Weathering Steel

Abstract

A. Need for weathering steel B. History B1. Applications B2. Expansion of the use of weathering steels C. Alloying elements C1. Mechanistic aspects D. Monitoring rust films E. Design parameters F. Guidelines for bare weathering steel G. Advancement in weathering steel in the past decade G1. Life-cycle design specification for highway bridges G2. "Minimum-Maintenance" concept G3. Advanced weathering steel References A. NEED FOR WEATHERING STEELRecognition of global warming and environmental degradation has caused the direction of technology to shift toward environmentally conscious and sustainable development, with the result that increased efficiency in the use of limited resources is now a focus (e.g., recycling industrial materials). In addition, the environmental characteristics of industrial products, structures, and materials through their life cycles are being improved by life-cycle assessment (LCA) of the International Organization for Standardization (ISO) 14000s. Although LCA needs further improvement, it is a potentially useful methodology for systematically analyzing a product from the extraction of resources to eventual abandonment, including reuse, recycling, or disposal in terms of energy, in most cases, and materials, emissions of hazardous substances, and wastes.The LCA approach is being used to clarify quantitatively the important role of steel and steel products in our society in terms of their abundant resources, economic availability in large quantities, workability, reliability, reasonable life-cycle cost, relatively low environmental burden, and recycling possibilities.Structural steel is expected to remain as one of most environmentally friendly materials available in the twentyfirst century. In addition, the recent life-cycle study of automobiles, houses, bridges and so on conducted by the Engineering Academy of Japan has demonstrated that 7085% of the energy consumption by these products throughout their life cycle occurs during service period, rather than during production or product assembly [1]. This observation indicates that materials performance, durability, and reliability are key considerations in the design of a product or a structure for its life-cycle energy efficiency. Figure 48.1 shows an example of the framework for the systematic assessment of materials performance, including (a) life-cycle cost (LCC) analysis, (b) life-cycle safety (LCS) design, (c) LCA for energy and materials, and (d) diagnosis of life prediction based on the operating mechanisms.Our living environments consist mainly of freshwater, seawater, the atmosphere, and soil. These four categories include the environments in which the majority of structural steel products and large structures are exposed. Corrosion mechanisms of structural steels and the dominant corrosion parameters in these environments are discussed in other chapters. In this chapter, carbon and low-alloy structural steels resistant to atmospheric corrosion (i.e., weathering steels) are discussed. Weathering steels have been widely accepted i...

Assessment of rust layers formed on weathering steel in saline environment by gas adsorption

“…It is noteworthy that the present adsorption method distinctly demonstrates the depression in particle size of the real rusts by alloying metals. It is known that alloying with nickel enhances the corrosion resistance of steels in saline environment . To confirm the effect of alloying with nickel, the S N and S W of the rusts of steels are plotted against the nickel content of the steels in Fig.…”

Evolution and Evaluation of Aesthetic Properties in Weathering Steel Accelerated Patinas: The Role of Lepidocrocite

“…Weathering steels (WS) are classified as high strength low alloy steels (HSLA) with a quantity of carbon less than 0.2% and with a total amount of alloy elements, such as Cu, Cr, Ni and Mn lower than 3-5% in weight [1]. Their commercial name Cor-Ten © refers to the atmospheric corrosion resistance and tensile strength of WS.…”

Ten years outdoor exposure of steel in an urban and coastal tropical atmosphere

“…Other factors such as rainfall and winds also influence this process [1]. WSs, also known as low-alloy steels, are actually mild steels, with a carbon content of less than 0.2% w/w, to which mainly Cu, Cr, Ni and P have been added as alloying elements in a total amount not exceeding 3-5% w/w [2].…”