Nickel in Steels

Nickel in Steels  Nickel (Ni) (atomic number 28 and atomic weight 58.69) has density of 8.902 gm/cc. Melting point of Ni is 1455 deg C and boiling point is 2910 deg C. The phase diagram of the Fe-Ni binary system is at Fig 1. Ni has a face centered cubic (f.c.c.) crystal structure. It is ferromagnetic up to 353 deg C, its curie point.   Fig 1 Fe-Ni phase diagram Ni is an important and widely used constituent of alloy steels. It is best known as a solid solution strengthener, a mild hardenability agent and, most important, as a means of promoting high toughness, especially at low temperatures. Ni is an important ingredient in stainless steel, helping it to prevent rust, scratches and resist heat. Around 65 % of global Ni production goes into the production of stainless steel. Ni alloyed steels contain as little as fraction of a percent to almost 30 % Ni. As may be expected, properties of these alloy steels range from strengths similar to plain carbon steel to some of the strongest metallic materials known. On the lower side of the Ni percentage in the steels are the alloy and HSLA (high strength and low alloy) structural steels. Hot rolled steels with yield strengths of 345 MPa may contain 0.50 % to 2.00 % Ni for toughness and added corrosion resistance. Age hardening steels contain 1.3 % to 1.5 % Ni plus copper (Cu) and niobium (Nb). Quenched and tempered or normalized and tempered structural steels contain nickel (Ni) up to 2.25 %, as well as a variety of other constituents including chromium (Cr), molybdenum (Mo) or boron (B). Nickel bearing addition agents Ni bearing addition agents are ferro- nickel (Fe- Ni) ferroalloy, Ni containing steel scrap, Nickel oxide...

Succession Planning

Succession Planning  In the present day highly competitive environment, the most important asset for an organization is its manpower which is a major factor in differentiating a highly successful organization from an organization which is struggling. Successful organization uses succession planning to develop and maintain strong leadership in all the critical positions and to ensure that this leadership has all the skills and competencies needed for the success of the organization in the environment under which it operates. An organization cannot have strong and capable employees in every critical position by concentrating its efforts only on recruitment and training. For this a systematic approach to succession planning is needed. Succession planning is perhaps a necessary component of the management efforts in building the organization and it helps tremendously the organization in achieving its strategic goals. Unfortunately, planning for succession is often overlooked or occurs when it is too late i.e. after key people have left the organization and there are no right internal candidates to fill the key positions. However If the organization executes succession planning in a right way then it fully prepares the identified personnel to step into positions left vacant because of retirement and general attrition. The primary task of succession planning is to plan a sequence of personnel moves so that candidates for key positions are known in advance of actual need. This prior identification permits opportunities for mentoring and developmental activities to improve a person’s readiness to succeed to specific positions. It also provides concrete decision making information necessary to minimize the chance of poor selections or the adverse impacts of unforeseen vacancies that can disrupt the continuity of proper management of the operations in the organization. Succession planning is a process whereby an organization ensures that employees are...

Argon Rinsing of Steels Oct26

Argon Rinsing of Steels...

Argon Rinsing of Steels Gas rinsing process is a method where rinsing of liquid steel in the teeming ladle is carried out through injection of inert gas into the steel bath. Argon (Ar) gas is preferred for rinsing since it is not only inert in nature but its solubility in steel is also very low. Rinsing results from the expansion of gas due to heating and decrease in pressure as the gas rises. The Ar rinsing of liquid steel is carried out for obtaining homogenous temperature, composition, and promotion of slag metal refining reaction.  The Ar rinsing of liquid steel is reported to be an excellent process for floatation and separation of non-metallic inclusions. The liquid steel after tapping is stratified in the teeming ladle due to the additions of the ferro alloys and the carburizer in the teeming ladle at the time of tapping of the steel. This stratified steel is agitated by purging of Ar gas in the Ar rinsing station. Ar gas purging through the liquid steel bath help generate enough bath turbulence to effect rapid thermal homogenization. Stirring with Ar also enhances mixing rate for chemical additions. Different variables for argon rinsing include gas purging rate, amount of liquid steel (heat size), amount of superheat available in the liquid steel, amount of carry over slag, amount of synthetic slag or ladle covering compound added, amount of mixing needed for chemical additions. Experienced operators and metallurgists recognize the importance of accurate and consistent Ar gas rinsing in the teeming ladle. Clean steel and good castability in the continuous casting machine (CCM) depend on a consistent and gentle rinse stir. A good Ar rinsing control system at the Ar rinsing station facilitates reproducible and accurate argon rinsing rates and durations. Ar gas can...

