Bulletin of the Geological Society of America . ore represents all of thatcomponent that it was able to retain at the temperature and pressureexistent during fusion. A temperature very nearly equal to that requiredfor dry fusion must therefore have obtained. Chaxges effected IX THE Steel of the Core Barrel This conclusion as to the high temperature that was attained is com-pletely confirmed by a study of the changes that have taken place in the CHANGES IN STEEL OF CORE BARREL 439 steel. A cutting from the tip of the core barrel and, for comparison, acutting taken 2 feet higher up were submitte
Bulletin of the Geological Society of America . ore represents all of thatcomponent that it was able to retain at the temperature and pressureexistent during fusion. A temperature very nearly equal to that requiredfor dry fusion must therefore have obtained. Chaxges effected IX THE Steel of the Core Barrel This conclusion as to the high temperature that was attained is com-pletely confirmed by a study of the changes that have taken place in the CHANGES IN STEEL OF CORE BARREL 439 steel. A cutting from the tip of the core barrel and, for comparison, acutting taken 2 feet higher up were submitted to the Bureau of Stand-ards with the request that the temperature to which the tip was sub-jected be determined as closely as possible. The report was accompaniedby two micrographs showing the difference in structure. These are re-produced in figure 3. The conclusion reached is that the structure atthe tij:) indicates that the metal was heated above the upper critical range(900 degrees centigrade) and then cooled fairly rapidly (more rapidly. Figure 3.—Micrographs of Steel from Core Barrel a, unhealed steel 2 feet from tip; 6, heated steel tip. The change of structure isdue to the heating of the steel at tip to a temperature as high as 1,050 degrees centi-grade, followed by rapid cooling. than in air). The tip of the pipe was not heated long enough to producepronounced grain growth, which occurs in this type of steel after pro-longed heating above 950 degrees centigrade. It was estimated, however,that the temperature reached was as high as 1,050 degrees centigrade. *This independent evidence is in agreement with the conclusion reachedon an earlier page, that the temperature was in the neighborhood of1,100 degrees centigrade. Production of Heat by Friction It is rather difficult to picture the conditions under which a steel,heated to a temperature at which it can be forged, though not easily,could nevertheless act as an abrasive in cutting rock. It is to be noted,however, th
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1890
