Carbon steel chemical analysis

The basic oxygen process produces steels that contain about 1% carbon but only very small amounts of phosphorus and sulfur. Usually, the composition of the liquid steel is monitored by chemical analysis, and the amounts of oxygen and impure iron used are adjusted to achieve the desired concentrations of carbon and other impurities. The hardness, strength, and malleability of the steel depend on its chemical composition, on the rate at which the liquid steel is cooled, and on subsequent heat treatment of the solid. The mechanical and chemical properties of a steel can also be altered by adding other metals. Stainless steel, for example, is a... 

Upon the liberation of the camp, the aircraft hangar protecting the block was partially damaged. The side room was empty. Zyklon B cans were initially piled up there to give the impression that their contents could have been emptied into the pipes of room Bl (instead of through the opening in the ceiling). Five steel carbon monoxide containers were found in the camp. After chemical analysis of their content, two of them were housed in the side room. 36... 

The particular advantage of diffraction analysis is that it discloses the presence of a substance as that substance actually exists in the sample, and not in terms of its constituent chemical elements. For example, if a sample contains the compound A By, the diffraction method will disclose the presence of A B as such, whereas ordinary chemical analysis would show only the presence of elements A and B. Furthermore, if the sample contained both A B, and Aj Bjy, both of these compounds would be disclosed by the diffraction method, but chemical analysis would again indicate only the presence of A and B. To consider another example, chemical analysis of a plain carbon steel reveals only the amounts of iron, carbon, manganese, etc., which the steel contains, but gives no information regarding the phases present. Is the steel in question wholly martensitic, does it contain both martensite and austenite, or is it composed only of ferrite and cementite Questions such as these can be answered by the diffraction method. Another rather obvious application of diffraction analysis is in distinguishing between different allotropic modifications of the same substance solid silica, for example, exists in one amorphous and six crystalline modifications, and the diffraction patterns of these seven forms are all different. 

Curves are included showing the temperatures above which commonly used carbon steels may be exempted from impact testing. Materials such as ASTM A53 for steel pipe and A285 FQ for steel plate, in which the chemical analysis is not fully specified are not permitted. Ultrasonic examination is required for plate and forgings over 4 in. thick, and examination required for castings is more stringent. 

In former times, two other processes were also used to burn out the excess carbon and other impurities for the production of steel from pig iron. In the Bessemer process, air was blown through the molten iron. The bottom of the converter was perforated with a number of channels through which the air is forced into the converter. The process was rapid (about 15 min) and so there was only little time for chemical analysis and adjustment of the alloying elements in the steel. Bessemer converters also did not remove phosphorus efficiently, and certain grades of steel were sensitive to nitrogen, which is the major part of the air blast. 

Carbon content control is crucial for the optimal control in steel making. The traditional method uses quick chemical analysis to determine the end point of a batch in steel making. This method is necessary to delay the time of one batch of steel making. In order to save the delayed time and make the steel making process smooth, it is desirable to use a mathematical model for the end point prediction in steel making. 

EGA-DTA has been applied to the analysis of Fe3C, amorphous carbon, and graphite in steel and cast iron (178). In general, the previous claims for isolation of these compounds have been correct. Different amounts of Fe3C are isolated by various chemical treatment, which explains the contradictions in the literature. 

One aspect of eluent compatibility with EC detection is that there should be no effect on the components of the detector. Detector cell bodies are now routinely constructed of PTFE, other fluoroplastics, glass or stainless steel, and seem stable to most eluents. Nevertheless electrodes are vulnerable to chemical attack. Problems with the longer term use of some eluents at potentials around +1 V vs Ag/AgCl have been experienced. For example, ammonium acetate buffers have caused flaking of the surface of glassy carbon electrodes held at as little as +0.1 V for one batch of electrodes. Noble metal electrodes are easily contaminated by a number of eluents unless the electrode is cleaned by pulsing the applied voltage as in carbohydrate analysis (Chapter 3, Section 6). 

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