Steel ingots and their Casting during Steelmaking...

Steel ingots and their Casting during Steelmaking Ingot casting is a conventional casting process for liquid steel. Production of crude steel through the ingot casting route constitutes a very small percentage of global crude steel production. However, the method of casting of the liquid steel in ingot moulds is still fundamental for specific low-alloy steel grades and for special forging applications, where products of large dimension, high quality or small lot size are needed. Typical application for conventional ingot casting includes the power engineering industry (e.g. shafts for power generation plants, turbine blades), the oil and gas industry (conveying equipment, seamless tubes), the aerospace industry (shafts, turbines, engine parts), ship building (shafts for engines and drives), tool making and mechanical engineering (heavy forgings, cold, hot and high-speed steels, bearing, drive gears) as well as automotive engineering (shafts, axes). As the demand of heavy ingot increases nowadays, especially from the power engineering industry and ship industry, there is a tendency of producing extreme large ingots over 600 t and continuous cast strands with thickness over 450 mm and rounds with diameter up to 800 mm, which are mainly applied for pressure retaining components such as reaction vessels for nuclear power plant and rotating components like drive shafts of gas turbines and generator rotors. The moulds used for casting of ingots are made of cast iron. Cast iron is used for the production of the mould since the thermal coefficient of cast iron is lower than that of steel. Because of this property of cast iron, liquid steel on solidification contracts more than cast iron which makes detachment of ingot easier from the mould. Inner walls of the mould are coated by either tar or fine carbon. The coated material decomposes during solidification and this prevents sticking...

Pipe and Tubular Products of Steel...

Pipe and Tubular Products of Steel The term pipe and tubular product of steel is the used to cover all hollow products of steel. These products are normally produced in cylindrical shape. However, they are frequently altered by different processing methods to produce square, oval, rectangular, and other symmetrical forms. Pipe and tubular products have a large number of applications, but they are most commonly used for conveying of fluids and as structural members. Steel pipe and tubular products are normally produced from wrought carbon (C) or alloy constructional steels and are usually designated by the terms pipe, specialty tubing, and oil country tubular goods (OCTG) etc. Pipes and tubular products have an outside dimension, an inside dimension and the wall thickness as shown in Fig 1. Fig 1 Dimensions of pipe and tubular products The steel pipe and tubular products are usually classified broadly as (i) pipe, and (ii) tube. The application of the terms pipe and tube is not always consistent. The term pipe is normally used to describe cylindrical products made to standard combinations of outside diameter and wall thickness. The main difference between a pipe and a tube is the way the diameter of the pipe or tube is designated. Pipe is normally designated by a “Nominal Pipe Size” based upon the ID (inside diameter) of the most common wall thickness while the tube is designated by the measured OD (outside diameter). As an example a 20 mm steel pipe with 4 mm thickness has an OD of 28 mm while a 20 mm steel tube has an OD of 20mm.  The two broad classifications of steel pipe and tubular products are subdivided into several named use groups. As an example, the term tube covers three such groups namely (i)...

Ductile Iron Pipes

Ductile Iron Pipes Ductile Iron pipes are pipes made of ductile iron. They are commonly used for potable water distribution and the pumping of slurries, sewage and process chemicals. Ductile iron is a spheroidized graphite cast iron. Ductile iron pipes are a direct development of earlier cast iron pipes which it has now almost replaced. The high level of dependability on ductile iron pipes is due to its various superior properties and it is a most sought after pipe for many applications. History of ductile iron pipes American Cast Iron Pipe Company pioneered the development of ductile iron pipes and produced experimental casts of these pipes as early as in 1948. The first shipment was made in 1955. Since then production of ductile iron pipes has grown steadily and it is now a predominant piping material for conveying water and other liquids. Ductile iron As the name suggest, it is a cast iron having the property of ductility. This quality of cast iron long sought after by metallurgists, was realized in 1948. Ductile iron is acclaimed as one of the most significant developments of the century and has had an increasing impact on the industry. Besides the property of ductility, ductile iron has, in addition, strength and impact resistance much greater than that of gray iron.  Ductile iron also retains the corrosion resistance property of gray iron hence it is an ideal material for pipes. Ductile iron is produced by treating molten low sulphur base iron with magnesium under closely controlled conditions. The startling change in the metal is characterized by the free graphite in ductile iron being deposited in spheroidal or nodular form instead flake form as  gray cast iron. With the free graphite in nodular form, the continuity of the metal matrix...