Search Results for structural steel specifications

Critical structural components must be fabricated from steels that exhibit adequate low-temperature fracture toughness because of the serious consequences of failure due to brittle fracture. This article reviews fracture resistance assessment procedures for welded joints and includes discussions on fatigue crack growth and fracture toughness. It presents the fracture toughness requirements specified by different design codes, summarizes the specifications for offshore structural steels provided by international standards organizations, and discusses the applications of these specifications. The article also focuses on advances made in steel technology and the impact of these advances on the fracture toughness of steel.

Hot-rolled steel bars and other hot-rolled steel shapes are produced from ingots, blooms, or billets converted from ingots or from strand cast blooms or billets and comprise a variety of sizes and cross sections. Most carbon steel and alloy steel hot-rolled bars and shapes contain surface imperfections with varying degrees of severity. Seams, laps, and slivers are probably the most common defects in hot-rolled bars and shapes. Another condition that could be considered a surface defect is decarburization. Hot-rolled steel bars and shapes can be produced to chemical composition ranges or limits, mechanical property requirements, or both. Hot-rolled carbon steel bars are produced to two primary quality levels: merchant quality and special quality. Merchant quality is the least restrictive descriptor for hot-rolled carbon steel bars. Special quality bars are employed when end use, method of fabrication, or subsequent processing treatment requires characteristics not available in merchant quality bars.

This article considers four types of high-strength structural steels: heat-treated low-alloy steels, as-rolled carbon-manganese steels, heat-treated (normalized or quenched and tempered) carbon steels, and as-rolled high-strength low-alloy (HSLA) steels (which are also known as microalloyed steels). The article places emphasis on HSLA steels, which are an attractive alternative in structural applications because of their competitive price per-yield strength ratios. HSLA steels are primarily hot-rolled into the usual wrought product forms and are furnished in the as-hot-rolled condition. In addition to hot-rolled products, HSLA steels are also furnished as cold-rolled sheet and forgings. This article describes the different categories of HSLA steels and provides a summary of characteristics and intended uses of HSLA steels described in the American Society for Testing and Materials (ASTM) specifications. The article also presents some applications of HSLA steels.

This article discusses the classifications, specifications, applications and methods for producing welded and seamless steel tubular products, including pipes and tubes. Common types of pipes include standard pipe, conduit pipe, piling pipe, pipe for nipples, transmission or line pipe, water main pipe, oil country tubular goods, water well pipe, and pressure pipe. Pipes in suitable sizes, and most of the products classified as tubing, both seamless and welded, may be cold finished. Pressure tubes are given a separate classification by both the American Society for Testing and Materials (ASTM) and producers. The term tube covers three groups, including pressure tubes, structural tubing, and mechanical tubing.

This article provides a discussion on the two basic steps of the batch hot dip galvanizing process: surface preparation and galvanizing. It describes the factors affecting coating thickness and coating structure. The mechanical properties of the coating and steel substrate are also discussed. The article also provides information on the various factors that should be considered before galvanizing a material. It examines the performances of galvanized coatings in corrosion service. The joining of galvanized structural members by bolting and welding is also discussed. The article describes the synergistic effects of galvanized and painted systems. It explains the applications of hot dip galvanized steel. The article concludes with information on pertinent galvanizing specifications under the authority of the American Society for Testing and Materials.

The production and use of steel plate is aided by a system of standard designations and associated specifications defining composition, property, and performance ranges. This article contains an extensive amount of information on the designations and grades of plate products and how they are made. Although most steel plate is used in the hot-finished condition, some applications require one or more heat treating steps to mitigate imperfections and/or improve relevant qualities. The article discusses these interconnected factors as well as their impact on mechanical properties and critical fabrication issues, including formability, machinability, and weldability.

The selection of materials for welded construction applications involves a number of considerations, including design codes and specifications. Mobile structures have quite different materials requirements for weight, durability, and safety than stationary structures, which are built to last for many years. This article provides an overview of the service conditions. It offers guidance for material selection applications, including bridges and buildings, pressure vessels and piping, shipbuilding and offshore structures, aerospace systems, machinery and equipment, automobiles, railroad systems, and sheet metal. Material properties and welding processes that may be significant in meeting design goals are also described.

This article discusses factors involved in selecting welding processes and consumables and establishing procedures and practices for the arc welding of low-alloy steels. It provides information on welding consumables in terms of filler metals and fluxes and shielding gases. The article describes the various categories of low-alloy steels, such as high-strength low-alloy (HSLA) structural steels, high-strength low-alloy quenched and tempered(HSLA Q&T) structural steels, low-alloy steels for pressure vessels and piping, medium-carbon heat-treatable (quenched and tempered) low-alloy (HTLA) steels, ultrahigh-strength low-alloy steels, and low-alloy tool and die steels. It concludes with a discussion on repair practices for tools and dies.

This article discusses tubular products made from wrought carbon or alloy constructional steels, particularly pipe, specialty tubing, and oil country tubular goods. The article covers product classifications, available specifications, chemical compositions, sizes, and other dimensional attributes. Some of the common types of pipe are standard pipe, conduit pipe, piling pipe, pipe for nipples, transmission or line pipe, water main and water well pipe, and pressure pipe. Pipe in suitable sizes and most products classified as tubing, both seamless and welded, may be cold finished. Pressure tubes, a separate classification, include double-wall brazed tubing, structural tubing, welded mechanical tubing, continuous-welded cold-finished mechanical tubing, and seamless mechanical tubing.

