Soaking Pits Research Articles

Use of corundum phosphate-bonded concretes for bottoms of soaking pits

Corundum concrete blocks with aluminophosphate bonds laid in sections of the base of heat-treatment (soaking pit) furnaces subjected to sudden thermal impact have a greater resistance than fusion-cast corundum blocks. The concrete blocks should be made with waste fusion cast blocks.

An optimal design of a soaking-pit rolling-mill system

While attention in the iron and steel industry has been focused on the study and analysis of the flow of materials through the main productive units (blast furnaces, steel works, and rolling mills), the analysis of this flow through the nonproductive units (the mixer and soaking pits) is generally over looked. These two units would create serious bottle necks in production if their capacities were not properly determined before being installed. This paper considers the soaking-pit/rolling-mill complex as a queueing system in which the soaking pits are viewed as units circulating a cyclic queue, and the rolling mill as the service station. A simulation model representing the pit-mill system is developed: (1) To predict the improvement in the capacity of the system through adding more pits (2) To predict the effect of breakdowns and mainte nance or the shutdown of a pit. Several criteria, including their economic aspects, are used to measure the performance of the system. The optimal capacity of the system is determined such that an economic balance between the cost of service and the cost of waiting for that service is achieved.

Influence of Glassy Matrix on the Service Performance of the Aluminous Refractories

While a fair reflection of the characteristics of the refractories may be obtained by the normal tests given in various standard specifications, they are inadequate to explain the actual difference in the durability under service conditions of apparently similar bricks supplied by different manufacturers to meet the same specification. The service conditions bring in certain intangibles owing to the degree of vitrification and continuation of mineralogical changes depending on the method of manufacture and the nature of the constituents. Consequently, a proper appraisal of the refractories requires further tests which simulate service conditions.The aluminous refractories used in the soaking pit covers are subjected to the combined effect of high temperature and ferruginous fumes. When these bricks failed, the nature of their failure was studied over a period of ten years to understand the difference between the bricks.The investigations included studies of viscous flow, plastic deformation, creep or chan...

Laboratory study of the resistance of refractories for soaking pit hearths

Laboratory study of the resistance of refractories for soaking pit hearths

Raising the temperature at which metal is charged into soaking pits

The temperature of the hot metal charge exerts a great effect on the productivity of blooming mills, This accounts for the importance of finding ways to shorten the time required to get the metal from the heating furnace to the mill, shortening the time required to make up the roiling stock to transport the metal within the steel plant, and the importance of selecting efficient traffic routes for the metal within the plant.

The Capacity of The Soaking Pit-Rolling Mill Complex in Steel Production

AbstractThis paper considers a problem in the production of steel at the Hilton Works of Stelco in Hamilton, Ontario. The necessity of having uniformly hot steel, provided by a battery of soaking pits, limits the production capacity of a rolling mill. At times there is nohot steel and the mill comes into “nothiag hot” delays.The obvious approach is to consider the soaking pits as parallel servers feeding the mill in a tandem manner. However, a more fruitful approach is to consider the pits as units circulating a cyclic queue. Clos dform solutions are found for the capacity of the pit-mill complex which take into accountthe individual heating rates of each pit as well as the possible necessity of repairs.

On-line Computer Control of Soaking Pits

The paper describes the research work being carried out jointly by Queen Mary College, London and the British Steel Corporation (Strip Mills Division). The work involves the application of a mathematical model which describes the cooling of the ingots prior to loading into the pits and secondly it describes the heating of the ingots whilst they are in the Soaking Pit. The model is in the form of a set of non-linear partial differential equations and the paper compares the results obtained for, firstly a one dimensional solution and, secondly, for a two dimensional solution.The work is being evaluated and developed using one of the Soaking Pits at the Llanwern Group of the British Steel Corporation. It is intended to apply the techniques developed to 16 new Soaking Pits at present under erection.The paper compares the advantages of using a hybrid computer against a pure digital computer.The model at present can be used for predicting the time required to heat and soak the ingots to a state suitable for rolling. It is intended to extend the use of the model for optimising the heating of ingots and the optimal loading of the pits.

