products.
<>
*1 Technical Development Award
The Japan Institute of Metals presents this award to engineers who have written in "New Technologies and New Products", the column in the Institute's Bulletin magazine called "Materia Japan", and who are engaged in the development of original technologies such as a new technology or a new product relating to metal engineering.
*2 PCCS
Abbreviation of Porosity Control of Casting Slab.
*3 Porosity
Porosities occur as a result of volume shrinkage of molten steel remaining in the slab center during solidification. The common size of the porosities is approximately 2mm.
*4 Polymer electrolyte fuel cell
A fuel cell is a power-generating system that produces electricity by causing hydrogen (retrieved from a fuel) to react with oxygen (from air). Its high-power generating efficiency and low emission of CO2 make it an environmentally-friendly system. Fuel cells have an electrolyte membrane that enables protons to permeate inside. When the membrane is made of solid polymer, such a fuel cell is called a polymer electrolyte fuel cell. Depending on the materials used for the electrolyte membrane, various types of fuel cells are available. Among these, the polymer electrolyte fuel cell is considered to be the closest to commercial mass production.
*5 Passive-state surface
Chrome and steel that are contained in stainless steel react with oxygen in the air to form a thin oxide film on its surface. This oxide film is called a passive-state surface and provides excellent corrosion protection for stainless steel.
*6 Nitrocarburization
Nitrocarburization is one of the widely-used means for the surface hardening of crankshafts. Nitrogen (and carbon) are diffused into the steel at a temperature of around 600°C in a nitrocarburization furnace. This process improves the fatigue strength of the material.
*7 Normalizing
A heat treatment method to refine grain size after heat forging.
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