Industrial High Capacity Metal Granulation – Application & Results from Over 40 Installations Oct20

Industrial High Capacity Metal Granulation – Application & Results from Over 40 Installations...

Industrial High Capacity Metal Granulation – Application & Results from Over 40 Installations Mr Per Vesterberg, UHT Sweden Dr Kristina Beskow, UHT Sweden  Abstract  The industrial and high capacity GRANSHOT metal granulation process will be presented with operational experience from installations at integrated steel plants. The use of the end product; Granulated Pig Iron, GPI, will also be demonstrated. The GRANSHOT granulation process converts excess liquid metal into granules by immediate solidification in water. The ready–to–use bulk material, GPI, is produced directly from liquid metal, producing little to no fume emissions or dust. The GRANSHOT plant decouples ironmaking and steelmaking operations when required as to enable optimum operating conditions for the blast furnace. It  can be designed to process the entire output of the blast furnace.  Keywords Pig iron, granulation, blast furnace, GRANSHOT, beaching, sand bed casting, sand bed pooling, GPI, environment CHALLENGES IN STEEL MAKING  In integrated steelmaking, plant managers and operators are asked to match their production to downstream or client demand with respect to output as well as metallurgical parameters [1]. In addition, the plant performance that they’re held accountable for is assessed in terms of raw material consumption, achieved campaign lives of equipment and health, safety and environmental performance. Lack of synchronization between BF and BOF operations is the inevitable part of day–to–day operations which results in excess pig iron being buffered in torpedo or hot metal transfer ladles. Availability is, however, limited and prolonged buffering may be undesirable. Fluctuating demand from the BOF shop may also be met by adjusting the output of the blast furnace. However, this comes at considerable penalties, since a destabilized BF process may escalate at severe consequences and process stability is essential for achieving maximum campaign life. Being able to optimize the blast furnace...

Silicon in Steels

Silicon in Steels  Silicon (Si) (atomic number 14 and atomic weight 28.09) has density of 2.34 gm/cc. Melting point of Si is 1412 deg C and boiling point is 2355 deg C. The phase diagram of the Fe-Si binary system is at Fig 1. Fig 1 Fe-Si phase diagram  Si is present in all the types of steels either as an intentional addition or as a residual from the ore, scrap or deoxidizing agents. Available forms  There are many Si containing addition agents which are used in steel making. Ferrosilicon (Fe-Si) and silico manganese (Si- Mn) are by far the most common addition agents. Fe-Si is a ferroalloy of iron (Fe) and Si. Fe – Si contains 65 % to 90 % of Si and minor amounts of Fe, aluminum (Al) and carbon (C).  Fe – Si is usually produced in four grades. These are standard grade, low Al grade, low C grade, and high purity grade having low content of titanium (Ti). The standard grade of Fe- Si contains Al up to 2 % while the low Al grade has Al content of 0.5 % maximum. It is produced by reduction of quartzite (SiO2) with coke in presence of iron ore.  Fe- Si is made in the submerged arc furnace. Si – Mn is a ferroalloy with high content of Mn and Si. It is produced by heating a mixture of oxides of MnO2, SiO2 and Fe2O3 with C in a furnace. These oxides undergo a thermal decomposition reaction. The standard grade contains Mn in the range of 62 % to 68 %, Si in the range of 12 % to 18 % and C in the range of around 2.0 %.  The low C grade of Si – Mn has a C...