リムド鋼中非金属介在物と地鉄との反応について

Steel ingots are generally subjected to various heat treatments during processing to final products.For example, those are annealed for a long time in a soaking pit prior to rolling. In this period, there is a possibility that some reactions between non-metallic inclusions and matrix around them can occur.The reactions during annealing of ingot and slab of a rimmed steel were studied here by examining the changes in composition of inclusions and matrix by means of the electron probe microanalyser. Results obtained are as follows. 1) When the ingot was annealed at the soaking temperature for a long time, compositions of inclusions changed probably to attain the equilibrium with matrix at the temperature. The magnitude of such changes varied with the position in ingot, hence it was supposed to depend on the rates of solidification at each position. Some reactions may take place between inclusion and matrix and between components of inclusion such as oxide and sulfide. 2) In the case of slab under similar treatment, inclusions changed their shapes to spherical readily at above 1300°, and the compositions changed largely at 1100°C resulting in an increase of manganese concentration.

Service of fireclay blocks with clay ? Phosphate bonds in blooming soaking pits

A technology was developed for making chamotted concrete blocks with clay-phosphate bond. A cycle was selected for thermal processing.

Ramming bodies for the bottoms of soaking pit furnaces

On the basis of sintered corundum and electrocorundum compositions were developed for ramming bodies containing phosphoric acid which can be recommended for making the bottoms of soaking pits.

The Measurement of Temperature of Soaking Pit Waste Gases

The Measurement of Temperature of Soaking Pit Waste Gases

Heating of large ingots in the recuperative soaking pits of the slabbing mill

Heating of large ingots in the recuperative soaking pits of the slabbing mill

Pits Simulation for Production Planning

Simulation techniques are used to study a deterministic problem in the aluminium industry. Mathematical methods alone are inadequate to solve this scheduling problem. Three segments are connected: 1) simulation model, 2) optimization with dynamic programming, and 3) sorting, heuristic, and manual treatments. The economical function is the cost of electrical energy consumed. With dynamic programming the energy consumption of the soaking pits is optimized by using simplified hypotheses. Simulation allows one to adapt mathematical results to the real process. The same simulation model was used during the analysis period and, repetitively, during the operational period.

Instrumentation and controls for operation of no. 2 soaking pits at fairless works

This paper describes the instrumentation and controls for operation of soaking pits. All components of the system are plug-in units of the solid-state type, except for input switching, which are mercury-wetted relays. The input signals to the logger emanate from sixty-four chromel-alumel thermocouples with a range of 0–2500°F. The points are periodically logged on thirty-minute intervals as well as on demand. Continuous scanning takes place at the rate of one point per second between the periodic logs. Upon detection of an off-normal signal, one that has exceeded the set point, all points will be logged with the off-normal being printed in red. When the process returns to normal, all points are logged again even between periodic logging time. With the detection of each off-normal, the alarm will sound and continue to sound until acknowledged by the operator.

A new method of removing slag from soaking pits

A new method of removing slag from soaking pits

Reconstruction of the bridgewalls of the checker chambers of blooming mill soaking pits

Reconstruction of the bridgewalls of the checker chambers of blooming mill soaking pits

The use of ceramic recuperators in soaking pit furnaces

Mixtures of SiC and slag and clinker do not fuse at 1300°C. Articles made of SiC are not penetrated and are scarcely damaged at up to 1500°C by slag or clinker. Mixtures of fireclay-kaolin refractory powders with slag or clinker melt at 1300°C. Fireclay-kaolin crucibles are not penetrated at 1500°C but are damaged by clinker and slag. The mixtures of fireclay-SiC refractory powders, slag and clinker melt at 1300°C. The fireclay-SiC articles are penetrated at 1500°C and partly destroyed by slag and clinker. In soaking pits it is desirable to use SiC recuperators at flue-gas temperatures of 1300–1400°C. The fireclay-SiC recuperators can be used in heating pits at flue-gas temperatures of below 1300°C. At higher temperatures in the heating pits, when the SiC may be strongly oxidized, it is desirable to test fireclay-kaolin recuperators.

Testing blocks of refractory concrete in the walls of soaking pits

The use of refractory concrete in recuperative soaking pits is quite feasible. The use of block structures of refractory concrete cuts repair time by half and increases the efficiency during repairs 10 times. It is favorable to continue the work on testing these concretes in the walls of slabbing pits. It is necessary to build the compartment walls entirely from blocks of one composition. This composition is one based on Portland cement with finely milled chromite and forsterite aggregate.

Recuperative soaking pits with top two-way heating

Recuperative soaking pits with top two-way heating

Simulation of the dynamic behaviour of a soaking pit by an analogue computer

Simulation of the dynamic behaviour of a soaking pit by an analogue computer