This article describes the types of steels, including high-strength structural carbon steels and high-strength low-alloy steels (HSLA), available in all standard wrought forms such as sheet, strip, plate, structural shapes, bars, bar-size shapes. It discusses the special sections that are characterized by higher yield strengths than those of plain carbon structural steels. The article tabulates the typical chemical compositions, tensile properties, heat treatment, product sizes, plate thickness and intended uses of high-strength steels. Further, it presents a short note on heat treated structural low-alloy grades.

Repair and maintenance of parts and components is carried out as a logical procedure that ensures the production of a usable and safe component or it can be approached haphazardly. This article describes the requirements and repair techniques of arc and oxyfuel welding processes to repair weld defects and structural failures. It further discusses the preliminary assessment and base-metal preparation involved in weld repair. Furthermore, the article provides information on the general repair guidelines that are followed to ensure successful weld repairs of both ferrous (carbon steels, cast irons, and stainless steels) and nonferrous (titanium) base metals.

Stainless steels are iron-base alloys containing minimum of approximately 11% Cr, and owing to its excellent corrosion resistance, are used for wide range of applications. These applications include nuclear reactor vessels, heat exchangers, oil industry tubular, chemical processing components, pulp and paper industries, furnace parts, and boilers used in fossil fuel electric power plants. The article provides a brief introduction on corrosion resistance of wrought stainless steel and its designations. It lists the chemical composition and describes the physical and mechanical properties of five major stainless steel families, of which four are based on the crystallographic structure of the alloys, including martensitic, ferritic, austenitic, or duplex. The fifth is precipitation-hardenable alloys, based on the type of heat treatment used. The article further discusses the factors in the selection of stainless steel, namely corrosion resistance, fabrication characteristics, product forms, thermally induced embrittlement, mechanical properties in specific temperature ranges, and product cost.

Stainless steels and nickel-base alloys are recognized for their resistance to general corrosion and other categories of corrosion. This article examines the effects of specific alloying elements, metallurgical structure, and mechanical conditioning on corrosion resistance of these materials. It provides information on the compositions of selected stainless steels, copper-nickel, and nickel-base alloys in a tabular form. The article also illustrates the compositional and property linkages for stainless steels and nickel-base alloys.

This article commences with a discussion on the characteristics of stress-corrosion cracking (SCC) and describes crack initiation and propagation during SCC. It reviews the various mechanisms of SCC and addresses electrochemical and stress-sorption theories. The article explains the SCC, which occurs due to welding, metalworking process, and stress concentration, including options for investigation and corrective measures. It describes the sources of stresses in service and the effect of composition and metal structure on the susceptibility of SCC. The article provides information on specific ions and substances, service environments, and preservice environments responsible for SCC. It details the analysis of SCC failures, which include on-site examination, sampling, observation of fracture surface characteristics, macroscopic examination, microscopic examination, chemical analysis, metallographic analysis, and simulated-service tests. It provides case studies for the analysis of SCC service failures and their occurrence in steels, stainless steels, and commercial alloys of aluminum, copper, magnesium, and titanium.

This article discusses the generic situation of steel reacting with the environments found in structures. Two environments are specifically discussed: atmospheric and cementitious. The article describes the utility of different corrosion protection methods for atmospheric corrosion and cementitious systems. It presents examples of problems that have arisen in the corrosion performance of steel.

Thermal spray coatings (TSCs) are surface coatings engineered to provide wear-, erosion-, abrasion-, and corrosion-resistant coatings for original equipment manufacture and for the repair and upgrading of in-service equipment. This article presents an overview of five thermal spray processes and the specific flame and arc spray processes used to preserve large steel components and structures. It describes the TSC selection guide and an industrial process procedure guide for applying aluminum and zinc TSCs onto steel.

Low-carbon steel sheet and strip are used primarily in consumer goods. This article discusses quality descriptors and mechanical properties of low-carbon steel sheet and strip and carbon and low-alloy steel plate. Alloy steel sheet and strip are used primarily for those special applications that require the mechanical properties normally obtained by heat treatment. Steel sheet is coated in coil form before fabrication either by the steel mills or by specialists called coil coaters. Porcelain enamels are glass coatings applied primarily to products or parts made of sheet steel, cast iron, or aluminum to improve appearance and to protect the metal surface.

This article provides an overview of the different classification and designation systems of wrought carbon steel and alloy steel product forms with total alloying element contents not exceeding 5″. It lists the quality descriptors, chemical compositions, cast or heat composition ranges, and product analysis tolerances of carbon and alloy steels. The major designation systems discussed include the Society of Automotive Engineers (SAE)-American Iron and Steel Institute (AISI) designations, Unified Numbering System (UNS) designations, American Society for Testing and Materials (ASTM) designations, Aerospace Material Specification (AMS), and other international designations and specifications.

Most alloys are susceptible to intergranular corrosion, also known as intergranular attack (IGA), when exposed to specific environments. This article reviews the theory and application of acceptance tests for detecting the susceptibility of stainless steels and nickel-base alloys to IGA. It describes the most serious forms of structure-dependent corrosion, such as stress-corrosion cracking and exfoliation, in aluminum alloys including strain-Hardened 5xxx (Al-Mg) alloys and heat treated high-strength alloys. The article concludes with information on the evaluation tests for other alloys such as magnesium alloys and zinc die casting alloys.

This article describes the process features, advantages, limitations, and applications of the flux cored arc welding (FCAW) as well as the equipment used in the process. Base metals, namely, carbon and low-alloy steels, stainless steels, and nickel-base alloys, welded by the FCAW process are reviewed. The article illustrates the manufacturing process for the electrodes used in FCAW and outlines the classification of carbon and low-alloy steel, stainless steel, and nickel-base electrodes.