Abstract: The present invention is directed to a technique for visually judging an exchange timing of a container which has been heated in the air and thus degraded. The container is a container having a storage section for storing products: wherein the constituent material of the container is a resin composition; wherein the composition contains an antistatic agent; wherein the composition contains no coloring material, or contains a coloring material, however in this case, at a time when (a surface electric resistance value of the container having been changed by heating of the container)/(a surface electric resistance value of the container at a time of starting the heating)=10, discoloration of the container caused by the heating is a recognizable degree; and wherein the container is exchanged in a case where the container is discolored to a defined color by the heating.

Abstract: Cold rolled steel sheets having improved bake hardenability is provided. Specifically, the present invention relates to a cold rolled steel sheet, with improved bake hardenability, comprising an ultra low carbon steel containing titanium and/or niobium, wherein the relationship between the contents of carbon and molybdenum in solid solution being regulated in a specified range, and a cold rolled steel sheet, with improved bake hardenability, which further contains a specified amount of boron in addition to the above constituents.

Abstract: A nitriding steel excellent in formability and susceptibility to nitriding, comprising, based on weight, 0.0002 to less than 0.08% of C, 0.005 to 1.00% of Si, 0.010 to 3.00% of Mn, 0.001 to 0.150% of P, 0.0002 to 0.0100% of N, greater than 0.15 to 5.00% of Cr, greater than 0.060 to 2.00% of Al (Al becoming a selective component in an amount of greater than 0.10 to 2.00% when the C content is from 0.0002 to less than 0.0100%), one or two elements selected from 0.010 to 1.00% of Ti and 0.010 to 1.00% of V, and the balance Fe and unavoidable impurities, and a press formed article formed from the steel and having a hard nitride layer at least on one side.

Abstract: An automobile body reinforcing steel pipe having a wall thickness-to-outer diameter ratio, t/D, defined by:0.09-4.8.times.10.sup.-5 .times.L.ltoreq.t/D.ltoreq.0.16-6.0.times.10.sup.-5 .times.Lwhere L(mm) is a span of a bending load applied to the pipe. The pipe has a tensile strength of 120 kgf/mm.sup.2 or more and an elongation of 10% or more, and is preferably made of a steel consisting of 0.15-0.25 wt % C, 1.8 wt % or less Mn, 0.5 wt % or less Si, 0.04 wt % or less Ti, 0.0003-0.0035 wt % B, and the balance of Fe and unavoidable impurities including 0.0080 wt % or less N. A process for producing the steel pipe comprises: coiling a hot rolled steel sheet at a temperature of 600.degree. C. or higher; electric welding the adjoining edges of the sheet to form a steel pipe; and quench hardening the pipe.

Abstract: An automobile body reinforcing steel pipe having a wall thickness-to-outer diameter ratio, t/D, defined by:0.09-4.8.times.10.sup.-5 .times.L.ltoreq.t/D.ltoreq.0.16-6.0.times.10.sup.-5 .times.Lwhere L(mm) is a span of a bending load applied to the pipe. The pipe has a tensile strength of 120 kgf/mm.sup.2 or more and an elongation of 10% or more, and is preferably made of a steel consisting of 0.15-0.25 wt % C, 1.8 wt % or less Mn, 0.5 wt % or less Si, 0.04 wt % or less Ti, 0.0003-0.0035 wt % B, and the balance of Fe and unavoidable impurities including 0.0080 wt % or less N. A process for producing the steel pipe comprises: coiling a hot rolled steel sheet at a temperature of 600.degree. C. or higher; electric welding the adjoining edges of the sheet to form a steel pipe; and quench hardening the pipe.

Abstract: A zinc- or zinc alloy-coated steel sheet having an excellent spot-weldability, comprising: a base steel sheet; one or more layers coated on the steel sheet, at least one of the coated layers containing zinc as a major component; and an oxidized layer formed on the outermost of the coated layers and containing zinc in an amount of from 0.03 to 3.0 g/m.sup.2, the oxidized layer containing at least one of zinc oxide and zinc hydroxide.