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effect in causing hot cracks as does the method of manufacture of the steel.
Data on Electric and Converter Heats
1 4 1 3 2 2 1 2 1 2 3 2 1 5 1 3
6/12 6/13 6/15 6/19 6/19 6/20 6/20 6/21 6/25 6/26 6/26 6/26 6/27 6/28 6/28 6/29 6/14 6/14
0.87 0.047 0.049 2 cracked, torn 68579 0.29 0.47 1.11 0.046 0.050 1 cracked, torn 68592 0.27 0.56 0.84 0.065 0.041 1 cracked, torn 68593 0.30
1.13 0.055 0.043 1 cracked 68609 0.26
0.98 0.057 0.049 1 cracked, torn 68657 0.27 0.38 1.00 0.070 0.045 68675 0.24
0.80 0.064 0.040 1 cracked, torn E528 0.27 0.19 1.31 0.016 0.020 68673 0.28 0.56 1.07 0.065 0.043
68691 0.26 0.61 0.94 0.055 0.048 E532 0.31 0.33 1.00 0.015 0.027 E533 0.35 0.24 1.00 0.018 0.031 E538 0.30 0.28 0.93 0.014 0.020 68562 0.33 0.38 0.94 0.054 0.047 2 cracked, torn 68528 0.28
0.88 0.038 0.045 1 cracked, torn
Discussion Electric Versus Con
Mr. Maher.—Do I understand that you met the physical and chemical requirements without any difficulty but you were troubled with hot checks?
MR. HAYKS.-We were able to meet conditions as to the checks.
COL. 4. E. WHTE.--I believe that the cracks are due to heat temperatures of the steel as much as to molding conditions. The inaccessibility of the converter makes it hard to determine the temperature of the steel before pouring, whereas with the electric furnace the steel can be tested by the film, rod and spoon tests.
The Effect of Sulphur on Steel
By A. E. WHITE, Ann Arbor, Mich.
It is not the object of this paper to add any new evidence to that which already has been presented. There has been no opportunity, since the writer was requested to prepare a paper on this subject, to make experiments and tests. It is the object of the paper to plead for a thorough survey of the items which affect the quality of steel castings and to judge of their acceptability on the basis of the properties they possess rather than to lay undue emphasis on one or more disputed points.
Considerable has been written concerning the effect of sulphur in steel. Numerous writers have pointed out that sulphur in percentages much above 0.04 or 0.05 gives material showing undesirable qualities. Now and then some one suggests that sulphur in percentages greater than 0.04 or 0.05, possibly as high as twice the values given, in no way affects the quality of the steel. Much that has been written is in the way of exposition and is not supported with evidence. Furthermore, a considerable amount of the evidence submitted is so beclouded by other factors that the data is valueless. Practically all of the literature discussing sulphur deals with its influence in rolled or forged steel and not in cast steel. Between cast steel on the one hand and rolled or forged steel on the other, there is, in the writer's opinion, a vast deal of difference. Therefore the observations on the influence of sulphur in rolled or forged steel, relatively speaking, may have little bearing if applied to cast steel. · This, briefly stated, is the status of the question at the present time.
Factors Affecting Quality of Castings Broadly speaking, there are five main factors which affect the quality of steel castings. These are design of castings, composition, molding practice, steelmaking practice and annealing practice.
Included in the molding practice may be listed the kind of mold, whether of green or dry sand; method of venting; weight and location of riser; method of gating; character of cores; length of time mold is kept around metal after pouring, etc.
In the steelmaking practice may be included place of recarbonization, whether in furnace, converter or ladle; size of heat; number of castings to be poured from a given ladle; temperature of pouring, etc.
In the annealing practice may be included the evenness of furnace temperature; the temperature employed; the time consumed in bringing to heat; the time at heat; the time consumed in cooling; the type of castings placed in a given furnace, whether all light, all heavy, or mixed; the type of furnace used, whether a furnace designed for heavy castings employed on light ones or vice versa; character of flame, whether oxidizing, reducing or neutral; etc.
