Tetsu-to-Hagane

Forming Processing and Thermomechanical Treatment

Regular Article

Influence of Film Adhesion on PET-hair of Laminated Steel in the Forming Process of DI Can

Masahiro Kai, Shinichi Taya, Hidekazu Tomaru

2013 Volume 99 Issue 8 Pages 503-508
Published: 2013
Released on J-STAGE: July 31, 2013

DOIhttps://doi.org/10.2355/tetsutohagane.99.503

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Application of polyethylene terephthalate (PET) film laminated steel to DI process was expected to be beneficial but had a problem (hereinafter referred to as PET-hair) of film shaving or breaking at formed can edge due to no flange making in process. We indicated in our previous study some findings related to the influences of material properties on the PET-hair. In this study, we investigated influences of PET film adhesion to substrate as a possible factor on the generation of PET-hair, through evaluating the PET-hair on DI forming with different PET laminated steels, where 4 kinds of plating as surface treatment on steel were used, and have reached the following conclusions. The steel substrates with tin nickel alloy plating, which indicate strong adhesion to PET film, tend to get the PET-hair generation reduced more than the substrates with the other plating materials. Reviewing the obtained data from the point of PET film adhesion, we found also reduction of the PET-hair generation in the case of over 15N in 180 degree peel strength of the laminated materials. We presume that stronger film adhesion makes smaller deformation of PET film at the interface, leading to reduction of the PET-hair generation.

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Mechanical Properties

Regular Article

Alloy Design of 5%Mn-Cr-C System Austenitic Steel

Hirokazu Tsukahara, Takuro Masumura, Toshihiro Tsuchiyama, Setsuo Taka ...

2013 Volume 99 Issue 8 Pages 509-516
Published: 2013
Released on J-STAGE: July 31, 2013

DOIhttps://doi.org/10.2355/tetsutohagane.99.509

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The range of chemical composition for obtaining austenitic single structure was defined in medium-manganese carbon steels. Among the defined composition, Fe-5%Mn-4%Cr-(0.8~1.4)%C was selected as the optimum range of composition to form stable austenitic structure. The tensile property and deformation substructure were investigated in the austenitic steels with corresponding composition. As a result, the work hardening behavior of the steels was varied depending on the carbon content, which was closely related with the development of deformation microstructure. In the 0.8%C steel, deformation-induced martensitic transformation as well as deformation twinning caused large work hardening until fracture took place. With increasing carbon content, namely increasing SFE, the deformation mode tended to shift to dislocation slipping, resulting in the lower work hardening rate. This trend seems to be similar to conventional TWIP steel where the work hardening behavior is explained with SFE.

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Effects of Temperature and Strain Rate on Tensile Properties in a Lean Duplex Stainless Steel

Noriyuki Tsuchida, Taiji Kawahata, Eiichiro Ishimaru, Akihiko Takahash ...

2013 Volume 99 Issue 8 Pages 517-523
Published: 2013
Released on J-STAGE: July 31, 2013

DOIhttps://doi.org/10.2355/tetsutohagane.99.517

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Effects of temperature and strain rate on tensile properties in a lean duplex stainless steel S32101 were investigated. In the temperature dependence on tensile properties, the uniform elongation increased from 273 K to 283 K and indicated the maximum uniform elongation at 258 K. From the x-ray diffraction experiments in the S32101, austenite was transformed to stress-induced martensite at temperatures below 283 K. The stress-induced transformation behavior at 258 K, at which the maximum uniform elongation was obtained, had things in common with the case of metastable austenitic stainless steels. When the tensile properties were compared between the S32101 and the metastable austenitic stainless steels, the increase in the uniform elongation due to TRIP effect was almost the same. At low temperatures below about 250 K, the uniform elongations of the metastable austenitic steels were smaller than that of the S32101 because of the large amount of stress-induced martensite at small strains.

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Effect of Strain Rate on TRIP Effect in a 0.2C-1.5Si-1.2Mn Steel

Noriyuki Tsuchida, Keiko Osaki

2013 Volume 99 Issue 8 Pages 524-531
Published: 2013
Released on J-STAGE: July 31, 2013

DOIhttps://doi.org/10.2355/tetsutohagane.99.524

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Effect of strain rate on tensile properties and stress-induced martensitic transformation behavior in a 0.2C-1.5Si-1.2Mn (0.2C TRIP) steel was investigated at strain rates between 3.3◊10^–6 s^–1 and 10³ s^–1. The 0.2% proof stress and tensile strength increased and uniform elongation decreased with an increase in strain rate in the 0.2C TRIP steel. At low strain rates below 10^–4 s^–1, the 0.2C TRIP steel was obtained good uniform elongation. In the strain-rate dependence on stress-induced martensitic transformation behavior, the volume fraction of stress-induced martensite decreased at strain rates higher than about 10^–2 s^–1 due to the temperature rise caused by adiabatic deformation. The difference of stress-induced transformation behavior between the 0.2C and 0.4C TRIP steels seems to be associated with the stress partitioning to retained austenite. Furthermore, the stress partitioning is affected by the volume fraction of not only retained austenite but also ferrite and bainite.

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Social and Environmental Engineering

Regular Article

Solidification Conditions to Reduce Porosity of Air-cooled Blast Furnace Slag for Coarse Aggregate

Hiroyuki Tobo, Yoko Miyamoto, Keiji Watanabe, Michihiro Kuwayama, Tats ...

2013 Volume 99 Issue 8 Pages 532-541
Published: 2013
Released on J-STAGE: July 31, 2013

DOIhttps://doi.org/10.2355/tetsutohagane.99.532

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The solidification conditions to reduce the porosity of air-cooled blast furnace slag were investigated. From cross-sectinal observation of solidified slag, growth of gas bubble generated in molten slag was estimated to be cause of high porosity. With low thermal conductivity slag, increasing the cooling rate by thin slag casting was effective for reducing the porosity of air-cooled blast furnace slag.
As a method of reducing the porosity of air-cooled blast furnace slag, a process was developed in which the slag is solidified to a plate thickness of 20-30mm in about 2 minutes by pouring the molten slag in a cast steel mold. When porosity reduced, the abrasion resistance of the slag improved. The possibility of using low porosity slag as aggregate for drainage pavement was confirmed in an experiment with test pavement.

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