There are times when too little attention is given to the question of design of steel castings. Many designs are made by men who know too little about the characteristics of metal when it is changing from a liquid to a solid. Much improvement in the matter of quality of finished castings could be brought about by closer co-operation between the designer and foundryman, and it is trusted that as time goes on, this suggested closer co-operation will become more and more common.
Purchaser Depends l'pon Foundryman In general, the steelmaking and molding practice is of an acceptable character. In large measure, however, the purchaser is in the hands of the founder since it is not feasible for him to employ as expert a steelmaker or steel founder as the steel-casting operator can afford to do, and only by the employment of an abler steelmaker or founder can he expect to properly pass upon these phases of the process. Even if he can get a man of suitable experience, it is questionable if he should employ him, for by so doing, a status of divided authority in the steel castings plant would develop, and such a condition would be most unsatisfactory and in fact, quite impossible. Also, by chemical, physical and visual tests the purchaser can gather sufficient information regarding the character of the castings to decide whether or not they are acceptable, so that he is not as much at the mercy of the founder as might appear to be the case at first glance.
The writer believes much greater attention should be given to the matter of annealing in the future than has been accorded it in the past. As a rule, steel founders have not awakened to the latent possibilities of scientifically controlled annealing. Many furnaces bear indications that the only things thought of in their design are walls, a floor, a roof, and some kind of ports for the admission of heat.
There seems to be an utter disregard of such questions as fuel efficiency, through proper combustion and control of heat losses by radiation and by the stack; character of the flame, whether oxidizing, reducing or neutral; scientific temperature control, for in most furnaces there is as much as 200 degrees Fahr. difference in temperature in different portions of the same furnace; accurate temperature measurements, for such furnaces as have pyrometers usually have only one and it is neither frequently calibrated nor does it necessarily record the real conditions in the furnace because of the varying temperature distribution in the same; and care in the selection of only pieces of approximately the same cross section for each furnace per anneal, for there exists a more or less haphazard method of placing castings with different cross sections in the same furnace with the resultant of either overheating the thin ones or failing to remove the dendritic structure in the thick ones.
It was the writer's privilege in the fall of 1916 and the winter of 1916-1917 to visit nearly all of the important steel casting plants in the eastern half of the United States. It was also his privilege to have under his supervision the inspection of all of the steel casting plants producing ordnance material for the United States army from January, 1918, until he left the service in March, 1919. As a result of this experience, he has come to feel to a greater and greater extent that the acceptance of steel castings should be placed on a broad basis and that the minute scrutiny of castings for a few hundredths of a per cent of sulphur is both irrational and unwise.
To talk about the effect of an increase of 0.01 or 0.02 per cent of sulphur when by improper annealing, improper steelmaking or by improper foundry practice, properties many times worse than those produced by sulphur are acquired by the steel, is, in the writer's judgment, placing undue emphasis on the wrong factor.
Sulphur in steel may increase blow holes—it is granted that this is a disputed point—but assuming that it does, it will not do so to nearly the same extent as an improper temper to the mold; improper venting of the mold or core, especially the core; or an improper pouring temperature. It may increase shrinkage, but it will not do it nearly as much as an improper casting design, an improper pouring temperature, or too rapid a heating or cooling during the annealing. It may decrease the metal's resistance to shock but not to the degree that a poorly designed casting will, or one in which the metal has been overheated, burned or underannealed with the dendritic structure still in evidence.
It was because of the feelings expressed in the preceeding paragraph that the writer championed, while connected with the ordnance department, a more liberal specification as applied to sulphur, though accompanied at the same time with such a method of inspection at the casting plant consisting of an examination of test bars, annealing lugs, visual examination, etc., that the real quality of the castings, or as near real as could be obtained, might be ascertained.